Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/20/15
AREA FORECAST DISCUSSION
NWS RENO NV
300 PM PDT MON MAY 18 2015
.SYNOPSIS...
LOW PRESSURE ALOFT WILL REMAIN OVER CALIFORNIA AND NEVADA THROUGH
THE END OF THE WORK WEEK, BRINGING BELOW AVERAGE TEMPERATURES
AND ROUNDS OF SHOWERS AND THUNDERSTORMS, MAINLY IN THE AFTERNOONS
AND EVENINGS. PRECIPITATION CHANCES DECREASE OVER THE MEMORIAL
DAY WEEKEND ALTHOUGH A FEW SHOWERS AND THUNDERSTORMS WILL STILL
BE POSSIBLE.
&&
.SHORT TERM...
A TROUGH OF LOW PRESSURE REMAINS OVER THE WEST. AN UPPER
DISTURBANCE OVER SOUTHEAST CALIFORNIA AND SOUTHERN NEVADA IS
ROTATING AROUND THE TROUGH, BRINGING INCREASED DIVERGENCE ALOFT
AND HELPING TO INITIATE SHOWERS AND THUNDERSTORMS OVER SOUTHERN
AND EASTERN NEVADA.
FOR NORTHEAST CALIFORNIA AND WESTERN NEVADA, ACTIVITY IS RESTRICTED
EARLY THIS AFTERNOON WITH THE BEST FORCING SOUTH AND EAST OF THE
AREA. HOWEVER, SCATTERED SHOWERS SHOULD STILL DEVELOP GIVEN THE
MOIST AND WEAKLY UNSTABLE ATMOSPHERE, ESPECIALLY FOR EASTERN
CALIFORNIA AND FAR WESTERN NEVADA WHERE THE HRRR AND NAM SHOW A
LIGHT WESTERLY FLOW OFF THE SIERRA (TO AID LOW LEVEL CONVERGENCE
AND UPWARD MOTION) INTO THE EVENING. AS FAR AS THUNDERSTORMS, LOW
FREEZING LEVELS AND WEAK INSTABILITY MAKE IT HARD TO RULE OUT
BRIEF, ISOLATED CELLS. ANY STORMS THIS EVENING WILL BE WEAK WITH
THE MAIN THREAT BEING LIGHTNING AND LARGE QUANTITIES OF SMALL,
SOFT HAIL (GRAUPEL TECHNICALLY).
LATE TONIGHT, THE HRRR AND LESS-SO THE GFS AND NAM ARE INDICATING
WRAP-AROUND PRECIPITATION OVER NORTHEAST CALIFORNIA AND NORTHWEST
NEVADA AS THE UPPER LOW ADVANCES INTO EASTERN NEVADA. WITH THIS IN
MIND, I HAVE LEFT IN SCATTERED SHOWERS NORTH OF RENO AND FALLON
WITH ISOLATED COVERAGE ELSEWHERE.
TUESDAY, THE REGION IS BETWEEN UPPER WAVES. HOWEVER, MOISTURE
REMAINS IN PLACE AND BETTER HEATING IS POSSIBLE WITH LITTLE UPPER
FORCING ALLOWING FOR LESS/THINNER CLOUD COVER IN THE MORNING. THIS
SHOULD FACILITATE SCATTERED SHOWERS IN THE AFTERNOON AND EVENING,
WITH A LOW CHANCE FOR THUNDERSTORMS.
WEDNESDAY, THE BEST UPPER FORCING OF THE SHORT TERM IS EXPECTED AS
ANOTHER DISTURBANCE RELOADS THE SOUTHWEST CONUS TROUGH. THE
DISTURBANCE IS EXPECTED TO MOVE FROM SOUTH TO NORTH THROUGH
CALIFORNIA WITH THE BEST FORCING IN THE AFTERNOON AND EVENING.
WITH THIS IN MIND, I HAVE BUMPED POP A BIT MORE OVER MUCH OF FAR
WESTERN NEVADA AND EASTERN CALIFORNIA WITH NUMEROUS SHOWERS EXPECTED
BY AFTERNOON. WITH THE FORCING, I WOULD EXPECTED AT LEAST ISOLATED
THUNDERSTORMS WITH HIGHER COVERAGE POSSIBLE IF WE CAN GET DECENT
MORNING HEATING (CLEARER SKIES). SNYDER
.LONG TERM...THURSDAY THROUGH MONDAY...
BY THURSDAY AN AREA OF LOW PRESSURE WILL AGAIN BE ALONG THE
CENTRAL CALIFORNIA COAST. THIS WILL CONTINUE TO BRING WIDESPREAD
CHANCES OF PRECIPITATION, ISOLATED THUNDERSTORMS, AND BELOW
AVERAGE DAYTIME TEMPERATURES. THURSDAY CURRENTLY LOOKS TO BE THE
WETTEST DAY WITH MOISTURE WRAPPING AROUND THE LOW PRESSURE AND
BANKING AGAINST THE SIERRA FROM THE EAST. RELATIVELY DEEP MOISTURE
AND UPSLOPE FLOW COULD ALLOW SOME AREAS TO PICK UP ANOTHER ROUND
OF SIGNIFICANT PRECIPITATION, ESPECIALLY IN THE CENTRAL SIERRA.
BY FRIDAY THE LOW PRESSURE WILL MOVE INTO SOUTHERN NEVADA
BRINGING NORTHERLY FLOW TO THE AREA. THIS WILL DECREASE THE CHANCE
OF SIGNIFICANT QPF IN THE SIERRA, BUT WILL STILL ALLOW WIDESPREAD
PRECIPITATION TO WESTERN NEVADA AND THE SIERRA.
FOR THE HOLIDAY WEEKEND...
CHANCES FOR THUNDERSTORMS WILL BE ON THE DECREASE BY THE HOLIDAY
WEEKEND AS THE LOW PRESSURE MOVES INTO THE ROCKIES, BUT WITH SOME
RESIDUAL MOISTURE AND INCREASING TEMPERATURES THERE IS STILL A
SLIGHT CHANCE OF THUNDERSTORM ACTIVITY IN SIERRA AND WESTERN
NEVADA THROUGH THE WEEKEND. SIGNIFICANT MODEL DISCREPANCIES EXIST
BY THE WEEKEND SO FORECAST CONFIDENCE IS CURRENTLY LOW ON THE
BEST AREA FOR THUNDERSTORM CHANCES.
EXPECT A WARMING TREND THROUGH THE WEEKEND WITH DAYTIME
TEMPERATURES RIGHT AROUND SEASONAL AVERAGES WITH MID 70`S IN
WESTERN NEVADA AND MID 60`S IN THE SIERRA. BY MONDAY WESTERN
NEVADA VALLEYS COULD HIT 80 WITH SIERRA VALLEYS REACHING 70.
TOLBY
&&
.AVIATION...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED
THROUGHOUT THE SIERRA AND WESTERN NEVADA THROUGH THIS EVENING.
LOW CLOUD DECKS AND RAIN SHOWERS WILL CREATE SOME MOUNTAIN
OBSCURATION IN THE SIERRA. GENERALLY LIGHT WEST WINDS WITH THE
CHANCE OF GUSTS TO AROUND 30 KTS NEAR THUNDERSTORMS. TOLBY
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
903 PM MDT TUE MAY 19 2015
.UPDATE...
ISSUED AT 848 PM MDT TUE MAY 19 2015
SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE TO SLOWLY MARCH
ENE THIS EVENING...WITH PUNCH OF DRIER AIR WORKING INTO THE
SOUTHERN ZONES. WILL CONTINUE TO UPDATE POPS GRIDS TO BRING THEM
MORE INTO LINE WITH CURRENT TRENDS. HRRR BRINGS ONE LAST WAVE OF
ENERGY OUT OF CENTRAL UTAH AND ACROSS OUR NORTHERN ZONES AFTER
MIDNIGHT...WHICH SHOULD CARRY A FEW LINGERING SHOWERS WITH IT.
AREAS SOUTH OF INTERSTATE 70 WILL BE DRYING OUT. EXPECT A CHILLY
NIGHT IN MOST AREAS WITH COMBINATION OF FALLING DEW POINT
TEMPS...CLEARING SKIES AND LIGHT WINDS.
&&
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 252 PM MDT TUE MAY 19 2015
THE LATEST PACIFIC STORM WAS CENTERED OVER THE SALT LAKE CITY AREA
EARLY THIS AFTERNOON. A WEAK SHORTWAVE ROTATING THROUGH THE BASE
OF THE ZONALLY ELONGATED LOW GOT THUNDERSTORMS OFF TO AN EARLY
START TODAY. SEVERAL STORMS GENERATED DIME-SIZED HAIL...THOUGH
WIND GUSTS WERE SUBSTANTIALLY WEAKER AS THE LOWER LEVELS OF THE
ATMOSPHERE HAVE MOISTENED THEREBY LIMITING DOWNDRAFT SPEED.
MEANWHILE...WEB CAM IMAGES FROM THE MOUNTAIN AREAS INDICATED SOME
SNOW HERE AND THERE BUT MOUNTAIN PASSES HAD ALL IMPROVED
SIGNIFICANTLY AS COMPARED TO THIS MORNING.
EXPECT SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO THE EVENING
THOUGH THE LOSS OF DAYTIME HEATING COMBINED WITH THE EXIT OF THE
SHORTWAVE DESCRIBED PREVIOUSLY WILL CAUSE MOIST CONVECTION TO
DIMINISH SIGNIFICANTLY BY MIDNIGHT. MODELS INDICATED A FEW SHOWERS
MAY LINGER OVER THE HIGHER TERRAIN OF THE NORTH LATE TONIGHT IN AN
AREA OF WEAK OVERRUNNING...THOUGH ADDITIONAL SNOW ACCUMULATIONS
WILL BE LIGHT AND LOCALIZED. PARTIAL CLEARING WILL TRANSLATE INTO
COOLER OVERNIGHT LOWS WITH READINGS RUNNING ABOUT 5 DEGREES BELOW
NORMAL.
A RIDGE WILL BUILD OVER THE AREA ON WED AND PERSIST THROUGH WED
NIGHT. WHILE DRIER AIR WILL WORK IN FROM THE SOUTH...SOME MOISTURE
WILL LINGER MAINLY OVER THE NORTH AND MOUNTAINS. MODEL CROSS
SECTIONS INDICATE THAT AN OROGRAPHICALLY FAVORED WEST FLOW WILL
CONTINUE TO PRODUCE SHOWERS OVER THE NORTHERN MOUNTAINS EARLY IN
THE DAY...ESPECIALLY ALONG THE PARK...GORE AND FLATTOPS RANGES.
MOISTURE WILL DIMINISH LATE IN THE DAY THROUGH THE EVENING.
HOWEVER DAYTIME HEATING WILL HELP BOOST AFTERNOON CONVECTION...
AGAIN MAINLY OVER THE MOUNTAINS. BY LATE EVENING THUNDERSTORMS
SHOULD DIE OFF...WITH ONLY A FEW SHOWERS LINGERING BEYOND
MIDNIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 252 PM MDT TUE MAY 19 2015
THE NEXT LOW PRESSURE SYSTEM RELOADS ALONG THE CENTRAL CA COAST
ON THU. THEN SWINGS INLAND LATE THU NIGHT AND ACROSS THE DESERT
SOUTHWEST/SOUTHERN GREAT BASIN ON FRI/FRI NIGHT. THE RESULTING
SOUTH-SOUTHWEST FLOW WILL BRING ENOUGH MOISTURE FOR SOME DIURNALLY
DRIVEN SHOWERS AND THUNDERSTORMS EACH LATE DAY PERIOD. THE
MOUNTAINS WILL BE FAVORED. ALSO A LEADING DISTURBANCE WILL EJECT
FROM THE PARENT LOW...AND BRUSH THE FORECAST AREA THU EVENING.
THIS WILL PROVIDE A BOOST TO CONVECTION THROUGH THE EVENING...WITH
SHOWERS LINGERING OVERNIGHT.
THERE CONTINUES TO BE SOME DIFFERENCES AT TO THE TRACK OF THE
MAIN LOW PRESSURE TROUGH LATE FRI THROUGH SAT...WITH THE GFS
SLOWER AND FARTHER SOUTH. BUT IT APPEARS THAT A WET WEEKEND IS
AGAIN IN STORE FOR THE AREA. FOR SUNDAY AND BEYOND...THE ECMWF
INDICATES THAT ADDITIONAL AND CLOSELY TIMED LOW PRESSURE
DISTURBANCES WILL PASS OVER THE REGION. THE GFS SHOWS A DISTINCT
RIDGE EARLY IN THE WORK WEEK AFTER THE FIRST LOW EXITS TO THE
EAST...BUT WITH SOME DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS
EACH LATE DAY PERIOD. THEREFORE THE FORECAST WILL REMAIN UNSETTLED
THROUGH THE END OF THE PERIOD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 848 PM MDT TUE MAY 19 2015
A FEW SHOWERS WILL LINGER OVER NORTHEAST UTAH AND NORTHWEST
COLORADO THROUGH 14Z...WITH LITTLE TO NO IMPACT EXPECTED AT
TERMINAL SITES. THE SHOWERS WILL OBSTRUCT MOUNTAIN TOPS AT
TIMES...WITH BRIEF MVFR CIGS EXPECTED IN THE VICINITY. ANOTHER
ROUND OF MOUNTAIN CONVECTION IS EXPECTED AFTER 18Z WITH BULK OF
THIS ACTIVITY REMAINING ANCHORED TO THE HIGHER TERRAIN.
OTHERWISE...VFR CONDITIONS ARE EXPECTED THROUGH LATE WEDNESDAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JDC
SHORT TERM...NL/EH
LONG TERM...EH
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1129 PM MDT SUN MAY 17 2015
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 331 PM MDT SUN MAY 17 2015
IN SPITE OF BUILDING HIGH PRESSURE OVER UTAH AND WARMING TEMPS
ALOFT...AFTERNOON CAPE VALUES OF 250-500 J/KG SUGGEST CONVECTIVE
SHOWERS WITH SOME THUNDERSTORMS. MOISTURE TRANSPORT DOES EXIST
FROM THE UINTA MOUNTAINS TOWARD VAIL AND INDEPENDENCE PASS
REGION...AND SHOWERS/STORMS WILL BE CONCENTRATED ACROSS THIS AREA.
CONVECTIVE POTENTIAL EXIST ELSEWHERE BUT NOT AS NUMEROUS OVER SW
COLORADO...AND MOSTLY DRY OVER SE UTAH.
CONVECTIVE POTENTIAL MOSTLY DIMINISHES WITH SUNSET. NOT SO SURE
THIS WILL BE THE CASE ACROSS PARTS OF ERN UTAH AS MOISTURE
TRANSPORT INCREASES OVERNIGHT...THE HRRR SHOW CONVECTIVE SHOWERS
PERSISTING PAST MIDNIGHT AND TRACKING OVER THE UINTA
BASIN/MOUNTAINS. BY DAYBREAK...HIGH CLOUDS WILL BE SPREADING FROM
THE SOUTH AS THE NEXT CALIFORNIA UPPER LOW ADVECTS MOISTURE
TOWARDS THE FOUR CORNERS REGION.
THE PACIFIC WAVE TRAIN CONTINUES MONDAY AS THE NEXT STORM SYSTEM
MOVES SLOWLY ONSHORE...ITS CENTER SETTLING OVER CALIFORNIA/S SAN
JOAQUIN VALLEY LATE IN THE AFTERNOON. SOUTHERLY FLOW AHEAD OF THE
TROUGH WILL CAUSE MOISTURE LEVELS TO RISE ONCE AGAIN AS GULF
MOISTURE IS TAPPED. GFS AND NAM BOTH INDICATED PRECIPITABLE WATER
VALUES RISING TO NEAR 0.6 OF AN INCH. MEANWHILE...AN 110 KT JET
ROTATES THROUGH THE BASE OF THE TROUGH GIVING IT A SLIGHTLY
NEGATIVE TILT. THE NOSE OF THE JET PUSHES TOWARD THE FOUR CORNERS
WHICH WILL PROVIDE CONSIDERABLE DIVERGENCE TO ADD TO THE DIFFLUENT
FLOW ALOFT. THE DYNAMIC LIFT JUST DESCRIBED COMBINED WITH DAYTIME
HEATING WILL GENERATE SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS FAVORING THE MOUNTAINS. AS MENTIONED IN THE PREVIOUS
DISCUSSION...ARRIVING MOISTURE WILL BE HIGH BASED ACCORDING TO
AREA TIME SECTIONS SO EXPECT MAIN STORM THREAT...ASIDE FROM
LIGHTNING...WILL BE STRONG AND GUSTY OUTFLOW WINDS. WAA ADVECTION
WILL CAUSE TEMPERATURES TO CLIMB CLOSER TO SEASONAL NORMS...
THOUGH EXPECT CLOUDS AND SHOWERS WILL LIMIT HIGHS. THEREFORE...
NUDGED MONDAY/S HIGHS TOWARD COOLER MAV GUIDANCE.
MONDAY NIGHT WILL REMAIN ACTIVE AS THE PACIFIC SYSTEM MOVES OVER
SOUTHERN NEVADA DURING THE NIGHT. DIFFLUENT/DIVERGENT FORCING
REMAINS IN PLACE WHILE MOISTURE CONTINUES TO STREAM INTO THE AREA
FROM THE SOUTH. AS A RESULT...WILL CONTINUE WITH LIKELY POPS IN
THE MOUNTAINS WITH CHANCE POPS ACROSS THE VALLEYS. COLDER AIR
BEGINS TO ADVECT OVER THE REGION DURING THE NIGHT CAUSING SNOW
LEVELS TO LOWER TO AROUND 9000 TO 9500 FEET. EXPECT ACCUMULATING
SNOW FOR AREAS ABOVE 10000 FEET WITH AMOUNTS OF UP TO 8 INCHES
POSSIBLE ABOVE THE TIMBERLINE. MODELS SUGGEST AMOUNTS OF 12 INCHES
OR MORE BUT APPEARS CONVECTIVE PARAMETERIZATION MAY BE A BIT
OVERDONE AS LAPSE RATES ONLY MODERATELY UNSTABLE. IMPACTS TO
ROADWAYS OVER THE HIGH PASSES PROBABLY NEGLIGIBLE WITH MOST SNOW
MELTING ON CONTACT SO WILL HOLD OFF ISSUING HILITES. CLOUDS...
SHOWERS AND WAA WILL YIELD MILDER OVERNIGHT LOWS AS PREVIOUSLY
FORECAST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 331 PM MDT SUN MAY 17 2015
COOL AND UNSETTLED CONDITIONS WILL CONTINUE TUESDAY AS THE
PACIFIC STORM MOVES OVER THE REGION. SNOW LEVELS WILL RISE WITH
DAYTIME WARMING...ESPECIALLY SOUTH...WHICH WILL INHIBIT ANY
ADDITIONAL ACCUMULATIONS BELOW 10000 FEET. CONDITIONS IMPROVE
TUESDAY NIGHT AS A TRANSIENT SHORTWAVE RIDGE BUILDS OVER THE AREA.
ANOTHER LOW DEVELOPS OVER THE EASTERN PACIFIC AT MIDWEEK BUT STAYS
QUASI-STATIONARY UNTIL THURSDAY NIGHT. A DRIER SOUTHWEST FLOW
WILL MOVE OVER THE FORECAST AREA AHEAD OF THIS SYSTEM LIMITING
MOIST CONVECTION TO THE MOUNTAIN AREAS DURING THE AFTERNOON AND
EVENING WEDNESDAY AND THURSDAY. TEMPERATURES WILL RECOVER DURING
THIS PERIOD REACHING NEAR NORMAL LEVELS THURSDAY AFTERNOON.
THE PACIFIC SYSTEM THEN FOLLOWS THE WELL BEATEN PATH PREVIOUS
STORMS HAVE TAKEN OVER THE PAST COUPLE OF WEEKS...TRACKING OVER
EASTERN UTAH AND WESTERN COLORADO FRIDAY AND SATURDAY.
CONSEQUENTLY...LOOK FOR AN UPTICK IN SHOWER AND THUNDERSTORM
ACTIVITY ONCE AGAIN ALONG WITH COOLER THAN NORMAL TEMPERATURES.
CONDITIONS ON SUNDAY LESS CERTAIN AS LATEST ECMWF DRIVES A
SHORTWAVE TROUGH ACROSS THE REGION FROM THE NORTHWEST WHILE GFS
FAVORS A TRANSITORY RIDGE. BOTH SOLUTIONS POINT TO A CONTINUATION
OF UNSETTLED CONDITIONS AS MOISTURE WILL LINGER IN EITHER CASE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1123 PM MDT SUN MAY 17 2015
A FEW SHOWERS WILL CONTINUE FOR THE NEXT SEVERAL HOURS ACROSS THE
NORTH BEFORE DIMINISHING OVERNIGHT. VFR CONDITIONS WILL CONTINUE
THROUGH THE MORNING HOURS ON MONDAY. SHOWERS AND THUNDERSTORMS
WILL INCREASE LATE MONDAY AFTERNOON AND INCREASE IN COVERAGE BY
MONDAY EVENING. HAVE INCREASED POPS AT TAF SITES WITH TEMPO/SHOWERS
WORDING WITH CATEGORICAL PRECIPITATION OVER MOUNTAIN TAF SITES AT
ASE AND TEX DEVELOPING BY 19/02Z. EXPECT VISIBILITY AND CEILINGS
TO LOWER IN THE SHOWERS AND THUNDERSTORMS WITH MOUNTAIN BECOMING
OBSCURED. SNOW LEVELS ARE EXPECTED TO BE AROUND 10000 FEET BUT LOWERING
TO 9000 FEET IN HEAVIER SHOWERS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...PF/NL
LONG TERM...NL
AVIATION...MPM
AREA FORECAST DISCUSSION
NWS TAUNTON MA
318 PM EDT MON MAY 18 2015
.SYNOPSIS...
MARITIME HIGH PRESSURE BUILDS OVER NEW ENGLAND BRINGING COOLER
MARINE AIR TODAY...BUT IT SILL WILL BE A RATHER MILD DAY ACROSS THE
INTERIOR. ANOTHER COLD FRONT WILL BRING SCATTERED SHOWERS
TO THE REGION TONIGHT INTO TUE WITH A LOW POTENTIAL FOR AN
ISOLATED THUNDERSTORM. WIDELY SCATTERED SHOWERS ARE POSSIBLE
WEDNESDAY...FRIDAY...AND MONDAY. BUT IN GENERAL DRY WEATHER AND
SEASONABLE TEMPS ARE EXPECTED FROM MID WEEK THROUGH EARLY NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
200 PM UPDATE...
SKIES HAVE BECOME MOSTLY SUNNY ACROSS THE VAST MAJORITY OF THE
REGION AT MID AFTERNOON. TEMPS HAVE CLIMBED INTO THE 70S ACROSS THE
INTERIOR...60S JUST INLAND FROM THE COAST...AND BETWEEN 55 AND 60
ALONG THE IMMEDIATE COAST.
TEMPS MAY CLIMB ANOTHER FEW DEGREES ESPECIALLY ACROSS THE INTERIOR.
HOWEVER...THE MAIN CONCERN ARE THE LOW CLOUDS AND AREAS OF FOG JUST
MOVING ONTO THE OUTER-CAPE. MOST OF THE GUIDANCE IS NOT HANDLING
THIS WELL...BUT THE HRRR AND TO SOME DEGREE THE RAP SHOWS THESE LOW
CLOUDS AND FOG BACKING INTO EASTERN MAY LATE THIS AFTERNOON/EARLY
THIS EVENING. CONFIDENCE IS LOW...BUT GIVEN EASTERLY FLOW LEANING
TOWARDS THAT HAPPENING. WILL CONTINUE TO MONITOR.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
LOW PRESSURE MOVES INTO QUEBEC BRINGING A COLD FRONT TOWARDS
SOUTHERN NEW ENGLAND. MUCH OF TONIGHT SHOULD BE DRY WITH INCREASING
CLOUDS. SHOWERS SHOULD HOLD OFF UNTIL WELL AFTER MIDNIGHT.
TEMPERATURES OVERNIGHT WILL BE A COUPLE OF DEGREES COOLER THAN THIS
MORNINGS TEMPS WITH THE CONTINUED EASTERLY FLOW AND HIGH PRESSURE
EAST OF SOUTHERN NEW ENGLAND.
SHOWERS WILL BEGIN WELL AFTER MIDNIGHT AS THE FRONT APPROACHES
SOUTHERN NEW ENGLAND. INSTABILITY INCREASES AS DAYBREAK APPROACHES
WITH INCREASING MID LEVEL LAPSE RATES AND K INDICES ABOVE 30.
SHOWALTER INDICES FALL BELOW 0 IN A FEW LOCATIONS BUT THIS IS NOT
WIDESPREAD. WITH THE INSTABILITY IN PLACE...EXPECT WE WILL SEE A
FEW THUNDERSTORMS BUT BELIEVE THE MAIN THREAT WILL BE FROM AREAS OF
HEAVY RAINFALL. PWATS OF 1.5 TO 1.75 INCHES ARE ABOUT 2 STD ABOVE
NORMAL FOR MID MAY. IN ADDITION...850MB WINDS ARE ONLY 20-25KTS.
NOT ENOUGH TO MOVE STORMS ALONG QUICKLY. DON/T BELIEVE THERE WILL
BE WIDESPREAD FLOODING BUT DEPENDING ON THE TRACKS OF STORMS COULD
SEE SOME POOR DRAINAGE FLOODING WHERE STORMS TRAIN.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
BIG PICTURE... THE PATTERN EVOLVES THROUGH THE WEEKEND WITH FLAT
FLOW IN THE EASTERN USA GIVING WAY TO A DIGGING TROUGH LATE WEEK.
THE TROUGH RELAXS A LITTLE OVER THE WEEKEND. TWO SHORTWAVES MOVE
THROUGH THE FLOW...ONE ON WEDNESDAY AND THE SECOND ON FRIDAY.
CONTOUR HEIGHTS LOWER BELOW SEASONAL NORMS WEDNESDAY-THURSDAY...THEN
RETURN TO NEAR SEASONABLE LEVELS OVER THE WEEKEND. JET PATTERN
STARTS WITH NORTHERN AND SOUTHERN STREAMS...BUT THESE MERGE LATER IN
THE WEEK IN THE EASTERN USA AS THE UPPER TROUGH DIGS.
THE DAILIES...
WEDNESDAY... COLD FRONT MOVES WELL OFFSHORE WEDNESDAY WITH COOLER
DRIER AIR MOVING INTO NEW ENGLAND. UPPER SHORTWAVE AND COLDER
TEMPS/MOISTURE ALOFT WILL GENERATE DIURNAL CU ESPECIALLY ALONG AND
NORTH OF THE MASS PIKE. THE AIRMASS IS PROBABLY TOO DRY BELOW 5000
FEET FOR SCATTERED AFTERNOON SHOWERS. MIXING SHOULD REACH 850 MB
WHICH WHERE TEMPS OF 1-4C SHOULD SUPPORT MAX SFC TEMPS IN THE 60S.
TEMPS COULD REACH 70 IN THE SOUTH ESPECIALLY RI/SOUTHEAST MASS WHERE
TEMPS ALOFT MAY BE A LITTLE MILDER OR MIXING A LITTLE DEEPER. WINDS
IN THE MIXED LAYER WILL BE 20-25 KNOTS...SO WIND GUSTS SHOULD
APPROACH THOSE SPEEDS.
WINDS DIMINISH WEDNESDAY NIGHT AS HIGH PRESSURE BUILDS IN. WITH DEW
POINTS IN THE 30S...TEMPS SHOULD FALL TO THE 30S IN THE COLDER
SPOTS...WITH 40S SOUTH AND EAST.
THURSDAY...AFTER THE CHILLY START HIGH PRESSURE SHOULD PROVIDE A
FAIR DRY DAY. MIXING SHOULD REACH 800 MB WHERE TEMPS 0-2C SUPPORT
MAX SFC TEMPS 65 TO 70.
FRIDAY-SATURDAY-SUNDAY... UPPER SHORTWAVE AND CORRESPONDING SURFACE
COLD FRONT SWEEP THROUGH ON FRIDAY. THIS MAY CAUSE WIDELY SCATTERED
SHOWERS BUT PRECIP WATER VALUES AT OR BELOW 0.5 INCHES SUGGEST A DRY
ENVIRONMENT TO OVERCOME. WE USED LOW-END SLIGHT CHANCE POPS FOR THIS
PASSAGE. HIGH PRESSURE THEN BUILDS EAST SATURDAY AND PROVIDES DRY
WEATHER MUCH OF THE WEEKEND.
SUNDAY NIGHT-MONDAY...A COLD FRONT DROPS SOUTH INTO NEW ENGLAND.
MODEL CONSENSUS SUGGESTS A FEW SHOWERS MOVING THROUGH THE REGION
DURING THIS PERIOD...BUT QUESTIONS ABOUT HOW FAR SOUTH THE FRONT
PROGRESSES BEFORE STALLING. WE WILL CONTINUE TO INDICATE A CHANCE OF
SHOWERS.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THIS AFTERNOON THROUGH TUESDAY NIGHT/...
THIS AFTERNOON AND TONIGHT...LOW TO MODERATE CONFIDENCE. VFR
CONDITIONS AT MID AFTERNOON WILL DETERIORATE TO LOW END MVFR/IFR
WITH EVEN SOME LIFR CONDITIONS POSSIBLE TONIGHT...BUT TIMING HIGHLY
UNCERTAIN.
MODELS NOT PICKING UP ON A DECK OF LOW CLOUDS/FOG SITTING OFF CAPE
COD WHICH MAY BACK INTO EASTERN MA LATER THIS AFTERNOON/EVENING.
OTHER AREAS OF LOW CLOUDS AND FOG ARE EXPECTED TO DEVELOP ACROSS THE
REST OF THE REGION...BUT TIMING UNCERTAIN. A CLUSTER OF SHOWERS AND
PERHAPS A FEW EMBEDDED THUNDERSTORMS WILL MAY WORK INTO OUR WESTERN
ZONES TOWARD DAYBREAK.
TUESDAY AND TUESDAY NIGHT...LOW TO MODERATE CONFIDENCE. A CLUSTER
OF SHOWERS AND PERHAPS A FEW EMBEDDED THUNDERSTORMS ARE EXPECTED TO
MOVE ACROSS THE REGION TUE MORNING INTO EARLY AFTERNOON...BEFORE
EXITING THE REGION. LOW END MVFR TO IFR CONDITIONS EXPECTED FOR AT
LEAST THE MORNING. TEMPORARY IMPROVEMENT TO VFR MAY OCCUR
ESPECIALLY ACROSS THE INTERIOR TUE AFTERNOON. A FEW STRONG
THUNDERSTORMS MAY WORK INTO WESTERN MA/NORTHERN CT LATE TUE
AFTERNOON/EVENING. ISOLATED STRONG WIND GUSTS/HAIL WILL BE POSSIBLE
WITH THIS ACTIVITY. EXPECT THE ACTIVITY TO WEAKEN AS IT MOVES INTO
EASTERN MA/RI. CONDITIONS THEN IMPROVE TO VFR FROM WEST TO EAST.
KBOS TERMINAL...LOW CONFIDENCE. WATCHING A BANK OF LOW CLOUDS/FOG
THAT MAY MOVE INTO THE TERMINAL LATE THIS AFTERNOON/EARLY EVENING
BUT LOW CONFIDENCE.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. LOW END MVFR TO IFR
EXPECTED TO DEVELOP TONIGHT BUT TIMING UNCERTAIN.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...MODERATE CONFIDENCE.
VFR THROUGH THE PERIOD. NORTHWEST WINDS WILL GUST TO 25 KNOTS
WEDNESDAY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SUNDAY NIGHT/...HIGH CONFIDENCE.
QUIET BOATING WEATHER EXPECTED WITH HIGH PRESSURE
OVER THE WATERS. EASTERLY WINDS 5 TO 10 KTS WILL SHIFT TO THE SOUTH
TONIGHT AND INCREASE TO 10 TO 15 KTS WITH GUSTS TO 20 KTS TUESDAY.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...MODERATE CONFIDENCE.
WEDNESDAY... INCREASING NORTHWEST WINDS DURING THE DAY. THIS MAY
BRING A PERIOD OF GUSTS TO 25 KNOTS DURING THE AFTERNOON. SEAS
SHOULD REMAIN BELOW 5 FEET. WILL MONITOR FOR POTENTIAL SMALL CRAFT
HEADLINES DUE TO AFTERNOON WIND GUSTS.
THURSDAY-FRIDAY... HIGH PRESSURE MOVES OVERHEAD THURSDAY. A WEAK
COLD FRONT PASSES THROUGH ON FRIDAY. WINDS AND SEAS SHOULD REMAIN
BELOW SMALL CRAFT THRESHOLDS.
FRIDAY NIGHT-SATURDAY... NORTHWEST WINDS BEHIND THE COLD FRONT WILL
INCREASE AND BRING GUSTS TO 25 KNOTS ACROSS THE WATERS. THIS MAY
BRIEFLY BRING SEAS UP TO 5 FEET. A SMALL CRAFT ADVISORY MAY BE
NEEDED.
&&
.FIRE WEATHER...
WEDNESDAY...COOLER DRIER AIR MOVES IN. THE FORECAST HAS STAYED CLOSE
TO MODEL CONSENSUS WHICH BRINGS DEW POINTS DOWN INTO THE 30S WITH
RESULTING MINIMUM RELATIVE HUMIDITY PERCENTAGES IN THE 30S. THERE IS
SOME CONCERN THAT THIS DATA IS MISSING THE PRESENCE OF DRIER AIR
AT 5000 FEET/850 MB...WHERE DEW POINTS ARE FORECAST AT 26-30F
DURING THE AFTERNOON. DAYTIME MIXING OF THIS AIRMASS MAY LOWER
SURFACE DEW POINTS INTO THE UPPER 20S AND CREATE MIN RH VALUES OF
27-31 PERCENT. ALONG WITH THIS WILL BE EXPECTED WIND GUSTS NEAR 25
KNOTS. SO THE WEATHER PORTION OF THE FIRE WEATHER EQUATION IS
INCHING TOWARD HIGHER CONCERN AND WILL NEED TO BE MONITORED.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...WTB/RLG
NEAR TERM...FRANK
SHORT TERM...RLG
LONG TERM...WTB
AVIATION...WTB/FRANK
MARINE...WTB/RLG
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
200 PM EDT MON MAY 18 2015
.SYNOPSIS...
MARITIME HIGH PRESSURE BUILDS OVER NEW ENGLAND BRINGING COOLER
MARINE AIR TODAY...BUT IT SILL WILL BE A RATHER MILD DAY ACROSS THE
INTERIOR. ANOTHER COLD FRONT WILL BRING SCATTERED SHOWERS
TO THE REGION TONIGHT INTO TUE WITH A LOW POTENTIAL FOR AN
ISOLATED THUNDERSTORM. DRY WEATHER AND SEASONABLE TEMPS WILL
FOLLOW FOR MID WEEK LASTING THROUGH NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
200 PM UPDATE...
SKIES HAVE BECOME MOSTLY SUNNY ACROSS THE VAST MAJORITY OF THE
REGION AT MID AFTERNOON. TEMPS HAVE CLIMBED INTO THE 70S ACROSS THE
INTERIOR...60S JUST INLAND FROM THE COAST...AND BETWEEN 55 AND 60
ALONG THE IMMEDIATE COAST.
TEMPS MAY CLIMB ANOTHER FEW DEGREES ESPECIALLY ACROSS THE INTERIOR.
HOWEVER...THE MAIN CONCERN ARE THE LOW CLOUDS AND AREAS OF FOG JUST
MOVING ONTO THE OUTER-CAPE. MOST OF THE GUIDANCE IS NOT HANDLING
THIS WELL...BUT THE HRRR AND TO SOME DEGREE THE RAP SHOWS THESE LOW
CLOUDS AND FOG BACKING INTO EASTERN MAY LATE THIS AFTERNOON/EARLY
THIS EVENING. CONFIDENCE IS LOW...BUT GIVEN EASTERLY FLOW LEANING
TOWARDS THAT HAPPENING. WILL CONTINUE TO MONITOR.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
LOW PRESSURE MOVES INTO QUEBEC BRINGING A COLD FRONT TOWARDS
SOUTHERN NEW ENGLAND. MUCH OF TONIGHT SHOULD BE DRY WITH INCREASING
CLOUDS. SHOWERS SHOULD HOLD OFF UNTIL WELL AFTER MIDNIGHT.
TEMPERATURES OVERNIGHT WILL BE A COUPLE OF DEGREES COOLER THAN THIS
MORNINGS TEMPS WITH THE CONTINUED EASTERLY FLOW AND HIGH PRESSURE
EAST OF SOUTHERN NEW ENGLAND.
SHOWERS WILL BEGIN WELL AFTER MIDNIGHT AS THE FRONT APPROACHES
SOUTHERN NEW ENGLAND. INSTABILITY INCREASES AS DAYBREAK APPROACHES
WITH INCREASING MID LEVEL LAPSE RATES AND K INDICES ABOVE 30.
SHOWALTER INDICES FALL BELOW 0 IN A FEW LOCATIONS BUT THIS IS NOT
WIDESPREAD. WITH THE INSTABILITY IN PLACE...EXPECT WE WILL SEE A
FEW THUNDERSTORMS BUT BELIEVE THE MAIN THREAT WILL BE FROM AREAS OF
HEAVY RAINFALL. PWATS OF 1.5 TO 1.75 INCHES ARE ABOUT 2 STD ABOVE
NORMAL FOR MID MAY. IN ADDITION...850MB WINDS ARE ONLY 20-25KTS.
NOT ENOUGH TO MOVE STORMS ALONG QUICKLY. DON/T BELIEVE THERE WILL
BE WIDESPREAD FLOODING BUT DEPENDING ON THE TRACKS OF STORMS COULD
SEE SOME POOR DRAINAGE FLOODING WHERE STORMS TRAIN.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
HIGHLIGHTS...
* SCT SHOWERS AND AN ISOLD TSTM POSSIBLE TUE EVENING
* DRY AND SEASONABLE CONDITIONS MID WEEK INTO NEXT WEEKEND WITH
WARMING TEMPS NEXT SUNDAY
OVERVIEW...
MODELS REMAIN IN GOOD AGREEMENT ON LARGE SCALE FLOW PATTERN WITH
MID LEVEL VORTEX SETTING UP ACROSS SE CANADA MID TO LATE WEEK WITH
BROAD LONGWAVE TROF ACROSS THE GT LAKES AND NEW ENG. A FEW
SHORTWAVES ROTATING THROUGH THE CYCLONIC FLOW WILL BRING A FEW
FRONTS INTO THE REGION BUT MAINLY DRY AND SEASONABLE CONDITIONS AS
POLAR JET WILL KEEP VERY WARM TEMPS SUPPRESSED TO THE SE US. NEXT
WEEKEND...THE TROF BEGINS TO LIFT NE WITH RISING HEIGHTS AS RIDGE
BUILDS OVER SE US. THIS WILL RESULT IN WARMING TEMPS TOWARD THE
END OF THE WEEKEND.
TUESDAY NIGHT...
COLD FRONT WILL BE MOVING INTO W NEW ENG AROUND 00Z WED. AXIS OF
MARGINAL SFC INSTABILITY WITH CAPES AROUND 500 J/KG WILL BE CONFINED
TO W ZONES INVOF THE FRONT SO A FEW THUNDERSTORMS POSSIBLE ALONG THE
BOUNDARY IN THE EVENING IN THE WEST. 0-6KM SHEAR AROUND 40 KT BUT
INSTABILITY WILL BE A LIMITING FACTOR FOR SEVERE WEATHER. LOW PROB
OF A STRONG TSTM IN W NEW ENG IN THE EVENING. OTHERWISE...EXPECT A
FEW SHOWERS REST OF SNE IN THE EVENING UNTIL THE FROPA...THEN
PARTIAL CLEARING OVERNIGHT BEHIND THE FRONT.
WEDNESDAY...
DRY POST-FRONTAL NW FLOW WILL PREVAIL AND IT WILL BE GUSTY AT TIMES
WITH GUSTS 25-30 MPH. MID LEVEL SHORTWAVE WILL BE MOVING TO THE
NORTH WITH MAIN IMPACT BEING SOME DIURNAL CU...ESPECIALLY N ZONES.
HIGHS WILL BE MOSTLY IN THE 60S...WITH A FEW 70 DEGREE READINGS IN
RI/SE MA.
THURSDAY THROUGH SUNDAY...
MODELS BRING A WEAK TROF INTO NEW ENG THU FOLLOWED BY A STRONGER
COLD FRONT LATE FRI/FRI EVENING. MAINLY DRY WEATHER EXPECTED
ALTHOUGH CANT RULE OUT A SHOWER ON FRI WITH THE COLD FRONT.
SEASONABLE TEMPS THU WITH SOME MODERATION FRI AHEAD OF THE FRONT.
STRONG HIGH PRES BUILDS INTO THE REGION SAT WITH SOMEWHAT COOLER
TEMPS...THEN HIGH MOVES S OF NEW ENG SUN WITH RETURN FLOW BRINGING
WARMER TEMPS.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THIS AFTERNOON THROUGH TUESDAY NIGHT/...
THIS AFTERNOON AND TONIGHT...LOW TO MODERATE CONFIDENCE. VFR
CONDITIONS AT MID AFTERNOON WILL DETERIORATE TO LOW END MVFR/IFR
WITH EVEN SOME LIFR CONDITIONS POSSIBLE TONIGHT...BUT TIMING HIGHLY
UNCERTAIN.
MODELS NOT PICKING UP ON A DECK OF LOW CLOUDS/FOG SITTING OFF CAPE
COD WHICH MAY BACK INTO EASTERN MA LATER THIS AFTERNOON/EVENING.
OTHER AREAS OF LOW CLOUDS AND FOG ARE EXPECTED TO DEVELOP ACROSS THE
REST OF THE REGION...BUT TIMING UNCERTAIN. A CLUSTER OF SHOWERS AND
PERHAPS A FEW EMBEDDED THUNDERSTORMS WILL MAY WORK INTO OUR WESTERN
ZONES TOWARD DAYBREAK.
TUESDAY AND TUESDAY NIGHT...LOW TO MODERATE CONFIDENCE. A CLUSTER
OF SHOWERS AND PERHAPS A FEW EMBEDDED THUNDERSTORMS ARE EXPECTED TO
MOVE ACROSS THE REGION TUE MORNING INTO EARLY AFTERNOON...BEFORE
EXITING THE REGION. LOW END MVFR TO IFR CONDITIONS EXPECTED FOR AT
LEAST THE MORNING. TEMPORARY IMPROVEMENT TO VFR MAY OCCUR
ESPECIALLY ACROSS THE INTERIOR TUE AFTERNOON. A FEW STRONG
THUNDERSTORMS MAY WORK INTO WESTERN MA/NORTHERN CT LATE TUE
AFTERNOON/EVENING. ISOLATED STRONG WIND GUSTS/HAIL WILL BE POSSIBLE
WITH THIS ACTIVITY. EXPECT THE ACTIVITY TO WEAKEN AS IT MOVES INTO
EASTERN MA/RI. CONDITIONS THEN IMPROVE TO VFR FROM WEST TO EAST.
KBOS TERMINAL...LOW CONFIDENCE. WATCHING A BANK OF LOW CLOUDS/FOG
THAT MAY MOVE INTO THE TERMINAL LATE THIS AFTERNOON/EARLY EVENING
BUT LOW CONFIDENCE.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. LOW END MVFR TO IFR
EXPECTED TO DEVELOP TONIGHT BUT TIMING UNCERTAIN.
OUTLOOK...WEDNESDAY THROUGH FRIDAY...
WED THROUGH FRI...HIGH CONFIDENCE. VFR. W/NW GUSTS TO 25 KT ON
WED.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SUNDAY NIGHT/...HIGH CONFIDENCE.
QUIET BOATING WEATHER EXPECTED WITH HIGH PRESSURE
OVER THE WATERS. EASTERLY WINDS 5 TO 10 KTS WILL SHIFT TO THE SOUTH
TONIGHT AND INCREASE TO 10 TO 15 KTS WITH GUSTS TO 20 KTS TUESDAY.
OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY...HIGH CONFIDENCE.
TUE NIGHT...SW WINDS WITH GUSTS TO 20 KT BECOMING NW AFTER
MIDNIGHT. SCT SHOWERS AND PATCHY FOG MAY REDUCE VSBYS IN THE
EVENING.
WED...W/NW WINDS WITH GUSTS TO 25 KT. MARGINAL SCA CONDITIONS
POSSIBLE.
THU INTO FRI...MAINLY SW WINDS BELOW SCA WITH SEAS BELOW SCA.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KJC/RLG
NEAR TERM...FRANK
SHORT TERM...RLG
LONG TERM...KJC
AVIATION...FRANK/KJC
MARINE...KJC/RLG
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
349 PM EDT MON MAY 18 2015
.SYNOPSIS...
19Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS YET ANOTHER IN A SERIES
OF STRONG LONGWAVE TROUGH ABOUT TO PIVOT OUT OF THE SOUTHWESTERN
STATES. THE LAST TROUGH IS JUST NOW BEGINNING TO EXIT THE UPPER
MIDWEST...BUT HERE COMES THE NEXT ONE CROSSING INTO THE INTER-
MOUNTAIN WEST. THANKFULLY FOR OUR LOCAL AREA...THIS INCLEMENT
WEATHER WILL REMAIN WELL TO OUR NORTHWEST...WHILE WE REMAIN UNDER
THE CONTROL OF WEAK RIDGING ALOFT INTO TUESDAY.
AT THE SURFACE...ATLANTIC HIGH PRESSURE IS RIDGING BACK INTO THE
NORTHERN FLORIDA PENINSULA THIS AFTERNOON AND WILL CONTINUE TO
BOTH SETTLE SLOWLY SOUTHWARD AND WEAKEN DURING THE NEXT 12-24
HOURS. THE POSITION OF THE RIDGE IS RESULTING IN A LIGHT EASTERLY
FLOW FOR THE SOUTHERN HALF OF THE AREA...AND A LIGHT AND VARIABLE
FLOW TO THE NORTH OF THE TAMPA BAY AREA. ALTHOUGH EASTERLY FLOW IS
GENERALLY FAVORABLE FOR CONVECTIVE DEVELOPMENT ALONG THE WEST
COAST SEA BREEZE...TODAY IS DIFFERENT FROM PREVIOUS DAYS WITH A
SUBSTANTIAL LAYER OF DRY/HOSTILE AIR TOWARD DEEP CONVECTION IN THE
MID LEVELS. CAN NOT RULE OUT A FEW ISOLATED STORMS THAT WILL BE
ABLE TO SURVIVE THIS DRIER COLUMN TO THE SOUTH OF THE I-4
CORRIDOR...BUT THEY WILL BE FEW AND FAR BETWEEN. MOISTURE PROFILES
ARE SLIGHTLY BETTER OVER OUR FAR NORTHERN AREAS...AND ACTUALLY
STARTING TO SEE SOME STORMS DEVELOP UP TOWARD PERRY/CROSS CITY.
THINK BETTER CHANCES FOR A FEW EVENING STORMS FOR OUR AREA WILL BE
UP TOWARD CITRUS/LEVY/NORTHERN SUMTER COUNTY...AS THE SEA-BREEZE
SLOWLY MIGRATES INLAND.
&&
.SHORT TERM...
SCT EVENING STORMS DECAY QUICKLY WITH THE LOSS OF DIURNAL HEATING
LATER THIS EVENING...SETTING UP A GENERALLY DRY AND SEASONABLY
WARM MID MAY OVERNIGHT. OVERNIGHT LOWS GENERALLY IN THE UPPER 60S
TO LOWER 70S FOR MOST SPOTS...ALTHOUGH NORMALLY WARMER LOCATIONS
SUCH AS SOUTHERN PINELLAS COUNTY AND THE ISLANDS OF CHARLOTTE
HARBOR WILL STAY EVEN WARMER WITH DEVELOPING LAND BREEZE FLOW OFF
THE BAYS.
FOR TUESDAY...UPPER RIDGE IS STILL IN PLACE...BUT WILL BEGIN TO
WEAKEN WITH HEIGHTS SLOWLY DROPPING THROUGH THE DAY. AT THE
SURFACE THE RIDGE AXIS WILL SETTLE DOWN INTO THE CENTRAL OR EVEN
SOUTH-CENTRAL FL PENINSULA. THIS MOTION WILL BE FORCED BY THE SLOW
APPROACH OF A WEAK FRONT FROM THE NORTH. THIS FRONT MAY REACH AS
FAR SOUTH AS THE I-10 CORRIDOR BEFORE TUESDAY IS OVER. THE
SYNOPTIC FLOW SOUTH OF THIS FRONT WILL FINALLY SHIFT TO A MORE
WESTERLY DIRECTION ACROSS A LARGE PORTION OF OUR AREA. THE
WESTERLY FLOW WILL CERTAINLY BE WEAKER DOWN TOWARD FORT
MYERS...BUT SHOULD STILL BE PRESENT. THE WEST FLOW WILL ACT TO
STEADILY PROGRESS THE SEA BREEZE INLAND...ESPECIALLY FOR THE
NATURE COAST. BETTER MOISTURE PROFILES...AND ADDED FOCUS
ASSOCIATED WITH THE APPROACHING SYNOPTIC BOUNDARY SHOULD KEEP THE
BEST CHANCES FOR DIURNAL CONVECTION ALONG AND NORTH OF THE I-4
CORRIDOR. WILL HAVE 40-50% POPS FOR THE NORTHERN HALF OF THE
AREA...AND GENERALLY 20-30% (AT BEST) FURTHER SOUTH. HOWEVER...AS
MENTIONED...AS THE SEA-BREEZE MOVES INLAND...RAIN CHANCES WILL
DECREASE NEAR THE COAST (EVEN FOR THE NATURE COAST) AS THE
AFTERNOON PROGRESSES. BY THE EVENING HOURS...MUCH OF THE STORM
ACTIVITY SHOULD BE WELL INLAND. HIGH TEMPERATURES THURSDAY REACH
THE MIDDLE 80S AT THE BEACHES WITH UPPER 80S TO LOWER 90S ALONG
THE I-75 CORRIDOR AND FURTHER INLAND.
&&
.LONG TERM (WEDNESDAY THROUGH NEXT MONDAY)...
WED-FRI: AN UPPER LOW ROTATES OVER EASTERN CANADA WITH A TROUGH THAT
PIVOTS FROM THE UPPER MID-WEST TO THE EASTERN SEA BOARD...FLATTENING
AND SHIFTING AN UPPER RIDGE OVER THE GULF BACK TO THE WEST. AT THE
SURFACE INITIALLY...HIGH PRESSURE SPRAWLS ACROSS THE NORTHERN PLAINS
AND MID-MISSISSIPPI VALLEY WITH A FRONT THAT ARCS FROM THE SAINT
LAWRENCE VALLEY SOUTH ALONG THE EASTERN U.S. COAST THEN BACK WEST
THROUGH THE GULF COASTAL STATES...AND ATLANTIC HIGH PRESSURE
RIDGES ACROSS SOUTHERN FL INTO THE GULF. WITH TIME...THE HIGH
PRESSURE SAGS SOUTH AS IT BUILDS EAST WITH THE FRONT PUSHING EAST
AND SOUTH...WITH THE SOUTHERN/WESTERN END DROPPING DOWN ALONG THE
GULF COAST AND THROUGH NORTHERN FL. THE ATLANTIC RIDGE MEANDERS
OVER OR OFF SOUTHERN FL.
SAT-MON: A PACIFIC UPPER LOW MOVES ACROSS THE GREAT BASIN AND OUT
OVER THE PLAINS AS AN OPEN WAVE WITH UPPER RIDGING BUILDING BACK OVER
THE GULF THEN SLIDING ACROSS THE SOUTHEAST U.S. TO THE ATLANTIC.
THE SURFACE HIGH...BY NOW OVER THE UPPER MID-WEST AND UPPER GREAT
LAKES...TRACKS ACROSS THE MID-ATLANTIC STATES THEN OFFSHORE. AS IT
DOES IT BRIDGES THE DECAYING FRONT IN THE NORTHERN GULF AND
NORTHERN FL AND BUILDS IN ACROSS FL.
THE CURRENT FORECAST PHILOSOPHY REMAINS VERY SIMILAR TO THE PAST FEW
DAYS. THE ATMOSPHERE CONTINUES WITH AMPLE MOISTURE FOR ISOLATED TO
SCATTERED SHOWERS AND STORMS. A WESTERLY FLOW PATTERN SETS UP WED
AND CONTINUES THROUGH FRI...WITH A FEW MORNING SHOWERS OR STORMS
POSSIBLE ON THE GULF THEN MORE COVERAGE IN THE AFTERNOONS WITH THE
HIGHEST INLAND. FOR THE WEEKEND THE PATTERN GOES BACK TO EAST AND
SOUTHEAST...AS HIGH PRESSURE BUILDS IN FROM THE NORTH...WITH THE
GREATEST SHOWER/STORM COVERAGE IN THE AFTERNOON AND EARLY EVENING ON
THE WEST COAST...A RESULT OF SEA BREEZE CIRCULATIONS. TEMPERATURES
WILL RUN ABOVE NORMAL...ALTHOUGH THERE MAY BE A SLIGHT DIP LATE IN
THE PERIOD.
&&
.AVIATION...
VFR CONDITIONS PREVAILING ACROSS WEST-CENTRAL AND SOUTHWEST
FLORIDA THIS AFTERNOON. JUST A SLIGHT CHANCE FOR AN ISOLATED STORM
FOR ANY OF THE TERMINALS THROUGH 00Z...HOWEVER MOST AREAS WILL
REMAIN DRY. VFR CONDITIONS GENERALLY PREVAIL FOR THE REMAINDER OF
THE OVERNIGHT INTO TUESDAY MORNING. TOWARD THE END OF THE TAF
PERIOD (18Z)...A FEW SHOWERS SHOULD START TO FORM ALONG THE SEA-
BREEZE IN THE VICINITY OF KTPA/KPIE...AND MAY NEED MENTION IN
UPCOMING TAF PACKAGES.
&&
.MARINE...
HIGH PRESSURE THAT HAS BEEN OVER THE EASTERN SEABOARD
SHIFTS SOUTHWARD AS A WEAK FRONTAL SYSTEM APPROACHES FROM THE
NORTH ON TUESDAY. THIS INTERACTION WILL ALLOW FOR THE WINDS TO
SHIFT TO A MORE WEST OR NORTHWEST DIRECTION THROUGH THE MIDDLE OF
THE WEEK. THE WESTERLY FLOW WILL HELP KEEP THE BEST CHANCES FOR
STORMS INLAND THE NEXT SEVERAL DAYS. WINDS AND SEAS REMAIN BELOW
HEADLINE CRITERIA.
&&
.FIRE WEATHER...
NO SIGNIFICANT FIRE WEATHER CONCERNS FOR THE NEXT
FEW DAYS AS RELATIVE HUMIDITY VALUES WILL REMAIN ABOVE CRITICAL
LEVELS. THE THUNDERSTORM PATTERN THE NEXT FEW DAYS WILL FAVOR THE
SEA-BREEZE MOVING INLAND BEYOND THE I-75 CORRIDOR...AND THEREFORE
THE HIGHEST RAIN CHANCES WILL BE AWAY FROM THE COAST AND
PROGRESSING INLAND THROUGH THE AFTERNOON AND EARLY EVENING.
FOG IMPACT...NO SIGNIFICANT FOG IS EXPECTED FOR THE NEXT FEW
DAYS...BUT LATE NIGHT PATCHY GROUND FOG COULD DEVELOP IN AREAS
THAT SEE RAIN DURING THE EVENING HOURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 75 87 75 89 / 10 30 20 30
FMY 72 89 74 91 / 10 20 20 40
GIF 72 90 73 92 / 10 30 30 50
SRQ 73 86 74 87 / 20 20 20 30
BKV 69 90 70 90 / 10 30 10 30
SPG 76 87 76 88 / 20 20 20 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WEATHER...14/MROCZKA
LONG TERM/DECISION SUPPORT...09/RUDE
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
954 PM EDT TUE MAY 19 2015
.SYNOPSIS...
A WEAK FRONT WILL CROSS THE AREA TONIGHT WITH ISOLATED SHOWERS AND
STORMS EXPECTED AHEAD OF THE FRONT. THE FRONT WILL STALL JUST TO
OUR SOUTH WEDNESDAY. AN UPPER DISTURBANCE AND SURFACE WAVE WILL
MOVE THROUGH THURSDAY.
&&
.NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/...
AS OF 23Z...COLD FRONT IS CURRENTLY DRAPED ACROSS THE WESTERN
CAROLINAS AND NORTHEAST GEORGIA. RADAR IMAGERY SHOWS ISOLATED
SHOWERS AND THUNDERSTORMS WHICH HAVE DEVELOPED DUE TO CONVERGENCE
AHEAD OF THE FRONT. CONVERGENCE APPEARS WEAK AND HI-RESOLUTION
MODELS DO NOT SHOW MUCH COVERAGE THROUGH WEDNESDAY MORNING SO HAVE
ADJUSTED POPS DOWN A BIT. THE FRONTAL BOUNDARY WILL BE SLOW TO
MOVE THROUGH THE AREA AS LATEST GUIDANCE SUGGESTS FRONT MAY HANG
UP ACROSS THE SOUTHEASTERN MIDLANDS/CSRA.
LOWS TONIGHT WILL RANGE FROM THE MID 60S NORTHERN MIDLANDS TO
UPPER 60S SOUTHEASTERN MIDLANDS.
&&
.SHORT TERM /7 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
MODELS HAVE INDICATED THAT THE FRONT MAY STALL SLIGHTLY MORE TO
THE NORTH THAN PREVIOUS RUNS. THIS WOULD KEEP MOISTURE OVER A
GREATER PORTION OF THE CWA. HAVE SHIFTED THE CHANCE FOR DIURNAL
SHOWERS AND THUNDERSTORMS NORTHWARD INTO THE MIDLANDS. THE
GREATEST CHANCE OF CONVECTION WILL STILL BE ALONG THE SC COAST
INTO THE SOUTHERN MIDLANDS AND CSRA. STORMS SHOULD REMAIN
UNORGANIZED DUE TO WEAK SHEAR VALUES. THE THREAT OF SEVERE WEATHER
IS SLIGHT BUT CANNOT RULE OUT ISOLATED SEVERE STORMS ALONG THE
BOUNDARY.
A MID-LEVEL SHORTWAVE IS EXPECTED TO MOVE EAST INTO THE CWA LATE
WEDNESDAY NIGHT AND THURSDAY. THE UPPER LEVEL ENERGY WILL ALLOW
FOR CYCLOGENISIS ALONG THE STALLED BOUNDARY...DEVELOPING A
SURFACE LOW OVER THE CAROLINAS. THERE IS A DEEP ELEVATED MIXED
LAYER PRESENT OVERNIGHT WEDNESDAY AS THE SHORTWAVE PASSES. THIS MAY
ALLOW FOR ELEVATED CONVECTION TO DEVELOP IN THE UPSTATE AND MOVE
INTO THE CWA EARLY THURSDAY. THE SEVERE POTENTIAL WILL BE LIMITED
DUE TO THE NOCTURNAL BOUNDARY LAYER.
AS THE LOW MOVES EAST WINDS BECOME WESTERLY AND DRY OUT THE CWA BY
THURSDAY AFTERNOON. HIGH PRESSURE WILL THEN BUILD INTO THE
REGION.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
HIGH PRESSURE CROSSING THE CENTRAL GREAT LAKES FRIDAY WILL USHER
SLIGHTLY COOLER AND DRIER AIR SOUTHWARD INTO THE REGION. IT WILL
CONTINUE TO MOVE EAST INTO THE MID-ATLANTIC STATES KEEPING THE
REGION DRY SATURDAY. AS THE HIGH SHIFTS OFF THE COAST EARLY NEXT
WEEK MOISTURE WILL RETURN TO THE AREA ALLOWING FOR DIURNAL SHOWERS
AND THUNDERSTORMS TO RETURN TO THE AREA. TEMPERATURES THROUGH THE
LONG TERM WILL BE NEAR TO SLIGHTLY ABOVE NORMAL.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
EXPECT MAINLY VFR CONDITIONS DURING THE TAF PERIOD. LITTLE
CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT MOVING INTO THE
AREA OVERNIGHT. THERE IS ALSO LIMITED NEAR-SURFACE MOISTURE. MOST
OF THE GUIDANCE MAINTAINS VFR CONDITIONS. HOWEVER...THE HRRR DOES
INDICATE A FEW PATCHES OF IFR IN THE CSRA. THE MODELS SHOW A
LITTLE MORE CONVERGENCE IN THE CSRA TOWARD SUNRISE AND WITH THE
ADDED RIVER VALLEY MOISTURE A PERIOD OF MVFR OF IFR FOG MAY OCCUR
AT AGS. HEATING AND MIXING SHOULD DISSIPATE ANY FOG LATER
WEDNESDAY MORNING. SOME WEAK CONVERGENCE ASSOCIATED WITH THE FRONT
LINGERING NEAR THE AREA AND HEATING MAY SUPPORT THUNDERSTORMS
DURING THE AFTERNOON. H85 WESTERLY FLOW AND SHALLOW MOISTURE PLUS
A LACK OF SIGNIFICANT UPPER-LEVEL LIFT SHOULD LIMIT THUNDERSTORM
COVERAGE. THE CHANCE OF THUNDERSTORMS IS TOO LOW TO INCLUDE IN THE
TERMINAL FORECASTS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN MAINLY
SCATTERED AFTERNOON AND EVENING THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
99
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
708 PM EDT TUE MAY 19 2015
.SYNOPSIS...
A WEAK FRONT WILL CROSS THE AREA TONIGHT WITH ISOLATED SHOWERS AND
STORMS EXPECTED AHEAD OF THE FRONT. THE FRONT WILL STALL JUST TO
OUR SOUTH WEDNESDAY. AN UPPER DISTURBANCE AND SURFACE WAVE WILL
MOVE THROUGH THURSDAY.
&&
.NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/...
AS OF 23Z...COLD FRONT IS CURRENTLY DRAPED ACROSS THE WESTERN
CAROLINAS AND NORTHEAST GEORGIA. RADAR IMAGERY SHOWS ISOLATED
SHOWERS AND THUNDERSTORMS WHICH HAVE DEVELOPED DUE TO CONVERGENCE
AHEAD OF THE FRONT. CONVERGENCE APPEARS WEAK AND HI-RESOLUTION
MODELS DO NOT SHOW MUCH COVERAGE THROUGH WEDNESDAY MORNING SO HAVE
ADJUSTED POPS DOWN A BIT. THE FRONTAL BOUNDARY WILL BE SLOW TO
MOVE THROUGH THE AREA AS LATEST GUIDANCE SUGGESTS FRONT MAY HANG
UP ACROSS THE SOUTHEASTERN MIDLANDS/CSRA.
LOWS TONIGHT WILL RANGE FROM THE MID 60S NORTHERN MIDLANDS TO
UPPER 60S SOUTHEASTERN MIDLANDS.
&&
.SHORT TERM /7 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
MODELS HAVE INDICATED THAT THE FRONT MAY STALL SLIGHTLY MORE TO
THE NORTH THAN PREVIOUS RUNS. THIS WOULD KEEP MOISTURE OVER A
GREATER PORTION OF THE CWA. HAVE SHIFTED THE CHANCE FOR DIURNAL
SHOWERS AND THUNDERSTORMS NORTHWARD INTO THE MIDLANDS. THE
GREATEST CHANCE OF CONVECTION WILL STILL BE ALONG THE SC COAST
INTO THE SOUTHERN MIDLANDS AND CSRA. STORMS SHOULD REMAIN
UNORGANIZED DUE TO WEAK SHEAR VALUES. THE THREAT OF SEVERE WEATHER
IS SLIGHT BUT CANNOT RULE OUT ISOLATED SEVERE STORMS ALONG THE
BOUNDARY.
A MID-LEVEL SHORTWAVE IS EXPECTED TO MOVE EAST INTO THE CWA LATE
WEDNESDAY NIGHT AND THURSDAY. THE UPPER LEVEL ENERGY WILL ALLOW
FOR CYCLOGENISIS ALONG THE STALLED BOUNDARY...DEVELOPING A
SURFACE LOW OVER THE CAROLINAS. THERE IS A DEEP ELEVATED MIXED
LAYER PRESENT OVERNIGHT WEDNESDAY AS THE SHORTWAVE PASSES. THIS MAY
ALLOW FOR ELEVATED CONVECTION TO DEVELOP IN THE UPSTATE AND MOVE
INTO THE CWA EARLY THURSDAY. THE SEVERE POTENTIAL WILL BE LIMITED
DUE TO THE NOCTURNAL BOUNDARY LAYER.
AS THE LOW MOVES EAST WINDS BECOME WESTERLY AND DRY OUT THE CWA BY
THURSDAY AFTERNOON. HIGH PRESSURE WILL THEN BUILD INTO THE
REGION.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
HIGH PRESSURE CROSSING THE CENTRAL GREAT LAKES FRIDAY WILL USHER
SLIGHTLY COOLER AND DRIER AIR SOUTHWARD INTO THE REGION. IT WILL
CONTINUE TO MOVE EAST INTO THE MID-ATLANTIC STATES KEEPING THE
REGION DRY SATURDAY. AS THE HIGH SHIFTS OFF THE COAST EARLY NEXT
WEEK MOISTURE WILL RETURN TO THE AREA ALLOWING FOR DIURNAL SHOWERS
AND THUNDERSTORMS TO RETURN TO THE AREA. TEMPERATURES THROUGH THE
LONG TERM WILL BE NEAR TO SLIGHTLY ABOVE NORMAL.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
EXPECT MAINLY VFR CONDITIONS DURING THE TAF PERIOD. LITTLE
CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT MOVING INTO THE
AREA TONIGHT. THERE IS ALSO LIMITED NEAR-SURFACE MOISTURE. MOST OF
THE GUIDANCE INCLUDING THE HRRR AND SREF INDICATE VFR CONDITIONS.
THE MODELS DO SHOW A LITTLE MORE CONVERGENCE IN THE CSRA TOWARD
SUNRISE AND WITH THE ADDED RIVER VALLEY MOISTURE A PERIOD OF MVFR OF
IFR FOG MAY OCCUR AT AGS. HEATING AND MIXING SHOULD DISSIPATE ANY
FOG LATER WEDNESDAY MORNING. SOME WEAK CONVERGENCE ASSOCIATED WITH
THE FRONT LINGERING IN THE AREA AND HEATING MAY SUPPORT
THUNDERSTORMS DURING THE AFTERNOON. H85 WESTERLY FLOW AND SHALLOW
MOISTURE PLUS A LACK OF SIGNIFICANT UPPER-LEVEL LIFT SHOULD LIMIT
THUNDERSTORM COVERAGE. THE CHANCE OF THUNDERSTORMS IS TOO LOW TO
INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN MAINLY
SCATTERED AFTERNOON AND EVENING THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
99
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1145 PM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 852 PM CDT SUN MAY 17 2015
OVERNIGHT FORECAST DOING WELL. SOUTHERLY WINDS MAINTAINING SOME
WARM TEMPS FOR THE OVERNIGHT...AND MAJORITY OF PRECIP THREAT ALONG
AND SOUTH OF A LINE FROM TAYLORVILLE TO CHAMPAIGN. SHORT TERM
MODELS PREV BLEW SOME CONVECTION INTO SOUTHEASTERN IL WORKING OFF
OF OUTFLOW FROM ACTIVITY IN MO. HOWEVER, ATMOSPHERE HAVING
DIFFICULT TIME FOCUSING ANY LIFT, PARTICULARLY WITH THE LOSS OF
THE DIURNAL COMPONENT TO THE INSTABILITY. SHOWERS SO FAR HAVE
REMAINED LIMITED AND THE BULK OF THE THUNDER FURTHER TO THE SOUTH.
ISO TS POSSIBLE IN THE FAR SE...BUT NOT WIDESPREAD. NOT MUCH IN
THE WAY OF UPDATES ANTICIPATED AT THIS TIME.
&&
.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT SUN MAY 17 2015
POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON/EVENING IS STILL BEING
MONITORED...HOWEVER IT IS BEGINNING TO LOOK LIKE ANY SEVERE WILL BE
ISOLATED AT BEST. 18Z KILX UPPER AIR SOUNDING SHOWS SBCAPE OF
2000J/KG AND 0-6KM BULK SHEAR OF 35KT: HOWEVER, A WARM LAYER AT
AROUND 900MB IS KEEPING THE ATMOSPHERE MOSTLY CAPPED. REGIONAL
MESOSCALE ANALYSIS INDICATES A POCKET OF GREATER INSTABILITY ACROSS
NORTH-CENTRAL ILLINOIS FROM PEORIA/BLOOMINGTON NORTHWARD...MAKING
THIS THE PRIMARY SPOT FOR POTENTIAL CONVECTIVE DEVELOPMENT OVER THE
NEXT COUPLE OF HOURS. HRRR SHOWS THIS SCENARIO UNFOLDING...WITH
SCATTERED STORMS LIFTING NORTHWARD INTO NORTHERN ILLINOIS/SOUTHERN
WISCONSIN LATER THIS AFTERNOON. FURTHER SOUTH...THE UPSTREAM
AIRMASS ACROSS MISSOURI/SOUTHWEST ILLINOIS REMAINS STABLE AND CAPPED
IN THE WAKE OF A MORNING OUTFLOW BOUNDARY THAT HAS PUSHED WELL TO
THE EAST INTO WESTERN SECTIONS OF KENTUCKY AND TENNESSEE. END
RESULT WILL LIKELY BE ONLY WIDELY SCATTERED STORMS DEVELOPING ALONG
THE I-55 CORRIDOR AFTER 21Z...WITH MINIMAL SEVERE WEATHER THREAT.
HIGH-RES MODELS CONTINUE TO SUGGEST CONVECTION WILL RE-DEVELOP OVER
SOUTHEAST MISSOURI/ARKANSAS THIS EVENING...THEN LIFT INTO SOUTHEAST
ILLINOIS TONIGHT. PARTIAL CLEARING HAS OCCURRED ACROSS THIS
AREA...HOWEVER AIRMASS REMAINS STABLE BEHIND THE PREVIOUS OUTFLOW
BOUNDARY...SO AM SKEPTICAL OF THIS SOLUTION. WILL CONTINUE TO
MONITOR SOUTHEAST MISSOURI FOR DEVELOPMENT OVER THE NEXT SEVERAL
HOURS. AT THIS TIME...WILL CARRY ONLY SLIGHT OR LOW CHANCE POPS
WEST OF THE I-57 CORRIDOR THROUGH THE EVENING HOURS...WITH DRY
CONDITIONS OVERNIGHT. FURTHER EAST...WILL GO WITH HIGHER POPS IN
THE HIGHER DEWPOINT/MORE UNSTABLE AIRMASS ALONG/EAST OF I-57.
.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 256 PM CDT SUN MAY 17 2015
COLD FRONT WILL PASS THROUGH CENTRAL ILLINOIS ON MONDAY...DROPPING
SOUTH OF THE I-70 CORRIDOR BY LATE AFTERNOON. SCATTERED SHOWERS AND
THUNDERSTORMS MAY DEVELOP AHEAD OF THE FRONT...HOWEVER AREAL
COVERAGE WILL BE GREATEST FURTHER EAST ACROSS THE OHIO RIVER VALLEY.
WILL MAINTAIN CHANCE POPS ALONG/EAST OF A DANVILLE TO SHELBYVILLE
LINE THROUGHOUT THE DAY UNTIL THE BOUNDARY EXITS. HIGH PRESSURE
WILL TAKE CONTROL OF THE WEATHER BEHIND THE DEPARTING
FRONT...PROVIDING COOL/DRY WEATHER FOR TUESDAY. RESULTING HIGH
TEMPERATURES WILL REMAIN IN THE LOWER TO MIDDLE 60S...WHILE
OVERNIGHT LOWS DIP INTO THE 40S.
PIECE OF ENERGY IS EXPECTED TO EJECT FROM WESTERN CONUS UPPER LOW BY
MID-WEEK...BRINGING CLOUDS AND PERHAPS A FEW SHOWERS INTO THE AREA
ON WEDNESDAY. MODELS DEPICT A WEAKENING WAVE COMING INTO A VERY DRY
AIRMASS...SO THINK ANY RAINFALL WILL BE QUITE LIGHT. HAVE CUT BACK
ON POPS...FEATURING LIKELY ACROSS THE FAR SOUTHWEST CWA AROUND
JACKSONVILLE TAPERING DOWN TO JUST SLIGHT ALONG THE INDIANA BORDER.
ONCE THIS WAVE DEPARTS...COOL/DRY WEATHER WILL RETURN FOR THURSDAY
AND FRIDAY.
MAIN UPPER LOW WILL GRADUALLY LIFT INTO THE PLAINS LATE IN THE
PERIOD...BRINGING THE NEXT SIGNIFICANT CHANCE FOR RAIN BY LATE IN
THE WEEKEND. WHILE MODEL DIFFERENCES STILL EXIST...GFS/ECMWF
CONSENSUS POINTS TO THE SUNDAY/MONDAY TIME FRAME AS THE PRIMARY TIME
FOR SHOWERS AND THUNDERSTORMS. HAVE THEREFORE KEPT RAIN CHANCES OUT
OF THE FORECAST FOR SATURDAY...THEN HAVE HIT POPS HARD FOR SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1136 PM CDT SUN MAY 17 2015
SOME MINOR ADJUSTMENTS TO INCLUDE A SCT LAYER AT 120-150 THIS
EVENING WITH AUGMENTED SITES PICKING UP ON THE MID LEVEL MOISTURE
STREAMING IN. SOME PRECIP WELL TO THE WEST KICKING UP ON OUTFLOW
BOUNDARY FROM EARLIER STORMS IN SOUTH CENTRAL IOWA. MODELS NOT
PICKING UP ON IT AT THIS POINT BUT SEE NO REASON TO INCLUDE IT AT
THIS EARLY STAGE...WILL WATCH PIA FOR POTENTIAL IF IT HOLDS
TOGETHER. FRONT MOVING THROUGH WILL BRING THE WINDS AROUND TO MORE
WESTERLY MID MORNING FOR PIA... MORE MID DAY FOR REMAINING TAF
SITES. MOSTLY A CIRRUS KIND OF DAY, THOUGH FORECAST SOUNDINGS AND
CU RULE POINT TO A CU FIELD ROUGHLY ALONG AND SOUTHEAST OF A LINE
FROM SPI TO BMI...DENSER TO THE SOUTH AND EAST AHEAD OF THE
BOUNDARY.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
148 PM EDT MON MAY 18 2015
.SYNOPSIS...
ISSUED AT 135 PM EDT MON MAY 18 2015
A COLD FRONT DROPPING ACROSS THE AREA THIS AFTERNOON WILL BRING A
CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS THROUGH EARLY EVENING.
COOLER AND DRIER AIR WILL SETTLE IN FOR THE WEEK. HIGHS THIS
AFTERNOON WILL REACH THE LOWER 80S. LOWS TONIGHT WILL DROP BACK
INTO UPPER 40S TO LOWER 50S. EXPECT MUCH COOLER TEMPERATURES TUESDAY
AND WEDNESDAY...WITH HIGHS IN THE MID 50S TO LOWER 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EDT MON MAY 18 2015
DRIER MID LEVEL AIR HAS ADVECTED INTO MOST OF THE FORECAST AREA THIS
MORNING. DEEPEST MOISTURE THROUGH THE MORNING HOURS IS EXPECTED TO
RESIDE ACROSS APPROXIMATELY THE SOUTHEAST THIRD OF THE AREA WHERE
SOME UPSWING IN 850-700 HPA MOISTURE TRANSPORT IS EXPECTED OVER THE
NEXT SEVERAL HOURS. 3-6 HOUR RAP PROGS DO INDICATE ABOUT 250-500
J/KG OF INSTABILITY LINGERING ACROSS THESE LOCATIONS EXPERIENCING
STRONGER MOISTURE TRANSPORT THIS MORNING...SO HAVE CONTINUED TO
CONCENTRATE LOW CHANCE POPS ACROSS THE SOUTHEAST THIS MORNING AS
ADDITIONAL WEAK SHORT WAVES TRACK NORTHEAST THROUGH THE OHIO VALLEY
IN ASSOCIATION WITH SOUTHERN STREAM.
ATTENTION FOR THE REMAINDER OF THE DAY WILL CENTER ON EVOLUTION OF
SFC COLD FRONTAL BOUNDARY AND POTENTIAL OF ANY ADDITIONAL SCATTERED
CONVECTION THIS AFTERNOON/EARLY EVENING. INSPECTION OF SHORT TERM
TRENDS SUGGESTS NAM MAY BE JUST A BIT SLOW WITH COLD FRONT ACROSS
THE MID MS RVR VALLEY...AND THE NAM CONTINUES TO BE SOMEWHAT OF A
SLOW OUTLIER THROUGH THE NEXT 24 HOURS WITH THE FRONTAL PROGRESSION.
EVEN WITH A PROGRESSION SOMEWHAT FASTER THAN THE NAM...PREFRONTAL
WARMING SHOULD SUPPORT HIGHS IN THE LOWER 80S FOR MOST LOCATIONS
THIS AFTERNOON. OUTSIDE OF FRONTAL CONVERGENCE...MID/UPPER LEVEL
FORCING IS EXPECTED TO BE QUITE WEAK...ALTHOUGH WATER VAPOR EARLY
THIS MORNING DOES DEPICT SOME INTEGRITY TO AN UPSTREAM WAVE LIFTING
NORTHEAST OUT OF OKLAHOMA/SOUTHEAST MISSOURI. THIS FEATURE SHOULD
RAPIDLY EJECT NORTHEAST...BUT BECOME LESS POTENT AS IT BECOMES MORE
HIGHLY SHEARED ACROSS THE OHIO VALLEY/SOUTHERN GREAT LAKES REGION
LATER THIS AFTERNOON/THIS EVENING.
SOME OF THE NAM AND HIRES OUTPUT DOES INDICATE A NARROW ZONE OF
PREFRONTAL CONFLUENCE WITH SOME SUBSTANTIAL MOISTURE POOLING. HAVE
SOME SUSPICION THE SLOWER NAM OUTLIER MAY BE A BIT AGGRESSIVE IN
TERMS OF THE MAGNITUDE OF THIS MOISTURE POOLING AND HAVE GENERALLY
TRENDED AWAY FROM THE INSTABILITY MAGNITUDES ADVERTISED BY THE NAM
ALONG THIS PREFRONTAL CORRIDOR. HAVE MAINTAINED LOW TO MID CHANCE
TSRA FOR TODAY GIVEN AT LEAST SOME WEAK MID/UPPER FORCING LIFTING
INTO THE AREA WITH AFOREMENTIONED OK/MO VORT...ALTHOUGH OUTSIDE OF
ANY AREAS OF PREFRONTAL MOISTURE POOLING...LOW LEVELS MAY MIX OUT
ENOUGH TO TEMPER INSTABILITY QUITE A BIT BY LATER THIS AFTERNOON. IF
SCATTERED CONVECTION IS ABLE TO DEVELOP THERE MAY BE TWO PRIMARY
CORRIDORS FOR INITIATION...ONE ALONG ANY WEAK PREFRONTAL CONVERGENCE
ZONE...AND THEN ALONG THE ACTUAL FRONTAL BOUNDARY. SEVERE STORMS ARE
NOT EXPECTED IN TRENDING TOWARD NON-NAM GUIDANCE FOR THERMAL
PROFILES...AND ALSO GIVEN MORE OF THE SUBSTANTIAL DEEP LAYER SHEAR
WILL BE POST-FRONTAL.
SOME ISOLATED CONVECTION MAY LINGER INTO THE EVENING ACROSS
SOUTHEAST HALF OF THE AREA...WITH MAIN STORY THROUGH THE REMAINDER
OF THE NIGHT CENTERING ON THE APPROACH OF A MUCH COOLER AND LESS
HUMID AIR MASS. SOME COLD ADVECTION STRATOCU MAY WORK INTO FAR
NORTHERN LOCATIONS OVERNIGHT...BUT OTHERWISE MOST LOCATIONS WILL
EXPERIENCE CLEARING SKIES IN THE EVENING.
&&
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 358 AM EDT MON MAY 18 2015
TRANQUIL WEATHER ANTICIPATED FOR MUCH OF THIS LONG TERM PERIOD.
SPLIT FLOW OVER WESTERN NOAM WITH A HIGHLY AMPLIFIED AND ENDURING
NORTHERN STREAM PATTERN ACROSS CANADA WILL LEAVE THE GREAT LAKES IN
A REGION OF STRONG CONFLUENCE AND GENERAL SUBSIDENCE FOR MOST OF
THIS WEEK. WILL ALSO BE MUCH COOLER BEHIND TODAY`S COLD FRONT WITH
PERSISTENT N/NW FLOW MAINTAINING AN EFFICIENT FEED OF CANADIAN AIR
INTO OUR REGION. EXPECT TEMPS ROUGHLY 10-15 DEGREES BELOW NORMAL
DURING THE MIDWEEK PERIOD. TUESDAY NIGHT WILL BE THE COLDEST PERIOD
WITH NUMEROUS SOURCES OF RAW AND STATISTICAL GUIDANCE SUGGESTING MID
30S IN OUR NORTHERN COUNTIES...WITH LOWER 40S IN OUR SOUTH. SOME
CONCERN FOR PATCHY FROST...ESPECIALLY IN OUR MICHIGAN COUNTIES AWAY
FROM THE LAKE. HOWEVER...HIGH BASED CLOUDS WILL BE INCREASING BY
WEDNESDAY MORNING AND MODELS SHOW ENOUGH OF A SURFACE PRESSURE
GRADIENT TO KEEP WINDS IN THE 5-10 MPH RANGE. GIVEN THESE CONCERNS
AND MARGINAL TEMPS WILL HOLD OFF ON MENTIONING ANY FROST IN THE
FORECAST AT THIS POINT AND CONTINUE TO MONITOR.
ONE WEAK SOUTHERN STREAM WAVE DOES EJECT OUT OF THE FOUR CORNERS AND
ATTEMPT TO PHASE WITH SUBTLE NORTHERN STREAM VORT MAX AS IT CROSSES
OUR AREA LATE WEDNESDAY. DEGREE OF DRY AND STABLE LOWER LEVELS IS
CONCERNING BUT FAVORABLE 300MB JET PLACEMENT AND SOME MODEST
CVA/HEIGHT FALLS COULD GENERATE A FEW LIGHT RAIN SHOWERS. NO MAJOR
QUALMS WITH INHERITED LOW CHANCE POPS BUT DID ADJUST THE TIMING UP A
LITTLE BIT BASED ON LATEST NAM AND ECMWF SOLUTIONS. NEXT CHANCE OF
RAIN THEREAFTER WILL NOT BE UNTIL SUNDAY WHEN SOUTHWEST FLOW FINALLY
RETURNS AHEAD OF NEXT WESTERN CONUS TROUGH EJECTING NORTHEAST. THIS
PATTERN SHIFT WILL ALSO SIGNAL THE RETURN OF WARMER AND MORE HUMID
CONDITIONS FOR AT LEAST THE LATTER HALF OF THE HOLIDAY WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 135 PM EDT MON MAY 18 2015
ABUNDANT CLOUD COVER AND LACK OF SIGNIFICANT INSTABILITY /
BOUNDARY LAYER MOISTURE IS PREVENTING CONVECTIVE DEVELOPMENT OVER
THE AREA. ISOLATED SHOWERS HAVE FORMED SOUTH AND EAST OF THE
FORECAST AREA AND EXPECT THIS TREND TO CONTINUE THROUGH THE EARLY
EVENING. AS OF 17Z THE SURFACE COLD FRONT IS LOCATED OVER THE
SOUTHERN TIP OF LAKE MICHIGAN...CROSSING THE IL/IN BORDER. IN THE
CLOUD FREE AREAS THE CU FIELD HAS EXPANDED IN THE PAST FEW HOURS
AND EXPECT THAT TREND TO CONTINUE THROUGH THE EVENING.
FRONTAL PASSAGE WILL BRING IN DRIER AIR AND EXPECT TO SEE AN
ABRUPT WIND SHIFT WITH THE PASSAGE. ADDITIONALLY ALL MODELS
INDICATE STRONG BOUNDARLY LAYER PRESSURE GRADIENT SO GUSTING WINDS
WILL PERSIST THROUGH MUCH OF THE FORECAST PERIOD. LLWS IS NOT
FORECAST...HOWEVER WITH THE ORIENTATION OF THE TROF/SFC
FRONT...EXPECT TO HAVE A BRIEF AND NARROW CORRIDOR OF TURBULENCE
DURING THE PASSAGE.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 5 PM EDT TUESDAY
FOR LMZ043-046.
&&
$$
SYNOPSIS...LEWIS
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...LEWIS
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1029 AM EDT MON MAY 18 2015
.SYNOPSIS...
ISSUED AT 1024 AM EDT MON MAY 18 2015
A COLD FRONT WILL APPROACH THE REGION THIS AFTERNOON. SCATTERED
SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG AND JUST IN ADVANCE OF
THE FRONT THIS AFTERNOON INTO EARLY THIS EVENING BEFORE
DIMINISHING. THE PASSAGE OF THIS COLD FRONT WILL RESULT IN MUCH
COOLER CONDITIONS THROUGH THE MIDDLE PORTIONS OF THE WEEK. HIGH
TEMPERATURES THIS AFTERNOON WILL BE MAINLY IN THE LOWER 80S.
LOW TEMPERATURES TONIGHT WILL DROP BACK INTO UPPER 40S TO LOWER
50S. HIGHS TUESDAY AND WEDNESDAY WILL RANGE FROM THE MID 50S TO
LOWER 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EDT MON MAY 18 2015
DRIER MID LEVEL AIR HAS ADVECTED INTO MOST OF THE FORECAST AREA THIS
MORNING. DEEPEST MOISTURE THROUGH THE MORNING HOURS IS EXPECTED TO
RESIDE ACROSS APPROXIMATELY THE SOUTHEAST THIRD OF THE AREA WHERE
SOME UPSWING IN 850-700 HPA MOISTURE TRANSPORT IS EXPECTED OVER THE
NEXT SEVERAL HOURS. 3-6 HOUR RAP PROGS DO INDICATE ABOUT 250-500
J/KG OF INSTABILITY LINGERING ACROSS THESE LOCATIONS EXPERIENCING
STRONGER MOISTURE TRANSPORT THIS MORNING...SO HAVE CONTINUED TO
CONCENTRATE LOW CHANCE POPS ACROSS THE SOUTHEAST THIS MORNING AS
ADDITIONAL WEAK SHORT WAVES TRACK NORTHEAST THROUGH THE OHIO VALLEY
IN ASSOCIATION WITH SOUTHERN STREAM.
ATTENTION FOR THE REMAINDER OF THE DAY WILL CENTER ON EVOLUTION OF
SFC COLD FRONTAL BOUNDARY AND POTENTIAL OF ANY ADDITIONAL SCATTERED
CONVECTION THIS AFTERNOON/EARLY EVENING. INSPECTION OF SHORT TERM
TRENDS SUGGESTS NAM MAY BE JUST A BIT SLOW WITH COLD FRONT ACROSS
THE MID MS RVR VALLEY...AND THE NAM CONTINUES TO BE SOMEWHAT OF A
SLOW OUTLIER THROUGH THE NEXT 24 HOURS WITH THE FRONTAL PROGRESSION.
EVEN WITH A PROGRESSION SOMEWHAT FASTER THAN THE NAM...PREFRONTAL
WARMING SHOULD SUPPORT HIGHS IN THE LOWER 80S FOR MOST LOCATIONS
THIS AFTERNOON. OUTSIDE OF FRONTAL CONVERGENCE...MID/UPPER LEVEL
FORCING IS EXPECTED TO BE QUITE WEAK...ALTHOUGH WATER VAPOR EARLY
THIS MORNING DOES DEPICT SOME INTEGRITY TO AN UPSTREAM WAVE LIFTING
NORTHEAST OUT OF OKLAHOMA/SOUTHEAST MISSOURI. THIS FEATURE SHOULD
RAPIDLY EJECT NORTHEAST...BUT BECOME LESS POTENT AS IT BECOMES MORE
HIGHLY SHEARED ACROSS THE OHIO VALLEY/SOUTHERN GREAT LAKES REGION
LATER THIS AFTERNOON/THIS EVENING.
SOME OF THE NAM AND HIRES OUTPUT DOES INDICATE A NARROW ZONE OF
PREFRONTAL CONFLUENCE WITH SOME SUBSTANTIAL MOISTURE POOLING. HAVE
SOME SUSPICION THE SLOWER NAM OUTLIER MAY BE A BIT AGGRESSIVE IN
TERMS OF THE MAGNITUDE OF THIS MOISTURE POOLING AND HAVE GENERALLY
TRENDED AWAY FROM THE INSTABILITY MAGNITUDES ADVERTISED BY THE NAM
ALONG THIS PREFRONTAL CORRIDOR. HAVE MAINTAINED LOW TO MID CHANCE
TSRA FOR TODAY GIVEN AT LEAST SOME WEAK MID/UPPER FORCING LIFTING
INTO THE AREA WITH AFOREMENTIONED OK/MO VORT...ALTHOUGH OUTSIDE OF
ANY AREAS OF PREFRONTAL MOISTURE POOLING...LOW LEVELS MAY MIX OUT
ENOUGH TO TEMPER INSTABILITY QUITE A BIT BY LATER THIS AFTERNOON. IF
SCATTERED CONVECTION IS ABLE TO DEVELOP THERE MAY BE TWO PRIMARY
CORRIDORS FOR INITIATION...ONE ALONG ANY WEAK PREFRONTAL CONVERGENCE
ZONE...AND THEN ALONG THE ACTUAL FRONTAL BOUNDARY. SEVERE STORMS ARE
NOT EXPECTED IN TRENDING TOWARD NON-NAM GUIDANCE FOR THERMAL
PROFILES...AND ALSO GIVEN MORE OF THE SUBSTANTIAL DEEP LAYER SHEAR
WILL BE POST-FRONTAL.
SOME ISOLATED CONVECTION MAY LINGER INTO THE EVENING ACROSS
SOUTHEAST HALF OF THE AREA...WITH MAIN STORY THROUGH THE REMAINDER
OF THE NIGHT CENTERING ON THE APPROACH OF A MUCH COOLER AND LESS
HUMID AIR MASS. SOME COLD ADVECTION STRATOCU MAY WORK INTO FAR
NORTHERN LOCATIONS OVERNIGHT...BUT OTHERWISE MOST LOCATIONS WILL
EXPERIENCE CLEARING SKIES IN THE EVENING.
&&
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 358 AM EDT MON MAY 18 2015
TRANQUIL WEATHER ANTICIPATED FOR MUCH OF THIS LONG TERM PERIOD.
SPLIT FLOW OVER WESTERN NOAM WITH A HIGHLY AMPLIFIED AND ENDURING
NORTHERN STREAM PATTERN ACROSS CANADA WILL LEAVE THE GREAT LAKES IN
A REGION OF STRONG CONFLUENCE AND GENERAL SUBSIDENCE FOR MOST OF
THIS WEEK. WILL ALSO BE MUCH COOLER BEHIND TODAY`S COLD FRONT WITH
PERSISTENT N/NW FLOW MAINTAINING AN EFFICIENT FEED OF CANADIAN AIR
INTO OUR REGION. EXPECT TEMPS ROUGHLY 10-15 DEGREES BELOW NORMAL
DURING THE MIDWEEK PERIOD. TUESDAY NIGHT WILL BE THE COLDEST PERIOD
WITH NUMEROUS SOURCES OF RAW AND STATISTICAL GUIDANCE SUGGESTING MID
30S IN OUR NORTHERN COUNTIES...WITH LOWER 40S IN OUR SOUTH. SOME
CONCERN FOR PATCHY FROST...ESPECIALLY IN OUR MICHIGAN COUNTIES AWAY
FROM THE LAKE. HOWEVER...HIGH BASED CLOUDS WILL BE INCREASING BY
WEDNESDAY MORNING AND MODELS SHOW ENOUGH OF A SURFACE PRESSURE
GRADIENT TO KEEP WINDS IN THE 5-10 MPH RANGE. GIVEN THESE CONCERNS
AND MARGINAL TEMPS WILL HOLD OFF ON MENTIONING ANY FROST IN THE
FORECAST AT THIS POINT AND CONTINUE TO MONITOR.
ONE WEAK SOUTHERN STREAM WAVE DOES EJECT OUT OF THE FOUR CORNERS AND
ATTEMPT TO PHASE WITH SUBTLE NORTHERN STREAM VORT MAX AS IT CROSSES
OUR AREA LATE WEDNESDAY. DEGREE OF DRY AND STABLE LOWER LEVELS IS
CONCERNING BUT FAVORABLE 300MB JET PLACEMENT AND SOME MODEST
CVA/HEIGHT FALLS COULD GENERATE A FEW LIGHT RAIN SHOWERS. NO MAJOR
QUALMS WITH INHERITED LOW CHANCE POPS BUT DID ADJUST THE TIMING UP A
LITTLE BIT BASED ON LATEST NAM AND ECMWF SOLUTIONS. NEXT CHANCE OF
RAIN THEREAFTER WILL NOT BE UNTIL SUNDAY WHEN SOUTHWEST FLOW FINALLY
RETURNS AHEAD OF NEXT WESTERN CONUS TROUGH EJECTING NORTHEAST. THIS
PATTERN SHIFT WILL ALSO SIGNAL THE RETURN OF WARMER AND MORE HUMID
CONDITIONS FOR AT LEAST THE LATTER HALF OF THE HOLIDAY WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 637 AM EDT MON MAY 18 2015
MVFR CIGS TO LINGER THIS MORNING AT KFWA...BUT SHOULD TREND TO VFR
BY THE 14Z OR 15Z TIMEFRAME WITH DIURNAL WARMING. MAIN FEATURE OF
INTEREST FOR TODAY WILL BE APPROACHING COLD FRONTAL BOUNDARY THAT
MAY TRIGGER SOME ISOLATED OR SCATTERED AFTERNOON SHOWERS AND
THUNDERSTORMS. LOW LEVEL MIXING IN THE AFTERNOON MAY TEND TO
DISCOURAGE LARGE MAGNITUDES TO AFTERNOON INSTABILITY HOWEVER...SO
CONFIDENCE REMAINS LOW ON THUNDER PROBABILITIES AT KFWA.
INSTABILITY EVEN LESS SUBSTANTIAL AT KSBN...SO WILL CONTINUE TO
OMIT ANY PRECIP MENTION. LIGHT SOUTH SOUTHWEST WINDS THIS MORNING
WILL BECOME GUSTY INTO THE 15 TO 22 KNOT RANGE THIS AFTERNOON
AHEAD OF THE FRONT...WITH A WIND SHIFT TO THE WEST OR WEST
NORTHWEST FOR LATE AFTERNOON/EARLY EVENING BEHIND THE COLD FRONT.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 5 PM EDT TUESDAY
FOR LMZ043-046.
&&
$$
SYNOPSIS...SKIPPER
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI/SKIPPER
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
646 AM EDT MON MAY 18 2015
.SYNOPSIS...
ISSUED AT 358 AM EDT MON MAY 18 2015
A COLD FRONT WILL APPROACH THE REGION THIS AFTERNOON. SCATTERED
SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG AND JUST IN ADVANCE OF
THE FRONT THIS AFTERNOON INTO EARLY THIS EVENING BEFORE
DIMINISHING. THE PASSAGE OF THIS COLD FRONT WILL RESULT IN MUCH
COOLER CONDITIONS THROUGH THE MIDDLE PORTIONS OF THE WEEK. HIGH
TEMPERATURES THIS AFTERNOON WILL RANGE FROM THE UPPER 70S TO LOWER
80S. LOW TEMPERATURES TONIGHT WILL DROP BACK INTO UPPER 40S TO
LOWER 50S. HIGH TEMPERATURES ON TUESDAY AND WEDNESDAY WILL RANGE
FROM THE MID 50S TO LOWER 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EDT MON MAY 18 2015
DRIER MID LEVEL AIR HAS ADVECTED INTO MOST OF THE FORECAST AREA THIS
MORNING. DEEPEST MOISTURE THROUGH THE MORNING HOURS IS EXPECTED TO
RESIDE ACROSS APPROXIMATELY THE SOUTHEAST THIRD OF THE AREA WHERE
SOME UPSWING IN 850-700 HPA MOISTURE TRANSPORT IS EXPECTED OVER THE
NEXT SEVERAL HOURS. 3-6 HOUR RAP PROGS DO INDICATE ABOUT 250-500
J/KG OF INSTABILITY LINGERING ACROSS THESE LOCATIONS EXPERIENCING
STRONGER MOISTURE TRANSPORT THIS MORNING...SO HAVE CONTINUED TO
CONCENTRATE LOW CHANCE POPS ACROSS THE SOUTHEAST THIS MORNING AS
ADDITIONAL WEAK SHORT WAVES TRACK NORTHEAST THROUGH THE OHIO VALLEY
IN ASSOCIATION WITH SOUTHERN STREAM.
ATTENTION FOR THE REMAINDER OF THE DAY WILL CENTER ON EVOLUTION OF
SFC COLD FRONTAL BOUNDARY AND POTENTIAL OF ANY ADDITIONAL SCATTERED
CONVECTION THIS AFTERNOON/EARLY EVENING. INSPECTION OF SHORT TERM
TRENDS SUGGESTS NAM MAY BE JUST A BIT SLOW WITH COLD FRONT ACROSS
THE MID MS RVR VALLEY...AND THE NAM CONTINUES TO BE SOMEWHAT OF A
SLOW OUTLIER THROUGH THE NEXT 24 HOURS WITH THE FRONTAL PROGRESSION.
EVEN WITH A PROGRESSION SOMEWHAT FASTER THAN THE NAM...PREFRONTAL
WARMING SHOULD SUPPORT HIGHS IN THE LOWER 80S FOR MOST LOCATIONS
THIS AFTERNOON. OUTSIDE OF FRONTAL CONVERGENCE...MID/UPPER LEVEL
FORCING IS EXPECTED TO BE QUITE WEAK...ALTHOUGH WATER VAPOR EARLY
THIS MORNING DOES DEPICT SOME INTEGRITY TO AN UPSTREAM WAVE LIFTING
NORTHEAST OUT OF OKLAHOMA/SOUTHEAST MISSOURI. THIS FEATURE SHOULD
RAPIDLY EJECT NORTHEAST...BUT BECOME LESS POTENT AS IT BECOMES MORE
HIGHLY SHEARED ACROSS THE OHIO VALLEY/SOUTHERN GREAT LAKES REGION
LATER THIS AFTERNOON/THIS EVENING.
SOME OF THE NAM AND HIRES OUTPUT DOES INDICATE A NARROW ZONE OF
PREFRONTAL CONFLUENCE WITH SOME SUBSTANTIAL MOISTURE POOLING. HAVE
SOME SUSPICION THE SLOWER NAM OUTLIER MAY BE A BIT AGGRESSIVE IN
TERMS OF THE MAGNITUDE OF THIS MOISTURE POOLING AND HAVE GENERALLY
TRENDED AWAY FROM THE INSTABILITY MAGNITUDES ADVERTISED BY THE NAM
ALONG THIS PREFRONTAL CORRIDOR. HAVE MAINTAINED LOW TO MID CHANCE
TSRA FOR TODAY GIVEN AT LEAST SOME WEAK MID/UPPER FORCING LIFTING
INTO THE AREA WITH AFOREMENTIONED OK/MO VORT...ALTHOUGH OUTSIDE OF
ANY AREAS OF PREFRONTAL MOISTURE POOLING...LOW LEVELS MAY MIX OUT
ENOUGH TO TEMPER INSTABILITY QUITE A BIT BY LATER THIS AFTERNOON. IF
SCATTERED CONVECTION IS ABLE TO DEVELOP THERE MAY BE TWO PRIMARY
CORRIDORS FOR INITIATION...ONE ALONG ANY WEAK PREFRONTAL CONVERGENCE
ZONE...AND THEN ALONG THE ACTUAL FRONTAL BOUNDARY. SEVERE STORMS ARE
NOT EXPECTED IN TRENDING TOWARD NON-NAM GUIDANCE FOR THERMAL
PROFILES...AND ALSO GIVEN MORE OF THE SUBSTANTIAL DEEP LAYER SHEAR
WILL BE POST-FRONTAL.
SOME ISOLATED CONVECTION MAY LINGER INTO THE EVENING ACROSS
SOUTHEAST HALF OF THE AREA...WITH MAIN STORY THROUGH THE REMAINDER
OF THE NIGHT CENTERING ON THE APPROACH OF A MUCH COOLER AND LESS
HUMID AIR MASS. SOME COLD ADVECTION STRATOCU MAY WORK INTO FAR
NORTHERN LOCATIONS OVERNIGHT...BUT OTHERWISE MOST LOCATIONS WILL
EXPERIENCE CLEARING SKIES IN THE EVENING.
&&
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 358 AM EDT MON MAY 18 2015
TRANQUIL WEATHER ANTICIPATED FOR MUCH OF THIS LONG TERM PERIOD.
SPLIT FLOW OVER WESTERN NOAM WITH A HIGHLY AMPLIFIED AND ENDURING
NORTHERN STREAM PATTERN ACROSS CANADA WILL LEAVE THE GREAT LAKES IN
A REGION OF STRONG CONFLUENCE AND GENERAL SUBSIDENCE FOR MOST OF
THIS WEEK. WILL ALSO BE MUCH COOLER BEHIND TODAY`S COLD FRONT WITH
PERSISTENT N/NW FLOW MAINTAINING AN EFFICIENT FEED OF CANADIAN AIR
INTO OUR REGION. EXPECT TEMPS ROUGHLY 10-15 DEGREES BELOW NORMAL
DURING THE MIDWEEK PERIOD. TUESDAY NIGHT WILL BE THE COLDEST PERIOD
WITH NUMEROUS SOURCES OF RAW AND STATISTICAL GUIDANCE SUGGESTING MID
30S IN OUR NORTHERN COUNTIES...WITH LOWER 40S IN OUR SOUTH. SOME
CONCERN FOR PATCHY FROST...ESPECIALLY IN OUR MICHIGAN COUNTIES AWAY
FROM THE LAKE. HOWEVER...HIGH BASED CLOUDS WILL BE INCREASING BY
WEDNESDAY MORNING AND MODELS SHOW ENOUGH OF A SURFACE PRESSURE
GRADIENT TO KEEP WINDS IN THE 5-10 MPH RANGE. GIVEN THESE CONCERNS
AND MARGINAL TEMPS WILL HOLD OFF ON MENTIONING ANY FROST IN THE
FORECAST AT THIS POINT AND CONTINUE TO MONITOR.
ONE WEAK SOUTHERN STREAM WAVE DOES EJECT OUT OF THE FOUR CORNERS AND
ATTEMPT TO PHASE WITH SUBTLE NORTHERN STREAM VORT MAX AS IT CROSSES
OUR AREA LATE WEDNESDAY. DEGREE OF DRY AND STABLE LOWER LEVELS IS
CONCERNING BUT FAVORABLE 300MB JET PLACEMENT AND SOME MODEST
CVA/HEIGHT FALLS COULD GENERATE A FEW LIGHT RAIN SHOWERS. NO MAJOR
QUALMS WITH INHERITED LOW CHANCE POPS BUT DID ADJUST THE TIMING UP A
LITTLE BIT BASED ON LATEST NAM AND ECMWF SOLUTIONS. NEXT CHANCE OF
RAIN THEREAFTER WILL NOT BE UNTIL SUNDAY WHEN SOUTHWEST FLOW FINALLY
RETURNS AHEAD OF NEXT WESTERN CONUS TROUGH EJECTING NORTHEAST. THIS
PATTERN SHIFT WILL ALSO SIGNAL THE RETURN OF WARMER AND MORE HUMID
CONDITIONS FOR AT LEAST THE LATTER HALF OF THE HOLIDAY WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 637 AM EDT MON MAY 18 2015
MVFR CIGS TO LINGER THIS MORNING AT KFWA...BUT SHOULD TREND TO VFR
BY THE 14Z OR 15Z TIMEFRAME WITH DIURNAL WARMING. MAIN FEATURE OF
INTEREST FOR TODAY WILL BE APPROACHING COLD FRONTAL BOUNDARY THAT
MAY TRIGGER SOME ISOLATED OR SCATTERED AFTERNOON SHOWERS AND
THUNDERSTORMS. LOW LEVEL MIXING IN THE AFTERNOON MAY TEND TO
DISCOURAGE LARGE MAGNITUDES TO AFTERNOON INSTABILITY HOWEVER...SO
CONFIDENCE REMAINS LOW ON THUNDER PROBABILITIES AT KFWA.
INSTABILITY EVEN LESS SUBSTANTIAL AT KSBN...SO WILL CONTINUE TO
OMIT ANY PRECIP MENTION. LIGHT SOUTH SOUTHWEST WINDS THIS MORNING
WILL BECOME GUSTY INTO THE 15 TO 22 KNOT RANGE THIS AFTERNOON
AHEAD OF THE FRONT...WITH A WIND SHIFT TO THE WEST OR WEST
NORTHWEST FOR LATE AFTERNOON/EARLY EVENING BEHIND THE COLD FRONT.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 5 PM EDT TUESDAY
FOR LMZ043-046.
&&
$$
SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
400 AM EDT MON MAY 18 2015
.SYNOPSIS...
ISSUED AT 358 AM EDT MON MAY 18 2015
A COLD FRONT WILL APPROACH THE REGION THIS AFTERNOON. SCATTERED
SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG AND JUST IN ADVANCE OF
THE FRONT THIS AFTERNOON INTO EARLY THIS EVENING BEFORE
DIMINISHING. THE PASSAGE OF THIS COLD FRONT WILL RESULT IN MUCH
COOLER CONDITIONS THROUGH THE MIDDLE PORTIONS OF THE WEEK. HIGH
TEMPERATURES THIS AFTERNOON WILL RANGE FROM THE UPPER 70S TO LOWER
80S. LOW TEMPERATURES TONIGHT WILL DROP BACK INTO UPPER 40S TO
LOWER 50S. HIGH TEMPERATURES ON TUESDAY AND WEDNESDAY WILL RANGE
FROM THE MID 50S TO LOWER 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EDT MON MAY 18 2015
DRIER MID LEVEL AIR HAS ADVECTED INTO MOST OF THE FORECAST AREA THIS
MORNING. DEEPEST MOISTURE THROUGH THE MORNING HOURS IS EXPECTED TO
RESIDE ACROSS APPROXIMATELY THE SOUTHEAST THIRD OF THE AREA WHERE
SOME UPSWING IN 850-700 HPA MOISTURE TRANSPORT IS EXPECTED OVER THE
NEXT SEVERAL HOURS. 3-6 HOUR RAP PROGS DO INDICATE ABOUT 250-500
J/KG OF INSTABILITY LINGERING ACROSS THESE LOCATIONS EXPERIENCING
STRONGER MOISTURE TRANSPORT THIS MORNING...SO HAVE CONTINUED TO
CONCENTRATE LOW CHANCE POPS ACROSS THE SOUTHEAST THIS MORNING AS
ADDITIONAL WEAK SHORT WAVES TRACK NORTHEAST THROUGH THE OHIO VALLEY
IN ASSOCIATION WITH SOUTHERN STREAM.
ATTENTION FOR THE REMAINDER OF THE DAY WILL CENTER ON EVOLUTION OF
SFC COLD FRONTAL BOUNDARY AND POTENTIAL OF ANY ADDITIONAL SCATTERED
CONVECTION THIS AFTERNOON/EARLY EVENING. INSPECTION OF SHORT TERM
TRENDS SUGGESTS NAM MAY BE JUST A BIT SLOW WITH COLD FRONT ACROSS
THE MID MS RVR VALLEY...AND THE NAM CONTINUES TO BE SOMEWHAT OF A
SLOW OUTLIER THROUGH THE NEXT 24 HOURS WITH THE FRONTAL PROGRESSION.
EVEN WITH A PROGRESSION SOMEWHAT FASTER THAN THE NAM...PREFRONTAL
WARMING SHOULD SUPPORT HIGHS IN THE LOWER 80S FOR MOST LOCATIONS
THIS AFTERNOON. OUTSIDE OF FRONTAL CONVERGENCE...MID/UPPER LEVEL
FORCING IS EXPECTED TO BE QUITE WEAK...ALTHOUGH WATER VAPOR EARLY
THIS MORNING DOES DEPICT SOME INTEGRITY TO AN UPSTREAM WAVE LIFTING
NORTHEAST OUT OF OKLAHOMA/SOUTHEAST MISSOURI. THIS FEATURE SHOULD
RAPIDLY EJECT NORTHEAST...BUT BECOME LESS POTENT AS IT BECOMES MORE
HIGHLY SHEARED ACROSS THE OHIO VALLEY/SOUTHERN GREAT LAKES REGION
LATER THIS AFTERNOON/THIS EVENING.
SOME OF THE NAM AND HIRES OUTPUT DOES INDICATE A NARROW ZONE OF
PREFRONTAL CONFLUENCE WITH SOME SUBSTANTIAL MOISTURE POOLING. HAVE
SOME SUSPICION THE SLOWER NAM OUTLIER MAY BE A BIT AGGRESSIVE IN
TERMS OF THE MAGNITUDE OF THIS MOISTURE POOLING AND HAVE GENERALLY
TRENDED AWAY FROM THE INSTABILITY MAGNITUDES ADVERTISED BY THE NAM
ALONG THIS PREFRONTAL CORRIDOR. HAVE MAINTAINED LOW TO MID CHANCE
TSRA FOR TODAY GIVEN AT LEAST SOME WEAK MID/UPPER FORCING LIFTING
INTO THE AREA WITH AFOREMENTIONED OK/MO VORT...ALTHOUGH OUTSIDE OF
ANY AREAS OF PREFRONTAL MOISTURE POOLING...LOW LEVELS MAY MIX OUT
ENOUGH TO TEMPER INSTABILITY QUITE A BIT BY LATER THIS AFTERNOON. IF
SCATTERED CONVECTION IS ABLE TO DEVELOP THERE MAY BE TWO PRIMARY
CORRIDORS FOR INITIATION...ONE ALONG ANY WEAK PREFRONTAL CONVERGENCE
ZONE...AND THEN ALONG THE ACTUAL FRONTAL BOUNDARY. SEVERE STORMS ARE
NOT EXPECTED IN TRENDING TOWARD NON-NAM GUIDANCE FOR THERMAL
PROFILES...AND ALSO GIVEN MORE OF THE SUBSTANTIAL DEEP LAYER SHEAR
WILL BE POST-FRONTAL.
SOME ISOLATED CONVECTION MAY LINGER INTO THE EVENING ACROSS
SOUTHEAST HALF OF THE AREA...WITH MAIN STORY THROUGH THE REMAINDER
OF THE NIGHT CENTERING ON THE APPROACH OF A MUCH COOLER AND LESS
HUMID AIR MASS. SOME COLD ADVECTION STRATOCU MAY WORK INTO FAR
NORTHERN LOCATIONS OVERNIGHT...BUT OTHERWISE MOST LOCATIONS WILL
EXPERIENCE CLEARING SKIES IN THE EVENING.
&&
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 358 AM EDT MON MAY 18 2015
TRANQUIL WEATHER ANTICIPATED FOR MUCH OF THIS LONG TERM PERIOD.
SPLIT FLOW OVER WESTERN NOAM WITH A HIGHLY AMPLIFIED AND ENDURING
NORTHERN STREAM PATTERN ACROSS CANADA WILL LEAVE THE GREAT LAKES IN
A REGION OF STRONG CONFLUENCE AND GENERAL SUBSIDENCE FOR MOST OF
THIS WEEK. WILL ALSO BE MUCH COOLER BEHIND TODAY`S COLD FRONT WITH
PERSISTENT N/NW FLOW MAINTAINING AN EFFICIENT FEED OF CANADIAN AIR
INTO OUR REGION. EXPECT TEMPS ROUGHLY 10-15 DEGREES BELOW NORMAL
DURING THE MIDWEEK PERIOD. TUESDAY NIGHT WILL BE THE COLDEST PERIOD
WITH NUMEROUS SOURCES OF RAW AND STATISTICAL GUIDANCE SUGGESTING MID
30S IN OUR NORTHERN COUNTIES...WITH LOWER 40S IN OUR SOUTH. SOME
CONCERN FOR PATCHY FROST...ESPECIALLY IN OUR MICHIGAN COUNTIES AWAY
FROM THE LAKE. HOWEVER...HIGH BASED CLOUDS WILL BE INCREASING BY
WEDNESDAY MORNING AND MODELS SHOW ENOUGH OF A SURFACE PRESSURE
GRADIENT TO KEEP WINDS IN THE 5-10 MPH RANGE. GIVEN THESE CONCERNS
AND MARGINAL TEMPS WILL HOLD OFF ON MENTIONING ANY FROST IN THE
FORECAST AT THIS POINT AND CONTINUE TO MONITOR.
ONE WEAK SOUTHERN STREAM WAVE DOES EJECT OUT OF THE FOUR CORNERS AND
ATTEMPT TO PHASE WITH SUBTLE NORTHERN STREAM VORT MAX AS IT CROSSES
OUR AREA LATE WEDNESDAY. DEGREE OF DRY AND STABLE LOWER LEVELS IS
CONCERNING BUT FAVORABLE 300MB JET PLACEMENT AND SOME MODEST
CVA/HEIGHT FALLS COULD GENERATE A FEW LIGHT RAIN SHOWERS. NO MAJOR
QUALMS WITH INHERITED LOW CHANCE POPS BUT DID ADJUST THE TIMING UP A
LITTLE BIT BASED ON LATEST NAM AND ECMWF SOLUTIONS. NEXT CHANCE OF
RAIN THEREAFTER WILL NOT BE UNTIL SUNDAY WHEN SOUTHWEST FLOW FINALLY
RETURNS AHEAD OF NEXT WESTERN CONUS TROUGH EJECTING NORTHEAST. THIS
PATTERN SHIFT WILL ALSO SIGNAL THE RETURN OF WARMER AND MORE HUMID
CONDITIONS FOR AT LEAST THE LATTER HALF OF THE HOLIDAY WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 122 AM EDT MON MAY 18 2015
MID LEVEL DRY SLOT HAS OVERSPREAD THE AREA WITH THE CHANCES OF
CONVECTION OVERNIGHT HAVING DIMINISHED SIGNIFICANTLY. ANOTHER WEAK
SHORT WAVE KICKING OUT OF SOUTHERN INDIANA MAY ALLOW FOR SOME
SCATTERED SHOWERS TO LIFT BACK INTO NORTHEAST INDIANA THROUGH
EARLY MONDAY MORNING...BUT BETTER CHANCES APPEAR TO BE SOUTHEAST OF
FWA. MVFR CIGS OF 2-3K FT ARE POSSIBLE AT KFWA THROUGH AROUND
12Z...WITH GENERALLY VFR CONDITIONS OTHERWISE. A COLD FRONT
TRACKING ACROSS THE AREA MONDAY AFTERNOON MAY ALLOW FOR ISOLD-SCT
CONVECTION TO DEVELOP BUT INSTABILITY OF ANY CONSEQUENCE SHOULD BE
LIMITED TO A FAIRLY NARROW ZONE ALONG AND IMMEDIATELY AHEAD OF THE
FRONT. WITH OVERALL MID/UPPER FORCING ON THE WEAK SIDE...HAVE
MAINTAINED VCTS MENTION AT KFWA DUE TO LOW CONFIDENCE OF THUNDER
OCCURRENCE AT TERMINALS. SOUTHWEST WINDS IN ADVANCE OF THE FRONT
SHOULD BECOME SOMEWHAT GUSTY INTO THE 18-23 KNOT RANGE THIS
AFTERNOON...WITH WINDS SHIFTING TO THE WEST BEHIND THE FRONT LATE
MONDAY AFTERNOON AT KSBN...AND EARLY MONDAY EVENING AT KFWA.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1013 PM CDT TUE MAY 19 2015
...UPDATE TO SYNOPSIS...
.SYNOPSIS...
ISSUED AT 1012 PM CDT TUE MAY 19 2015
WV IMAGERY AND 00Z UPPER AIR ANALYSIS INDICATE AN UPPER LEVEL
SHORTWAVE LIFTING NORTHEAST ACROSS THE WESTERN HIGH PLAINS. NEAR
THE SURFACE, A COLD FRONT IS PUSHING SLOWLY SOUTHWARD ACROSS THE
TEXAS PANHANDLE AND WESTERN OKLAHOMA.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 215 PM CDT TUE MAY 19 2015
LIGHT TO MODERATE RAIN SHOWERS WILL CONTINUE THIS EVENING AS THE
UPPER LEVEL SHORTWAVE MOVES NORTH OF THE AREA. LIGHT RAIN OR
DRIZZLE WILL BE POSSIBLE AFTER MIDNIGHT, OTHERWISE MOSTLY CLOUDY
SKIES WILL BE SEEN ACROSS WESTERN KANSAS. MOSTLY CLOUDY SKIES WILL
ALSO BE SEEN TOMORROW AS LOWER LEVELS OF THE ATMOSPHERE REMAIN
VERY MOIST. HOWEVER, A FEW BREAKS IN THE CLOUDS WILL BE POSSIBLE
ACROSS FAR SOUTHWESTERN KANSAS AROUND LATE AFTERNOON. HIGH
PRESSURE WILL BUILD INTO THE AREA THIS EVENING INTO TONIGHT
PUSHING A FRONTAL BOUNDARY SOUTHWARD INTO TEXAS. THIS WILL SHIFT
EASTERLY WINDS TO MORE OF A NORTHERLY DIRECTION OVERNIGHT. WINDS
FROM THE NORTHEAST ARE ANTICIPATED TOMORROW AS THE AREA OF HIGH
PRESSURE CONTINUES TO SAG SOUTHWARD. THE ABUNDANT CLOUD COVER WILL
KEEP OVERNIGHT TEMPERATURES UP WITH LOWS RANGING FROM AROUND 40
DEGREES ACROSS WEST CENTRAL KANSAS TO AROUND 50 DEGREES ACROSS
SOUTH CENTRAL KANSAS. CLOUDS WILL ALSO KEEP DAYTIME TEMPERATURES
DOWN WITH HIGHS RANGING FROM THE MID 50S ACROSS WEST CENTRAL
KANSAS TO LOWER 60S ACROSS SOUTH CENTRAL KANSAS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 240 PM CDT TUE MAY 19 2015
THE MAIN CHALLENGE IN THE LONG TERM CONTINUES TO BE TIMING, EXTENT,
AND QUANTITY OF RAINFALL THROUGH THE PERIOD BEYOND THURSDAY. ANOTHER
STORM SYSTEM WITH SUBTROPICAL INFLUENCE WILL ONCE AGAIN APPROACH THE
WESTERN PLAINS WITH THE INITIAL EFFECTS FELT LATE THURSDAY NIGHT AS
A LEAD WAVE FOSTERS PRECIPITATION DEVELOPMENT FROM EASTERN COLORADO
INTO THE TEXAS PANHANDLE...ALONG NEARLY THE SAME ORIENTATION AS
TODAY`S PRECIPITATION EVENT. THE COOL AIRMASS WILL REMAIN IN PLACE,
SO SEVERE WEATHER RISK OVERNIGHT APPEARS TO BE NON-EXISTENT. THIS
WILL LIFT ON NORTHEAST DURING THE DAY FRIDAY, HOWEVER EXTENSIVE
CLOUD COVER WILL REMAIN AS SOUTHEASTERLY WINDS AND RICH MOISTURE
WILL ACTUALLY HELP KEEP TEMPERATURES FAIRLY COOL WITH TRAJECTORIES
RECIRCULATING THE REMNANT CONTINENTAL POLAR AIRMASS. IN FACT, WE MAY
SEE A PROLONGED PERIOD OF VERY LIGHT PRECIPITATION IN THE FORM OF
DRIZZLE MUCH OF THE DAY FRIDAY. TEMPERATURES WILL LIKELY REMAIN IN
THE 50S...AND FUTURE FORECAST UPDATES WILL LIKELY SEE A FURTHER
REDUCTION IN HIGHS.
ON SATURDAY, THE MAIN UPPER LEVEL SYSTEM WILL APPROACH, AND WE WILL
LIKELY SEE EARLY DAY CONVECTION IN THE 850-700MB ZONE OF WARM
ADVECTION/FRONTOGENESIS. THE ECMWF IS STILL THE MODEL OF CHOICE
GIVEN PAST PERFORMANCE IN THIS REGIME WE HAVE BEEN IN OVER THE PAST
COUPLE OF WEEKS. THE LATEST RUN OF THE ECMWF KEEPS TEMPERATURES COOL
ON SATURDAY ACROSS MUCH OF SOUTHWEST KANSAS WITH AFTERNOON
TEMPERATURES IN THE UPPER 50S TO LOWER 60S. THE EXCEPTION WOULD BE
EXTREME SOUTHWEST KANSAS WITH PERHAPS UP TO 70 AT ELKHART. ALL OF
THIS SUGGESTS THAT ANY SURFACE-BASED SEVERE WEATHER THREAT WILL BE
LIMITED ACROSS OUR FORECAST AREA WITH MUCH OF THE ACTIVITY CONFINED
ONCE AGAIN TO PORTIONS OF NORTH/NORTHWEST TEXAS INTO OKLAHOMA. THE
UPPER LEVEL TROUGH WILL MOVE OUT SLOWLY ACROSS THE PLAINS LATE
WEEKEND, SO WE WILL PROBABLY SEE ADDITIONAL CONVECTION ON SUNDAY
ALONG THE TROUGH AXIS WITH YET ANOTHER SMALL SYSTEM SUGGESTED BY THE
ECMWF MOVING ACROSS THE SOUTHERN ROCKIES ON MONDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 604 PM CDT TUE MAY 19 2015
MOISTURE AND LIFT WILL CONTINUE THIS EVENING AHEAD OF AN UPPER
LEVEL DISTURBANCE WHICH WILL CROSS SOUTHWEST KANSAS BETWEEN 00Z
AND 03Z WEDNESDAY. THE STEADIER PRECIPITATION WILL TAPER OFF FROM
SOUTHWEST TO NORTHEAST AND THE SURFACE WINDS WILL BACK TO THE
NORTH/NORTHEAST EARLY TONIGHT AS THIS UPPER LEVEL SYSTEM PASSES.
BUFR SOUNDINGS, RAP, AND HRRR WERE ALL IN GOOD AGREEMENT WITH
KEEPING THE LOWER LEVELS SATURATED AND CEILINGS AT OR BELOW 800FT
AGL THROUGH AT LEAST 15Z WEDNESDAY. DENSE FOG AT THIS TIME DOES
NOT APPEAR TO BE AN ISSUE EARLY WEDNESDAY MORNING BUT VISIBILITIES
AS LOW AS ONE MILE WILL BE POSSIBLE AT TIME BETWEEN 09Z AND 15Z
WEDNESDAY. CEILINGS WILL IMPROVE LATE MORNING AND EARLY AFTERNOON
INTO THE 2000 TO 3000FT AGL LEVEL BASE ON THE NAM, ARW, AND NMM.
SURFACE WINDS WILL BE NORTHEAST AT 10 KNOTS OR LESS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 42 58 42 63 / 70 10 10 10
GCK 41 57 44 63 / 20 10 10 10
EHA 42 59 45 60 / 10 10 20 40
LBL 42 59 44 64 / 30 10 10 30
HYS 41 56 42 63 / 80 20 10 10
P28 50 62 47 66 / 70 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJOHNSON
SHORT TERM...HOVORKA_42
LONG TERM...UMSCHEID
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
606 PM CDT TUE MAY 19 2015
...UPDATED AVIATION DISCUSSION...
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 215 PM CDT TUE MAY 19 2015
LIGHT TO MODERATE RAIN SHOWERS WILL CONTINUE THIS EVENING AS THE
UPPER LEVEL SHORTWAVE MOVES NORTH OF THE AREA. LIGHT RAIN OR
DRIZZLE WILL BE POSSIBLE AFTER MIDNIGHT, OTHERWISE MOSTLY CLOUDY
SKIES WILL BE SEEN ACROSS WESTERN KANSAS. MOSTLY CLOUDY SKIES WILL
ALSO BE SEEN TOMORROW AS LOWER LEVELS OF THE ATMOSPHERE REMAIN
VERY MOIST. HOWEVER, A FEW BREAKS IN THE CLOUDS WILL BE POSSIBLE
ACROSS FAR SOUTHWESTERN KANSAS AROUND LATE AFTERNOON. HIGH
PRESSURE WILL BUILD INTO THE AREA THIS EVENING INTO TONIGHT
PUSHING A FRONTAL BOUNDARY SOUTHWARD INTO TEXAS. THIS WILL SHIFT
EASTERLY WINDS TO MORE OF A NORTHERLY DIRECTION OVERNIGHT. WINDS
FROM THE NORTHEAST ARE ANTICIPATED TOMORROW AS THE AREA OF HIGH
PRESSURE CONTINUES TO SAG SOUTHWARD. THE ABUNDANT CLOUD COVER WILL
KEEP OVERNIGHT TEMPERATURES UP WITH LOWS RANGING FROM AROUND 40
DEGREES ACROSS WEST CENTRAL KANSAS TO AROUND 50 DEGREES ACROSS
SOUTH CENTRAL KANSAS. CLOUDS WILL ALSO KEEP DAYTIME TEMPERATURES
DOWN WITH HIGHS RANGING FROM THE MID 50S ACROSS WEST CENTRAL
KANSAS TO LOWER 60S ACROSS SOUTH CENTRAL KANSAS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 240 PM CDT TUE MAY 19 2015
THE MAIN CHALLENGE IN THE LONG TERM CONTINUES TO BE TIMING, EXTENT,
AND QUANTITY OF RAINFALL THROUGH THE PERIOD BEYOND THURSDAY. ANOTHER
STORM SYSTEM WITH SUBTROPICAL INFLUENCE WILL ONCE AGAIN APPROACH THE
WESTERN PLAINS WITH THE INITIAL EFFECTS FELT LATE THURSDAY NIGHT AS
A LEAD WAVE FOSTERS PRECIPITATION DEVELOPMENT FROM EASTERN COLORADO
INTO THE TEXAS PANHANDLE...ALONG NEARLY THE SAME ORIENTATION AS
TODAY`S PRECIPITATION EVENT. THE COOL AIRMASS WILL REMAIN IN PLACE,
SO SEVERE WEATHER RISK OVERNIGHT APPEARS TO BE NON-EXISTENT. THIS
WILL LIFT ON NORTHEAST DURING THE DAY FRIDAY, HOWEVER EXTENSIVE
CLOUD COVER WILL REMAIN AS SOUTHEASTERLY WINDS AND RICH MOISTURE
WILL ACTUALLY HELP KEEP TEMPERATURES FAIRLY COOL WITH TRAJECTORIES
RECIRCULATING THE REMNANT CONTINENTAL POLAR AIRMASS. IN FACT, WE MAY
SEE A PROLONGED PERIOD OF VERY LIGHT PRECIPITATION IN THE FORM OF
DRIZZLE MUCH OF THE DAY FRIDAY. TEMPERATURES WILL LIKELY REMAIN IN
THE 50S...AND FUTURE FORECAST UPDATES WILL LIKELY SEE A FURTHER
REDUCTION IN HIGHS.
ON SATURDAY, THE MAIN UPPER LEVEL SYSTEM WILL APPROACH, AND WE WILL
LIKELY SEE EARLY DAY CONVECTION IN THE 850-700MB ZONE OF WARM
ADVECTION/FRONTOGENESIS. THE ECMWF IS STILL THE MODEL OF CHOICE
GIVEN PAST PERFORMANCE IN THIS REGIME WE HAVE BEEN IN OVER THE PAST
COUPLE OF WEEKS. THE LATEST RUN OF THE ECMWF KEEPS TEMPERATURES COOL
ON SATURDAY ACROSS MUCH OF SOUTHWEST KANSAS WITH AFTERNOON
TEMPERATURES IN THE UPPER 50S TO LOWER 60S. THE EXCEPTION WOULD BE
EXTREME SOUTHWEST KANSAS WITH PERHAPS UP TO 70 AT ELKHART. ALL OF
THIS SUGGESTS THAT ANY SURFACE-BASED SEVERE WEATHER THREAT WILL BE
LIMITED ACROSS OUR FORECAST AREA WITH MUCH OF THE ACTIVITY CONFINED
ONCE AGAIN TO PORTIONS OF NORTH/NORTHWEST TEXAS INTO OKLAHOMA. THE
UPPER LEVEL TROUGH WILL MOVE OUT SLOWLY ACROSS THE PLAINS LATE
WEEKEND, SO WE WILL PROBABLY SEE ADDITIONAL CONVECTION ON SUNDAY
ALONG THE TROUGH AXIS WITH YET ANOTHER SMALL SYSTEM SUGGESTED BY THE
ECMWF MOVING ACROSS THE SOUTHERN ROCKIES ON MONDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 604 PM CDT TUE MAY 19 2015
MOISTURE AND LIFT WILL CONTINUE THIS EVENING AHEAD OF AN UPPER
LEVEL DISTURBANCE WHICH WILL CROSS SOUTHWEST KANSAS BETWEEN 00Z
AND 03Z WEDNESDAY. THE STEADIER PRECIPITATION WILL TAPER OFF FROM
SOUTHWEST TO NORTHEAST AND THE SURFACE WINDS WILL BACK TO THE
NORTH/NORTHEAST EARLY TONIGHT AS THIS UPPER LEVEL SYSTEM PASSES.
BUFR SOUNDINGS, RAP, AND HRRR WERE ALL IN GOOD AGREEMENT WITH
KEEPING THE LOWER LEVELS SATURATED AND CEILINGS AT OR BELOW 800FT
AGL THROUGH AT LEAST 15Z WEDNESDAY. DENSE FOG AT THIS TIME DOES
NOT APPEAR TO BE AN ISSUE EARLY WEDNESDAY MORNING BUT VISIBILITIESAS
LOW AS ONE MILE WILL BE POSSIBLE AT TIME BETWEEN 09Z AND 15Z
WEDNESDAY. CEILINGS WILL IMPROVE LATE MORNING AND EARLY AFTERNOON
INTO THE 2000 TO 3000FT AGL LEVEL BASE ON THE NAM, ARW, AND NMM.
SURFACE WINDS WILL BE NORTHEAST AT 10 KNOTS OR LESS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 42 58 42 63 / 90 10 10 10
GCK 41 57 44 63 / 90 10 10 10
EHA 42 59 45 60 / 50 10 20 40
LBL 42 59 44 64 / 80 10 10 30
HYS 41 56 42 63 / 100 20 10 10
P28 50 62 47 66 / 90 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...HOVORKA_42
LONG TERM...UMSCHEID
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS JACKSON KY
126 PM EDT MON MAY 18 2015
.UPDATE...
ISSUED AT 938 AM EDT MON MAY 18 2015
JUST MADE SOME ADJUSTMENTS TO THE FORECAST GRIDS THROUGH THE REST
OF THE MORNING. BASED ON CURRENT RADAR IMAGERY...POPS IN OUR
SOUTHWESTERN AND WESTERN COUNTIES NEEDED TO BE INCREASED. WENT
THROUGH AND INCREASED HOURLY POPS OVER THE NEXT 4 HOURS BY 10 TO
15 PERCENT TO ACCOUNT FOR REAL TIME TRENDS. THIS DID NOT CHANGE
THE WORDING IN THE ZONE FORECAST TEXT PRODUCT SO NO UPDATE TO THAT
WAS NECESSARY. IN SUMMARY...THE POP...POP12...AND WEATHER TYPE
GRIDS HAVE ALL BEEN UPDATED.
UPDATE ISSUED AT 709 AM EDT MON MAY 18 2015
A FEW ISOLATED SHOWERS MAINLY ACROSS THE EAST SHOWING UP THIS
MORNING ON WSR-88D RADAR...WITH MORE SHOWERS SLOWLY MOVING EAST
INTO WESTERN PORTIONS OF THE REGION AS WE GO THROUGH THE MORNING.
STORM COVERAGE WILL CONTINUE TO INCREASE THIS AFTERNOON AHEAD OF A
COLD FRONT ACROSS THE UPPER MIDWEST. UPDATED GRIDS WITH LATEST
OBS AND TRENDS. OTHERWISE NO MAJOR CHANGES NEEDED THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON MAY 18 2015
03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER
MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE
CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL
THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT
UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS
CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE
THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY
MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN
KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS
ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED
ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST
FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY.
THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND
17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT
LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN
PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE
ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA
SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE
MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE
THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED
CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE
THIS AFTERNOON.
ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES
OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND
CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID
KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK
THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER
AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY
SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 434 AM EDT MON MAY 18 2015
SURFACE HIGH PRESSURE RIDGING SE FROM THE NORTH CENTRAL CONUS
WILL PROVIDE DRY WEATHER AT THE START OF THE PERIOD. A PIECE OF AN
UPPER LOW CURRENTLY OVER CA WILL MAKE ITS WAY EASTWARD ACROSS THE
CONUS AT MIDWEEK...AND AS ANOTHER UPPER LOW DROPS SE TOWARD NEW
ENGLAND...THE TWO WILL COMBINE TO BRING AN AMPLIFYING TROUGH TO
THE EASTERN CONUS. AS THE WEAK UPPER LEVEL SYSTEM MOVES IN FROM
THE WEST...THE ECMWF IS MORE ACTIVE WITH THE SYSTEM...AND IT SHOWS
A WEAKENING SURFACE LOW ASSOCIATED WITH IT. THIS BRINGS LIGHT
PRECIP TO OUR LOCAL AREA IN THE WEDNESDAY NIGHT/THURSDAY TIME
FRAME. THE GFS IS WEAKER WITH THE SYSTEM AND ONLY BRINGS CLOUDS.
HAVE OPTED TO USE A MINIMAL 20 PERCENT POP AT THIS POINT.
ONCE THIS SYSTEM MOVES TO OUR EAST BY THURSDAY NIGHT...MODELS AGREE
ON A SURFACE HIGH PRESSURE SYSTEM BUILDING IN FROM THE NW WITH A
REINFORCING PUSH OF DRY AIR. THIS SHOULD HOLD INTO THE WEEKEND.
LATE IN THE WEEKEND MOISTURE SHOULD BE ON THE INCREASE AGAIN AS
THE HIGH MOVES OFF THE EAST COAST AND LOW PRESSURE DEVELOPS OVER
THE PLAINS...TURNING OUR LOW LEVEL FLOW TO THE SOUTH. HAVE
INCLUDED LOW POPS ON SUNDAY...BUT THE BETTER CHANCE OF PRECIP WILL
BE TO OUR WEST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 126 PM EDT MON MAY 18 2015
THE PRIMARY FORECAST CONCERN IN THE TAFS WILL BE SHOWER AND
THUNDERSTORM ACTIVITY THAT IS CURRENTLY MOVING ACROSS EASTERN
KENTUCKY. THESE SHOWERS AND STORMS ARE EXPECTED TO BECOME MORE
NUMEROUS AS THE AFTERNOON WEARS ON AS A COLD FRONT APPROACHES FROM
THE WEST. THE STRONGER STORMS WILL BE CAPABLE OF PRODUCING LOCALLY
HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING. VFR CONDITIONS WILL
PREVAIL DURING BREAKS IN THE RAIN. OTHERWISE WE THE TAF SITES
COULD EXPERIENCE MVFR TO IFR CONDITIONS WHEN A STRONG SHOWER OR
ANY THUNDERSTORMS MOVES PAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...DJ
LONG TERM...HAL
AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
938 AM EDT MON MAY 18 2015
.UPDATE...
ISSUED AT 938 AM EDT MON MAY 18 2015
JUST MADE SOME ADJUSTMENTS TO THE FORECAST GRIDS THROUGH THE REST
OF THE MORNING. BASED ON CURRENT RADAR IMAGERY...POPS IN OUR
SOUTHWESTERN AND WESTERN COUNTIES NEEDED TO BE INCREASED. WENT
THROUGH AND INCREASED HOURLY POPS OVER THE NEXT 4 HOURS BY 10 TO
15 PERCENT TO ACCOUNT FOR REAL TIME TRENDS. THIS DID NOT CHANGE
THE WORDING IN THE ZONE FORECAST TEXT PRODUCT SO NO UPDATE TO THAT
WAS NECESSARY. IN SUMMARY...THE POP...POP12...AND WEATHER TYPE
GRIDS HAVE ALL BEEN UPDATED.
UPDATE ISSUED AT 709 AM EDT MON MAY 18 2015
A FEW ISOLATED SHOWERS MAINLY ACROSS THE EAST SHOWING UP THIS
MORNING ON WSR-88D RADAR...WITH MORE SHOWERS SLOWLY MOVING EAST
INTO WESTERN PORTIONS OF THE REGION AS WE GO THROUGH THE MORNING.
STORM COVERAGE WILL CONTINUE TO INCREASE THIS AFTERNOON AHEAD OF A
COLD FRONT ACROSS THE UPPER MIDWEST. UPDATED GRIDS WITH LATEST
OBS AND TRENDS. OTHERWISE NO MAJOR CHANGES NEEDED THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON MAY 18 2015
03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER
MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE
CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL
THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT
UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS
CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE
THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY
MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN
KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS
ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED
ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST
FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY.
THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND
17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT
LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN
PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE
ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA
SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE
MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE
THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED
CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE
THIS AFTERNOON.
ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES
OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND
CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID
KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK
THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER
AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY
SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 434 AM EDT MON MAY 18 2015
SURFACE HIGH PRESSURE RIDGING SE FROM THE NORTH CENTRAL CONUS
WILL PROVIDE DRY WEATHER AT THE START OF THE PERIOD. A PIECE OF AN
UPPER LOW CURRENTLY OVER CA WILL MAKE ITS WAY EASTWARD ACROSS THE
CONUS AT MIDWEEK...AND AS ANOTHER UPPER LOW DROPS SE TOWARD NEW
ENGLAND...THE TWO WILL COMBINE TO BRING AN AMPLIFYING TROUGH TO
THE EASTERN CONUS. AS THE WEAK UPPER LEVEL SYSTEM MOVES IN FROM
THE WEST...THE ECMWF IS MORE ACTIVE WITH THE SYSTEM...AND IT SHOWS
A WEAKENING SURFACE LOW ASSOCIATED WITH IT. THIS BRINGS LIGHT
PRECIP TO OUR LOCAL AREA IN THE WEDNESDAY NIGHT/THURSDAY TIME
FRAME. THE GFS IS WEAKER WITH THE SYSTEM AND ONLY BRINGS CLOUDS.
HAVE OPTED TO USE A MINIMAL 20 PERCENT POP AT THIS POINT.
ONCE THIS SYSTEM MOVES TO OUR EAST BY THURSDAY NIGHT...MODELS AGREE
ON A SURFACE HIGH PRESSURE SYSTEM BUILDING IN FROM THE NW WITH A
REINFORCING PUSH OF DRY AIR. THIS SHOULD HOLD INTO THE WEEKEND.
LATE IN THE WEEKEND MOISTURE SHOULD BE ON THE INCREASE AGAIN AS
THE HIGH MOVES OFF THE EAST COAST AND LOW PRESSURE DEVELOPS OVER
THE PLAINS...TURNING OUR LOW LEVEL FLOW TO THE SOUTH. HAVE
INCLUDED LOW POPS ON SUNDAY...BUT THE BETTER CHANCE OF PRECIP WILL
BE TO OUR WEST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 657 AM EDT MON MAY 18 2015
FOG DEVELOPMENT WAS WEAKENED BY THE CLOUDS THAT CONTINUED TO BUILD
ACROSS THE REGION OVERNIGHT INTO THIS MORNING. PATCHY FOG WILL BE
POSSIBLE ACROSS RIVER VALLEYS AND THOSE AREAS THAT RECEIVED RAIN.
A FEW ISOLATED SHOWERS CONTINUE TO POP UP ACROSS PORTIONS OF THE
REGION THIS MORNING AND HAVE INCLUDED VCSH AT A FEW SITES TO
START...BUT ADD TO ALL SITES AS WE MOVE THROUGH THE MORNING.
OTHERWISE BIGGEST ISSUE TODAY WILL BE SHOWERS AND THUNDERSTORMS
DEVELOPING ACROSS EASTERN KENTUCKY THIS AFTERNOON. THE BEST
COVERAGE WILL BE IN THE AFTERNOON WITH DAYTIME HEATING. THEREFORE
DID OPT TO ADD A TEMPO GROUP WITH MVFR VIS TO THE TAF SITES
GENERALLY BETWEEN 18Z AND 19Z. OTHERWISE THINK SITES WILL
GENERALLY KEEP VFR CONDITIONS FOR MUCH OF THE TAF PERIOD. KEPT
WINDS LIGHT TIL THIS AFTERNOON WITH SITES POSSIBLY SEEING GUSTS UP
TO 15 KTS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...DJ
LONG TERM...HAL
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
709 AM EDT MON MAY 18 2015
.UPDATE...
ISSUED AT 709 AM EDT MON MAY 18 2015
A FEW ISOLATED SHOWERS MAINLY ACROSS THE EAST SHOWING UP THIS
MORNING ON WSR-88D RADAR...WITH MORE SHOWERS SLOWLY MOVING EAST
INTO WESTERN PORTIONS OF THE REGION AS WE GO THROUGH THE MORNING.
STORM COVERAGE WILL CONTINUE TO INCREASE THIS AFTERNOON AHEAD OF A
COLD FRONT ACROSS THE UPPER MIDWEST. UPDATED GRIDS WITH LATEST
OBS AND TRENDS. OTHERWISE NO MAJOR CHANGES NEEDED THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON MAY 18 2015
03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER
MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE
CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL
THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT
UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS
CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE
THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY
MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN
KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS
ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED
ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST
FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY.
THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND
17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT
LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN
PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE
ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA
SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE
MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE
THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED
CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE
THIS AFTERNOON.
ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES
OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND
CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID
KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK
THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER
AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY
SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 434 AM EDT MON MAY 18 2015
SURFACE HIGH PRESSURE RIDGING SE FROM THE NORTH CENTRAL CONUS
WILL PROVIDE DRY WEATHER AT THE START OF THE PERIOD. A PIECE OF AN
UPPER LOW CURRENTLY OVER CA WILL MAKE ITS WAY EASTWARD ACROSS THE
CONUS AT MIDWEEK...AND AS ANOTHER UPPER LOW DROPS SE TOWARD NEW
ENGLAND...THE TWO WILL COMBINE TO BRING AN AMPLIFYING TROUGH TO
THE EASTERN CONUS. AS THE WEAK UPPER LEVEL SYSTEM MOVES IN FROM
THE WEST...THE ECMWF IS MORE ACTIVE WITH THE SYSTEM...AND IT SHOWS
A WEAKENING SURFACE LOW ASSOCIATED WITH IT. THIS BRINGS LIGHT
PRECIP TO OUR LOCAL AREA IN THE WEDNESDAY NIGHT/THURSDAY TIME
FRAME. THE GFS IS WEAKER WITH THE SYSTEM AND ONLY BRINGS CLOUDS.
HAVE OPTED TO USE A MINIMAL 20 PERCENT POP AT THIS POINT.
ONCE THIS SYSTEM MOVES TO OUR EAST BY THURSDAY NIGHT...MODELS AGREE
ON A SURFACE HIGH PRESSURE SYSTEM BUILDING IN FROM THE NW WITH A
REINFORCING PUSH OF DRY AIR. THIS SHOULD HOLD INTO THE WEEKEND.
LATE IN THE WEEKEND MOISTURE SHOULD BE ON THE INCREASE AGAIN AS
THE HIGH MOVES OFF THE EAST COAST AND LOW PRESSURE DEVELOPS OVER
THE PLAINS...TURNING OUR LOW LEVEL FLOW TO THE SOUTH. HAVE
INCLUDED LOW POPS ON SUNDAY...BUT THE BETTER CHANCE OF PRECIP WILL
BE TO OUR WEST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 657 AM EDT MON MAY 18 2015
FOG DEVELOPMENT WAS WEAKENED BY THE CLOUDS THAT CONTINUED TO BUILD
ACROSS THE REGION OVERNIGHT INTO THIS MORNING. PATCHY FOG WILL BE
POSSIBLE ACROSS RIVER VALLEYS AND THOSE AREAS THAT RECEIVED RAIN.
A FEW ISOLATED SHOWERS CONTINUE TO POP UP ACROSS PORTIONS OF THE
REGION THIS MORNING AND HAVE INCLUDED VCSH AT A FEW SITES TO
START...BUT ADD TO ALL SITES AS WE MOVE THROUGH THE MORNING.
OTHERWISE BIGGEST ISSUE TODAY WILL BE SHOWERS AND THUNDERSTORMS
DEVELOPING ACROSS EASTERN KENTUCKY THIS AFTERNOON. THE BEST
COVERAGE WILL BE IN THE AFTERNOON WITH DAYTIME HEATING. THEREFORE
DID OPT TO ADD A TEMPO GROUP WITH MVFR VIS TO THE TAF SITES
GENERALLY BETWEEN 18Z AND 19Z. OTHERWISE THINK SITES WILL
GENERALLY KEEP VFR CONDITIONS FOR MUCH OF THE TAF PERIOD. KEPT
WINDS LIGHT TIL THIS AFTERNOON WITH SITES POSSIBLY SEEING GUSTS UP
TO 15 KTS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...DJ
LONG TERM...HAL
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
657 AM EDT MON MAY 18 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON MAY 18 2015
03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER
MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE
CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL
THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT
UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS
CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE
THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY
MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN
KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS
ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED
ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST
FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY.
THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND
17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT
LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN
PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE
ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA
SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE
MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE
THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED
CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE
THIS AFTERNOON.
ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES
OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND
CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID
KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK
THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER
AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY
SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 434 AM EDT MON MAY 18 2015
SURFACE HIGH PRESSURE RIDGING SE FROM THE NORTH CENTRAL CONUS
WILL PROVIDE DRY WEATHER AT THE START OF THE PERIOD. A PIECE OF AN
UPPER LOW CURRENTLY OVER CA WILL MAKE ITS WAY EASTWARD ACROSS THE
CONUS AT MIDWEEK...AND AS ANOTHER UPPER LOW DROPS SE TOWARD NEW
ENGLAND...THE TWO WILL COMBINE TO BRING AN AMPLIFYING TROUGH TO
THE EASTERN CONUS. AS THE WEAK UPPER LEVEL SYSTEM MOVES IN FROM
THE WEST...THE ECMWF IS MORE ACTIVE WITH THE SYSTEM...AND IT SHOWS
A WEAKENING SURFACE LOW ASSOCIATED WITH IT. THIS BRINGS LIGHT
PRECIP TO OUR LOCAL AREA IN THE WEDNESDAY NIGHT/THURSDAY TIME
FRAME. THE GFS IS WEAKER WITH THE SYSTEM AND ONLY BRINGS CLOUDS.
HAVE OPTED TO USE A MINIMAL 20 PERCENT POP AT THIS POINT.
ONCE THIS SYSTEM MOVES TO OUR EAST BY THURSDAY NIGHT...MODELS AGREE
ON A SURFACE HIGH PRESSURE SYSTEM BUILDING IN FROM THE NW WITH A
REINFORCING PUSH OF DRY AIR. THIS SHOULD HOLD INTO THE WEEKEND.
LATE IN THE WEEKEND MOISTURE SHOULD BE ON THE INCREASE AGAIN AS
THE HIGH MOVES OFF THE EAST COAST AND LOW PRESSURE DEVELOPS OVER
THE PLAINS...TURNING OUR LOW LEVEL FLOW TO THE SOUTH. HAVE
INCLUDED LOW POPS ON SUNDAY...BUT THE BETTER CHANCE OF PRECIP WILL
BE TO OUR WEST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 657 AM EDT MON MAY 18 2015
FOG DEVELOPMENT WAS WEAKENED BY THE CLOUDS THAT CONTINUED TO BUILD
ACROSS THE REGION OVERNIGHT INTO THIS MORNING. PATCHY FOG WILL BE
POSSIBLE ACROSS RIVER VALLEYS AND THOSE AREAS THAT RECEIVED RAIN.
A FEW ISOLATED SHOWERS CONTINUE TO POP UP ACROSS PORTIONS OF THE
REGION THIS MORNING AND HAVE INCLUDED VCSH AT A FEW SITES TO
START...BUT ADD TO ALL SITES AS WE MOVE THROUGH THE MORNING.
OTHERWISE BIGGEST ISSUE TODAY WILL BE SHOWERS AND THUNDERSTORMS
DEVELOPING ACROSS EASTERN KENTUCKY THIS AFTERNOON. THE BEST
COVERAGE WILL BE IN THE AFTERNOON WITH DAYTIME HEATING. THEREFORE
DID OPT TO ADD A TEMPO GROUP WITH MVFR VIS TO THE TAF SITES
GENERALLY BETWEEN 18Z AND 19Z. OTHERWISE THINK SITES WILL
GENERALLY KEEP VFR CONDITIONS FOR MUCH OF THE TAF PERIOD. KEPT
WINDS LIGHT TIL THIS AFTERNOON WITH SITES POSSIBLY SEEING GUSTS UP
TO 15 KTS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DJ
LONG TERM...HAL
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
434 AM EDT MON MAY 18 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON MAY 18 2015
03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER
MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE
CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL
THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT
UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS
CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE
THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY
MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN
KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS
ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED
ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST
FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY.
THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND
17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT
LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN
PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE
ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA
SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE
MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE
THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED
CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE
THIS AFTERNOON.
ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES
OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND
CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID
KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK
THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER
AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY
SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 434 AM EDT MON MAY 18 2015
SURFACE HIGH PRESSURE RIDGING SE FROM THE NORTH CENTRAL CONUS
WILL PROVIDE DRY WEATHER AT THE START OF THE PERIOD. A PIECE OF AN
UPPER LOW CURRENTLY OVER CA WILL MAKE ITS WAY EASTWARD ACROSS THE
CONUS AT MIDWEEK...AND AS ANOTHER UPPER LOW DROPS SE TOWARD NEW
ENGLAND...THE TWO WILL COMBINE TO BRING AN AMPLIFYING TROUGH TO
THE EASTERN CONUS. AS THE WEAK UPPER LEVEL SYSTEM MOVES IN FROM
THE WEST...THE ECMWF IS MORE ACTIVE WITH THE SYSTEM...AND IT SHOWS
A WEAKENING SURFACE LOW ASSOCIATED WITH IT. THIS BRINGS LIGHT
PRECIP TO OUR LOCAL AREA IN THE WEDNESDAY NIGHT/THURSDAY TIME
FRAME. THE GFS IS WEAKER WITH THE SYSTEM AND ONLY BRINGS CLOUDS.
HAVE OPTED TO USE A MINIMAL 20 PERCENT POP AT THIS POINT.
ONCE THIS SYSTEM MOVES TO OUR EAST BY THURSDAY NIGHT...MODELS AGREE
ON A SURFACE HIGH PRESSURE SYSTEM BUILDING IN FROM THE NW WITH A
REINFORCING PUSH OF DRY AIR. THIS SHOULD HOLD INTO THE WEEKEND.
LATE IN THE WEEKEND MOISTURE SHOULD BE ON THE INCREASE AGAIN AS
THE HIGH MOVES OFF THE EAST COAST AND LOW PRESSURE DEVELOPS OVER
THE PLAINS...TURNING OUR LOW LEVEL FLOW TO THE SOUTH. HAVE
INCLUDED LOW POPS ON SUNDAY...BUT THE BETTER CHANCE OF PRECIP WILL
BE TO OUR WEST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 135 AM EDT MON MAY 18 2015
TAFS TONIGHT WILL START OFF VFR WITH SOME MVFR POSSIBLE OVERNIGHT
AND EARLY TUESDAY MORNING. THE MVFR WILL BE WITH FOG POTENTIAL AND
DID STAY CLOSE TO PREVIOUS TAF AT THIS TIME. THE UNCERTAINTY WITH
THIS REMAINS TO SEE HOW CLOUDS COULD WANE THE DEVELOPMENT. THE
FOG WILL HAVE THE BEST POTENTIAL IN THE RIVER VALLEYS AND
LOCATIONS THAT RECEIVED RAIN TODAY. SOME SHOWERS AND
THUNDERSTORMS SOUTH ACROSS THE TN VALLEY ARE EXPECTED TO
WEAKEN...HOWEVER HRRR DOES HOLD ONTO AT LEAST SOME RAIN SHOWERS BY
EARLY MORNING. THEREFORE DID KEEP THE VCSH CLOSE TO 12Z AND SEEMS
REASONABLE WHEN TIMING THE CURRENT PROGRESSION OF THE AREA OF
SHOWERS. WHILE THE RIDGE DOES BEGIN TO BREAKDOWN TOMORROW THINK
FORECAST WILL STAY PRETTY CLOSE TO THE SAME WITH
DIURNALLY/AFTERNOON DRIVEN THUNDERSTORMS. DID OPT TO KEEP THE VCTS
IN THERE FOR EARLY AFTERNOON...BUT DID ADJUST TIMING UP SLIGHTLY.
WINDS ARE EXPECTED TO BE LIGHT TONIGHT...BUT DID BRING WINDS UP
TOMORROW AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DJ
LONG TERM...HAL
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
350 AM EDT MON MAY 18 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON MAY 18 2015
03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER
MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE
CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL
THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT
UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS
CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE
THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY
MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN
KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS
ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED
ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST
FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY.
THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND
17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT
LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN
PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE
ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA
SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE
MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE
THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED
CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE
THIS AFTERNOON.
ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES
OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND
CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID
KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK
THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER
AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY
SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 350 AM EDT MON MAY 18 2015
LONG TERM DISCUSSION WILL BE ISSUES SHORTLY...
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 135 AM EDT MON MAY 18 2015
TAFS TONIGHT WILL START OFF VFR WITH SOME MVFR POSSIBLE OVERNIGHT
AND EARLY TUESDAY MORNING. THE MVFR WILL BE WITH FOG POTENTIAL AND
DID STAY CLOSE TO PREVIOUS TAF AT THIS TIME. THE UNCERTAINTY WITH
THIS REMAINS TO SEE HOW CLOUDS COULD WANE THE DEVELOPMENT. THE
FOG WILL HAVE THE BEST POTENTIAL IN THE RIVER VALLEYS AND
LOCATIONS THAT RECEIVED RAIN TODAY. SOME SHOWERS AND
THUNDERSTORMS SOUTH ACROSS THE TN VALLEY ARE EXPECTED TO
WEAKEN...HOWEVER HRRR DOES HOLD ONTO AT LEAST SOME RAIN SHOWERS BY
EARLY MORNING. THEREFORE DID KEEP THE VCSH CLOSE TO 12Z AND SEEMS
REASONABLE WHEN TIMING THE CURRENT PROGRESSION OF THE AREA OF
SHOWERS. WHILE THE RIDGE DOES BEGIN TO BREAKDOWN TOMORROW THINK
FORECAST WILL STAY PRETTY CLOSE TO THE SAME WITH
DIURNALLY/AFTERNOON DRIVEN THUNDERSTORMS. DID OPT TO KEEP THE VCTS
IN THERE FOR EARLY AFTERNOON...BUT DID ADJUST TIMING UP SLIGHTLY.
WINDS ARE EXPECTED TO BE LIGHT TONIGHT...BUT DID BRING WINDS UP
TOMORROW AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DJ
LONG TERM...HAL
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
145 AM EDT MON MAY 18 2015
.UPDATE...
ISSUED AT 145 AM EDT MON MAY 18 2015
AREA OF SHOWERS MOVING SLOWLY EAST ALONG THE TN/KY BORDER
CONTINUE TO DIMINISH AT THIS LATE NIGHT HOUR. THIS WEAKENING TREND
IS EXPECTED TO CONTINUE AND DID UPDATE POP GRIDS TO REFLECT THIS
THOUGHT. THERE IS STILL SOME QUESTION AS TO HOW MUCH FOG WE WILL
SEE WITH SOME AREAS ABLE TO CLEAR OUT...WHILE OTHERS MAY SEE
LITTLE CLEARING. RIGHT NOW THINK THE BEST CHANCES WILL BE ALONG
RIVER VALLEYS AND AREAS THAT RECEIVED RAIN EARLY TODAY AND
TONIGHT. UPDATED GRIDS WITH LATEST OBS AND TRENDS WITH NO MAJOR
CHANGES NEEDED AT THIS POINT.
UPDATE ISSUED AT 1030 PM EDT SUN MAY 17 2015
THE EARLIER CLUSTER OF STORMS FELL APART AS THEY ENCOUNTERED CELLS
RUNNING OUT AHEAD OF THEIR LINE AND IN THE FACE OF A WEAKENING
COLD POOL. ACCORDINGLY...HAVE UPDATED THE FORECAST TO LOWER POPS
THROUGH THE REST OF THE NIGHT AND FINE TUNE SKY COVER. ALSO
ADJUSTED THE T AND TD GRIDS TO REFLECT THE LATEST SHORTBLEND
GUIDANCE...OBS...AND TRENDS. THESE UPDATED GRIDS HAVE BEEN SENT
TO THE NDFD AND WEB SERVERS. FRESHENED ZONES HAVE ALSO BEEN
ISSUED.
UPDATE ISSUED AT 730 PM EDT SUN MAY 17 2015
23Z SFC ANALYSIS SHOWS A FAIRLY TIGHT GRADIENT OVER THE AREA
BETWEEN HIGH PRESSURE TO THE SOUTHEAST AND BROAD LOW PRESSURE TO
THE NORTHWEST. THE DIURNAL CYCLE BROUGHT ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS TO EAST KENTUCKY THAT HAVE NOW WANED. HOWEVER...
AN ARC OF MORE ORGANIZED STORMS IS NOW MOVING EAST THROUGH CENTRAL
KENTUCKY. THIS AREA HAS DEVELOPED A COLD POOL AND THIS SHOULD
HELP IT HOLD TOGETHER AS IT APPROACHES THE SOUTHWEST PARTS OF THE
CWA OVER THE NEXT COUPLE OF HOURS. A FEW STORMS HAVE POPPED UP
AHEAD OF THESE AND MAY HELP TO BREAK UP THE LINE OR LOCALLY
ENHANCE IT. THE NEAR TERM MODELS HAVE NOT CAPTURED THIS MESOSCALE
FEATURE WELL AND FOR THE MOST PART DAMPEN IT OUT FAR TOO QUICK.
FOR OUR FORECAST...HAVE BEEFED UP POPS ALONG THIS LINE OF
STORMS...AND THE COLD POOL SHOWERS BEHIND IT...AS IT TRACKS
THROUGH THE CWA BETWEEN NOW AND 04Z. THIS ENTAILED HIGHER QPF AS
WELL AS GUSTIER WINDS AMID THE PASSAGE. LATER AS THE CLOUDS START
TO BREAK UP IN THE WAKE OF THE STORMS AND STRATIFORM RAIN...EXPECT
PATCHY FOG TO DEVELOP AND LINGER THROUGH DAWN...MAINLY IN THE
VALLEYS. THE WHOLE FORECAST HAS BEEN UPDATED FOR THE NIGHT ALSO
INCORPORATING THE LATEST SHORTBLEND GUIDANCE...OBS...AND TRENDS.
THESE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
ADDITIONALLY...A NEW SET OF ZONES IS FORTHCOMING.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EDT SUN MAY 17 2015
THE HRRR MODEL HAS HAD THE BEST HANDLE ON THIS AFTERNOONS SHOWER
AND STORM ACTIVITY...WITH THE BULK OF CURRENT ACTIVITY OCCURRING
IN OUR FAR WESTERN COUNTIES. THE NAM12 HAS BEEN KEEPING CONVECTIVE
ACTIVITY MOST EXTENSIVE ACROSS OUR FAR EASTERN COUNTIES...WHICH IS
THE OPPOSITE OF WHAT IS ACTUALLY HAPPENING. THEREFORE...THE HRRR
SOLUTION WAS USED TO COMPOSE THE FIRST 12 HOURS OF THE SHORT TERM
FORECAST...AFTER 12Z...THE CONSALL SOLUTION WAS USED FOR THE
FORECAST. MORE SHOWERS AND STORMS WILL CONTINUE TO FORM WEST AND
SOUTHWEST OF THE AREA THROUGH THIS EVENING...AND THIS ACTIVITY
WILL SLOWLY MOVE WESTWARD INTO AND ACROSS EASTERN KENTUCKY THROUGH
0Z OR SO. AFTER THAT...ONCE THE SUN IS DOWN AND LOSS OF HEATING
OCCURS...THE SHOWERS AND STORMS WILL DROP OFF IN COVERAGE PRETTY
QUICKLY. AFTER HIGH RAIN CHANCES THIS AFTERNOON AND EVENING...THE
OVERNIGHT HOURS ARE FORECAST TO SEE ONLY ISOLATED SHOWERS AND
STORMS. SHOWERS AND STORMS WILL BE ON THE INCREASE AGAIN ON
MONDAY...BEGINNING IN THE LATE MORNING HOURS...AS A COLD FRONT
SLOWLY APPROACHES FROM THE WEST. THE PEAK OF ACTIVITY LOOKS TO BE
DURING THE AFTERNOON AND EVENING HOURS ONCE AGAIN...DURING PEAK
HEATING AND FRONTAL PASSAGE. SOME OF THE STRONGER STORMS COULD
PRODUCE LOCALLY HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING.
TEMPERATURES DURING THE SHORT TERM ARE STILL ON TRACK TO RUN WELL
ABOVE NORMAL FOR THIS TIME OF YEAR...REMAINING IN STEP WITH
CURRENT TRENDS AND A PERSISTENT SOUTHERLY FLOW PATTERN THAT HAS
BEEN CONSISTENTLY PUMPING WARM MOIST AIR OFF THE GULF OF MEXICO
INTO THE REGION. HIGHS ON MONDAY ARE STILL EXPECTED TO TOP OUT IN
THE LOWER 80S ACROSS THE AREA...WITH OVERNIGHT LOWS TONIGHT AND
TOMORROW NIGHT ONLY FALLING INTO THE LOW TO MID 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 300 PM EDT SUN MAY 17 2015
MODELS APPEAR TO BE IN GOOD AGREEMENT WITH THE MID AND UPPER LEVEL
PATTERN OVER OUR REGION...BUT DIFFER MORE ON DETAILS OF SENSIBLE
WEATHER WITH A SHORTWAVE DISTURBANCE LATE WEDNESDAY OR WEDNESDAY
NIGHT INTO EARLY THURSDAY.
IN GENERAL ZONAL FLOW WILL DOMINATE THE PATTERN UNTIL THE LAST 48
HOURS OF THE EXTENDED WHERE SHORT WAVE RIDGING WILL BUILD INTO AND
ACROSS THE OHIO VALLEY IN RESPONSE TO EASTWARD MOVEMENT OF WEST
COAST CUT OFF LOW. AT THE SURFACE A COOL CANADIAN AIR MASS...HIGH
PRESSURE SYSTEM WILL SETTLE DOWN INTO THE HEART OF THE CONUS BEHIND
AN EXITING COLD FRONT...NOSING ITS WAY INTO THE OHIO VALLEY. AS A
RESULT WE CAN EXPECT DRY...PLEASANTLY COOL WEATHER FOR THE START OF
THE EXTENDED. ALOFT...THE AFOREMENTIONED DISTURBANCE WILL ROUND A
DEEP HUDSON BAY LOW WEDNESDAY NIGHT. WE APPEAR TO RECEIVE A GLANCING
BLOW FROM THIS FEATURE AS IT TRACKS THROUGH THE GREAT LAKES REGION.
A SECOND LESS IMPRESSIVE DISTURBANCE BRUSHES THE OHIO VALLEY BY LATE
IN THE WEEK...DY6 FRI.
THE MAIN FORECAST CHALLENGE IN THE EXTENDED WILL BE THE SHORT WAVE
DISTURBANCE MOVING THROUGH THE AREA WEDNESDAY NIGHT INTO EARLY
THURSDAY. THE 0Z AND 12Z ECMWF PRODUCE CONSIDERABLY MORE SENSIBLE
WEATHER WITH THIS FEATURE THAN EITHER THE 0Z OR 12Z GFS. NOT SEEING
MUCH IN THE WAY OF TRENDS TO HELP WITH PREFERENCE OF SOLUTIONS.
THEREFORE RELIED STRONGLY ON MODEL BLENDS CONSIDERING THE MURKY
DETAILS WITH SENSIBLE WEATHER. INCREASING HEIGHTS THROUGH THE END OF
THE EXTENDED WILL MEAN A GRADUAL RISE IN TEMPS...INTO THE 80S BY THE
END OF THE FORECAST WINDOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 135 AM EDT MON MAY 18 2015
TAFS TONIGHT WILL START OFF VFR WITH SOME MVFR POSSIBLE OVERNIGHT
AND EARLY TUESDAY MORNING. THE MVFR WILL BE WITH FOG POTENTIAL AND
DID STAY CLOSE TO PREVIOUS TAF AT THIS TIME. THE UNCERTAINTY WITH
THIS REMAINS TO SEE HOW CLOUDS COULD WANE THE DEVELOPMENT. THE
FOG WILL HAVE THE BEST POTENTIAL IN THE RIVER VALLEYS AND
LOCATIONS THAT RECEIVED RAIN TODAY. SOME SHOWERS AND
THUNDERSTORMS SOUTH ACROSS THE TN VALLEY ARE EXPECTED TO
WEAKEN...HOWEVER HRRR DOES HOLD ONTO AT LEAST SOME RAIN SHOWERS BY
EARLY MORNING. THEREFORE DID KEEP THE VCSH CLOSE TO 12Z AND SEEMS
REASONABLE WHEN TIMING THE CURRENT PROGRESSION OF THE AREA OF
SHOWERS. WHILE THE RIDGE DOES BEGIN TO BREAKDOWN TOMORROW THINK
FORECAST WILL STAY PRETTY CLOSE TO THE SAME WITH
DIURNALLY/AFTERNOON DRIVEN THUNDERSTORMS. DID OPT TO KEEP THE VCTS
IN THERE FOR EARLY AFTERNOON...BUT DID ADJUST TIMING UP SLIGHTLY.
WINDS ARE EXPECTED TO BE LIGHT TONIGHT...BUT DID BRING WINDS UP
TOMORROW AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...AR
LONG TERM...AR
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
135 AM EDT MON MAY 18 2015
.UPDATE...
ISSUED AT 1030 PM EDT SUN MAY 17 2015
THE EARLIER CLUSTER OF STORMS FELL APART AS THEY ENCOUNTERED CELLS
RUNNING OUT AHEAD OF THEIR LINE AND IN THE FACE OF A WEAKENING
COLD POOL. ACCORDINGLY...HAVE UPDATED THE FORECAST TO LOWER POPS
THROUGH THE REST OF THE NIGHT AND FINE TUNE SKY COVER. ALSO
ADJUSTED THE T AND TD GRIDS TO REFLECT THE LATEST SHORTBLEND
GUIDANCE...OBS...AND TRENDS. THESE UPDATED GRIDS HAVE BEEN SENT
TO THE NDFD AND WEB SERVERS. FRESHENED ZONES HAVE ALSO BEEN
ISSUED.
UPDATE ISSUED AT 730 PM EDT SUN MAY 17 2015
23Z SFC ANALYSIS SHOWS A FAIRLY TIGHT GRADIENT OVER THE AREA
BETWEEN HIGH PRESSURE TO THE SOUTHEAST AND BROAD LOW PRESSURE TO
THE NORTHWEST. THE DIURNAL CYCLE BROUGHT ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS TO EAST KENTUCKY THAT HAVE NOW WANED. HOWEVER...
AN ARC OF MORE ORGANIZED STORMS IS NOW MOVING EAST THROUGH CENTRAL
KENTUCKY. THIS AREA HAS DEVELOPED A COLD POOL AND THIS SHOULD
HELP IT HOLD TOGETHER AS IT APPROACHES THE SOUTHWEST PARTS OF THE
CWA OVER THE NEXT COUPLE OF HOURS. A FEW STORMS HAVE POPPED UP
AHEAD OF THESE AND MAY HELP TO BREAK UP THE LINE OR LOCALLY
ENHANCE IT. THE NEAR TERM MODELS HAVE NOT CAPTURED THIS MESOSCALE
FEATURE WELL AND FOR THE MOST PART DAMPEN IT OUT FAR TOO QUICK.
FOR OUR FORECAST...HAVE BEEFED UP POPS ALONG THIS LINE OF
STORMS...AND THE COLD POOL SHOWERS BEHIND IT...AS IT TRACKS
THROUGH THE CWA BETWEEN NOW AND 04Z. THIS ENTAILED HIGHER QPF AS
WELL AS GUSTIER WINDS AMID THE PASSAGE. LATER AS THE CLOUDS START
TO BREAK UP IN THE WAKE OF THE STORMS AND STRATIFORM RAIN...EXPECT
PATCHY FOG TO DEVELOP AND LINGER THROUGH DAWN...MAINLY IN THE
VALLEYS. THE WHOLE FORECAST HAS BEEN UPDATED FOR THE NIGHT ALSO
INCORPORATING THE LATEST SHORTBLEND GUIDANCE...OBS...AND TRENDS.
THESE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
ADDITIONALLY...A NEW SET OF ZONES IS FORTHCOMING.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EDT SUN MAY 17 2015
THE HRRR MODEL HAS HAD THE BEST HANDLE ON THIS AFTERNOONS SHOWER
AND STORM ACTIVITY...WITH THE BULK OF CURRENT ACTIVITY OCCURRING
IN OUR FAR WESTERN COUNTIES. THE NAM12 HAS BEEN KEEPING CONVECTIVE
ACTIVITY MOST EXTENSIVE ACROSS OUR FAR EASTERN COUNTIES...WHICH IS
THE OPPOSITE OF WHAT IS ACTUALLY HAPPENING. THEREFORE...THE HRRR
SOLUTION WAS USED TO COMPOSE THE FIRST 12 HOURS OF THE SHORT TERM
FORECAST...AFTER 12Z...THE CONSALL SOLUTION WAS USED FOR THE
FORECAST. MORE SHOWERS AND STORMS WILL CONTINUE TO FORM WEST AND
SOUTHWEST OF THE AREA THROUGH THIS EVENING...AND THIS ACTIVITY
WILL SLOWLY MOVE WESTWARD INTO AND ACROSS EASTERN KENTUCKY THROUGH
0Z OR SO. AFTER THAT...ONCE THE SUN IS DOWN AND LOSS OF HEATING
OCCURS...THE SHOWERS AND STORMS WILL DROP OFF IN COVERAGE PRETTY
QUICKLY. AFTER HIGH RAIN CHANCES THIS AFTERNOON AND EVENING...THE
OVERNIGHT HOURS ARE FORECAST TO SEE ONLY ISOLATED SHOWERS AND
STORMS. SHOWERS AND STORMS WILL BE ON THE INCREASE AGAIN ON
MONDAY...BEGINNING IN THE LATE MORNING HOURS...AS A COLD FRONT
SLOWLY APPROACHES FROM THE WEST. THE PEAK OF ACTIVITY LOOKS TO BE
DURING THE AFTERNOON AND EVENING HOURS ONCE AGAIN...DURING PEAK
HEATING AND FRONTAL PASSAGE. SOME OF THE STRONGER STORMS COULD
PRODUCE LOCALLY HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING.
TEMPERATURES DURING THE SHORT TERM ARE STILL ON TRACK TO RUN WELL
ABOVE NORMAL FOR THIS TIME OF YEAR...REMAINING IN STEP WITH
CURRENT TRENDS AND A PERSISTENT SOUTHERLY FLOW PATTERN THAT HAS
BEEN CONSISTENTLY PUMPING WARM MOIST AIR OFF THE GULF OF MEXICO
INTO THE REGION. HIGHS ON MONDAY ARE STILL EXPECTED TO TOP OUT IN
THE LOWER 80S ACROSS THE AREA...WITH OVERNIGHT LOWS TONIGHT AND
TOMORROW NIGHT ONLY FALLING INTO THE LOW TO MID 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 300 PM EDT SUN MAY 17 2015
MODELS APPEAR TO BE IN GOOD AGREEMENT WITH THE MID AND UPPER LEVEL
PATTERN OVER OUR REGION...BUT DIFFER MORE ON DETAILS OF SENSIBLE
WEATHER WITH A SHORTWAVE DISTURBANCE LATE WEDNESDAY OR WEDNESDAY
NIGHT INTO EARLY THURSDAY.
IN GENERAL ZONAL FLOW WILL DOMINATE THE PATTERN UNTIL THE LAST 48
HOURS OF THE EXTENDED WHERE SHORT WAVE RIDGING WILL BUILD INTO AND
ACROSS THE OHIO VALLEY IN RESPONSE TO EASTWARD MOVEMENT OF WEST
COAST CUT OFF LOW. AT THE SURFACE A COOL CANADIAN AIR MASS...HIGH
PRESSURE SYSTEM WILL SETTLE DOWN INTO THE HEART OF THE CONUS BEHIND
AN EXITING COLD FRONT...NOSING ITS WAY INTO THE OHIO VALLEY. AS A
RESULT WE CAN EXPECT DRY...PLEASANTLY COOL WEATHER FOR THE START OF
THE EXTENDED. ALOFT...THE AFOREMENTIONED DISTURBANCE WILL ROUND A
DEEP HUDSON BAY LOW WEDNESDAY NIGHT. WE APPEAR TO RECEIVE A GLANCING
BLOW FROM THIS FEATURE AS IT TRACKS THROUGH THE GREAT LAKES REGION.
A SECOND LESS IMPRESSIVE DISTURBANCE BRUSHES THE OHIO VALLEY BY LATE
IN THE WEEK...DY6 FRI.
THE MAIN FORECAST CHALLENGE IN THE EXTENDED WILL BE THE SHORT WAVE
DISTURBANCE MOVING THROUGH THE AREA WEDNESDAY NIGHT INTO EARLY
THURSDAY. THE 0Z AND 12Z ECMWF PRODUCE CONSIDERABLY MORE SENSIBLE
WEATHER WITH THIS FEATURE THAN EITHER THE 0Z OR 12Z GFS. NOT SEEING
MUCH IN THE WAY OF TRENDS TO HELP WITH PREFERENCE OF SOLUTIONS.
THEREFORE RELIED STRONGLY ON MODEL BLENDS CONSIDERING THE MURKY
DETAILS WITH SENSIBLE WEATHER. INCREASING HEIGHTS THROUGH THE END OF
THE EXTENDED WILL MEAN A GRADUAL RISE IN TEMPS...INTO THE 80S BY THE
END OF THE FORECAST WINDOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 135 AM EDT MON MAY 18 2015
TAFS TONIGHT WILL START OFF VFR WITH SOME MVFR POSSIBLE OVERNIGHT
AND EARLY TUESDAY MORNING. THE MVFR WILL BE WITH FOG POTENTIAL AND
DID STAY CLOSE TO PREVIOUS TAF AT THIS TIME. THE UNCERTAINTY WITH
THIS REMAINS TO SEE HOW CLOUDS COULD WANE THE DEVELOPMENT. THE
FOG WILL HAVE THE BEST POTENTIAL IN THE RIVER VALLEYS AND
LOCATIONS THAT RECEIVED RAIN TODAY. SOME SHOWERS AND
THUNDERSTORMS SOUTH ACROSS THE TN VALLEY ARE EXPECTED TO
WEAKEN...HOWEVER HRRR DOES HOLD ONTO AT LEAST SOME RAIN SHOWERS BY
EARLY MORNING. THEREFORE DID KEEP THE VCSH CLOSE TO 12Z AND SEEMS
REASONABLE WHEN TIMING THE CURRENT PROGRESSION OF THE AREA OF
SHOWERS. WHILE THE RIDGE DOES BEGIN TO BREAKDOWN TOMORROW THINK
FORECAST WILL STAY PRETTY CLOSE TO THE SAME WITH
DIURNALLY/AFTERNOON DRIVEN THUNDERSTORMS. DID OPT TO KEEP THE VCTS
IN THERE FOR EARLY AFTERNOON...BUT DID ADJUST TIMING UP SLIGHTLY.
WINDS ARE EXPECTED TO BE LIGHT TONIGHT...BUT DID BRING WINDS UP
TOMORROW AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...AR
LONG TERM...AR
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
949 PM CDT TUE MAY 19 2015
.AVIATION...
VFR FLIGHT CATEGORIES WILL PREVAIL UNTIL AFTER 20/06Z WITH
EXCEPTION TO ISOLATED SHOWERS AND THUNDERSTORMS THAT MAY PRODUCE
MVFR BRIEFLY. DURING THE NIGHT EXPECTING THE CEILINGS TO LOWER TO
MVFR AND IFR LATE WITH A SLOW IMPROVEMENT BETWEEN 20/16Z TO 2018Z
TO VFR AND POSSIBLY MVFR WITH SHOWERS AND THUNDERSTORMS. AN AREA
OF SHOWERS AND THUNDERSTORMS WILL BE MOVING ACROSS NORTH TEXAS AND
CENTRAL OKLAHOMA INTO SOUTHEAST OKLAHOMA AND PARTS OF EAST AND
NORTHEAST TEXAS AND SOUTHWEST ARKANSAS IN THE HOURS SHORTLY AFTER
MIDNIGHT. THESE WILL LINGER LONGER INTO THE LATE MORNING TO MID
DAY HOURS FOR TEXAS AND SOUTHWEST ARKANSAS AND INTO THE AFTERNOON
FOR NORTH LOUISIANA AND SOUTH CENTRAL ARKANSAS. WINDS WILL BE
SOUTHERLY 5-10 KNOTS OVERNIGHT AND MORE SOUTH TO SOUTHWEST DURING
THE DAY WEDNESDAY. A SHIFT TO THE WEST WILL FOLLOW THE BAND OF
SHOWERS AND THUNDERSTORMS ENTERING FROM THE WEST OVERNIGHT. /06/
&&
.PREV DISCUSSION... /ISSUED 345 PM CDT TUE MAY 19 2015/
DISCUSSION...
OUR TEMPERATURES ARE IN THE LOW 80S NORTH TO MID 80S ELSEWHERE.
THE NORTHEAST WINDS ARE RUNNING OUT OF GAS. AS EXPECTED AFTERNOON
THUNDERSTORM INITIATION HAS OCCURRED OVER OUR TEXAS COUNTIES
LIFTING NORTHEAST WARD WITH MEAGER COVERAGE SO FAR. THE WINDS
THERE ARE MOIST FROM THE SOUTHEAST. FOR NOW...THE MORE STABLE AIR
REMAINS OVER OUR EAST AND MAYBE FOR A WHILE YET.
FARTHER WEST...THUNDERSTORMS ARE STRONGER AND TO SOME EXTENT A
BIT MORE NUMEROUS. THE WATER VAPOR SHOWS THE REASON IS A GOOD PUSH
OUT OF THE ROCKIES OUT INTO THE PLAINS WITH A LARGE UPPER LOW. THE
TAIL END OF THIS FEATURE WILL CONTINUE IT/S EVOLUTION BEYOND
SUNDOWN WITH THE EXPECTATION OF THE UPPER DIVERGENCE ALOFT AHEAD
OF THE LOW WORKING EAST OUT INTO THE MID SOUTH OVERNIGHT.
SO AFTER A BRIEF BREAK FROM THE ACTION WE HAVE THE WEAK FRONTAL
BOUNDARY NOW ALONG THE AR/LA STATE LINE OR SO WITH A CONTINUED
LIFT BACK TO THE NORTH OVERNIGHT. THE HRRR SHOWS A GOOD PUSH OF
QPF INTO OUR NW CORNER AFTER MIDNIGHT WITH MUCH OF THE DIURNAL
COVERAGE GONE HOURS EARLIER IN THE MID EVENING. THE NAM IS
SIMILAR...BUT MUCH SLOWER. THE RAIN THAT ACTUALLY FALLS IN THIS
AREA IS CRUCIAL TO RIVER FORECAST WHICH IS QPF DRIVEN. SO CLOSE
ATTENTION TO CONDITIONS IS MORE THAN WARRANTED WITH ALREADY PRETTY
HIGH WATER AND SOIL SATURATION AS YET ANOTHER FRONTAL BOUNDARY
WILL SETTLE INTO THE I-20 CORRIDOR LATE TOMORROW AND INTO EARLY
THURSDAY.
THE WEATHER PATTERN WILL NOT CHANGE GREATLY AS WE SEE ANOTHER
DEEP TROUGH MOVING INTO THE ROCKIES OVER THE WEEKEND AND OUT INTO
THE PLAINS EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 69 86 70 79 / 20 30 50 40
MLU 69 88 69 79 / 20 30 50 40
DEQ 68 82 62 74 / 60 50 50 30
TXK 68 83 67 75 / 50 40 50 40
ELD 67 83 65 75 / 20 30 50 40
TYR 70 84 66 78 / 30 30 50 40
GGG 69 85 68 79 / 30 30 50 40
LFK 71 86 71 83 / 20 20 30 40
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
06
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1253 PM CDT MON MAY 18 2015
.AVIATION...A THUNDERSTORM COMPLEX CONTINUES TO PUSH SOUTH THROUGH
THE TERMINAL AREA. AEX HAS ALREADY ENCOUNTERED VLIFR AT TIMES WITH
HEAVY RAIN. ACTIVITY WILL BE TAPERING OFF AS THE MCS PUSHES ON
SOUTH...WILL GO MVFR WITH SOME IFR UNTIL LATER THIS AFTERNOON
BECOMING VFR LATE THIS AFTERNOON. COULD SEE SOME MVFR CIG/VIS WITH
LIGHT FOG TOWARDS DAYBREAK. VFR LATE MORNING.
THE REMAINDER OF THE TERMINALS WILL BE DEALING WITH THE
CONVECTIVE COMPLEX THIS AFTERNOON WITH MVFR AS THE SYSTEM WEAKENS
UNTIL LATE AFTERNOON. IFR CIGS LATE TNITE BECOMING MVFR DURING THE
MORNING ON TUESDAY EXCEPT BPT WHERE IFR CIGS COULD LINGER. MVFR
EXPECTED LATE TNITE AT LFT WITH FOG DOWN TO IFR AT ARA.
SWEENEY
&&
.PREV DISCUSSION... /ISSUED 1004 AM CDT MON MAY 18 2015/
DISCUSSION...
SLOW MOVING MCS ACROSS E TX/C LA WILL BE THE MAIN CONCERN THIS
MORNING...ESPECIALLY FOR FLASH FLOOD POTENTIAL ACROSS THIS REGION.
FOR THIS...ISSUED FLASH FLOOD WATCH FOR TYLER & N JASPER/NEWTON
COUNTIES IN SE TX...AND VERNON/RAPIDES/AVOYELLES PARISHES IN C LA.
HIGH POPS REMAIN FOR THE REST OF THE AFTERNOON FROM THE I-10
CORRIDOR NORTHWARD. FURTHER SOUTH SOUTH OF THE I-10 CORRIDOR...POPS
DROP OFF SIGNIFICANTLY AT THIS TIME...BUT WILL HAVE TO WATCH IF
ANY ADDITIONAL OUTFLOW BOUNDARIES MAY GENERATE PRECIP LATER THIS
EVENING AND OVERNIGHT ACROSS THIS REGION.
DML
PREV DISCUSSION... /ISSUED 701 AM CDT MON MAY 18 2015/
DISCUSSION...
FOR THE 12Z TAF PACKAGE.
AVIATION...
ISOLATED SHOWERS CONTINUING TO DEVELOP AND STREAM NORTH ACROSS
PARTS OF SOUTH AND EAST CENTRAL LOUISIANA...WITH MORE ROBUST
CONVECTION TO THE NORTH ACROSS NORTH LA...AND FARTHER WEST TO THE
NW OF HOUSTON OVER SE TX. CONDITIONS ACROSS THE REGION RANGE FROM
LIFR AT KAEX TO VFR AT KLCH. PRIMARY CHALLENGE IS CONVECTIVE
EVOLUTION TODAY...WITH THE TEMPO AND PREVAILING THUNDER IN THE TAFS
REPRESENTING A BLEND OF THE LATEST HRRR RUNS AND THE ONLINE SPC
4KM WRF...WHICH DEPICT THE ACTIVITY BOTH TO THE NORTH AND WEST
EVENTUALLY WORKING INTO THE AREA EITHER LATER THIS MORNING OR THIS
AFTERNOON. A MIX OF MVFR AND VFR WILL OTHERWISE PREVAIL WITH CU
GENERALLY IN THE 1500 TO 3500 FT RANGE AND SOUTHERLY WINDS NOT AS
STRONG AND/OR GUSTY AS YESTERDAY.
13
PREV DISCUSSION... /ISSUED 459 AM CDT MON MAY 18 2015/
SYNOPSIS...
LATEST UA ANALYSIS AND WV IMAGERY SHOWS A MOIST SWLY FLOW ALOFT
CONTINUING WITH A BROAD TROF OVER THE WRN CONUS AND A RIDGE OVER THE
SE. A PAIR OF LOWS WERE SPINNING WITHIN THE TROF...ONE CROSSING THE
NRN PLAINS AND ANOTHER ENTERING CA. MEANWHILE...A PERTURBATION
OVERRIDING AN OUTFLOW BOUNDARY LEFT BEHIND FROM LAST NIGHTS MCV
WAS PRODUCING AN INCREASE IN SHOWERS AND THUNDERSTORMS ACRS NRN LA
WITH SCT ACTIVITY DEVELOPING DOWN TO OUR NRN TIER OF PARISHES AND
COUNTIES. AT THE SFC...S-SE WINDS AROUND THE WRN PERIPHERY OF HIGH
PRES OFF THE SE ATL COAST CONTINUE TO STREAM GULF MOISTURE OVER
THE REGION.
DISCUSSION...
MAIN FCST CONCERN IN THE NEAR TERM IS RAIN CHCS AND THE POTENTIAL
FOR HEAVY RAINFALL. CONVECTION ACRS NRN LA INTO E TX WILL CONTINUE
TO INCREASE THROUGH THE MORNING AS SLY/SWLY WINDS SPREAD ABUNDANT
MOISTURE OVER THE REGION. LIFT WILL BE AUGMENTED BY DIFFLUENCE
ALOFT AND LOW LVL FORCING ALONG THE REMNANT BOUNDARY ACRS CNTL LA
AND THIS WILL HELP TO FOCUS THE PRECIPITATION ACRS NRN/CNTL LA.
RECENT HRRR AND NAM PROGS INDICATE CONVECTION SHOULD SLOWLY
PROPAGATE SOUTHWARD DURING THE DAY. AT THIS TIME...THE HIGHEST
RAINFALL TOTALS ARE EXPECTED TO REMAIN NORTH OF THE CWA.
HOWEVER...PRECIP WATER VALUES ARE RUNNING BETWEEN 1.8-2.0 INCHES
OVER THE AREA...MORE THAN ADEQUATE TO PRODUCE EFFICIENT RAINFALL
RATES AND LOCALIZED HEAVY RAIN ESPECIALLY ACRS THE NRN TIER OF
ZONES. HAVE HELD OFF ON ISSUANCE OF A FLASH FLOOD WATCH FOR NOW
WITH FLOODING EXPECTED TO BE MOSTLY LOCALIZED IN NATURE...BUT WILL
NEED TO MONITOR TRENDS FOR POSSIBLY ISSUANCE LATER THIS MORNING.
RAIN CHCS WILL DIMINISH DURING THE EVENING WITH THE LOSS OF
DAYTIME HEATING. A WEAK FRONT WILL SAG SOUTH INTO THE AREA
TUESDAY...BECOMING STALLED NW-SE ACRS NERN TX INTO CNTL LA. THE
PERSISTENT MOIST SWLY FLOW ALOFT AND EMBEDDED DISTURBANCES WILL
AGAIN BRING ABOUT SCT CONVECTION ON TUESDAY. ALTHOUGH COVERAGE IS
EXPECTED TO BE SLIGHTLY LESS THAN TODAY...EXPECT THE HIGHEST POPS
WILL BE CONCENTRATED ALONG THE FRONTAL BOUNDARY ACRS CNTL LA.
WEAK FLAT RIDGING WILL BEGIN TO DEVELOP ALOFT BY
MIDWEEK...HELPING TO REDUCE BUT NOT ELIMINATE SHOWER COVERAGE AND
CHANCES ON WEDNESDAY. ANOTHER FRONT IS FCST TO MOVE INTO THE AREA
THURSDAY...BRINGING ANOTHER ROUND OF SCT SHOWERS AND TSTMS. THE
FRONT WILL STALL NEAR THE COAST FRIDAY THEN SLOWLY RETREAT BACK
NORTH OVER THE WEEKEND. THE RIDGE ALOFT WILL KEEP RAIN CHCS CLOSER
TO 20-30 PERCENT FOR FRIDAY AND SATURDAY...WITH POPS EASING BACK
INTO THE SCT RANGE BY SUNDAY AS THE RIDGE GETS SHIFTED BACK TO THE
EAST OVER THE WEEKEND.
THROUGH THE NEXT FEW DAYS...THE THREAT FOR ANY ORGANIZED SVR
STORMS WILL REMAIN WELL WEST OF THE AREA. HOWEVER...A FEW ISLTD
STORMS COULD PULSE TO STRONG OR MARGINALLY SVR LIMITS DURING THE
AFTN WHEN MAX HEATING CONTRIBUTES TO ENHANCED INSTABILITY. THE
PRIMARY THREAT WILL STILL BE HEAVY RAINFALL AND LOCALIZED FLOODING
IN LOW-LYING OR URBAN AREAS.
LITTLE VARIATION IN TEMPERATURE IS EXPECTED THROUGH NEXT WEEKEND
WITH MAIN IMPACTS TO DAILY TEMPS FROM CLOUDS AND SHOWERS. IN
GENERAL...EXPECT LOWS FROM AROUND 70 INTO THE MIDDLE 70S WHICH IS
ABOUT 5-10 DEGREES ABV NORMAL WHILE HIGHS WILL RUN NEAR NORMAL IN
THE MIDDLE 80S.
24
MARINE...
MODT SELY WINDS WERE OCCURRING OVER THE COASTAL WATERS THIS EARLY
MORNING IN RESPONSE TO ELEVATED WINDS ALOFT AND INFLOW INTO
COMPLEX OF STORMS ACRS NRN LA INTO SE TX. SUSTAINED WINDS HAVE
APPROACHED 20 KNOTS AT TIMES. WITH THIS IN MIND...ADDED EXERCISE
CAUTION HEADLINE TO CWF FOR EARLY THIS MORNING. WINDS WILL
DIMINISH DURING THE MORNING.
OTHERWISE...EXPECT A LT TO MODT ONSHORE FLOW CONTINUING THROUGH
THE WEEK AS HIGH PRES REMAINS EAST OF THE REGION. WIDELY SCT
SHOWERS AND TSTMS WILL BE POSSIBLE THROUGH WEDNESDAY AS A SERIES
OF DISTURBANCES CROSSES THE REGION. CONVECTION WILL BECOME MORE
ISLTD TOWARD THE END OF THE WEEK AS WEAK RIDGING BUILDS IN ALOFT.
24
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 77 68 86 70 / 80 30 40 30
LCH 84 72 86 73 / 40 20 30 20
LFT 84 72 86 72 / 60 20 50 20
BPT 84 75 86 74 / 40 20 20 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR LAZ027>029.
TX...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR TXZ180-259-260.
GM...NONE.
&&
$$
AVIATION...11
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1004 AM CDT MON MAY 18 2015
.DISCUSSION...
SLOW MOVING MCS ACROSS E TX/C LA WILL BE THE MAIN CONCERN THIS
MORNING...ESPECIALLY FOR FLASH FLOOD POTENTIAL ACROSS THIS REGION.
FOR THIS...ISSUED FLASH FLOOD WATCH FOR TYLER & N JASPER/NEWTON
COUNTIES IN SE TX...AND VERNON/RAPIDES/AVOYELLES PARISHES IN C LA.
HIGH POPS REMAIN FOR THE REST OF THE AFTERNOON FROM THE I-10
CORRIDOR NORTHWARD. FURTHER SOUTH SOUTH OF THE I-10 CORRIDOR...POPS
DROP OFF SIGNIFICANTLY AT THIS TIME...BUT WILL HAVE TO WATCH IF
ANY ADDITIONAL OUTFLOW BOUNDARIES MAY GENERATE PRECIP LATER THIS
EVENING AND OVERNIGHT ACROSS THIS REGION.
DML
&&
.PREV DISCUSSION... /ISSUED 701 AM CDT MON MAY 18 2015/
DISCUSSION...
FOR THE 12Z TAF PACKAGE.
AVIATION...
ISOLATED SHOWERS CONTINUING TO DEVELOP AND STREAM NORTH ACROSS
PARTS OF SOUTH AND EAST CENTRAL LOUISIANA...WITH MORE ROBUST
CONVECTION TO THE NORTH ACROSS NORTH LA...AND FARTHER WEST TO THE
NW OF HOUSTON OVER SE TX. CONDITIONS ACROSS THE REGION RANGE FROM
LIFR AT KAEX TO VFR AT KLCH. PRIMARY CHALLENGE IS CONVECTIVE
EVOLUTION TODAY...WITH THE TEMPO AND PREVAILING THUNDER IN THE TAFS
REPRESENTING A BLEND OF THE LATEST HRRR RUNS AND THE ONLINE SPC
4KM WRF...WHICH DEPICT THE ACTIVITY BOTH TO THE NORTH AND WEST
EVENTUALLY WORKING INTO THE AREA EITHER LATER THIS MORNING OR THIS
AFTERNOON. A MIX OF MVFR AND VFR WILL OTHERWISE PREVAIL WITH CU
GENERALLY IN THE 1500 TO 3500 FT RANGE AND SOUTHERLY WINDS NOT AS
STRONG AND/OR GUSTY AS YESTERDAY.
13
PREV DISCUSSION... /ISSUED 459 AM CDT MON MAY 18 2015/
SYNOPSIS...
LATEST UA ANALYSIS AND WV IMAGERY SHOWS A MOIST SWLY FLOW ALOFT
CONTINUING WITH A BROAD TROF OVER THE WRN CONUS AND A RIDGE OVER THE
SE. A PAIR OF LOWS WERE SPINNING WITHIN THE TROF...ONE CROSSING THE
NRN PLAINS AND ANOTHER ENTERING CA. MEANWHILE...A PERTURBATION
OVERRIDING AN OUTFLOW BOUNDARY LEFT BEHIND FROM LAST NIGHTS MCV
WAS PRODUCING AN INCREASE IN SHOWERS AND THUNDERSTORMS ACRS NRN LA
WITH SCT ACTIVITY DEVELOPING DOWN TO OUR NRN TIER OF PARISHES AND
COUNTIES. AT THE SFC...S-SE WINDS AROUND THE WRN PERIPHERY OF HIGH
PRES OFF THE SE ATL COAST CONTINUE TO STREAM GULF MOISTURE OVER
THE REGION.
DISCUSSION...
MAIN FCST CONCERN IN THE NEAR TERM IS RAIN CHCS AND THE POTENTIAL
FOR HEAVY RAINFALL. CONVECTION ACRS NRN LA INTO E TX WILL CONTINUE
TO INCREASE THROUGH THE MORNING AS SLY/SWLY WINDS SPREAD ABUNDANT
MOISTURE OVER THE REGION. LIFT WILL BE AUGMENTED BY DIFFLUENCE
ALOFT AND LOW LVL FORCING ALONG THE REMNANT BOUNDARY ACRS CNTL LA
AND THIS WILL HELP TO FOCUS THE PRECIPITATION ACRS NRN/CNTL LA.
RECENT HRRR AND NAM PROGS INDICATE CONVECTION SHOULD SLOWLY
PROPAGATE SOUTHWARD DURING THE DAY. AT THIS TIME...THE HIGHEST
RAINFALL TOTALS ARE EXPECTED TO REMAIN NORTH OF THE CWA.
HOWEVER...PRECIP WATER VALUES ARE RUNNING BETWEEN 1.8-2.0 INCHES
OVER THE AREA...MORE THAN ADEQUATE TO PRODUCE EFFICIENT RAINFALL
RATES AND LOCALIZED HEAVY RAIN ESPECIALLY ACRS THE NRN TIER OF
ZONES. HAVE HELD OFF ON ISSUANCE OF A FLASH FLOOD WATCH FOR NOW
WITH FLOODING EXPECTED TO BE MOSTLY LOCALIZED IN NATURE...BUT WILL
NEED TO MONITOR TRENDS FOR POSSIBLY ISSUANCE LATER THIS MORNING.
RAIN CHCS WILL DIMINISH DURING THE EVENING WITH THE LOSS OF
DAYTIME HEATING. A WEAK FRONT WILL SAG SOUTH INTO THE AREA
TUESDAY...BECOMING STALLED NW-SE ACRS NERN TX INTO CNTL LA. THE
PERSISTENT MOIST SWLY FLOW ALOFT AND EMBEDDED DISTURBANCES WILL
AGAIN BRING ABOUT SCT CONVECTION ON TUESDAY. ALTHOUGH COVERAGE IS
EXPECTED TO BE SLIGHTLY LESS THAN TODAY...EXPECT THE HIGHEST POPS
WILL BE CONCENTRATED ALONG THE FRONTAL BOUNDARY ACRS CNTL LA.
WEAK FLAT RIDGING WILL BEGIN TO DEVELOP ALOFT BY
MIDWEEK...HELPING TO REDUCE BUT NOT ELIMINATE SHOWER COVERAGE AND
CHANCES ON WEDNESDAY. ANOTHER FRONT IS FCST TO MOVE INTO THE AREA
THURSDAY...BRINGING ANOTHER ROUND OF SCT SHOWERS AND TSTMS. THE
FRONT WILL STALL NEAR THE COAST FRIDAY THEN SLOWLY RETREAT BACK
NORTH OVER THE WEEKEND. THE RIDGE ALOFT WILL KEEP RAIN CHCS CLOSER
TO 20-30 PERCENT FOR FRIDAY AND SATURDAY...WITH POPS EASING BACK
INTO THE SCT RANGE BY SUNDAY AS THE RIDGE GETS SHIFTED BACK TO THE
EAST OVER THE WEEKEND.
THROUGH THE NEXT FEW DAYS...THE THREAT FOR ANY ORGANIZED SVR
STORMS WILL REMAIN WELL WEST OF THE AREA. HOWEVER...A FEW ISLTD
STORMS COULD PULSE TO STRONG OR MARGINALLY SVR LIMITS DURING THE
AFTN WHEN MAX HEATING CONTRIBUTES TO ENHANCED INSTABILITY. THE
PRIMARY THREAT WILL STILL BE HEAVY RAINFALL AND LOCALIZED FLOODING
IN LOW-LYING OR URBAN AREAS.
LITTLE VARIATION IN TEMPERATURE IS EXPECTED THROUGH NEXT WEEKEND
WITH MAIN IMPACTS TO DAILY TEMPS FROM CLOUDS AND SHOWERS. IN
GENERAL...EXPECT LOWS FROM AROUND 70 INTO THE MIDDLE 70S WHICH IS
ABOUT 5-10 DEGREES ABV NORMAL WHILE HIGHS WILL RUN NEAR NORMAL IN
THE MIDDLE 80S.
24
MARINE...
MODT SELY WINDS WERE OCCURRING OVER THE COASTAL WATERS THIS EARLY
MORNING IN RESPONSE TO ELEVATED WINDS ALOFT AND INFLOW INTO
COMPLEX OF STORMS ACRS NRN LA INTO SE TX. SUSTAINED WINDS HAVE
APPROACHED 20 KNOTS AT TIMES. WITH THIS IN MIND...ADDED EXERCISE
CAUTION HEADLINE TO CWF FOR EARLY THIS MORNING. WINDS WILL
DIMINISH DURING THE MORNING.
OTHERWISE...EXPECT A LT TO MODT ONSHORE FLOW CONTINUING THROUGH
THE WEEK AS HIGH PRES REMAINS EAST OF THE REGION. WIDELY SCT
SHOWERS AND TSTMS WILL BE POSSIBLE THROUGH WEDNESDAY AS A SERIES
OF DISTURBANCES CROSSES THE REGION. CONVECTION WILL BECOME MORE
ISLTD TOWARD THE END OF THE WEEK AS WEAK RIDGING BUILDS IN ALOFT.
24
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 84 68 86 70 / 80 30 40 30
LCH 86 72 86 73 / 50 20 30 20
LFT 87 72 86 72 / 40 20 50 20
BPT 87 75 86 74 / 50 20 20 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR LAZ027>029.
TX...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR TXZ180-259-260.
GM...NONE.
&&
$$
PUBLIC...04
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
701 AM CDT MON MAY 18 2015
.DISCUSSION...
FOR THE 12Z TAF PACKAGE.
&&
.AVIATION...
ISOLATED SHOWERS CONTINUING TO DEVELOP AND STREAM NORTH ACROSS
PARTS OF SOUTH AND EAST CENTRAL LOUISIANA...WITH MORE ROBUST
CONVECTION TO THE NORTH ACROSS NORTH LA...AND FARTHER WEST TO THE
NW OF HOUSTON OVER SE TX. CONDITIONS ACROSS THE REGION RANGE FROM
LIFR AT KAEX TO VFR AT KLCH. PRIMARY CHALLENGE IS CONVECTIVE
EVOLUTION TODAY...WITH THE TEMPO AND PREVAILING THUNDER IN THE TAFS
REPRESENTING A BLEND OF THE LATEST HRRR RUNS AND THE ONLINE SPC
4KM WRF...WHICH DEPICT THE ACTIVITY BOTH TO THE NORTH AND WEST
EVENTUALLY WORKING INTO THE AREA EITHER LATER THIS MORNING OR THIS
AFTERNOON. A MIX OF MVFR AND VFR WILL OTHERWISE PREVAIL WITH CU
GENERALLY IN THE 1500 TO 3500 FT RANGE AND SOUTHERLY WINDS NOT AS
STRONG AND/OR GUSTY AS YESTERDAY.
13
&&
.PREV DISCUSSION... /ISSUED 459 AM CDT MON MAY 18 2015/
SYNOPSIS...
LATEST UA ANALYSIS AND WV IMAGERY SHOWS A MOIST SWLY FLOW ALOFT
CONTINUING WITH A BROAD TROF OVER THE WRN CONUS AND A RIDGE OVER THE
SE. A PAIR OF LOWS WERE SPINNING WITHIN THE TROF...ONE CROSSING THE
NRN PLAINS AND ANOTHER ENTERING CA. MEANWHILE...A PERTURBATION
OVERRIDING AN OUTFLOW BOUNDARY LEFT BEHIND FROM LAST NIGHTS MCV
WAS PRODUCING AN INCREASE IN SHOWERS AND THUNDERSTORMS ACRS NRN LA
WITH SCT ACTIVITY DEVELOPING DOWN TO OUR NRN TIER OF PARISHES AND
COUNTIES. AT THE SFC...S-SE WINDS AROUND THE WRN PERIPHERY OF HIGH
PRES OFF THE SE ATL COAST CONTINUE TO STREAM GULF MOISTURE OVER
THE REGION.
DISCUSSION...
MAIN FCST CONCERN IN THE NEAR TERM IS RAIN CHCS AND THE POTENTIAL
FOR HEAVY RAINFALL. CONVECTION ACRS NRN LA INTO E TX WILL CONTINUE
TO INCREASE THROUGH THE MORNING AS SLY/SWLY WINDS SPREAD ABUNDANT
MOISTURE OVER THE REGION. LIFT WILL BE AUGMENTED BY DIFFLUENCE
ALOFT AND LOW LVL FORCING ALONG THE REMNANT BOUNDARY ACRS CNTL LA
AND THIS WILL HELP TO FOCUS THE PRECIPITATION ACRS NRN/CNTL LA.
RECENT HRRR AND NAM PROGS INDICATE CONVECTION SHOULD SLOWLY
PROPAGATE SOUTHWARD DURING THE DAY. AT THIS TIME...THE HIGHEST
RAINFALL TOTALS ARE EXPECTED TO REMAIN NORTH OF THE CWA.
HOWEVER...PRECIP WATER VALUES ARE RUNNING BETWEEN 1.8-2.0 INCHES
OVER THE AREA...MORE THAN ADEQUATE TO PRODUCE EFFICIENT RAINFALL
RATES AND LOCALIZED HEAVY RAIN ESPECIALLY ACRS THE NRN TIER OF
ZONES. HAVE HELD OFF ON ISSUANCE OF A FLASH FLOOD WATCH FOR NOW
WITH FLOODING EXPECTED TO BE MOSTLY LOCALIZED IN NATURE...BUT WILL
NEED TO MONITOR TRENDS FOR POSSIBLY ISSUANCE LATER THIS MORNING.
RAIN CHCS WILL DIMINISH DURING THE EVENING WITH THE LOSS OF
DAYTIME HEATING. A WEAK FRONT WILL SAG SOUTH INTO THE AREA
TUESDAY...BECOMING STALLED NW-SE ACRS NERN TX INTO CNTL LA. THE
PERSISTENT MOIST SWLY FLOW ALOFT AND EMBEDDED DISTURBANCES WILL
AGAIN BRING ABOUT SCT CONVECTION ON TUESDAY. ALTHOUGH COVERAGE IS
EXPECTED TO BE SLIGHTLY LESS THAN TODAY...EXPECT THE HIGHEST POPS
WILL BE CONCENTRATED ALONG THE FRONTAL BOUNDARY ACRS CNTL LA.
WEAK FLAT RIDGING WILL BEGIN TO DEVELOP ALOFT BY
MIDWEEK...HELPING TO REDUCE BUT NOT ELIMINATE SHOWER COVERAGE AND
CHANCES ON WEDNESDAY. ANOTHER FRONT IS FCST TO MOVE INTO THE AREA
THURSDAY...BRINGING ANOTHER ROUND OF SCT SHOWERS AND TSTMS. THE
FRONT WILL STALL NEAR THE COAST FRIDAY THEN SLOWLY RETREAT BACK
NORTH OVER THE WEEKEND. THE RIDGE ALOFT WILL KEEP RAIN CHCS CLOSER
TO 20-30 PERCENT FOR FRIDAY AND SATURDAY...WITH POPS EASING BACK
INTO THE SCT RANGE BY SUNDAY AS THE RIDGE GETS SHIFTED BACK TO THE
EAST OVER THE WEEKEND.
THROUGH THE NEXT FEW DAYS...THE THREAT FOR ANY ORGANIZED SVR
STORMS WILL REMAIN WELL WEST OF THE AREA. HOWEVER...A FEW ISLTD
STORMS COULD PULSE TO STRONG OR MARGINALLY SVR LIMITS DURING THE
AFTN WHEN MAX HEATING CONTRIBUTES TO ENHANCED INSTABILITY. THE
PRIMARY THREAT WILL STILL BE HEAVY RAINFALL AND LOCALIZED FLOODING
IN LOW-LYING OR URBAN AREAS.
LITTLE VARIATION IN TEMPERATURE IS EXPECTED THROUGH NEXT WEEKEND
WITH MAIN IMPACTS TO DAILY TEMPS FROM CLOUDS AND SHOWERS. IN
GENERAL...EXPECT LOWS FROM AROUND 70 INTO THE MIDDLE 70S WHICH IS
ABOUT 5-10 DEGREES ABV NORMAL WHILE HIGHS WILL RUN NEAR NORMAL IN
THE MIDDLE 80S.
24
MARINE...
MODT SELY WINDS WERE OCCURRING OVER THE COASTAL WATERS THIS EARLY
MORNING IN RESPONSE TO ELEVATED WINDS ALOFT AND INFLOW INTO
COMPLEX OF STORMS ACRS NRN LA INTO SE TX. SUSTAINED WINDS HAVE
APPROACHED 20 KNOTS AT TIMES. WITH THIS IN MIND...ADDED EXERCISE
CAUTION HEADLINE TO CWF FOR EARLY THIS MORNING. WINDS WILL
DIMINISH DURING THE MORNING.
OTHERWISE...EXPECT A LT TO MODT ONSHORE FLOW CONTINUING THROUGH
THE WEEK AS HIGH PRES REMAINS EAST OF THE REGION. WIDELY SCT
SHOWERS AND TSTMS WILL BE POSSIBLE THROUGH WEDNESDAY AS A SERIES
OF DISTURBANCES CROSSES THE REGION. CONVECTION WILL BECOME MORE
ISLTD TOWARD THE END OF THE WEEK AS WEAK RIDGING BUILDS IN ALOFT.
24
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 84 68 86 70 / 70 30 40 30
LCH 86 72 86 73 / 50 20 30 20
LFT 87 72 86 72 / 50 20 50 20
BPT 87 75 86 74 / 50 20 20 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT EXERCISE CAUTION UNTIL 9 AM CDT THIS MORNING FOR
GMZ430-432-435-450-452-455-470-472-475.
&&
$$
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
459 AM CDT MON MAY 18 2015
.SYNOPSIS...
LATEST UA ANALYSIS AND WV IMAGERY SHOWS A MOIST SWLY FLOW ALOFT
CONTINUING WITH A BROAD TROF OVER THE WRN CONUS AND A RIDGE OVER THE
SE. A PAIR OF LOWS WERE SPINNING WITHIN THE TROF...ONE CROSSING THE
NRN PLAINS AND ANOTHER ENTERING CA. MEANWHILE...A PERTURBATION
OVERRIDING AN OUTFLOW BOUNDARY LEFT BEHIND FROM LAST NIGHTS MCV
WAS PRODUCING AN INCREASE IN SHOWERS AND THUNDERSTORMS ACRS NRN LA
WITH SCT ACTIVITY DEVELOPING DOWN TO OUR NRN TIER OF PARISHES AND
COUNTIES. AT THE SFC...S-SE WINDS AROUND THE WRN PERIPHERY OF HIGH
PRES OFF THE SE ATL COAST CONTINUE TO STREAM GULF MOISTURE OVER
THE REGION.
&&
.DISCUSSION...
MAIN FCST CONCERN IN THE NEAR TERM IS RAIN CHCS AND THE POTENTIAL
FOR HEAVY RAINFALL. CONVECTION ACRS NRN LA INTO E TX WILL CONTINUE
TO INCREASE THROUGH THE MORNING AS SLY/SWLY WINDS SPREAD ABUNDANT
MOISTURE OVER THE REGION. LIFT WILL BE AUGMENTED BY DIFFLUENCE
ALOFT AND LOW LVL FORCING ALONG THE REMNANT BOUNDARY ACRS CNTL LA
AND THIS WILL HELP TO FOCUS THE PRECIPITATION ACRS NRN/CNTL LA.
RECENT HRRR AND NAM PROGS INDICATE CONVECTION SHOULD SLOWLY
PROPAGATE SOUTHWARD DURING THE DAY. AT THIS TIME...THE HIGHEST
RAINFALL TOTALS ARE EXPECTED TO REMAIN NORTH OF THE CWA.
HOWEVER...PRECIP WATER VALUES ARE RUNNING BETWEEN 1.8-2.0 INCHES
OVER THE AREA...MORE THAN ADEQUATE TO PRODUCE EFFICIENT RAINFALL
RATES AND LOCALIZED HEAVY RAIN ESPECIALLY ACRS THE NRN TIER OF
ZONES. HAVE HELD OFF ON ISSUANCE OF A FLASH FLOOD WATCH FOR NOW
WITH FLOODING EXPECTED TO BE MOSTLY LOCALIZED IN NATURE...BUT WILL
NEED TO MONITOR TRENDS FOR POSSIBLY ISSUANCE LATER THIS MORNING.
RAIN CHCS WILL DIMINISH DURING THE EVENING WITH THE LOSS OF
DAYTIME HEATING. A WEAK FRONT WILL SAG SOUTH INTO THE AREA
TUESDAY...BECOMING STALLED NW-SE ACRS NERN TX INTO CNTL LA. THE
PERSISTENT MOIST SWLY FLOW ALOFT AND EMBEDDED DISTURBANCES WILL
AGAIN BRING ABOUT SCT CONVECTION ON TUESDAY. ALTHOUGH COVERAGE IS
EXPECTED TO BE SLIGHTLY LESS THAN TODAY...EXPECT THE HIGHEST POPS
WILL BE CONCENTRATED ALONG THE FRONTAL BOUNDARY ACRS CNTL LA.
WEAK FLAT RIDGING WILL BEGIN TO DEVELOP ALOFT BY
MIDWEEK...HELPING TO REDUCE BUT NOT ELIMINATE SHOWER COVERAGE AND
CHANCES ON WEDNESDAY. ANOTHER FRONT IS FCST TO MOVE INTO THE AREA
THURSDAY...BRINGING ANOTHER ROUND OF SCT SHOWERS AND TSTMS. THE
FRONT WILL STALL NEAR THE COAST FRIDAY THEN SLOWLY RETREAT BACK
NORTH OVER THE WEEKEND. THE RIDGE ALOFT WILL KEEP RAIN CHCS CLOSER
TO 20-30 PERCENT FOR FRIDAY AND SATURDAY...WITH POPS EASING BACK
INTO THE SCT RANGE BY SUNDAY AS THE RIDGE GETS SHIFTED BACK TO THE
EAST OVER THE WEEKEND.
THROUGH THE NEXT FEW DAYS...THE THREAT FOR ANY ORGANIZED SVR
STORMS WILL REMAIN WELL WEST OF THE AREA. HOWEVER...A FEW ISLTD
STORMS COULD PULSE TO STRONG OR MARGINALLY SVR LIMITS DURING THE
AFTN WHEN MAX HEATING CONTRIBUTES TO ENHANCED INSTABILITY. THE
PRIMARY THREAT WILL STILL BE HEAVY RAINFALL AND LOCALIZED FLOODING
IN LOW-LYING OR URBAN AREAS.
LITTLE VARIATION IN TEMPERATURE IS EXPECTED THROUGH NEXT WEEKEND
WITH MAIN IMPACTS TO DAILY TEMPS FROM CLOUDS AND SHOWERS. IN
GENERAL...EXPECT LOWS FROM AROUND 70 INTO THE MIDDLE 70S WHICH IS
ABOUT 5-10 DEGREES ABV NORMAL WHILE HIGHS WILL RUN NEAR NORMAL IN
THE MIDDLE 80S.
&&
.MARINE...
MODT SELY WINDS WERE OCCURRING OVER THE COASTAL WATERS THIS EARLY
MORNING IN RESPONSE TO ELEVATED WINDS ALOFT AND INFLOW INTO
COMPLEX OF STORMS ACRS NRN LA INTO SE TX. SUSTAINED WINDS HAVE
APPROACHED 20 KNOTS AT TIMES. WITH THIS IN MIND...ADDED EXERCISE
CAUTION HEADLINE TO CWF FOR EARLY THIS MORNING. WINDS WILL
DIMINISH DURING THE MORNING.
OTHERWISE...EXPECT A LT TO MODT ONSHORE FLOW CONTINUING THROUGH
THE WEEK AS HIGH PRES REMAINS EAST OF THE REGION. WIDELY SCT
SHOWERS AND TSTMS WILL BE POSSIBLE THROUGH WEDNESDAY AS A SERIES
OF DISTURBANCES CROSSES THE REGION. CONVECTION WILL BECOME MORE
ISLTD TOWARD THE END OF THE WEEK AS WEAK RIDGING BUILDS IN ALOFT.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 84 68 86 70 / 70 30 40 30
LCH 86 72 86 73 / 50 20 30 20
LFT 87 72 86 72 / 50 20 50 20
BPT 87 75 86 74 / 50 20 20 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT EXERCISE CAUTION UNTIL 9 AM CDT THIS MORNING FOR
GMZ430-432-435-450-452-455-470-472-475.
&&
$$
PUBLIC...24
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1154 PM CDT SUN MAY 17 2015
.AVIATION...
REDEVELOPMENT OF TSTMS IS EXPECTED OVER THE NEXT FEW HOURS...WITH
N LA TERMINALS MOST PRONE TO BE AFFECTED. CONVECTION IS EXPECTED
AT LEAST INTERMITTENTLY FOR THE ENTIRE 06Z TAF PD. FOR
TONIGHT...LIGHT WINDS AND MOIST SOILS FROM PREVIOUS RAINS WILL
ALLOW FOR SOME PATCHY FOG DEVELOPMENT...ESPECIALLY WHERE CLOUDS
ARE ABLE TO THIN OUT. ADDITIONALLY...PATCHY MVFR STRATUS WILL BE
POSSIBLE AT A FEW OF THE TERMINALS AS WELL. OTHERWISE...EXPECT SLY
WINDS GENERALLY LESS THAN 10 KTS THROUGHOUT THE PD. /12/
&&
.PREV DISCUSSION... /ISSUED 1032 PM CDT SUN MAY 17 2015/
UPDATE...
TO MAKE ADJUSTMENTS TO THE RAIN CHANCES TONIGHT THROUGH MONDAY
NIGHT AND CONTINUED THE THREAT FOR FLASH FLOODING FOR EAST AND
NORTHEAST TEXAS...NORTHWEST AND NORTH CENTRAL LOUISIANA AND
ADJACENT SOUTHWEST AND SOUTH CENTRAL ARKANSAS AND SOUTHEAST
OKLAHOMA.
DISCUSSION...
A CONTINUED SOUTHERLY FLOW OF GULF MOISTURE TO GO ALONG WITH A
CONTRIBUTING SUPPLY OF PACIFIC MOISTURE AND A SERIES OF UPPER
LEVEL DISTURBANCES RIDING TOWARD THE FOUR STATE REGION WILL
CONTINUE TO PROVIDE SHOWERS AND THUNDERSTORMS OVERNIGHT. SOME OF
THE STORMS WILL DEVELOP AND SPREAD OVER THE SAME AREAS THAT HAVE
HAD LOCALLY HEAVY RAIN LATELY RESULTING IN FLASH FLOODING. /06/
PREV DISCUSSION... /ISSUED 455 PM CDT SUN MAY 17 2015/
DISCUSSION...
MOST OF THE REMNANTS OF THE MORNING MCS HAVE EXITED THE REGION AS
OF 2115Z...ALTHOUGH SCT CONVECTION HAS REDEVELOPED OVER SE TX/SW
LA AND HAVE BEGUN TO SPREAD NE INTO THE HIGHER INSTABILITY AIR
WHERE MLCAPES STILL RANGE FROM 2000-2500 J/KG. BELIEVE THAT MUCH
OF THIS CONVECTION WILL GRADUALLY DIMINISH BY EARLY/MID EVENING
WITH THE LOSS OF HEATING/STABILITY. HOWEVER...OUR FOCUS WILL TURN
TO THE W AS THE AFTERNOON WATER VAPOR IMAGERY DEPICTS A WELL-
DEFINED SHORTWAVE OVER ERN NM ENTERING FAR W TX...WHICH REMAINS
PROGGED TO LIFT NE ACROSS THE RED RIVER VALLEY LATE THIS
EVENING/OVERNIGHT. THE AIR MASS OVER E TX/SE OK/SW AR REMAINS
SOMEWHAT STABLE THIS AFTERNOON IN WAKE OF THE MORNING
MCS...ALTHOUGH SBCIN HAS WEAKENED OVER THIS AREA OVER THE LAST FEW
HOURS AS SOME HEATING HAS OCCURRED BENEATH THE DENSE CONVECTIVE
DEBRIS IN PLACE. THE SHORT TERM PROGS ARE IN GENERAL AGREEMENT
WITH SCT CONVECTION REDEVELOPING LATER THIS EVENING OVER THE
REGION...ATOP A STILL MOIST AND SOMEWHAT UNSTABLE AIRMASS WHERE
DIFLUENT FLOW ALOFT SPREADS OVER THE REGION. COULD ALREADY BE
SEEING EVIDENCE OF THE FORCING ALOFT OVER SCNTRL/WCNTRL TX...WHERE
VISIBLE SATELLITE IMAGERY DEPICTS AN ELEVATED CU/AC FIELD
DEVELOPING OVER THESE AREAS. THE NAM/GFS ARE A LITTLE MORE
AGGRESSIVE IN DEVELOPING SCT CONVECTION BY MID TO LATE
EVENING...WITH THE HRRR A BIT SLOWER /AFTER 06Z/ OVER NE TX/SW
AR/POSSIBLY NW LA. HOWEVER...QPF PLACEMENTS VARY CONSIDERABLE WITH
THE MODELS THIS AFTERNOON...AND HAVE TAKEN A BLEND OF THE MODELS
AND ISSUED A FLASH FLOOD WATCH FROM 03Z THIS EVENING THROUGH 18Z
MONDAY FOR MUCH OF E TX/SE OK/SW AR/NW LA. THESE AREAS REMAIN
SATURATED FROM HEAVY RAINFALL THAT HAS FALLEN OVER THE LAST COUPLE
OF WEEKS...AND WILL BE FAIR GAME FOR CELL TRAINING LATER TONIGHT.
HAVE ADDED HEAVY RAINFALL TO THE FORECAST LATE TONIGHT THROUGH
MONDAY MORNING FOR THE WATCH AREA...AS PW/S CLIMB TO 1.8-2.0
INCHES...VERY NEAR THE MAX MOVING AVERAGE OF CLIMO FOR THE DATE.
AREAS TO THE SE OVER THE SRN SECTIONS OF NCNTRL LA HAVE NOT SEEN
NEARLY AS MUCH RAIN AS AREAS FARTHER N AND W...AND SHOULD BE ABLE
TO TAKE THE HEAVY RAIN AS IT MOVES THROUGH THE AREAS MONDAY. THE
HEAVY RAINFALL/FLASH FLOOD THREAT OVER THE WATCH AREAS SHOULD
DIMINISH BY EARLY MONDAY AFTERNOON AS THE SHORTWAVE QUICKLY
SPREADS ENE INTO THE MID-SOUTH/LOWER MS VALLEY.
THE CLOSED LOW A CPL HUNDRED MILES W OF THE CA COAST THIS
AFTERNOON IS EXPECTED TO COME ASHORE INTO CA EARLY MONDAY...WITH
THE MAIN ATTENDANT TROUGH LIFTING NE INTO THE SRN ROCKIES BY
EARLY TUESDAY AND INTO THE PLAINS TUESDAY AFTERNOON. THIS TROUGH
WILL HELP TO AMPLIFY SOMEWHAT FLAT UPPER RIDGING ALOFT OVER THE
SRN PLAINS/MID AND LOWER MS VALLEY AND SE STATES TUESDAY...WITH
THE FLAT RIDGING PERSISTING THROUGH MUCH OF THIS WEEK. THE SHORT
TERM PROGS REMAIN IN AGREEMENT WITH A WEAK SFC FRONT BACKDOORING
SW INTO ERN OK/CNTRL AR TUESDAY MORNING BEFORE BECOMING
STATIONARY. PREFER THE NAM/ECMWF POSITION OF THE FRONT THAN THE
GFS...WHICH SEEMS MUCH TOO FAR S GIVEN THE LACK OF HEIGHT FALLS
ALOFT TO HELP DRIVE THE FRONT FARTHER S. THE FRONT SHOULD HELP
FOCUS SCT CONVECTION DURING PEAK HEATING TUESDAY...WHILE OTHER
ISOLATED TO WIDELY SCT CONVECTION DEVELOPS FARTHER S WHERE
INSTABILITY/MOISTURE LIE OVER E TX/N LA...EVEN A WEAK
PERTURBATIONS SHIFT E ATOP THE FLAT RIDGE ALOFT. THE SFC FRONT
SHOULD LIFT BACK N TUESDAY NIGHT...BEFORE ANOTHER WEAK COOL FRONT
BEGINS TO BUILD S ACROSS OK/NW AR WEDNESDAY AFTERNOON. THE PROGS
ARE AGAIN KEYING IN WEAKNESSES IN THE FLOW ALOFT ATOP THE RIDGE TO
ENHANCE SCT CONVECTION DEVELOPMENT MAINLY OVER CNTRL/SRN OK/SW AR
WEDNESDAY AFTERNOON...BEFORE THE FRONT SLOWLY SLIDE INTO THE
REGION WEDNESDAY NIGHT/THURSDAY BEFORE BECOMING STATIONARY.
HAVE MAINTAINED LIKELY/HIGH CHANCE POPS WEDNESDAY NIGHT AHEAD OF
THE FRONT...WITH MID CHANCE POPS THURSDAY WITH THE FROPA. HAVING
THE SFC BNDRY AROUND THROUGH LATE FRIDAY WILL FOCUS SCT CONVECTION
DEVELOPMENT THROUGH LATE WEEK...BEFORE THE FRONT BEGINS TO LIFT
BACK N OUT OF THE AREA. TEMPS WILL REMAIN NEAR/SLIGHTLY ABOVE
CLIMO THROUGH MUCH OF THE PERIOD.
PRELIMS TO FOLLOW BELOW...
15
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 82 71 82 70 / 60 70 70 30
MLU 89 72 81 69 / 50 60 70 40
DEQ 79 68 83 67 / 80 50 40 40
TXK 80 70 83 68 / 80 60 50 40
ELD 84 70 81 68 / 60 70 70 40
TYR 78 71 82 69 / 80 60 50 30
GGG 78 70 82 69 / 80 70 60 30
LFK 81 72 82 71 / 80 40 70 30
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR ARZ050-051-
059>061-070>073.
LA...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR LAZ001>006-
010>012.
OK...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR OKZ077.
TX...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR TXZ096-097-
108>112-124>126-136>138-149>153.
&&
$$
12
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1200 AM EDT WED MAY 20 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 407 PM EDT TUE MAY 19 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER
WRN CANADA AND A DOWNSTREAM TROUGH FROM ERN CANADA INTO THE NRN
GREAT LAKES. STRONG MID-LEVEL DRYING WAS EVIDENT THROUGH THE NORTHERN
LAKES BEHIND A SHORTWAVE TROUGH THAT HAS MOVED EAST OF LAKE
SUPERIOR. AT THE SFC...HIGH PRES OVER THE ERN DAKOTAS WAS BUILDING
INTO THE UPPER MS VALLEY AN WRN LAKES BRINGING DIMINISHING NW WINDS
AND CLEARING SKIES. VIS LOOP SHOWED CLEAR SKIES OVER THE WEST AND
THINNING CLOUDS CENTRAL. RADAR ALSO INDICATED THAT THE REMAINING -
SHSN HAD QUICKLY DISSIPATED WITH ONLY SOME ISOLD FLURRIES OVER THE
EAST.
TONIGHT...AS THE HIGH PRES RIDGE BUILDS FROM WI INTO LOWER
MI...EXPECT SKIES TO CLEAR AND WEST WINDS TO DIMINISH/DECOUPLE.
FAVORABLE RADIATIONAL COOLING CONDITIONS WITH PWAT VALUES AT OR
BELOW 0.25 INCH WILL ALLOW TEMPS TO DROP TOWARD THE LOWER END OF
GUIDANCE. MIN READINGS INTO THE MID TO UPPER 20S INLAND ARE EXPECTED
TO TEMPS TO AROUND 30 CLOSER TO THE LAKES. ALTHOUGH OUR FROST/FREEZE
PROGRAM HAS NOT STARTED YET...WOULD EXPECT A WIDESPREAD FROST ACROSS
UPPER MICHIGAN AND A HARD FREEZE OVER THE INTERIOR WEST. AN SPS HAS
BEEN ISSUED TO HIGHLIGHT THE EXPECTED CONDITIONS.
WEDNESDAY...WITH DRY HIGH PRES DOMINATING...ABUNDANT SUNSHINE AND
MIXING TO AROUND 6K FT (850 MB TEMPS AROUND 4C) WILL SUPPORT INLAND
HIGHS IN TOE LOW TO MID 60S. LAKE BREEZES WILL KEEP READINGS IN THE
50S ALONG THE GREAT LAKES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 328 PM EDT TUE MAY 19 2015
A QUIET FIRST HALF OF THE LONG TERM PERIOD IS IN STORE FOR THE UPPER
GREAT LAKES REGION...DUE TO THE AREA BEING BETWEEN AN UPPER TROUGH
OVER EASTERN CANADA AND ANOTHER OVER THE SOUTHWESTERN
CONUS. WHILE THE UPPER GREAT LAKES REGION WILL BE BRUSHED BY A FEW
WAVES ASSOCIATED WITH THESE FEATURES...THE OVERALL FLOW WILL BE OUT
OF THE NORTHWEST OR WEST-NORTHWEST WITH LIMITED MOISTURE.
HIGH PRESSURE WILL DOMINATE MUCH OF THE WEDNESDAY TO SATURDAY
PERIOD...WITH TEMPERATURES GENERALLY RUNNING BELOW NORMAL
(ESPECIALLY NEAR LAKE SUPERIOR). THE ONLY SIGNIFICANT ITEM OF NOTE
IS A COLD FRONT THAT WILL DROP SOUTH ACROSS THE REGION ON WEDNESDAY
NIGHT AND THURSDAY. WITH MOISTURE CONTINUING TO LOOK LIMITED...WILL
JUST SHOW PARTLY CLOUDY SKIES AS IT MOVES THROUGH THE AREA. THERE
ARE SOME HINTS THAT DIURNAL HEATING MAY BE ENOUGH TO KICK OFF A
STRAY SHOWER OVER SOUTHERN MENOMINEE COUNTY (MORE LIKELY IN
NORTHEAST WISCONSIN) WITH SOME HELP FROM A LAKE BREEZE OFF THE BAY
OF GREEN BAY. DON/T HAVE ENOUGH CONFIDENCE TO INCLUDE POPS FOR
ANY FARTHER NORTH THAN THE CITY OF MENOMINEE...BUT IT WILL BE
SOMETHING TO WATCH. ANOTHER BRIEF COOL DOWN IS EXPECTED BEHIND THE
FRONT WITH THE NORTHERLY FLOW OFF LAKE SUPERIOR BEFORE HIGHS SLOWLY
RISE TOWARDS MORE NORMAL VALUES ON SATURDAY (DUE TO THE HIGH
DEPARTING AND SOUTHERLY FLOW STARTING TO DEVELOP.
MODELS REMAIN CONSISTENT ON ENERGY FROM THE SOUTHWESTERN CONUS
TROUGH EJECTING NORTHEAST TOWARDS THE AREA SATURDAY NIGHT INTO
EARLY NEXT WEEK. A SURFACE LOW DEVELOPING IN THE PLAINS WITH THIS
FEATURE WILL MOVE INTO IOWA BY SUNDAY NIGHT BEFORE LIFTING
NORTHEAST THROUGH THE GREAT LAKES REGION MONDAY INTO MONDAY NIGHT.
THE LATEST TREND IS FOR THE LOW AND ASSOCIATED UPPER LEVEL WAVE TO
LIFT FARTHER TO THE NORTH THAN THOUGHT YESTERDAY...SO WILL TREND
POPS UP ON SUNDAY NIGHT AND MONDAY AS THE LOW MOVES THROUGH.
INSTABILITY AND MID LEVEL LAPSE RATES REMAIN WEAK DURING THAT
PERIOD...WITH THE AREA GENERALLY ON THE NORTHWEST SIDE OF THE
SURFACE LOW...SO WILL KEEP THUNDER OUT OF THE FORECAST. NEXT WEEK
STILL LOOKS TO BE UNSETTLED...AS THE UPPER TROUGH IN THE SOUTHWEST
CONUS WEAKENS AND LIFTS THROUGH THE CENTRAL CONUS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1200 AM EDT WED MAY 20 2015
VFR CONDITIONS WILL CONTINUE THROUGH THE FORECAST PERIOD. SAW WILL
SEE A NORTHEAST LAKE BREEZE AGAIN WITH WEAK WINDS WED AFTERNOON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EDT TUE MAY 19 2015
AS HIGH PRES BUILDS ACROSS THE REGION FROM THE WEST AND THE PRES
GRADIENT WEAKENS...WINDS WILL DIMINISH TO LESS THAN 20 KNOTS. WED
THROUGH SAT...WINDS WILL BE UNDER 20KT AS SFC HIGH PRES REMAINS IN
CONTROL THROUGH MUCH OF THE PERIOD. A WEAK FRONT IS EXPECTED TO SAG
INTO THE REGION BY SUNDAY BUT WINDS WILL REMAIN GENERALLY LIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
725 PM EDT TUE MAY 19 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 330 PM EDT TUE MAY 19 2015
A COOL AIR MASS HAS SETTLED INTO SOUTHWEST LOWER MICHIGAN AND FROST
AND FREEZING TEMPERATURES ARE A DISTINCT POSSIBILITY TONIGHT. A
FREEZE WARNING HAS BEEN POSTED FOR CENTRAL LOWER MICHIGAN AND A
FROST ADVISORY HAS BEEN HOISTED FOR THE REMAINING AREAS OF SOUTHWEST
LOWER MICHIGAN. DRY WEATHER IS EXPECTED THE REMAINDER OF THE WORK
WEEK. CONDITIONS WILL REMAIN ON THE COOL SIDE OF NORMAL THIS
WEEK...WITH A WARMUP AS WE MOVE THROUGH THE HOLIDAY WEEKEND. ALONG
WITH THE WARMER AIR WILL COME CHANCES FOR RAIN...ESPECIALLY SUNDAY
INTO MEMORIAL DAY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 330 PM EDT TUE MAY 19 2015
MAIN FOCUS OF THE SHORT TERM WAS ON WHETHER TO EXPAND A FROST
HEADLINE INTO THE COUNTIES THAT WERE NOT COVERED BY THE FREEZE
WARNING ACROSS CENTRAL LOWER. DECIDED TO DO THAT...SO A FROST
ADVISORY IS NOW IN PLACE FOR THE REST OF THE FORECAST
AREA...ESSENTIALLY FROM INTERSTATE 96 TO THE SOUTH. DRIER AIR
CONTINUES TO POUR INTO THE AREA ON NORTHWEST WINDS...WITH THE DEW
POINT CURRENTLY AT GRAND RAPIDS AT 31 DEGREES. THINKING THE
STRATOCUMULUS WILL FADE WITH THE SETTING SUN THIS EVENING WHICH
SHOULD SET UP OK RADIATIONAL CONDITIONS. ONE ITEM OF CONCERN IS A
CORE OF WIND THAT IS SEEN IN NAM CROSS SECTIONS IN BUFKIT.
STILL...GIVEN A DECENT AMOUNT OF MAINLY CLEAR SKIES TONIGHT AND VERY
DRY/COOL AIR ALREADY IN PLACE FELT HEADLINES WERE WARRANTED ACROSS
THE FORECAST AREA.
THE REMAINDER OF THE SHORT TERM WILL BE QUIET. WE HAVE A DRY
FORECAST IN PLACE TONIGHT THROUGH THURSDAY NIGHT. THERE IS A
SHORTWAVE THAT SLIDES BY THE SOUTHERN GREAT LAKES TOMORROW NIGHT
INTO THURSDAY...BUT HAVE SIDED WITH THE DRY ECMWF AND GFS MODELS.
THE PRECIP SHOULD MISS US JUST TO THE SOUTH. ALSO ON THURSDAY...A
WEAK TROUGH MOVES THROUGH THE LOWER PENINSULA WITH SOME SPOTTY
PRECIP AMOUNTS BEING KICKED OUT BY THE MODELS. MOISTURE IS NOT ALL
THAT DEEP IN THE WED NIGHT THROUGH THURS NIGHT TIME FRAME SO AM
OPTING FOR DRY.
IT WILL BE COOL THE NEXT SEVERAL DAYS WITH NO MAJOR WARM ADVECTION
PUSH AT 850MB/S.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 330 PM EDT TUE MAY 19 2015
THE MAIN FOCUS IN THE LONG TERM WILL BE THE POSSIBILITY FOR WET
WEATHER AND GUSTY WINDS GOING INTO THE HOLIDAY WEEKEND.
HIGH PRESSURE WILL BE IN CONTROL EARLY IN THE PERIOD FROM FRIDAY
THROUGH THE MAJORITY OF SATURDAY. AS HIGH PRESSURE PROGRESSES TO THE
EAST AN AREA OF LOW PRESSURE WILL BEGIN TO EJECT OUT OF THE
SOUTHWEST AND INTO THE CENTRAL PLAINS. A WARM FRONTAL BOUNDARY WILL
EXTEND OUT AHEAD OF THE SYSTEM...GIVING WAY TO SOUTHERLY INFLUENCE.
THIS SYSTEM WILL TAKE SOMEWHAT OF A SIMILAR TRACK TO LAST WEEKENDS
SYSTEM...THROUGH THE UPPER MIDWEST.
THE BEST PRECIPITATION CHANCES WILL LIKELY BE LATE SATURDAY NIGHT
INTO SUNDAY MORNING AND AGAIN MONDAY AFTERNOON AND EVENING. SATURDAY
NIGHTS RAINFALL WILL BE ASSOCIATED WITH THE RESULTING ISENTROPIC
LIFT WITH THE PASSAGE OF THE WARM FRONT. LOW PRESSURE THEN
TRANSITIONS FROM A CLOSED LOW TO A SHORT WAVE THAT IS EVENTUALLY
CONSUMED AROUND THE MAIN CYCLONIC FLOW NEAR THE HUDSON BAY. THE WARM
FRONTAL BOUNDARY GETS HINGED UP OVER CENTRAL AND NORTHERN LOWER
MICHIGAN AND BECOMES NEARLY STATIONARY. WE MAY VERY WELL SEE A LULL
IN ACTIVITY SUNDAY AFTERNOON AS WE LOSE THE LIFT.
GOING INTO MEMORIAL DAY IS WHERE WE SEE THE POSSIBILITY OF GUSTY
WINDS AND THE POTENTIAL FOR THUNDERSTORMS. WHILE UPPER LEVEL WINDS
ARE NOT SO IMPRESSIVE...AN 850MB JET CORE OF 40-50KTS MOVES OVER THE
SOUTHERN PORTIONS OF THE FORECAST AREA. THIS IS SOMETHING THAT WOULD
USUALLY TRIGGER SOME CONCERN...BUT THERE ARE A COUPLE OF LIMITING
FACTORS TO ANY REAL ORGANIZED CONVECTION. THE BEST LIFT WOULD REMAIN
NORTH ALONG THE BOUNDARY...WHILE THE BEST CAPE STAYS SOUTHEAST OF
GRAND RAPIDS. THIS MAY BE SOMETHING TO WATCH AS WE CREEP CLOSER TO
MONDAY IF CONDITIONS BECOME BETTER ORGANIZED. OTHERWISE...IT SEEMS
THE HOLIDAY WILL HAVE SCATTERED AFTERNOON THUNDERSTORMS...SOME
LOCALIZED HEAVY RAINFALL AND GUSTY WINDS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 724 PM EDT TUE MAY 19 2015
WITH A DRY AIRMASS SETTLING IN ON THE REGION...VFR WEATHER IS
FORECASTED TO PREVAIL THROUGH THE PERIOD. GUSTY WINDS INITIALLY
WILL SETTLE DOWN THROUGH THE EVENING AS THE MIXING GRADUALLY
DECREASES. AN ONSHORE FLOW SHOULD DEVELOP WED AFTN ALONG THE
LAKESHORE.
&&
.MARINE...
ISSUED AT 330 PM EDT TUE MAY 19 2015
EXTENDED THE SMALL CRAFT ADVISORY THROUGH 800 PM. OBS ARE STILL GUST
TO AROUND 20 KNOTS IN MOST AREAS. THE BUOYS AT LAST CHECK ARE IN THE
3 TO 5 FOOT RANGE AT MUSKEGON...PORT SHELDON AND SOUTH HAVEN IN
TERMS OF WAVE HEIGHTS. EXPECTING THINGS TO DIMINISH TONIGHT. ONE
POSSIBLE ISSUE IS HIGH RESOLUTION GUIDANCE LIKE THE HRRR IS SHOWING
A SURGE IN WINDS FROM HOLLAND SOUTH AFTER DARK. THIS IS LIKELY DUE
TO SOME CHANNELING AND FUNNELING DOWN THE SHORELINE IN NORTHERLY
FLOW. THE EVENING SHIFT WILL BE MONITORING THE LATEST TRENDS IN THE
HIGH RESO GUIDANCE FOR A POSSIBLE EXTENTION IN TIME SOUTH OF
HOLLAND. THE SOUTH HAVEN GLERL OB ON THE PIER AND THE BUOY JUST
OFFSHORE WILL BE THE PIECES OF DATA TO WATCH AFTER DARK TO SEE IF
THE HRRR VERIFIES. OTHERWISE FAIRLY LIGHT WINDS THE NEXT FEW DAYS.
&&
.HYDROLOGY...
ISSUED AT 140 PM EDT MON MAY 18 2015
IN GENERAL...RIVER LEVELS ACROSS SOUTHWEST LOWER MICHIGAN ARE
GRADUALLY FALLING. THAT WILL CONTINUE TO BE THE CASE WITH LIMITED
QPF THIS WEEK. FAIR WEATHER WILL DOMINATE FOR THE REST OF THE WEEK
INTO AT LEAST SATURDAY. THE NEXT SIGNIFICANT CHANCE FOR WIDESPREAD
RAINFALL WILL BE LATE IN THE HOLIDAY WEEKEND INTO NEXT WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM EDT WEDNESDAY FOR
MIZ050-056>059-064>067-071>074.
FREEZE WARNING FROM MIDNIGHT TONIGHT TO 8 AM EDT WEDNESDAY FOR
MIZ037>040-043>046-051-052.
LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ844>849.
&&
$$
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...JAM
AVIATION...MJS
HYDROLOGY...EBW/CAS
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
401 PM EDT MON MAY 18 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 359 PM EDT MON MAY 18 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NW ONTARIO INTO THE WRN GREAT LAKES WITH THE LOW CIRCULATION CENTER
NEAR CYQT. AT THE SFC...A TROUGH EXTENDED THROUGH NRN LAKE SUPERIOR
FROM LOW PRES E OF LAKE SUPERIOR. WITH THE WRAP-AROUND MOISTURE/PCPN
MOVING EDGING TOWARD THE AREA...RADARS INDICATED DIURNALLY ENHANCED
SCT/NMRS -SHSN/SHRA FROM NE MN INTO NW WI. SOME LIGHT RAIN OR
DRIZZLE HAD ALSO DEVELOPED INTO UPSLOPE FLOW LOCATIONS OF NW UPPER
MI.
TONIGHT...THE COMBINATION OF DEEP MOISTURE SLIDING INTO THE AREA
BEHIND THE MID LEVEL LOW AND CAA DROPPING 850 MB TEMPS INTO THE -8C
TO -11C RANGE WILL SUPPORT SCT/NMRS -SHRA/-SHSN INTO MAINLY THE WEST
HALF OF UPPER MI. THE MOST FAVORABLE UPSLOPE FLOW AND LOW LEVEL CONV
WILL SHIFT TO LOCATIONS OVER THE W FAVORED BY NRLY FLOW AND INTO N
CNTRL UPPER MI LATE. LOW LEVEL THICKNESS AND WET-BULB ZERO HEIGHTS
SUGGEST ANY PCPN WILL CHANGE OVER TO MAINLY SNOW FROM WEST TO EAST
THIS EVENING. ALTHOUGH QPF AMOUNTS TO AROUND A TENTH OF AN INCH ARE
EXPECTED...WITH THE RELATIVELY WARM GROUND...ANY SNOWFALL AMOUNTS
SHOULD REMAIN AROUND A HALF INCH OR LESS...MAINLY ON GRASSY SURFACES.
TUE...AS HIGH PRES BUILDS TOWARD THE AREA WITH INCREASINGLY ACYC
LOW LEVEL FLOW...AND THE DEEPER MOISTURE DEPARTS TO THE EAST...THE
LINGERING SNOW SHOWERS SHOULD GRADUALLY DIMINISH AND END OVER MOST OF
THE CWA BY 18Z. THERE MAY BE SOME LIGHT PCPN LINGERING OVER THE EAST
DURING THE AFTERNOON. CLOUDS WILL ALSO ONLY SLOWLY DISSIPATE FROM
WEST TO EAST DURING THE MID TO LATE AFTERNOON.
OTHERWISE...UNSEASONABLY COLD CONDITIONS ARE EXPECTED WITH HIGHS
ONLY FROM AROUND 40 NORTH TO THE MID AND UPPER 40S SOUTH AND WEST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 320 PM EDT MON MAY 18 2015
A GENERALLY QUIET LONG TERM PERIOD IS IN STORE FOR THE UPPER GREAT
LAKES REGION. THIS IS DUE TO THE AREA LARGELY BEING BETWEEN AN
UPPER TROUGH OVER EASTERN CANADA AND ANOTHER OVER THE SOUTHWESTERN
CONUS. WHILE THE UPPER GREAT LAKES REGION WILL BE BRUSHED BY A FEW
WAVES ASSOCIATED WITH THESE FEATURES...THE OVERALL FLOW WILL BE OUT
OF THE NORTHWEST OR WEST-NORTHWEST WITH LIMITED MOISTURE.
HIGH PRESSURE BUILDS INTO THE AREA ON TUESDAY NIGHT AND REMAINS
INTO WEDNESDAY. THE DRY AIR ASSOCIATED WITH THE HIGH WILL DIMINISH
ANY LINGERING CLOUDS OVER THE EASTERN CWA QUICKLY DURING THE EARLY
EVENING HOURS. THE CLEARING SKIES AND WEAKENING WINDS WILL LEAD TO
A COLD NIGHT ACROSS THE AREA ON TUESDAY NIGHT. HAVE FOLLOWED THE
LOWER END OF GUIDANCE (WITH PWAT VALUES ONLY AROUND 0.25IN)...WHICH
GIVES VALUES IN THE 20S FOR MOST INTERIOR LOCATIONS. ALTHOUGH OUR
FROST/FREEZE PROGRAM HASN/T STARTED...WOULD EXPECT A WIDESPREAD
FROST (AND A HARD FREEZE FOR THE INTERIOR WEST) ACROSS UPPER
MICHIGAN AND PERSONS WITH SENSITIVE PLANTS WOULD BE WISE TO PREPARE
FOR A SOLID FROST.
A WEAK COLD FRONT DROPS SOUTH FROM ONTARIO WEDNESDAY NIGHT AND WITH
THE LACK OF MOISTURE ONLY SHOWED A PERIOD OF PARTLY CLOUDY SKIES
AS IT MOVES THROUGH. BEHIND THE FRONT...NORTHERLY FLOW OFF LAKE
SUPERIOR WILL KEEP TEMPERATURES COOLER NEAR LAKE SUPERIOR ON
THURSDAY (50S) WHILE AREAS INLAND RISE TO OR JUST ABOVE 60.
FRIDAY/SATURDAY CONTINUE TO LOOK DRY (WITH TEMPERATURES WARMING
TOWARDS NORMAL) AS ANOTHER CANADIAN HIGH PRESSURE MOVES ACROSS THE
AREA.
THE HIGH WILL DEPART SATURDAY NIGHT...AS ENERGY FROM THE
SOUTHWESTERN CONUS TROUGH EJECTS NORTHEAST TOWARDS THE AREA. A
SURFACE LOW DEVELOPING IN THE PLAINS WITH THIS FEATURE WILL MOVE
INTO IOWA BY SUNDAY NIGHT BEFORE SLOWLY SHIFTING EAST THROUGH
SOUTHERN WISCONSIN BY MONDAY NIGHT. AT THIS POINT...EXPECT THE CWA
TO BE ON THE NORTHERN EDGE OF MUCH OF THE FORCING (WARM FRONT
STALLS OVER SOUTHERN WISCONSIN) AND BEST CHANCES FOR RAIN WILL BE
OVER THE SOUTHERN HALF OF THE CWA AS WEAK SHORTWAVES LIFT NORTHEAST
ACROSS THE AREA IN THE SOUTHWESTERLY FLOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 128 PM EDT MON MAY 18 2015
WRAPAROUND MOISTURE INTO THE WRN TAF SITES WILL PRODUCE SOME SCT
RAIN SHOWERS THIS AFTERNOON AT IWD AND CMX UNDER MVFR CONDITIONS.
EXPECT CIGS NEAR OF JUST ABOVE THRESHOLD AT SAW UNTIL THIS EVENING
WHEN THE COLDER AIR AND GREATER LOW LEVEL MOISTURE MOVE IN. THE PUSH
OF COLDER AIR BEHIND SECONDARY COLD FRONT WILL CHANGE RAIN SHOWERS
AT KIWD AND KCMX OVER TO SNOW SHOWERS THIS EVENING WITH IFR
CONDITIONS DEVELOPING. SCT -SHRA DEVELOPING AT KSAW EARLY EVENING
WILL ALSO CHANGE OVER TO -SHSN LATE TONIGHT WITH CONDITIONS NEAR
IFR. LOW LEVEL MOISTURE WITH NNW WINDS WILL MAINTAIN MVFR CIGS
INTO EARLY TUE AFTERNOON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 359 PM EDT MON MAY 18 2015
LOW PRES EAST OF LAKE SUPERIOR WILL CONTINUE TO MOVE TO THE EAST
TONIGHT. A TIGHTENING PRES GRADIENT AHEAD OF HIGH PRES BUILDING
TOWARD THE AREA FROM THE NRN PLAINS WILL BOOST NNW WINDS TO 20 TO 30
KNOTS WITH THE POTENTIAL FOR A FEW GALE FORCE GUSTS OVER THE E HALF
LATE TONIGHT AND TUE MORNING. WINDS WILL DIMINISH W TO E TUE
AFTERNOON/NIGHT THE HIGH BUILDS IN FM THE WEST. WED THRROUGH
SAT...WINDS WILL BE UNDER 20KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
320 PM EDT MON MAY 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EDT MON MAY 18 2015
WATER VAPOR LOOP AND RAP ANALYSIS SHOWS MID-LVL LOW ROTATING OVER
NRN MN WITH A DRY SLOT AHEAD OF LOW REACHING ACROSS MUCH OF THE
UPPER MI. COLD FRONT MOVING ACROSS MUCH OF THE AREA OVERNIGHT HAS
ALLOWED DRIER AIR TO ADVECT IN FROM THE SW WHICH HAS DISSIPATED THE
DENSE FOG OVER LAKE MI AND AREAS DOWNSTREAM OVER ERN UPPER MI. DRY
SLOT HAS LEFT UPPER MI GENERALLY PCPN FREE OVER THE EARLY MORNING
HRS.
TODAY AND TONIGHT...THE FOCUS TODAY WILL ON COLD SURGE WHICH WILL BE
MOVING INTO THE WEST MID-LATE MORNING AND CONTINUE EASTWARD THROUGH
THE DAY. AHEAD OF THE FRONT OVER THE EAST HALF OF UPPER MI AND AWAY
FROM THE MODERATING INFLUENCE OF LAKE MICHIGAN...SHOULD SEE
TEMPERATURES REACH IN THE MID TO UPPER 60S (WITH A FEW 70S POSSIBLE
IF THERE ARE BREAKS IN THE LOW CLOUDS). OVER THE WEST HALF WHERE
FRONTAL PASSAGE WILL OCCUR EARLIER...MORNING TO EARLY AFTERNOON HIGH
TEMPS WILL RANGE FROM UPPER 40S/50F NEAR IRONWOOD TO LOWER 60S ALONG
A LINE FM MQT TO MENOMINEE. IN ADDITION...ALL OF THE HIGHER
RESOLUTION MODELS ARE SURGING IN A LAKE BREEZE OFF LAKE SUPERIOR
(FROM MARQUETTE EASTWARD) WHICH WILL LEAD TO COOLER NORTHERLY FLOW
BY MID-LATE AFTERNOON OVER NCNTRL AREAS. WITH THE COLD AIR AND
ABUNDANT MOISTURE SURGING INTO THE AREA AS WINDS TURN
WESTERLY...EXPECT ISOLATED TO SCATTERED SHOWERS TO DEVELOP OVER THE
WEST FIRST (ESPECIALLY IN THE FAVORED UPSLOPE AREAS) AND THEN SPREAD
INTO THE CENTRAL AREAS EVENING AND POSSIBLY EASTERN COUNTIES LATE
EVENING/OVERNIGHT. CAA ON BLUSTERY NW TO N WINDS WILL ALLOW 8H TEMPS
TO FALL TO -8 TO -10C OVER MUCH OF THE WEST HALF OF UPPER MI BY 12Z
TUE. 8H TEMPS WILL FALL TO AROUND -5C OVER THE EAST HALF OVERNIGHT.
BEST FORCING OUT AHEAD ANOTHER SHORTWAVE TRACKING ALONG THE
MN/ONTARIO BORDER TONIGHT WILL STAY MAINLY NW OF UPPER MI KEEPING
MUCH OF THE ASSOCIATED LIGHT PCPN N OF UPPER MI. HOWEVER...DEEP
CYCLONIC FLOW/MOISTURE WILL STILL SUPPORT SOME LIGHT PCPN IN UPPER
MI AS WELL...ESPECIALLY IN THE UPSLOPE AREAS OF THE W AND N. WITH
COLD ADVECTION TAKING PLACE AS NOTED BEFORE...THE -SHRA WILL MIX
WITH OR CHANGE TO -SHSN TONIGHT FROM WEST TO EAST. DUE TO THE COLD
ADVECTION AND PCPN OCCURRING DURING THE OVERNIGHT HOURS...CAN`T RULE
OUT A DUSTING TO LOCALLY A HALFINCH OF SNOW ON GRASSY SFCS BY 12Z
TUE.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 320 PM EDT MON MAY 18 2015
A GENERALLY QUIET LONG TERM PERIOD IS IN STORE FOR THE UPPER GREAT
LAKES REGION. THIS IS DUE TO THE AREA LARGELY BEING BETWEEN AN
UPPER TROUGH OVER EASTERN CANADA AND ANOTHER OVER THE SOUTHWESTERN
CONUS. WHILE THE UPPER GREAT LAKES REGION WILL BE BRUSHED BY A FEW
WAVES ASSOCIATED WITH THESE FEATURES...THE OVERALL FLOW WILL BE OUT
OF THE NORTHWEST OR WEST-NORTHWEST WITH LIMITED MOISTURE.
HIGH PRESSURE BUILDS INTO THE AREA ON TUESDAY NIGHT AND REMAINS
INTO WEDNESDAY. THE DRY AIR ASSOCIATED WITH THE HIGH WILL DIMINISH
ANY LINGERING CLOUDS OVER THE EASTERN CWA QUICKLY DURING THE EARLY
EVENING HOURS. THE CLEARING SKIES AND WEAKENING WINDS WILL LEAD TO
A COLD NIGHT ACROSS THE AREA ON TUESDAY NIGHT. HAVE FOLLOWED THE
LOWER END OF GUIDANCE (WITH PWAT VALUES ONLY AROUND 0.25IN)...WHICH
GIVES VALUES IN THE 20S FOR MOST INTERIOR LOCATIONS. ALTHOUGH OUR
FROST/FREEZE PROGRAM HASN/T STARTED...WOULD EXPECT A WIDESPREAD
FROST (AND A HARD FREEZE FOR THE INTERIOR WEST) ACROSS UPPER
MICHIGAN AND PERSONS WITH SENSITIVE PLANTS WOULD BE WISE TO PREPARE
FOR A SOLID FROST.
A WEAK COLD FRONT DROPS SOUTH FROM ONTARIO WEDNESDAY NIGHT AND WITH
THE LACK OF MOISTURE ONLY SHOWED A PERIOD OF PARTLY CLOUDY SKIES
AS IT MOVES THROUGH. BEHIND THE FRONT...NORTHERLY FLOW OFF LAKE
SUPERIOR WILL KEEP TEMPERATURES COOLER NEAR LAKE SUPERIOR ON
THURSDAY (50S) WHILE AREAS INLAND RISE TO OR JUST ABOVE 60.
FRIDAY/SATURDAY CONTINUE TO LOOK DRY (WITH TEMPERATURES WARMING
TOWARDS NORMAL) AS ANOTHER CANADIAN HIGH PRESSURE MOVES ACROSS THE
AREA.
THE HIGH WILL DEPART SATURDAY NIGHT...AS ENERGY FROM THE
SOUTHWESTERN CONUS TROUGH EJECTS NORTHEAST TOWARDS THE AREA. A
SURFACE LOW DEVELOPING IN THE PLAINS WITH THIS FEATURE WILL MOVE
INTO IOWA BY SUNDAY NIGHT BEFORE SLOWLY SHIFTING EAST THROUGH
SOUTHERN WISCONSIN BY MONDAY NIGHT. AT THIS POINT...EXPECT THE CWA
TO BE ON THE NORTHERN EDGE OF MUCH OF THE FORCING (WARM FRONT
STALLS OVER SOUTHERN WISCONSIN) AND BEST CHANCES FOR RAIN WILL BE
OVER THE SOUTHERN HALF OF THE CWA AS WEAK SHORTWAVES LIFT NORTHEAST
ACROSS THE AREA IN THE SOUTHWESTERLY FLOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 128 PM EDT MON MAY 18 2015
WRAPAROUND MOISTURE INTO THE WRN TAF SITES WILL PRODUCE SOME SCT
RAIN SHOWERS THIS AFTERNOON AT IWD AND CMX UNDER MVFR CONDITIONS.
EXPECT CIGS NEAR OF JUST ABOVE THRESHOLD AT SAW UNTIL THIS EVENING
WHEN THE COLDER AIR AND GREATER LOW LEVEL MOISTURE MOVE IN. THE PUSH
OF COLDER AIR BEHIND SECONDARY COLD FRONT WILL CHANGE RAIN SHOWERS
AT KIWD AND KCMX OVER TO SNOW SHOWERS THIS EVENING WITH IFR
CONDITIONS DEVELOPING. SCT -SHRA DEVELOPING AT KSAW EARLY EVENING
WILL ALSO CHANGE OVER TO -SHSN LATE TONIGHT WITH CONDITIONS NEAR
IFR. LOW LEVEL MOISTURE WITH NNW WINDS WILL MAINTAIN MVFR CIGS
INTO EARLY TUE AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT MON MAY 18 2015
LOW PRES OVER NRN MN WILL MOVE ACROSS LAKE SUPERIOR TODAY INTO THIS
EVENING. AS A RESULT...WINDS ON LAKE SUPERIOR WILL VEER FM SW THIS
MORNING TO NNW LATE TODAY AND TONIGHT AND RAMP UP TO 20 TO 30 KTS
TONIGHT AND TUE...STRONGEST OVER THE EAST HALF. NOT OUT OF THE
QUESTION THAT THERE COULD BE SOME GALE FORCE GUSTS OVER THE E HALF
OF THE LAKE LATE TONIGHT/TUE MORNING. WINDS WILL DIMINISH W TO E TUE
AFTN/NIGHT AS A HIGH PRES RIDGE BUILDS IN FM THE WEST. WED THRU
FRI...WINDS WILL BE UNDER 20KT. LINGERING WARM MOIST AIR WILL ALLOW
FOG TO CONTINUE OVER THE LAKE TODAY...POSSIBLE LOCALLY DENSE OVER
THE EAST HALF THIS MORNING. ALL FOG SHOULD DISSIPATE BY THIS EVENING
AS COLDER AIR ARRIVES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
156 PM EDT MON MAY 18 2015
.UPDATE...
ISSUED AT 156 PM EDT MON MAY 18 2015
SCT SHRA HAVE DEVELOPED OVER THE PAST HOUR...A LITTLE FURTHER
INLAND THAN EXPECTED (FROM W BRANCH TO NEAR BLACK RIVER).
FORECAST ADJUSTED ACCORDINGLY...EXPANDING AND BOOSTING POPS.
FORECAST ALSO ADJUSTED EARLIER TO BOOST MAX TEMPS IN PARTS OF NE
LOWER...ESPECIALLY NEAR APN/ROGERS...PER OBS.
UPDATE ISSUED AT 947 AM EDT MON MAY 18 2015
A STRONG COLD FRONT IS OVER EASTERN WI THIS MORNING. TEMPS ARE
PUSHING 70F ALONG THE WI LAKE MI COAST...BUT ARE IN THE LOW 40S IN
THE NW CORNER OF THE STATE. THERE IS NO PRECIP ALONG THE
FRONT...IN FACT THERE IS NO CLOUD COVER ALONG THE FRONT...THOUGH
POST-FRONTAL CLOUD COVER IS SUBSTANTIAL. CLOSER TO HOME...PATCHY
MID/HIGH CLOUDS ARE SEEN OVER NORTHERN MI...A BIT THICKER ACROSS
EASTERN UPPER.
A COUPLE OF POINTS OF CONCERN TODAY. THE COLD FRONT WILL CROSS THE
REGION THIS AFTERNOON. ANY POTENTIAL CONVECTION ALONG IT LOOKS TO
BE CONFINED TO THE EXTREME SE...AS A GENERAL LACK OF FORCING AND
WARM TEMPS ALOFT WILL PROVE A SIGNIFICANT OBSTACLE. WE MIGHT BE
ABLE TO MUSTER 500J/KG OF SBCAPE IN FAR SE SECTIONS. THE MOST
RECENT HRRR AND RUC RUNS DO TRY TO POP SOMETHING EARLY THIS
AFTERNOON...BEFORE DRIER AIR ARRIVES LATER IN THE DAY. HAVE ADDED
A SLIGHT CHANCE OF A SHRA EARLY/MID AFTERNOON FROM OSC TO
STANDISH.
THE OTHER ISSUE IS ANY POTENTIAL FIRE WX CONCERNS. JUST BEHIND A COLD
FRONT IS A CLASSIC SUMMER FIRE WX PATTERN FOR US...AS WITH STRONG
HEATING WE TEND TO DRY OUT FASTER THAN WE COOL OFF. HOWEVER...
IDEALLY COLD FROPA WOULD HAPPEN A FEW HOURS EARLIER...IN THE
MORNING AS OPPOSED TO THE PM. HAVE LOWERED DEW POINTS A BIT DURING
THE AFTERNOON...BUT HAVE ALSO DONE THE SAME TO LATE-DAY TEMPS AS
THE COOLER AIR MAKES INITIAL INROADS. SO DON/T HAVE RH LEVELS
GOING BELOW 35 PERCENT OR SO.
&&
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 319 AM EDT MON MAY 18 2015
ALL REMAINING SHOWERS HAVE EXITED NE OUT OF OUR CWA EARLY THIS
MORNING...WITH NO ADDITIONAL SHOWER ACTIVITY CURRENTLY PRESENT
UPSTREAM AS THE WRN GREAT LAKES REMAINS FIRMLY WITHIN THE DRY SLOT
ASSOCIATED WITH DEEP LOW PRESSURE NOW CENTERED OVER NRN MINNESOTA.
SKIES HAVE AT LEAST PARTIALLY CLEARED IN RESPONSE TO THIS DRIER AIR
WORKING ITS WAY INTO MICHIGAN. OUR CWA WILL REMAIN WITHIN THE DRY
SLOT THRU MUCH OF TODAY AS THE SURFACE LOW CENTER MAKES SLOW
EASTWARD PROGRESS THRU UPPER MICHIGAN AND INTO QUEBEC BY 00Z
TUESDAY. EXPECT A PARTLY TO MOSTLY SUNNY AND DRY DAY ALONG WITH
UNSEASONABLY WARM TEMPS FOR MOST OF OUR CWA. AFTERNOON HIGHS WILL
ONLY REACH TO AROUND 70 DEGREES ACROSS ERN UPR MICHIGAN WHERE CAA ON
THE BACKSIDE OF THE LOW WILL INITIALLY BEGIN THIS AFTERNOON. BUT
TEMPS WILL ONCE AGAIN WARM INTO THE UPPER 70S AND LOWER 80S FOR NRN
LWR MICHIGAN (COOLER NEAR THE LAKES)...GIVING US ONE LAST DAY OF
SUMMER WARMTH BEFORE THE REALITY OF NRN MICHIGAN IN MID MAY KICKS
BACK IN ON TUESDAY.
LOW LEVEL MOISTURE/CLOUDS WILL WRAP BACK INTO NRN MICHIGAN TONIGHT
ON THE BACKSIDE OF THE DEPARTING LOW. THE CAA BEHIND THE LOW WILL BE
RAPID AND IMPRESSIVE THRU THE NIGHT...AS 850 MB TEMPS DROP FROM +13C
THIS AFTERNOON TO AROUND -2C BY 12Z TUESDAY. AT THIS POINT...THINK
THE ONLY LOCATION THAT WILL SEE A CHANCE OF SHOWERS WILL BE NW
CHIPPEWA COUNTY THIS AFTERNOON AND TONIGHT WHERE CAA AND LOW LEVEL
WRAP AROUND MOISTURE ADVECTION TAKE PLACE SOONEST. THE REST OF OUR
CWA SHOULD BE GENERALLY DRY...BUT WITH DEEP CYCLONIC FLOW...
INCREASING LOW LEVEL MOISTURE AND EVENTUALLY SOME OVER-LAKE
INSTABILITY DEVELOPING LATE TONIGHT THANKS TO CAA...WILL NEED TO
KEEP AN EYE ON THE POTENTIAL FOR SOME SHOWER ACTIVITY TO DEVELOP.
FOR NOW...WILL MAINTAIN A DRY FORECAST WITH INCREASING CLOUDS
TONIGHT. TEMPS WILL BE NOTICEABLY COLDER TONIGHT...WITH LOWS FALLING
MAINLY INTO THE 40S.
&&
.SHORT TERM...(TUESDAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 319 AM EDT MON MAY 18 2015
HIGH IMPACT WEATHER: TUESDAY NIGHT LOW TEMPERATURES/FROST POTENTIAL
FOR N LOWER.
FORECAST CHALLENGE: HOW FAR WILL THE TEMPERATURES FALL TUESDAY
NIGHT.
(05/19)TUESDAY...WITH THE FRONT SEVERAL HUNDRED MILES TO THE EAST,
THE COLD AIR WILL BE PUSHING INTO THE REGION THROUGH THE DAY.
TEMPERATURES WILL PRETTY MUCH GO NO WHERE AS THE 850 MB TEMPERATURES
FALL FROM AROUND 0C TO ABOUT -4 OR -6C DEPENDING ON THE MODEL. THE
ECMWF IS BEGINNING TO BACK OFF ON THE -8C AIR THAT IT WAS
ADVERTISING THE LAST 2 RUNS, WITH IT AROUND -6C AT ANJ. WHILE THE
GFS WILL BE AROUND -4C. WILL HAVE A MIX OF RAIN AND SNOW IN THE
AFTERNOON AS THE SFC TEMPERATURES BEGIN TO FALL INTO THE UPPER 30S
BY IN E UPPER. THE MOISTURE DOESN`T LOOK DEEP ENOUGH FOR
PRECIPITATION IN N LOWER SO WILL LEAVE IT OUT OF THERE, JUST MOSTLY
CLOUDY. OVERNIGHT, THE RH AT 850 MB AND IN THE 700-500 MB LAYER WILL
DROP TO LESS THAN 20% ON BOTH MODELS BY 12Z. AND WITH THE 850 MB
TEMPERATURES MAINTAINING AROUND 0C OR BELOW, AND, AT LEAST ON THE
ECMWF, THE WINDS WILL PROBABLY DECOUPLE, FROST IS PROBABLE, AND
MAYBE A FREEZE IS POSSIBLE. FOR NOW WILL HAVE PATCHY AND AREAS OF
FROST, BUT THIS IS LOOKING MORE WIDE SPREAD IF THE WINDS DROP OFF
LIKE THE ECMWF WOULD SUGGEST.
(05/20)WEDNESDAY...LOOKS TO BE A SUNNY TO PARTLY CLOUDY DAY WITH LOW
RELATIVE HUMIDITY AND HIGH TEMPERATURES, BELOW NORMAL (LOOKS LIKE
NOW AROUND 5 TO 10 DEGREES BELOW) IF THE MODELS PAN OUT. OVERNIGHT,
A 500 MB SHORTWAVE PUSHES THROUGH THE FORECAST AREA, BUT THE MODELS
SUGGEST THAT ONLY THE MOISTURE IN THE 700-500 MB LAYER WOULD
INCREASE, IF ANY AT ALL. SO WILL EXPECT THAT THE NIGHT WOULD REMAIN
DRY. MAY IDEAS IS THAT THE SKY REMAINS CLEAR TO PARTLY CLOUDY, SO
TEMPERATURES LOOK TO BE IN THE LOWER TO MID 30S, SO ANOTHER FROST
NIGHT? PUT PATCHY IN FOR THE INLAND AREAS, AND LEFT THE LAKE SHORES
FROST FREE WHERE THE AIR TEMPERATURE IS EXPECTED TO BE A LITTLE
WARMER.
&&
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 319 AM EDT MON MAY 18 2015
EXTENDED (THURSDAY THROUGH SUNDAY)...WITH THE 500 MB TROUGH THAT
PARKS ITSELF OVER THE NEW ENGLAND STARTING TUESDAY AND HANGS THERE
THROUGH FRIDAY. FRIDAY, THE LOW BEGINS TO MOVE OUT ALLOWING THE 500
MB RIDGE TO BUILD IN THE UPPER GREAT LAKES. SO WHAT DOES THIS MEAN
FOR THE LONG TERM? SFC HIGH PRESSURE WILL CAMP OUT IN THE UPPER
GREAT LAKES THROUGH THE WEEK, KEEPING THE AREA DRY THROUGH SATURDAY
NIGHT, AND THE 500 MB PATTERN WILL KEEP THE HIGH TEMPERATURES AROUND
OR BELOW NORMAL THROUGH THE WEEK WHEN THE NORMAL HIGH TEMPERATURES
IN GAYLORD AND SAULT STE. MARIE ARE IN THE UPPER 60S. SUNDAY, THE
MODELS BEGIN TO KEY IN ON THE NEXT 500 MB LOW THAT MOVES OUT OF THE
CENTRAL ROCKIES AND INTO THE CENTRAL PLAINS, PRODUCING SHOWERS AND
POSSIBLY THUNDERSTORMS AS THE WARM FRONT PUSHES UP THROUGH THE
STATE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 126 PM EDT MON MAY 18 2015
VFR THRU THIS EVENING. MVFR CIGS DEVELOPING OVERNIGHT PLN/TVC/MBL.
LOW PRESSURE IS CENTERED JUST NE OF LAKE SUPERIOR...AND WILL MOVE
QUICKLY INTO QUEBEC THRU THIS EVENING. STRONG COLD FRONT WILL
CROSS NORTHERN MI THIS AFTERNOON/EARLY EVENING. MINIMAL RISK OF
PRECIP WITH THE FRONT...BUT LOW LEVEL MOISTURE WILL INCREASE IN
THE MUCH COLDER AIR BEHIND THE FRONT. MVFR CIGS WILL BECOME
ESTABLISHED AT PLN/TVC/MBL LATE TONIGHT...AND CONTINUE INTO TUE
MORNING. APN WILL STAY VFR.
SW WINDS WILL BE GUSTY (20-25KT) THIS AFTERNOON. WINDS VEER W AND
NW TONIGHT...BECOMING LESS GUSTY FOR A PERIOD...BEFORE
BLUSTERINESS RETURNS TUE MORNING.
&&
.MARINE...
ISSUED AT 319 AM EDT MON MAY 18 2015
WINDS AND WAVES WILL APPROACH SCA CRITERIA TODAY AND ESPECIALLY
TONIGHT AS CAA DEVELOPS ON THE WAKE OF A DEPARTING LOW. AT THIS
POINT...EXPECT CONDITIONS SHOULD REMAIN UNDER CRITERIA...SO WILL
NOT ISSUE A SCA AT THIS TIME. STRONGER NW WINDS WILL LIKELY DEVELOP
ON TUESDAY AS CAA STRENGTHENS BEHIND THE DEPARTING LOW. AREAS OF FOG
AND LOW STRATUS WILL CONTINUE TO IMPACT OUR NEARSHORE AREAS THRU
THIS MORNING BEFORE MIXING OUT THIS AFTERNOON.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LHZ345>347.
LM...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LMZ341-342.
LS...NONE.
&&
$$
UPDATE...JAZ
NEAR TERM...MLR
SHORT TERM...JSL
LONG TERM...JSL
AVIATION...JAZ
MARINE...MLR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
129 PM EDT MON MAY 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EDT MON MAY 18 2015
WATER VAPOR LOOP AND RAP ANALYSIS SHOWS MID-LVL LOW ROTATING OVER
NRN MN WITH A DRY SLOT AHEAD OF LOW REACHING ACROSS MUCH OF THE
UPPER MI. COLD FRONT MOVING ACROSS MUCH OF THE AREA OVERNIGHT HAS
ALLOWED DRIER AIR TO ADVECT IN FROM THE SW WHICH HAS DISSIPATED THE
DENSE FOG OVER LAKE MI AND AREAS DOWNSTREAM OVER ERN UPPER MI. DRY
SLOT HAS LEFT UPPER MI GENERALLY PCPN FREE OVER THE EARLY MORNING
HRS.
TODAY AND TONIGHT...THE FOCUS TODAY WILL ON COLD SURGE WHICH WILL BE
MOVING INTO THE WEST MID-LATE MORNING AND CONTINUE EASTWARD THROUGH
THE DAY. AHEAD OF THE FRONT OVER THE EAST HALF OF UPPER MI AND AWAY
FROM THE MODERATING INFLUENCE OF LAKE MICHIGAN...SHOULD SEE
TEMPERATURES REACH IN THE MID TO UPPER 60S (WITH A FEW 70S POSSIBLE
IF THERE ARE BREAKS IN THE LOW CLOUDS). OVER THE WEST HALF WHERE
FRONTAL PASSAGE WILL OCCUR EARLIER...MORNING TO EARLY AFTERNOON HIGH
TEMPS WILL RANGE FROM UPPER 40S/50F NEAR IRONWOOD TO LOWER 60S ALONG
A LINE FM MQT TO MENOMINEE. IN ADDITION...ALL OF THE HIGHER
RESOLUTION MODELS ARE SURGING IN A LAKE BREEZE OFF LAKE SUPERIOR
(FROM MARQUETTE EASTWARD) WHICH WILL LEAD TO COOLER NORTHERLY FLOW
BY MID-LATE AFTERNOON OVER NCNTRL AREAS. WITH THE COLD AIR AND
ABUNDANT MOISTURE SURGING INTO THE AREA AS WINDS TURN
WESTERLY...EXPECT ISOLATED TO SCATTERED SHOWERS TO DEVELOP OVER THE
WEST FIRST (ESPECIALLY IN THE FAVORED UPSLOPE AREAS) AND THEN SPREAD
INTO THE CENTRAL AREAS EVENING AND POSSIBLY EASTERN COUNTIES LATE
EVENING/OVERNIGHT. CAA ON BLUSTERY NW TO N WINDS WILL ALLOW 8H TEMPS
TO FALL TO -8 TO -10C OVER MUCH OF THE WEST HALF OF UPPER MI BY 12Z
TUE. 8H TEMPS WILL FALL TO AROUND -5C OVER THE EAST HALF OVERNIGHT.
BEST FORCING OUT AHEAD ANOTHER SHORTWAVE TRACKING ALONG THE
MN/ONTARIO BORDER TONIGHT WILL STAY MAINLY NW OF UPPER MI KEEPING
MUCH OF THE ASSOCIATED LIGHT PCPN N OF UPPER MI. HOWEVER...DEEP
CYCLONIC FLOW/MOISTURE WILL STILL SUPPORT SOME LIGHT PCPN IN UPPER
MI AS WELL...ESPECIALLY IN THE UPSLOPE AREAS OF THE W AND N. WITH
COLD ADVECTION TAKING PLACE AS NOTED BEFORE...THE -SHRA WILL MIX
WITH OR CHANGE TO -SHSN TONIGHT FROM WEST TO EAST. DUE TO THE COLD
ADVECTION AND PCPN OCCURRING DURING THE OVERNIGHT HOURS...CAN`T RULE
OUT A DUSTING TO LOCALLY A HALFINCH OF SNOW ON GRASSY SFCS BY 12Z
TUE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON MAY 18 2015
TUESDAY WILL BRING ABOUT ONLY SLOWLY RISING TEMPS AS A SECONDARY
TROUGH/COLD FRONT SINKING ACROSS CENTRAL TO E UPPER MI. 850MB TEMPS
AT A CHILLY -10C OVER THE KEWEENAW PENINSULA /2-5C WARMER OFF THE
17/18Z AND 18/00Z GFS RUNS...AS WELL AS THE REGIONAL WRF/. THE NAM
IS THE COLDEST WITH THE ENTIRE W HALF AROUND -11C TUESDAY MORNING.
850MB TEMPS WILL FALL FROM AROUND -4C AT ERY TO AROUND -9C BY 18Z
TUESDAY ON NW WINDS. THIS WILL BE AS ANOTHER SHORTWAVE OVER NE MN AT
12Z SLIDES ACROSS LAKE SUPERIOR. YES...SNOW IS POSSIBLE STILL ON
TUESDAY...BUT MAY BE LIMITED TO JUST A DUSTING ON MAINLY GRASSY
SURFACES THROUGH THE MORNING HOURS...BEFORE THE LOW LEVEL RH
DIMINISHES SIGNIFICANTLY.
EXPECT BREEZY CONDITIONS...WITH GUSTS AVERAGING 20-25KTS ACROSS MUCH
OF THE CWA...STRONGEST ACROSS THE KEWEENAW PENINSULA AND E NEAR LAKE
SUPERIOR. DESPITE LIGHT W FLOW RETURNING AT THE SFC TUESDAY NIGHT
AND 850MB TEMPS WARMING TO AROUND 0C...LOWS NEAR TO SLIGHTLY BELOW
FREEZING WILL BE POSSIBLE /COLDEST IN THE TRADITIONAL COOL SPOTS OF
THE INTERIOR W HALF OF UPPER MI/.
EXPECT DRIER CONDITIONS WITH LIGHTER WINDS WEDNESDAY AS SFC TEMPS
REBOUND TO AROUND 60F. THIS WILL BE DESPITE THE 500MB TROUGH WITH
ITS NW FLOW LINGERING OVERHEAD...AS THE LARGE SFC HIGH OVER THE
DAKOTAS BUILDS A RIDGE ACROSS UPPER MI. PW VALUES SHOULD BE AROUND
0.25IN FROM OVERNIGHT TUESDAY NIGHT THROUGH MUCH OF WEDNESDAY
/ALTHOUGH SLIGHTLY HIGHER NEAR LAKE MI FROM LATE MORNING ON/.
DRY WEATHER SHOULD REMAIN THROUGH THE REST OF THE WORK WEEK AT NW
FLOW LINGERS AT 500MB. THERE WILL BE A WEAK COLD FRONT STRETCHING
ACROSS N LAKE SUPERIOR AT 00Z THURSDAY THAT SINKS ACROSS UPPER MI
WEDNESDAY EVENING AND LOWER MI DURING THE DAY THURSDAY. NOT
EXPECTING MUCH MORE THAN THE POSSIBILITY OF TEMPORARY ADDITIONAL
CLOUD COVER. HIGH PRESSURE WILL SLIDE IN BEHIND THE FRONTAL BOUNDARY
TO WRAP UP THE END OF THE WORK WEEK. EXPECT THIS HIGH TO SHIFT TO
THE LOWER GREAT LAKES BY 18Z SATURDAY AND OFF THE MID-ATLANTIC COAST
SUNDAY MORNING. THIS EXITING HIGH WILL ALLOW MOISTURE TO
RETURN...ALONG WITH A GOOD CHANCE OF SHOWERS FOR SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 128 PM EDT MON MAY 18 2015
WRAPAROUND MOISTURE INTO THE WRN TAF SITES WILL PRODUCE SOME SCT
RAIN SHOWERS THIS AFTERNOON AT IWD AND CMX UNDER MVFR CONDITIONS.
EXPECT CIGS NEAR OF JUST ABOVE THRESHOLD AT SAW UNTIL THIS EVENING
WHEN THE COLDER AIR AND GREATER LOW LEVEL MOISTURE MOVE IN. THE PUSH
OF COLDER AIR BEHIND SECONDARY COLD FRONT WILL CHANGE RAIN SHOWERS
AT KIWD AND KCMX OVER TO SNOW SHOWERS THIS EVENING WITH IFR
CONDITIONS DEVELOPING. SCT -SHRA DEVELOPING AT KSAW EARLY EVENING
WILL ALSO CHANGE OVER TO -SHSN LATE TONIGHT WITH CONDITIONS NEAR
IFR. LOW LEVEL MOISTURE WITH NNW WINDS WILL MAINTAIN MVFR CIGS
INTO EARLY TUE AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT MON MAY 18 2015
LOW PRES OVER NRN MN WILL MOVE ACROSS LAKE SUPERIOR TODAY INTO THIS
EVENING. AS A RESULT...WINDS ON LAKE SUPERIOR WILL VEER FM SW THIS
MORNING TO NNW LATE TODAY AND TONIGHT AND RAMP UP TO 20 TO 30 KTS
TONIGHT AND TUE...STRONGEST OVER THE EAST HALF. NOT OUT OF THE
QUESTION THAT THERE COULD BE SOME GALE FORCE GUSTS OVER THE E HALF
OF THE LAKE LATE TONIGHT/TUE MORNING. WINDS WILL DIMINISH W TO E TUE
AFTN/NIGHT AS A HIGH PRES RIDGE BUILDS IN FM THE WEST. WED THRU
FRI...WINDS WILL BE UNDER 20KT. LINGERING WARM MOIST AIR WILL ALLOW
FOG TO CONTINUE OVER THE LAKE TODAY...POSSIBLE LOCALLY DENSE OVER
THE EAST HALF THIS MORNING. ALL FOG SHOULD DISSIPATE BY THIS EVENING
AS COLDER AIR ARRIVES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
948 AM EDT MON MAY 18 2015
.UPDATE...
ISSUED AT 947 AM EDT MON MAY 18 2015
A STRONG COLD FRONT IS OVER EASTERN WI THIS MORNING. TEMPS ARE
PUSHING 70F ALONG THE WI LAKE MI COAST...BUT ARE IN THE LOW 40S IN
THE NW CORNER OF THE STATE. THERE IS NO PRECIP ALONG THE
FRONT...IN FACT THERE IS NO CLOUD COVER ALONG THE FRONT...THOUGH
POST-FRONTAL CLOUD COVER IS SUBSTANTIAL. CLOSER TO HOME...PATCHY
MID/HIGH CLOUDS ARE SEEN OVER NORTHERN MI...A BIT THICKER ACROSS
EASTERN UPPER.
A COUPLE OF POINTS OF CONCERN TODAY. THE COLD FRONT WILL CROSS THE
REGION THIS AFTERNOON. ANY POTENTIAL CONVECTION ALONG IT LOOKS TO
BE CONFINED TO THE EXTREME SE...AS A GENERAL LACK OF FORCING AND
WARM TEMPS ALOFT WILL PROVE A SIGNIFICANT OBSTACLE. WE MIGHT BE
ABLE TO MUSTER 500J/KG OF SBCAPE IN FAR SE SECTIONS. THE MOST
RECENT HRRR AND RUC RUNS DO TRY TO POP SOMETHING EARLY THIS
AFTERNOON...BEFORE DRIER AIR ARRIVES LATER IN THE DAY. HAVE ADDED
A SLIGHT CHANCE OF A SHRA EARLY/MID AFTERNOON FROM OSC TO
STANDISH.
THE OTHER ISSUE IS ANY POTENTIAL FIRE WX CONCERNS. JUST BEHIND A COLD
FRONT IS A CLASSIC SUMMER FIRE WX PATTERN FOR US...AS WITH STRONG
HEATING WE TEND TO DRY OUT FASTER THAN WE COOL OFF. HOWEVER...
IDEALLY COLD FROPA WOULD HAPPEN A FEW HOURS EARLIER...IN THE
MORNING AS OPPOSED TO THE PM. HAVE LOWERED DEW POINTS A BIT DURING
THE AFTERNOON...BUT HAVE ALSO DONE THE SAME TO LATE-DAY TEMPS AS
THE COOLER AIR MAKES INITIAL INROADS. SO DON/T HAVE RH LEVELS
GOING BELOW 35 PERCENT OR SO.
&&
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 319 AM EDT MON MAY 18 2015
ALL REMAINING SHOWERS HAVE EXITED NE OUT OF OUR CWA EARLY THIS
MORNING...WITH NO ADDITIONAL SHOWER ACTIVITY CURRENTLY PRESENT
UPSTREAM AS THE WRN GREAT LAKES REMAINS FIRMLY WITHIN THE DRY SLOT
ASSOCIATED WITH DEEP LOW PRESSURE NOW CENTERED OVER NRN MINNESOTA.
SKIES HAVE AT LEAST PARTIALLY CLEARED IN RESPONSE TO THIS DRIER AIR
WORKING ITS WAY INTO MICHIGAN. OUR CWA WILL REMAIN WITHIN THE DRY
SLOT THRU MUCH OF TODAY AS THE SURFACE LOW CENTER MAKES SLOW
EASTWARD PROGRESS THRU UPPER MICHIGAN AND INTO QUEBEC BY 00Z
TUESDAY. EXPECT A PARTLY TO MOSTLY SUNNY AND DRY DAY ALONG WITH
UNSEASONABLY WARM TEMPS FOR MOST OF OUR CWA. AFTERNOON HIGHS WILL
ONLY REACH TO AROUND 70 DEGREES ACROSS ERN UPR MICHIGAN WHERE CAA ON
THE BACKSIDE OF THE LOW WILL INITIALLY BEGIN THIS AFTERNOON. BUT
TEMPS WILL ONCE AGAIN WARM INTO THE UPPER 70S AND LOWER 80S FOR NRN
LWR MICHIGAN (COOLER NEAR THE LAKES)...GIVING US ONE LAST DAY OF
SUMMER WARMTH BEFORE THE REALITY OF NRN MICHIGAN IN MID MAY KICKS
BACK IN ON TUESDAY.
LOW LEVEL MOISTURE/CLOUDS WILL WRAP BACK INTO NRN MICHIGAN TONIGHT
ON THE BACKSIDE OF THE DEPARTING LOW. THE CAA BEHIND THE LOW WILL BE
RAPID AND IMPRESSIVE THRU THE NIGHT...AS 850 MB TEMPS DROP FROM +13C
THIS AFTERNOON TO AROUND -2C BY 12Z TUESDAY. AT THIS POINT...THINK
THE ONLY LOCATION THAT WILL SEE A CHANCE OF SHOWERS WILL BE NW
CHIPPEWA COUNTY THIS AFTERNOON AND TONIGHT WHERE CAA AND LOW LEVEL
WRAP AROUND MOISTURE ADVECTION TAKE PLACE SOONEST. THE REST OF OUR
CWA SHOULD BE GENERALLY DRY...BUT WITH DEEP CYCLONIC FLOW...
INCREASING LOW LEVEL MOISTURE AND EVENTUALLY SOME OVER-LAKE
INSTABILITY DEVELOPING LATE TONIGHT THANKS TO CAA...WILL NEED TO
KEEP AN EYE ON THE POTENTIAL FOR SOME SHOWER ACTIVITY TO DEVELOP.
FOR NOW...WILL MAINTAIN A DRY FORECAST WITH INCREASING CLOUDS
TONIGHT. TEMPS WILL BE NOTICEABLY COLDER TONIGHT...WITH LOWS FALLING
MAINLY INTO THE 40S.
&&
.SHORT TERM...(TUESDAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 319 AM EDT MON MAY 18 2015
HIGH IMPACT WEATHER: TUESDAY NIGHT LOW TEMPERATURES/FROST POTENTIAL
FOR N LOWER.
FORECAST CHALLENGE: HOW FAR WILL THE TEMPERATURES FALL TUESDAY
NIGHT.
(05/19)TUESDAY...WITH THE FRONT SEVERAL HUNDRED MILES TO THE EAST,
THE COLD AIR WILL BE PUSHING INTO THE REGION THROUGH THE DAY.
TEMPERATURES WILL PRETTY MUCH GO NO WHERE AS THE 850 MB TEMPERATURES
FALL FROM AROUND 0C TO ABOUT -4 OR -6C DEPENDING ON THE MODEL. THE
ECMWF IS BEGINNING TO BACK OFF ON THE -8C AIR THAT IT WAS
ADVERTISING THE LAST 2 RUNS, WITH IT AROUND -6C AT ANJ. WHILE THE
GFS WILL BE AROUND -4C. WILL HAVE A MIX OF RAIN AND SNOW IN THE
AFTERNOON AS THE SFC TEMPERATURES BEGIN TO FALL INTO THE UPPER 30S
BY IN E UPPER. THE MOISTURE DOESN`T LOOK DEEP ENOUGH FOR
PRECIPITATION IN N LOWER SO WILL LEAVE IT OUT OF THERE, JUST MOSTLY
CLOUDY. OVERNIGHT, THE RH AT 850 MB AND IN THE 700-500 MB LAYER WILL
DROP TO LESS THAN 20% ON BOTH MODELS BY 12Z. AND WITH THE 850 MB
TEMPERATURES MAINTAINING AROUND 0C OR BELOW, AND, AT LEAST ON THE
ECMWF, THE WINDS WILL PROBABLY DECOUPLE, FROST IS PROBABLE, AND
MAYBE A FREEZE IS POSSIBLE. FOR NOW WILL HAVE PATCHY AND AREAS OF
FROST, BUT THIS IS LOOKING MORE WIDE SPREAD IF THE WINDS DROP OFF
LIKE THE ECMWF WOULD SUGGEST.
(05/20)WEDNESDAY...LOOKS TO BE A SUNNY TO PARTLY CLOUDY DAY WITH LOW
RELATIVE HUMIDITY AND HIGH TEMPERATURES, BELOW NORMAL (LOOKS LIKE
NOW AROUND 5 TO 10 DEGREES BELOW) IF THE MODELS PAN OUT. OVERNIGHT,
A 500 MB SHORTWAVE PUSHES THROUGH THE FORECAST AREA, BUT THE MODELS
SUGGEST THAT ONLY THE MOISTURE IN THE 700-500 MB LAYER WOULD
INCREASE, IF ANY AT ALL. SO WILL EXPECT THAT THE NIGHT WOULD REMAIN
DRY. MAY IDEAS IS THAT THE SKY REMAINS CLEAR TO PARTLY CLOUDY, SO
TEMPERATURES LOOK TO BE IN THE LOWER TO MID 30S, SO ANOTHER FROST
NIGHT? PUT PATCHY IN FOR THE INLAND AREAS, AND LEFT THE LAKE SHORES
FROST FREE WHERE THE AIR TEMPERATURE IS EXPECTED TO BE A LITTLE
WARMER.
&&
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 319 AM EDT MON MAY 18 2015
EXTENDED (THURSDAY THROUGH SUNDAY)...WITH THE 500 MB TROUGH THAT
PARKS ITSELF OVER THE NEW ENGLAND STARTING TUESDAY AND HANGS THERE
THROUGH FRIDAY. FRIDAY, THE LOW BEGINS TO MOVE OUT ALLOWING THE 500
MB RIDGE TO BUILD IN THE UPPER GREAT LAKES. SO WHAT DOES THIS MEAN
FOR THE LONG TERM? SFC HIGH PRESSURE WILL CAMP OUT IN THE UPPER
GREAT LAKES THROUGH THE WEEK, KEEPING THE AREA DRY THROUGH SATURDAY
NIGHT, AND THE 500 MB PATTERN WILL KEEP THE HIGH TEMPERATURES AROUND
OR BELOW NORMAL THROUGH THE WEEK WHEN THE NORMAL HIGH TEMPERATURES
IN GAYLORD AND SAULT STE. MARIE ARE IN THE UPPER 60S. SUNDAY, THE
MODELS BEGIN TO KEY IN ON THE NEXT 500 MB LOW THAT MOVES OUT OF THE
CENTRAL ROCKIES AND INTO THE CENTRAL PLAINS, PRODUCING SHOWERS AND
POSSIBLY THUNDERSTORMS AS THE WARM FRONT PUSHES UP THROUGH THE
STATE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY)
ISSUED AT 700 AM EDT MON MAY 18 2015
VFR CONDITIONS ARE EXPECTED AT ALL NRN LWR MICHIGAN TAF SITES
THRU TODAY AS THE DRY SLOT (ASSOCIATED WITH DEEP LOW PRESSURE
JUST WEST OF MICHIGAN) REMAINS OVERHEAD. A LARGE AREA OF LOW LEVEL
MOISTURE WILL WRAP BACK INTO NRN MICHIGAN TONIGHT AS THE SURFACE
LOW RIDES EAST THRU MICHIGAN AND THEN EXITS INTO QUEBEC. SW SURFACE
WINDS AROUND 10 KTS WILL SHIFT TO THE W/NW THIS EVENING.
&&
.MARINE...
ISSUED AT 319 AM EDT MON MAY 18 2015
WINDS AND WAVES WILL APPROACH SCA CRITERIA TODAY AND ESPECIALLY
TONIGHT AS CAA DEVELOPS ON THE WAKE OF A DEPARTING LOW. AT THIS
POINT...EXPECT CONDITIONS SHOULD REMAIN UNDER CRITERIA...SO WILL
NOT ISSUE A SCA AT THIS TIME. STRONGER NW WINDS WILL LIKELY DEVELOP
ON TUESDAY AS CAA STRENGTHENS BEHIND THE DEPARTING LOW. AREAS OF FOG
AND LOW STRATUS WILL CONTINUE TO IMPACT OUR NEARSHORE AREAS THRU
THIS MORNING BEFORE MIXING OUT THIS AFTERNOON.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JAZ
NEAR TERM...MLR
SHORT TERM...JSL
LONG TERM...JSL
AVIATION...MLR
MARINE...MLR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
751 AM EDT MON MAY 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EDT MON MAY 18 2015
WATER VAPOR LOOP AND RAP ANALYSIS SHOWS MID-LVL LOW ROTATING OVER
NRN MN WITH A DRY SLOT AHEAD OF LOW REACHING ACROSS MUCH OF THE
UPPER MI. COLD FRONT MOVING ACROSS MUCH OF THE AREA OVERNIGHT HAS
ALLOWED DRIER AIR TO ADVECT IN FROM THE SW WHICH HAS DISSIPATED THE
DENSE FOG OVER LAKE MI AND AREAS DOWNSTREAM OVER ERN UPPER MI. DRY
SLOT HAS LEFT UPPER MI GENERALLY PCPN FREE OVER THE EARLY MORNING
HRS.
TODAY AND TONIGHT...THE FOCUS TODAY WILL ON COLD SURGE WHICH WILL BE
MOVING INTO THE WEST MID-LATE MORNING AND CONTINUE EASTWARD THROUGH
THE DAY. AHEAD OF THE FRONT OVER THE EAST HALF OF UPPER MI AND AWAY
FROM THE MODERATING INFLUENCE OF LAKE MICHIGAN...SHOULD SEE
TEMPERATURES REACH IN THE MID TO UPPER 60S (WITH A FEW 70S POSSIBLE
IF THERE ARE BREAKS IN THE LOW CLOUDS). OVER THE WEST HALF WHERE
FRONTAL PASSAGE WILL OCCUR EARLIER...MORNING TO EARLY AFTERNOON HIGH
TEMPS WILL RANGE FROM UPPER 40S/50F NEAR IRONWOOD TO LOWER 60S ALONG
A LINE FM MQT TO MENOMINEE. IN ADDITION...ALL OF THE HIGHER
RESOLUTION MODELS ARE SURGING IN A LAKE BREEZE OFF LAKE SUPERIOR
(FROM MARQUETTE EASTWARD) WHICH WILL LEAD TO COOLER NORTHERLY FLOW
BY MID-LATE AFTERNOON OVER NCNTRL AREAS. WITH THE COLD AIR AND
ABUNDANT MOISTURE SURGING INTO THE AREA AS WINDS TURN
WESTERLY...EXPECT ISOLATED TO SCATTERED SHOWERS TO DEVELOP OVER THE
WEST FIRST (ESPECIALLY IN THE FAVORED UPSLOPE AREAS) AND THEN SPREAD
INTO THE CENTRAL AREAS EVENING AND POSSIBLY EASTERN COUNTIES LATE
EVENING/OVERNIGHT. CAA ON BLUSTERY NW TO N WINDS WILL ALLOW 8H TEMPS
TO FALL TO -8 TO -10C OVER MUCH OF THE WEST HALF OF UPPER MI BY 12Z
TUE. 8H TEMPS WILL FALL TO AROUND -5C OVER THE EAST HALF OVERNIGHT.
BEST FORCING OUT AHEAD ANOTHER SHORTWAVE TRACKING ALONG THE
MN/ONTARIO BORDER TONIGHT WILL STAY MAINLY NW OF UPPER MI KEEPING
MUCH OF THE ASSOCIATED LIGHT PCPN N OF UPPER MI. HOWEVER...DEEP
CYCLONIC FLOW/MOISTURE WILL STILL SUPPORT SOME LIGHT PCPN IN UPPER
MI AS WELL...ESPECIALLY IN THE UPSLOPE AREAS OF THE W AND N. WITH
COLD ADVECTION TAKING PLACE AS NOTED BEFORE...THE -SHRA WILL MIX
WITH OR CHANGE TO -SHSN TONIGHT FROM WEST TO EAST. DUE TO THE COLD
ADVECTION AND PCPN OCCURRING DURING THE OVERNIGHT HOURS...CAN`T RULE
OUT A DUSTING TO LOCALLY A HALFINCH OF SNOW ON GRASSY SFCS BY 12Z
TUE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON MAY 18 2015
TUESDAY WILL BRING ABOUT ONLY SLOWLY RISING TEMPS AS A SECONDARY
TROUGH/COLD FRONT SINKING ACROSS CENTRAL TO E UPPER MI. 850MB TEMPS
AT A CHILLY -10C OVER THE KEWEENAW PENINSULA /2-5C WARMER OFF THE
17/18Z AND 18/00Z GFS RUNS...AS WELL AS THE REGIONAL WRF/. THE NAM
IS THE COLDEST WITH THE ENTIRE W HALF AROUND -11C TUESDAY MORNING.
850MB TEMPS WILL FALL FROM AROUND -4C AT ERY TO AROUND -9C BY 18Z
TUESDAY ON NW WINDS. THIS WILL BE AS ANOTHER SHORTWAVE OVER NE MN AT
12Z SLIDES ACROSS LAKE SUPERIOR. YES...SNOW IS POSSIBLE STILL ON
TUESDAY...BUT MAY BE LIMITED TO JUST A DUSTING ON MAINLY GRASSY
SURFACES THROUGH THE MORNING HOURS...BEFORE THE LOW LEVEL RH
DIMINISHES SIGNIFICANTLY.
EXPECT BREEZY CONDITIONS...WITH GUSTS AVERAGING 20-25KTS ACROSS MUCH
OF THE CWA...STRONGEST ACROSS THE KEWEENAW PENINSULA AND E NEAR LAKE
SUPERIOR. DESPITE LIGHT W FLOW RETURNING AT THE SFC TUESDAY NIGHT
AND 850MB TEMPS WARMING TO AROUND 0C...LOWS NEAR TO SLIGHTLY BELOW
FREEZING WILL BE POSSIBLE /COLDEST IN THE TRADITIONAL COOL SPOTS OF
THE INTERIOR W HALF OF UPPER MI/.
EXPECT DRIER CONDITIONS WITH LIGHTER WINDS WEDNESDAY AS SFC TEMPS
REBOUND TO AROUND 60F. THIS WILL BE DESPITE THE 500MB TROUGH WITH
ITS NW FLOW LINGERING OVERHEAD...AS THE LARGE SFC HIGH OVER THE
DAKOTAS BUILDS A RIDGE ACROSS UPPER MI. PW VALUES SHOULD BE AROUND
0.25IN FROM OVERNIGHT TUESDAY NIGHT THROUGH MUCH OF WEDNESDAY
/ALTHOUGH SLIGHTLY HIGHER NEAR LAKE MI FROM LATE MORNING ON/.
DRY WEATHER SHOULD REMAIN THROUGH THE REST OF THE WORK WEEK AT NW
FLOW LINGERS AT 500MB. THERE WILL BE A WEAK COLD FRONT STRETCHING
ACROSS N LAKE SUPERIOR AT 00Z THURSDAY THAT SINKS ACROSS UPPER MI
WEDNESDAY EVENING AND LOWER MI DURING THE DAY THURSDAY. NOT
EXPECTING MUCH MORE THAN THE POSSIBILITY OF TEMPORARY ADDITIONAL
CLOUD COVER. HIGH PRESSURE WILL SLIDE IN BEHIND THE FRONTAL BOUNDARY
TO WRAP UP THE END OF THE WORK WEEK. EXPECT THIS HIGH TO SHIFT TO
THE LOWER GREAT LAKES BY 18Z SATURDAY AND OFF THE MID-ATLANTIC COAST
SUNDAY MORNING. THIS EXITING HIGH WILL ALLOW MOISTURE TO
RETURN...ALONG WITH A GOOD CHANCE OF SHOWERS FOR SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 743 AM EDT MON MAY 18 2015
WRAPAROUND MOISTURE BEGINNING TO ARRIVE AT THE WRN TAF SITES WILL
PRODUCE SOME SCT RAIN SHOWERS THIS AFTERNOON AT IWD AND CMX UNDER
MVFR CONDITIONS. DRY AIR WILL KEEP KSAW VFR UNTIL LATE MORNING WHEN
MOISTURE AND BANK OF STRATU MOVES IN FROM THE SW...THEN COULD SEE A
PERIOD OF MVFR CIGS. PUSH OF COLDER AIR BEHIND SECONDARY COLD FRONT
WILL CHANGE RAIN SHOWERS AT KIWD AND KCMX OVER TO SNOW SHOWERS THIS
EVENING WITH IFR CONDITIONS DEVELOPING. SCT -SHRA DEVELOPING AT KSAW
EARLY EVENING WILL ALSO CHANGE OVER TO -SHSN LATE TONIGHT WITH
POSSIBLE IFR CONDITIONS DEVELOPING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT MON MAY 18 2015
LOW PRES OVER NRN MN WILL MOVE ACROSS LAKE SUPERIOR TODAY INTO THIS
EVENING. AS A RESULT...WINDS ON LAKE SUPERIOR WILL VEER FM SW THIS
MORNING TO NNW LATE TODAY AND TONIGHT AND RAMP UP TO 20 TO 30 KTS
TONIGHT AND TUE...STRONGEST OVER THE EAST HALF. NOT OUT OF THE
QUESTION THAT THERE COULD BE SOME GALE FORCE GUSTS OVER THE E HALF
OF THE LAKE LATE TONIGHT/TUE MORNING. WINDS WILL DIMINISH W TO E TUE
AFTN/NIGHT AS A HIGH PRES RIDGE BUILDS IN FM THE WEST. WED THRU
FRI...WINDS WILL BE UNDER 20KT. LINGERING WARM MOIST AIR WILL ALLOW
FOG TO CONTINUE OVER THE LAKE TODAY...POSSIBLE LOCALLY DENSE OVER
THE EAST HALF THIS MORNING. ALL FOG SHOULD DISSIPATE BY THIS EVENING
AS COLDER AIR ARRIVES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
509 AM EDT MON MAY 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EDT MON MAY 18 2015
WATER VAPOR LOOP AND RAP ANALYSIS SHOWS MID-LVL LOW ROTATING OVER
NRN MN WITH A DRY SLOT AHEAD OF LOW REACHING ACROSS MUCH OF THE
UPPER MI. COLD FRONT MOVING ACROSS MUCH OF THE AREA OVERNIGHT HAS
ALLOWED DRIER AIR TO ADVECT IN FROM THE SW WHICH HAS DISSIPATED THE
DENSE FOG OVER LAKE MI AND AREAS DOWNSTREAM OVER ERN UPPER MI. DRY
SLOT HAS LEFT UPPER MI GENERALLY PCPN FREE OVER THE EARLY MORNING
HRS.
TODAY AND TONIGHT...THE FOCUS TODAY WILL ON COLD SURGE WHICH WILL BE
MOVING INTO THE WEST MID-LATE MORNING AND CONTINUE EASTWARD THROUGH
THE DAY. AHEAD OF THE FRONT OVER THE EAST HALF OF UPPER MI AND AWAY
FROM THE MODERATING INFLUENCE OF LAKE MICHIGAN...SHOULD SEE
TEMPERATURES REACH IN THE MID TO UPPER 60S (WITH A FEW 70S POSSIBLE
IF THERE ARE BREAKS IN THE LOW CLOUDS). OVER THE WEST HALF WHERE
FRONTAL PASSAGE WILL OCCUR EARLIER...MORNING TO EARLY AFTERNOON HIGH
TEMPS WILL RANGE FROM UPPER 40S/50F NEAR IRONWOOD TO LOWER 60S ALONG
A LINE FM MQT TO MENOMINEE. IN ADDITION...ALL OF THE HIGHER
RESOLUTION MODELS ARE SURGING IN A LAKE BREEZE OFF LAKE SUPERIOR
(FROM MARQUETTE EASTWARD) WHICH WILL LEAD TO COOLER NORTHERLY FLOW
BY MID-LATE AFTERNOON OVER NCNTRL AREAS. WITH THE COLD AIR AND
ABUNDANT MOISTURE SURGING INTO THE AREA AS WINDS TURN
WESTERLY...EXPECT ISOLATED TO SCATTERED SHOWERS TO DEVELOP OVER THE
WEST FIRST (ESPECIALLY IN THE FAVORED UPSLOPE AREAS) AND THEN SPREAD
INTO THE CENTRAL AREAS EVENING AND POSSIBLY EASTERN COUNTIES LATE
EVENING/OVERNIGHT. CAA ON BLUSTERY NW TO N WINDS WILL ALLOW 8H TEMPS
TO FALL TO -8 TO -10C OVER MUCH OF THE WEST HALF OF UPPER MI BY 12Z
TUE. 8H TEMPS WILL FALL TO AROUND -5C OVER THE EAST HALF OVERNIGHT.
BEST FORCING OUT AHEAD ANOTHER SHORTWAVE TRACKING ALONG THE
MN/ONTARIO BORDER TONIGHT WILL STAY MAINLY NW OF UPPER MI KEEPING
MUCH OF THE ASSOCIATED LIGHT PCPN N OF UPPER MI. HOWEVER...DEEP
CYCLONIC FLOW/MOISTURE WILL STILL SUPPORT SOME LIGHT PCPN IN UPPER
MI AS WELL...ESPECIALLY IN THE UPSLOPE AREAS OF THE W AND N. WITH
COLD ADVECTION TAKING PLACE AS NOTED BEFORE...THE -SHRA WILL MIX
WITH OR CHANGE TO -SHSN TONIGHT FROM WEST TO EAST. DUE TO THE COLD
ADVECTION AND PCPN OCCURRING DURING THE OVERNIGHT HOURS...CAN`T RULE
OUT A DUSTING TO LOCALLY A HALFINCH OF SNOW ON GRASSY SFCS BY 12Z
TUE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON MAY 18 2015
TUESDAY WILL BRING ABOUT ONLY SLOWLY RISING TEMPS AS A SECONDARY
TROUGH/COLD FRONT SINKING ACROSS CENTRAL TO E UPPER MI. 850MB TEMPS
AT A CHILLY -10C OVER THE KEWEENAW PENINSULA /2-5C WARMER OFF THE
17/18Z AND 18/00Z GFS RUNS...AS WELL AS THE REGIONAL WRF/. THE NAM
IS THE COLDEST WITH THE ENTIRE W HALF AROUND -11C TUESDAY MORNING.
850MB TEMPS WILL FALL FROM AROUND -4C AT ERY TO AROUND -9C BY 18Z
TUESDAY ON NW WINDS. THIS WILL BE AS ANOTHER SHORTWAVE OVER NE MN AT
12Z SLIDES ACROSS LAKE SUPERIOR. YES...SNOW IS POSSIBLE STILL ON
TUESDAY...BUT MAY BE LIMITED TO JUST A DUSTING ON MAINLY GRASSY
SURFACES THROUGH THE MORNING HOURS...BEFORE THE LOW LEVEL RH
DIMINISHES SIGNIFICANTLY.
EXPECT BREEZY CONDITIONS...WITH GUSTS AVERAGING 20-25KTS ACROSS MUCH
OF THE CWA...STRONGEST ACROSS THE KEWEENAW PENINSULA AND E NEAR LAKE
SUPERIOR. DESPITE LIGHT W FLOW RETURNING AT THE SFC TUESDAY NIGHT
AND 850MB TEMPS WARMING TO AROUND 0C...LOWS NEAR TO SLIGHTLY BELOW
FREEZING WILL BE POSSIBLE /COLDEST IN THE TRADITIONAL COOL SPOTS OF
THE INTERIOR W HALF OF UPPER MI/.
EXPECT DRIER CONDITIONS WITH LIGHTER WINDS WEDNESDAY AS SFC TEMPS
REBOUND TO AROUND 60F. THIS WILL BE DESPITE THE 500MB TROUGH WITH
ITS NW FLOW LINGERING OVERHEAD...AS THE LARGE SFC HIGH OVER THE
DAKOTAS BUILDS A RIDGE ACROSS UPPER MI. PW VALUES SHOULD BE AROUND
0.25IN FROM OVERNIGHT TUESDAY NIGHT THROUGH MUCH OF WEDNESDAY
/ALTHOUGH SLIGHTLY HIGHER NEAR LAKE MI FROM LATE MORNING ON/.
DRY WEATHER SHOULD REMAIN THROUGH THE REST OF THE WORK WEEK AT NW
FLOW LINGERS AT 500MB. THERE WILL BE A WEAK COLD FRONT STRETCHING
ACROSS N LAKE SUPERIOR AT 00Z THURSDAY THAT SINKS ACROSS UPPER MI
WEDNESDAY EVENING AND LOWER MI DURING THE DAY THURSDAY. NOT
EXPECTING MUCH MORE THAN THE POSSIBILITY OF TEMPORARY ADDITIONAL
CLOUD COVER. HIGH PRESSURE WILL SLIDE IN BEHIND THE FRONTAL BOUNDARY
TO WRAP UP THE END OF THE WORK WEEK. EXPECT THIS HIGH TO SHIFT TO
THE LOWER GREAT LAKES BY 18Z SATURDAY AND OFF THE MID-ATLANTIC COAST
SUNDAY MORNING. THIS EXITING HIGH WILL ALLOW MOISTURE TO
RETURN...ALONG WITH A GOOD CHANCE OF SHOWERS FOR SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 137 AM EDT MON MAY 18 2015
RAIN IS PRETTY MUCH DONE UNTIL WRAPAROUND MOISTURE ARRIVES WITH SOME
SHOWERS LATER MON AFTERNOON AND EVENING AT IWD AND CMX. VFR
CONDITIONS WILL TRANSITION TO MVFR OVERNIGHT AT KIWD AND KCMX AS
WRAPAROUND MOISTURE ASSOC WITH THE LOW COMES IN. WRAPAROUND MOISTURE
WON`T REACH SAW UNTIL LATE MON AFTERNOON/EVENING SO EXPECT TRANSITION
FROM VFR TO MVFR CONDITIONS TO OCCUR THERE LATER IN THE DAY. SAW
WILL ALSO SEE A LAKE BREEZE MON AFTERNOON THAT WILL SWITCH THEIR WIND
TO THE NORTHEAST.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT MON MAY 18 2015
LOW PRES OVER NRN MN WILL MOVE ACROSS LAKE SUPERIOR TODAY INTO THIS
EVENING. AS A RESULT...WINDS ON LAKE SUPERIOR WILL VEER FM SW THIS
MORNING TO NNW LATE TODAY AND TONIGHT AND RAMP UP TO 20 TO 30 KTS
TONIGHT AND TUE...STRONGEST OVER THE EAST HALF. NOT OUT OF THE
QUESTION THAT THERE COULD BE SOME GALE FORCE GUSTS OVER THE E HALF
OF THE LAKE LATE TONIGHT/TUE MORNING. WINDS WILL DIMINISH W TO E TUE
AFTN/NIGHT AS A HIGH PRES RIDGE BUILDS IN FM THE WEST. WED THRU
FRI...WINDS WILL BE UNDER 20KT. LINGERING WARM MOIST AIR WILL ALLOW
FOG TO CONTINUE OVER THE LAKE TODAY...POSSIBLE LOCALLY DENSE OVER
THE EAST HALF THIS MORNING. ALL FOG SHOULD DISSIPATE BY THIS EVENING
AS COLDER AIR ARRIVES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...07
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
105 PM CDT MON MAY 18 2015
.UPDATE FOR 18Z AVIATION DISCUSSION...
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT MON MAY 18 2015
SUB-1000MB LOW OVER NORTHERN MN CONTINUES TO FACILITATE WINDY
CONDITIONS AND STRATUS CLOUDS OVER THE FORECAST AREA EARLY THIS
MORNING. SLIGHT LOOSENING OF THE PRESSURE GRADIENT AS THE TROUGH
WEAKENS AND LIFTS TO THE GREAT LAKES SHOULD ALLOW WINDS TO DIP
BELOW WIND ADVISORY CRITERIA TODAY /SUSTAINED 30 MPH/...SO WILL
NOT REISSUE THE WIND ADVISORY. HOWEVER...IT WILL REMAIN QUITE
BREEZY THROUGH THE DAY. MEANWHILE...THE EXTENSIVE AREA OF SHOWERS
OVER NORTHERN MN AND THE EASTERN DAKOTAS WILL SLIP SLIGHTLY
FARTHER SOUTH INTO CENTRAL MN THIS MORNING. HAVE MAINTED HIGH
CHANCE POPS ACROSS CENTRAL MN TOWARD NORTHERN WI...AND ALSO
INCLUDED SPRINKLES FARTHER SOUTH TO INCLUDE THE TWIN CITIES AND
AREAS DOWN TOWARD SOUTH CENTRAL MN.
TEMPERATURES TODAY WILL BE QUITE CHILLY...AVERAGING 25 TO 30
DEGREES BELOW NORMAL. HIGHS WILL STRUGGLE TO REACH 40 IN WEST
CENTRAL MN NEAR ALEXANDRIA...WHILE THE REMAINDER OF THE AREA WILL
SEE HIGHS IN THE 40S. TEMPS TONIGHT WILL BE AROUND 10 TO 15
DEGREES BELOW NORMAL...WITH ANTICIPATED LOWS IN THE LOW TO MID
30S. HAVE INCLUDED THE MENTION OF FROST IN THE FORECAST...BUT WILL
HOLD OFF ON ANY SORT OF A FROST/FREEZE ADVISORY GIVEN SCT-BKN
CLOUDS ARE EXPECTED TO HANG IN UNTIL THE EARLY MORNING HOURS OF
TUESDAY...AND WINDS WILL BE IN THE 6-10 MPH RANGE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 352 AM CDT MON MAY 18 2015
NOT MUCH CHANGE IN THE EXTENDED PERIOD AS WAS PREVIOUSLY ADVERTISED
WITH A COOL PERIOD THIS WEEK...THEN WETTER NEXT WEEKEND.
THE MEAN UPPER LEVEL FLOW WILL START THIS WEEK FROM THE W-NW
DIRECTION WHICH SHOULD KEEP A STORM SYSTEM MOVING OUT OF THE
SOUTHERN ROCKIES AND INTO THE MIDWEST...SOUTH OF OUR REGION.
BASICALLY THE CONFLUENT FLOW ALOFT AND DRY E/NE FLOW IN THE BOUNDARY
LAYER WILL KEEP ANY PRECIPITATION CHANCES IN FAR SOUTHERN MN. EVEN
IN THIS AREA...VERY LIGHT PRECIPITATION IS EXPECTED...BUT THE DENSER
CLOUD COVER...AND THE CHANCE OF PRECIPITATION...WILL KEEP TEMPS A
FEW DEGREES COOLER THAN NORTH IN CENTRAL MN WHERE MORE SUNSHINE WILL
OCCUR.
CLIMATOLOGY...THIS WEEK WILL REMAIN ON THE COOL SIDE WITH AFTN HIGHS
SLOWLY REBOUNDING INTO THE UPPER 60S/LOWER 70S BY THURSDAY/FRIDAY.
THE UPPER LEVEL FLOW WILL BEGIN TO BUCKLE BY THE END OF THE WEEK AS
A STORM SYSTEM KICKS OUT OF THE SW CONUS...AND A STRONGER RIDGE
BUILDS IN THE SE CONUS. THIS WILL LEAD TO A WARMER AND UNSETTLED
PATTERN BY NEXT WEEKEND. HOWEVER...BASED ON THE CURRENT MODELS
DEPICTION OF THE MAIN SFC FRONT ALONG AND SOUTH OF MN/IA BORDER...MN
AND WESTERN WI MAY BE ON THE COOL SIDE WITH OCCASIONAL
SHRA/TSRA...BUT NOT AS WARM. THIS COULD CHANGE IF THE RIDGE IN THE
SOUTHEASTERN CONUS STRENGTHENS AND ALLOWS THIS SFC FRONT TO MOVE
FURTHER NORTHWARD INTO MN. THIS WOULD ALSO LEAD TO MORE SVR WX
CHANCES AS WE WOULD BE IN THE WARM SECTOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1257 PM CDT MON MAY 18 2015
WIDESPREAD MVFR CIGS ACROSS THE AREA. SOME RESIDUAL
SPRINKLES/LIGHT SHOWERS AROUND. STILL HAVE COLD POOL TO MOVE OVER
THE AREA INTO TONIGHT.THE HRRR CONTINUES TO SHOW SOME ISOLD -SHRA
INTO TONIGHT AS WEAK SURFACE TROUGH MOVES SOUTHEAST OVER THE
NORTHERN CWA. THIS MAY AFFECT CLOUD TRENDS...ESPECIALLY TO THE
EAST OVERNIGHT. SOME DRIER AIR TRYING TO WORK OVER SOUTHWEST
AREA...WITH MORE CUFORM CLOUDS THIS AFTERNOON. MAY SEE HIGHER END
MVFR OR IFR CONDITIONS AT A FEW LOCATIONS IN MN THIS AFTERNOON.
WILL TRY AND SCATTERED CLOUDS TO THE WEST OVERNIGHT AS DRIER AIR
MOVES EAST. THEY MAY HOLD FIRM FARTHER EAST...BUT OVERALL
CONFIDENCE IN CLOUD TREND IS LOW AT THIS TIME. WEST TO NORTHWEST
WINDS OVER THE AREA GUSTS OVER 30KT TO THE WEST...SHOULD GRADUALLY
DIMINISH INTO THE EVENING FROM WEST TO EAST. NORTHWEST/NORTH WINDS
GENERALLY 10-15 KTS INTO TUE WITH CLEARING TREND.
KMSP...
MVFR CIGS INTO THE NIGHT WITH VFR TRENDS INTO TUESDAY MORNING.
SOME QUESTION AS TO HOW LOW CIGS MAY DROP AGAIN INTO THE HE
EVENING AS A WEAK SURFACE TROUGH APPROACHES FROM THE NORTH. WILL
HAVE TO MONITOR THIS INTO THE EVENING. SOME SMALL CHANCE OF
-RA/-DZ ASSOCIATED WITH THIS FEATURE AS WELL...BUT FORCING IS
LACKING. NORTHWEST WINDS A BIT GUSTY INTO THE EVENING BECOMING
MORE NORTH INTO TUESDAY.
/OUTLOOK FOR KMSP/
WED...VFR. WINDS N 5 KTS.
THU...VFR. WINDS NNW 5 TO 10 KTS.
FRI...VFR. WINDS NE 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...LS
LONG TERM...JLT
AVIATION...DWE
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1104 AM CDT MON MAY 18 2015
.UPDATE...LARGE CONVECTIVE COMPLEX AFFECTING MAINLY SW PORTIONS HAS
BEEN RESPONSIBLE FOR PROLIFIC RAINFALL AMOUNTS OVERNIGHT AND THIS
MORNING. WHILE AREAS AROUND VICKSBURG SAW THE GREATEST AMOUNTS
OVERNIGHT AND EARLY THIS MORNING...EMPHASIS NOW HAS SHIFTED SOUTH
WITH THE ADVANCING COLD POOL AND A NEW SURGE OF CONVECTION DEVELOPING
OVER W LA. MOISTURE TRANSPORT VECTORS FROM THE HRRR AND NAM SUGGEST
THAT THE HEAVIEST RAINFALL THIS AFTERNOON WILL OCCUR IN FAR EC LA AND
SW PORTIONS OF MS. HAVE THEREFORE REPOSITIONED THE FFA TO ACCOUNT FOR
THIS. HAD TO MODIFY POP/WX GRIDS BASED ON CURRENT TRENDS. ALSO...MADE
ADJUSTMENT TO TEMPS AS CLOUDS/RAIN WILL SIGNIFICANTLY IMPACT WARMTH
OVER THE AREA THIS AFTERNOON./26
&&
.AVIATION...AREA RADARS WERE PICKING UP NUMEROUS SHRA/TSRA ACROSS
THE WEST HALF OF THE REGION. EXPECT IT TO SPREAD ACROSS THE REGION
CAUSING PERIODS OF CIG/VISBY IN IFR/MVFR CONDITIONS IN HEAVIER
RAINFALL. EXPECT RAIN CHANCES TO CONTINUE THROUGH TUESDAY MORNING.
SO MVFR/IFR CIGS WILL CONTINUE WITH PERIODS OF RAIN OVERNIGHT INTO
TUESDAY MORNING./17/
&&
.PREV DISCUSSION... /ISSUED 447 AM CDT MON MAY 18 2015/
DISCUSSION...
SHORT TERM (TODAY THROUGH TUESDAY NIGHT)...IT HAS BEEN AN ACTIVE
OVERNIGHT PERIOD AS AN MCV HAS INCITED PERSISTENT CONVECTION ACROSS
THE REGION. AFTER A TEMPORARY LULL IN INTENSITY/COVERAGE SHORTLY
AFTER MIDNIGHT...CONSIDERABLE NEW DEVELOPMENT OCCURRED ACROSS NORTH
LOUISIANA OVER THE PAST FEW HOURS. MODEL GUIDANCE...PARTICULARLY HIGH
RES GUIDANCE...HAS HAD AN EXTREMELY DIFFICULT TIME WITH DETAILS IN
THIS PATTERN DUE TO POOR INITIALIZATION. THUS LESS FOCUS WAS PLACED
ON ACTUAL QPF OUTPUT THAN THE OVERALL SYNOPTIC PICTURE.
WITH THAT IN MIND...AN UNSEASONABLY MOIST AIRMASS CURRENTLY RESIDES
ACROSS THE AREA (PARTICULARLY THE NORTHWESTERN PORTION OF THE
CWA)...WITH PWATS AROUND 2 INCHES (NEAR RECORD MAX FOR THIS TIME OF
YEAR). A SURFACE FRONT CURRENTLY EXTENDING ACROSS THE MISSOURI VALLEY
WILL SINK SOUTHWARD TOWARD THE AREA THROUGH THE DAY. AS AN UPPER
SHORTWAVE...WHICH IS CURRENTLY FORCING CONVECTION JUST WEST OF THE
REGION...MOVES EASTWARD SCATTERED TO NUMEROUS SHOWERS AND STORMS
WILL OCCUR ACROSS THE CWA TODAY. RADAR ESTIMATES SUGGEST 2 TO 4
INCHES HAVE ALREADY OCCURRED ACROSS PORTIONS OF THE DELTA...WITH
PERHAPS EVEN HIGHER LOCALIZED AMOUNTS. THUS IN MANY AREAS IT WILL
TAKE LITTLE ADDITIONAL RAIN TO CAUSE FLASH FLOODING. A FLASH FLOOD
WATCH WAS POSTED FOR MUCH OF THE DELTA REGION FOR TODAY TO HIGHLIGHT
THIS POTENTIAL.
THE SURFACE FRONT WILL SAG INTO THE AREA AND STALL ON TUESDAY...
PROVIDING A CONTINUED FOCUS FOR SCATTERED CONVECTION ACROSS THE AREA.
AS HAS BEEN THE CASE OVER THE PAST FEW DAYS...THOUGH LITTLE TO
MARGINAL WIND SHEAR IS EXPECTED SUFFICIENT INSTABILITY MAY EXIST TO
GENERATE SOME STRONG/SEVERE CONVECTION. HOWEVER THIS THREAT SHOULD BE
ISOLATED ENOUGH TO LEAVE MENTION OUT OF THE HWO AT THIS TIME. /DL/
LONG TERM (WEDNESDAY THROUGH MONDAY)...A SUMMERLIKE PATTERN WILL
CONTINUE ACROSS THE REGION THROUGH THE WEEK AS MID/UPPER LEVEL
RIDGING REMAINS IN PLACE. A MOIST AIRMASS WILL BE PRESENT OVER THE
REGION AS PW VALUES REMAIN AROUND 1.6-1.9 INCHES. SOME DRIER AIR MAY
BE PRESENT ACROSS THE NORTH WHICH COULD LIMIT CONVECTION AT TIMES. A
WEAK SFC FRONT WILL REMAIN ACROSS THE SOUTHERN PORTIONS OF THE
FORECAST AREA AND WILL LIKELY SERVE AS FOCUSING MECHANISM FOR MAINLY
DIURNAL SHOWERS AND THUNDERSTORMS. WARM CONDITIONS WILL PREVAIL
THROUGH THE WEEK INTO THE WEEKEND. ANOTHER POTENT WEATHER SYSTEM
ACROSS THE PLAINS WILL TRACK TO THE NORTHEAST AND SEND ANOTHER FRONT
IN OUR DIRECTION FOR EARLY NEXT WEEK...WHICH COULD BRING MORE RAIN TO
THE REGION. /28/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 79 69 86 68 / 77 37 43 25
MERIDIAN 84 69 85 67 / 52 37 46 20
VICKSBURG 78 69 86 69 / 100 43 43 25
HATTIESBURG 87 70 87 69 / 51 33 46 26
NATCHEZ 81 69 85 69 / 100 39 45 31
GREENVILLE 79 69 84 68 / 100 36 31 30
GREENWOOD 79 68 84 66 / 100 37 32 26
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR MSZ047-048-053-
054-059>063.
LA...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR LAZ015-016-
023>026.
AR...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
339 PM PDT MON MAY 18 2015
.SYNOPSIS...AN AREA OF LOW PRESSURE WILL MOVE EAST ACROSS NEVADA
TONIGHT RESULTING IN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
AROUND ESPECIALLY EARLY AND TO THE NORTH OF LAS VEGAS. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED AGAIN ON TUESDAY
ACROSS THE SOUTHERN GREAT BASIN. MOST AREAS WILL SEE DRY CONDITIONS
ON WEDNESDAY AND WEDNESDAY NIGHT. A NEW STORM SYSTEM WILL APPROACH
THE AREA ON THURSDAY THEN MOVE ACROSS ON FRIDAY BRINGING ADDITIONAL
CHANCES FOR SHOWERS AND THUNDERSTORMS. A SLOW DRYING AND WARMING
TREND IS EXPECTED FOR THE MEMORIAL DAY WEEKEND.
&&
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT.
CLARK AND LINCOLN COUNTIES HAVE REALLY SEEN AN ACTIVE DAY AS SHOWERS
AND THUNDERSTORMS GOT GOING SHORTLY AFTER DAYBREAK IN THE NORTHEAST
QUADRANT OF A MID/UPPER LEVEL LOW. THE CENTER OF THIS LOW COULD BE
SEEN THIS AFTERNOON ON WATER VAPOR AND SATELLITE OVER DEATH VALLEY
NATIONAL PARK. DESPITE ONLY 0.53 INCH OF PWAT IN THIS MORNING`S NWS
VEGAS SOUNDING AND RELATIVELY LOW-TOPPED CONVECTION, THERE HAVE BEEN
SOME IMPRESSIVE PRECIPITATION TOTALS TODAY WHERE STRONGER STORMS
DEVELOPED OR ACTIVITY TRAINED. A FEW SPOTS IN SUMMERLIN WEST PICKED
UP OVER AN INCH OF RAIN AS WELL AS ONE GUAGE JUST SOUTH OF INSPIRADA
IN HENDERSON. WHILE WIDESPREAD HEAVY RAIN IS NOT EXPECTED THIS
EVENING, ANY SLOWER MOVING OR STRONGER ACTIVITY COULD DUMP A HALF OF
AN INCH OR MORE OF RAIN ESPECIALLY IF IT TRAINS. GIVEN THE
ATMOSPHERE HAS BECOME WORKED OVER IN AND AROUND THE LAS VEGAS VALLEY
EARLIER TODAY, WE THINK THAT THE INTENSITY OF ACTIVITY IMMEDIATELY
IN AND AROUND THE VALLEY SHOULD STAY TOWARD THE LOW-MODERATE END.
HOWEVER, CLOSER TO THE LOW CENTER IN THE NORTHEAST QUADRANT WHERE
ACTIVITY WAS MORE LIMITED EARLIER TODAY, THINGS COULD BE MORE ACTIVE
IN ESMERALDA, EASTERN INYO AND CENTRAL NYE COUNTIES. THE HRRR AND
LOCAL NMM AND ARW MODELS ALL KEY IN ON THESE AREAS FOR ACTIVITY TO
DEVELOP OR PERSIST THIS EVENING AND THUS POPS WERE ADJUSTED UP IN
THESE AREAS. THESE AREAS MAY BE THE SLOWEST TO SEE ACTIVITY END THIS
EVENING WHILE ELSEWHERE THINGS SHOULD END BETWEEN 7 AND 9 PM. LOW
FREEZING LEVELS HAVE ALSO RESULTED IN STRONGER ACTIVITY PRODUCING
HAIL WITH REPORTS EARLIER TODAY AS LARGE AS AN INCH IN DIAMETER IN
THE MOST INTENSE ACTIVITY. IN ADDITION SNOW LEVELS AROUND 8500 FEET
WERE NOTED AND A LIGHT COATING TO AN INCH OR TWO OF SNOW IS POSSIBLE
IN THE HIGHEST ELEVATIONS UNDER ANY SHOWER OR THUNDERSTORM ACTIVITY
OVERNIGHT.
THE LOW CENTER WILL TRANSITION ACROSS THE AREA TONIGHT WHICH WILL
PLACE US ON THE BACK SIDE OF THE LOW FOR TUESDAY. LINGERING ENERGY
AND MID-LEVEL MOISTURE WILL BE ENOUGH TO TOUCH OFF SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS MAINLY ACROSS THE SOUTHERN GREAT BASIN
BUT OUTSIDE OF LINCOLN AND CENTRAL NYE COUNTIES THE COVERAGE OF
ACTIVITY SHOULD BE LOWER TOMORROW. ONCE AGAIN, LOW FREEZING LEVELS
WILL ALLOW FOR HAIL IN ANY STRONGER ACTIVITY. HIGH TEMPS SHOULD WARM
UP SEVERAL DEGREES AS DRIER AIR WORKS IN AND ERODES AWAY THE CLOUDS
OVER THE MOJAVE DESERT.
ANOTHER LOW WILL APPROACH THE COAST OF CALIFORNIA ON WEDNESDAY. THIS
WILL SPREAD LOTS OF HIGH LEVEL MOISTURE INTO THE AREA AS THE JET
STREAM PASSES BY ACROSS SOCAL INTO ARIZONA RESULTING IN A DECENT
AMOUNT OF CIRRUS CLOUDS TO START TO THE DAY AND AGAIN WEDNESDAY
NIGHT. OTHERWISE, THE BEST MOISTURE AND INSTABILITY WILL BE OVER THE
SOUTHERN SIERRA CREST AND EASTERN SLOPES AS WELL AS ESMERALDA COUNTY
AND A FEW SHOWERS AND THUNDERSTORMS ARE POSSIBLE HERE MAINLY IN THE
AFTERNOON. THE REST OF THE AREA LOOKS DRY WITH WINDS PICKING UP FROM
THE SOUTH IN THE AFTERNOON AND EVENING AND GUSTING TO 20-30 MPH.
HIGH TEMPS SHOULD WARM BACK UP ANOTHER 3-5 DEGREES OVER TUESDAY.
THIS LOW WILL EVENTUALLY LOOP BACK OUT AND MERGE WITH ANOTHER LOW
THAT HEADS TOWARD THE COAST ON THURSDAY.
.LONG TERM...THURSDAY THROUGH MONDAY.
THE NEXT UPPER LOW WILL APPROACH THE CENTRAL CALIFORNIA COAST
THURSDAY. A SHORTWAVE ROTATING AROUND THE LOW WILL MOVE NORTHEAST
INTO CALIFORNIA AND NEVADA DURING THE DAY. AN AREA OF DIFFLUENCE AND
DECENT MID LEVEL MOISTURE WILL LEAD TO A CHANCE OF SHOWERS OVER MUCH
OF INYO COUNTY AND ACROSS ESMERALDA...CENTRAL NYE AND NORTHERN
LINCOLN COUNTIES. THE UPPER LOW WILL MOVE INLAND THURSDAY NIGHT AND
ACROSS SOUTHERN NEVADA INTO NORTHWEST ARIZONA FRIDAY. PRECIPITATION
CHANCES WILL THUS SPREAD EAST ACROSS A GOOD PORTION OF THE FORECAST
AREA...MAINLY NORTH OF INTERSTATE 40. WITH THE LOW MOVING
OVERHEAD...HIGH TEMPERATURES FRIDAY WILL BE SOME 10 TO 15 DEGREES
BELOW NORMAL. PRECIPITATION CHANCES WILL DECREASE AND SHIFT
NORTHEAST FRIDAY NIGHT AS THE LOW STARTS TO EXIT THE AREA.
HOWEVER...A SHORTWAVE TROUGH FOLLOWING BEHIND FROM THE NORTH WILL
BRING A CHANCE OF SHOWERS SATURDAY TO AREAS MAINLY NORTH OF LAS
VEGAS.
FOR SUNDAY THROUGH MONDAY THE MODELS ARE NOT IN VERY GOOD AGREEMENT
BUT IN GENERAL IT LOOKS LIKE THERE WILL BE SOME SORT OF UPPER TROUGH
ROUGHLY OVER NORTHERN NEVADA. THIS WOULD KEEP AT LEAST A SLIGHT
CHANCE OF SHOWERS OVER THE FAR NORTHERN PART OF THE FORECAST AREA
AND I LEFT SLIGHT CHANCE POPS IN FOR THOSE AREAS.
&&
.AVIATION...FOR MCCARRAN...SCT SHRA AND ISO TSRA WILL CONTINUE
THROUGH AROUND 03Z TUESDAY. BASES COULD LOWER TO 5K-8K FEET IN AND
NEAR SHRA/TSRA AND WINDS MAY BECOME GUSTY AND ERRATIC POTENTIALLY
IMPACTING CONFIGURATIONS. OVERALL IT APPEARS WE SHOULD SEE AN
DOWNWARD TREND IN SHRA AND TSRA ACTIVITY BY LATER THIS EVENING IN
THE LAS VEGAS VALLEY AS WELL AS IN MOST OF THE APPROACH CORRIDORS
WITH THE BEATTY CORRIDOR LIKELY TO SEE ACTIVITY LINGER THE LONGEST.
WINDS OTHERWISE SHOULD FOLLOW TYPICAL DIURNAL DIRECTIONS AT 8 KTS OR
LESS THROUGH TUESDAY EVENING WITH CLOUDS GRADUALLY DECREASING AND
MAINLY ABOVE 10K FEET. ALTHOUGH CONDITIONS LOOK DRY IN THE LAS VEGAS
VALLEY ON TUESDAY, ISO SHRA/TSRA ARE POSSIBLE IN THE SPRING
MOUNTAINS. ADDITIONAL SHRA AND TSRA CHANCES EXIST FOR FRIDAY AND
FRIDAY NIGHT IN THE LAS VEGAS VALLEY.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...SHRA/TSRA ARE EXPECTED MAINLY NORTH OF KIYK-KLAS-KIGM
LINE WITH ACTIVITY GRADUALLY DIMINISHING BETWEEN 03Z AND 06Z TUESDAY.
ISOLATED SHRA/TSRA ACTIVITY MAY LINGER THOUGH THE NIGHT ESPECIALLY
IN THE SOUTHERN GREAT BASIN. SHRA/TSRA WILL AGAIN BE POSSIBLE ON
TUESDAY ESPECIALLY AFTER 18Z NORTH OF KIYK-KDRA-KACZ LINE. WINDS MAY
BE GUSTY AND ERRATIC IN AND NEAR SHRA/TSRA WITH CIGS LOWERING TO 5K-
8K FEET. OTHERWISE LOOK FOR WINDS TO TREND TOWARD TYPICAL DIURNAL
DIRECTIONS AT 10 KTS OR LESS WITH SCT-BKN CLOUDS AOA 10K FEET.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...STACHELSKI
LONG TERM...HARRISON
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS BUFFALO NY
757 AM EDT MON MAY 18 2015
.SYNOPSIS...
A WARM AND HUMID AIR MASS WILL REMAIN OVER THE REGION WITH A PERIOD
OF SHOWERS AND THUNDERSTORMS PUSHING ACROSS WESTERN AND CENTRAL NEW
YORK TODAY AHEAD OF A COLD FRONT. SOME OF THESE THUNDERSTORMS MAY
BRING LOCALIZED HEAVY RAIN. THE FRONT WILL CROSS EARLY TUESDAY THEN
A COOLER AND DRIER AIRMASS WILL ARRIVE BEHIND THE FRONT FOR THE
REMAINDER OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE FORECAST AREA LIES BENEATH AN AMPLIFIED 500MB RIDGE THIS MORNING
WITH STACKED SURFACE AND UPPER LEVEL LOW OVER THE MINNESOTA
ARROWHEAD CONTINUING TO SPREAD WARM AND MOIST AIR NORTH ACROSS THE
GREAT LAKES. DEWPOINTS RISING INTO THE MID 60S ACROSS WESTERN NEW
YORK AS A RIBBON OF HIGH PRECIPITABLE WATER VALUES AROUND 1.7 INCHES
/NEAR MAX ON MID MAY SOUNDING CLIMO/ RUNNING FROM NORTH OF GEORGIAN
BAY TO LAKE ERIE. PLENTY OF MOISTURE TO BE FOUND SO FOCUS FOR TIMING
OF SHOWER AND THUNDERSTORM ACTIVITY TODAY WILL BE ON ANY
SYNOPTIC/MESOSCALE FEATURES SHIFTING ACROSS THE EASTERN GREAT LAKES.
A PRE-FRONTAL TROUGH IS ANALYZED ROUGHLY FROM NORTHERN MI SOUTHEAST
TO NEAR KERI. THIS IS FORECAST TO SHIFT ACROSS WESTERN AND CENTRAL
NEW YORK TODAY. LOOKING TO THE MID-LEVELS...FORCING MAY ALSO COME
FROM ANY SUBTLE SHORTWAVES ROLLING UP THE WEST SIDE OF THE RIDGE
AXIS FROM THE MISS VALLEY TOWARD THE EASTERN GREAT LAKES. MESOSCALE
GUIDANCE SUCH AS WRF AND HRRR MODELS SUGGEST A FEW ISOLATED SHOWERS
AND STORMS MAY WORK INTO WNY ALONG THE TROUGH THIS MORNING. BY EARLY
AFTERNOON FORECAST CAPE OF 2-3K J/KG WILL FEED MORE NUMEROUS SHOWERS
AND THUNDERSTORMS DEVELOPING FROM THE SOUTHERN TIER ACROSS THE
GENESEE VALLEY AND FINGER LAKES. A STABLE SOUTHWEST FLOW OFF LAKE
ERIE SHOULD KEEP MUCH OF THE NIAGARA FRONTIER PROTECTED FROM THE
HEAVIER STORMS BUT LAKE BREEZES COULD TRIGGER ADDITIONAL CELLS TO THE
SOUTH AND EAST OF BUFFALO. BULK SHEAR THIS AFTERNOON IS FORECAST
ONLY AROUND 15 KTS SO TOO WEAK TO SUPPORT ANY SIGNIFICANT WIND/HAIL
THREAT. THE DEEP MOISTURE IN PLACE PER PWATS AND SKINNY CAPE
PROFILES WITH SLOW STORM MOTIONS WILL HOWEVER BRING A RISK FOR
LOCALLY HEAVY RAIN AND FLOODING IF ANY TRAINING CELLS DEVELOPS.
TONIGHT...THE SURFACE LOW WILL SHIFT NORTH OF THE GREAT LAKES TO
SOUTHERN QUEBEC. NEAR-TERM MODELS INDICATE THE MAJORITY OF REMAINING
CONVECTION WILL BE LIMITED FROM THE FINGER LAKES EASTWARD ACROSS
CENTRAL AND EASTERN NEW YORK. WESTERN NEW YORK WILL LARGELY REMAIN
DRY. THE COLD FRONT WILL CROSS WNY LATE TONIGHT AND IS FORECAST TO
BE NEAR THE FINGER LAKES BY 12Z TUESDAY WITH SKY COVER THINNING FROM
WEST TO EAST. THE OVERNIGHT TIMING OF THE FRONT SHOULD LIMIT A
SECOND ROUND OF SHOWER/TSTM ACTIVITY.
TEMPERATURES TODAY WILL AGAIN RISE ABOVE NORMAL WITHIN A HUMID
AIRMASS. 850MB TEMPS OF NEAR +15C WILL SUPPORT SURFACE HIGH TEMPS
RANGING FROM THE UPPER 70S TO MID 80S. THE U70S TEMPS WILL ONLY BE
LIMITED BY EARLIER START TO CONVECTION WHILE MORE HEATING ACROSS
FINGER LAKES AND NORTH COUNTRY WILL HELP BOOST TEMPS TO THE M80S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
A STRONG COLD FRONT WILL CROSS THE FORECAST AREA DURING THE DAY ON
TUESDAY. WHILE THE BULK OF THE PRECIPITATION WILL BE ASSOCIATED WITH
THE PRE-FRONTAL TROUGH AND ALREADY WELL TO THE EAST OF THE FORECAST
AREA OVER THE ADIRONDACKS/GREEN MOUNTAINS BY TUESDAY MORNING...A FEW
SHOWERS WILL STILL BE POSSIBLE ALONG/JUST AHEAD OF THE COLD
FRONT...PARTICULARLY ACROSS THE NORTH COUNTRY WHERE THE APPROACH OF
THE COLD FRONT WILL COINCIDE WITH THE AFTERNOON DIURNAL HEATING
MAXIMUM.
OTHERWISE...LOOK FOR BREEZY CONDITIONS WITH FALLING TEMPERATURES
BEHIND THE COLD FRONT. A PERIOD OF POST-FRONTAL SUBSIDENCE AND
SUNSHINE WILL GIVE WAY TO INCREASING CLOUDS LATER IN THE DAY AND
INTO THE EVENING AS THE UPPER LEVEL TROUGH SWINGS THROUGH.
TEMPERATURES WILL CONTINUE TO FALL INTO THE 40S TUESDAY NIGHT...WITH
HIGHER ELEVATIONS DIPPING JUST BELOW THE 40 DEGREE MARK AS THE CORE
OF THE COLD AIR ALOFT MOVES ACROSS THE REGION. WITH 850MB TEMPS
FALLING BELOW -2C...WE MAY EVEN SEE A DECENT AMOUNT OF LAKE-ENHANCED
CLOUD COVER TUESDAY NIGHT AND INTO WEDNESDAY MORNING. THIS COLD AIR
ALOFT AND THE ASSOCIATED CLOUD COVER WILL AID IN MAKING WEDNESDAY
THE COLDEST DAY OF THIS WEEK WITH HIGHS ONLY TOPPING OUT IN THE LOW
TO MID 50S.
BY WEDNESDAY AFTERNOON WE SHOULD SEE AN INCREASE IN SUNSHINE ONCE
MORE AS THE COLDEST AIR ALOFT IS QUICKLY SHUNTED OFF TO THE EAST AS
A FLATTER AND FASTER PATTERN TAKES SHAPE IN THE UPPER LEVELS AND
SURFACE RIDING BEGINS TO CREEP IN ACROSS THE AREA FROM THE UPPER
MIDWEST. A FAST-MOVING SHORTWAVE SHOULD BRING SOME CLOUD COVER TO
THE SOUTHERN TIER WEDNESDAY NIGHT BUT HAVE LITTLE OTHER IMPACT
OWING TO A DEARTH OF MOISTURE. LOWS ONCE AGAIN WILL RUN IN THE
40S...WITH A FEW UPPER 30S IN THE SOUTHERN TIER. IT NOW APPEARS THAT
THERE SHOULD BE ENOUGH OF A BREEZE BOTH TUESDAY AND WEDNESDAY NIGHTS
TO PRECLUDE THE DEVELOPMENT OF FROST IN THE SOUTHERN TIER/NORTH
COUNTRY IN SPITE OF TEMPERATURES THAT WILL BE DIPPING INTO THE 30S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
IT WILL BE A DRY DAY ON THURSDAY WITH PASSING HIGH CLOUDS AS THE
REGION WILL REMAIN UNDERNEATH THE FLATTENED BASE OF A DEEP UPPER
LEVEL LOW CENTERED NEAR JAMES BAY. THE UPPER LEVEL FLOW WILL AMPLIFY
ONCE MORE ACROSS THE AREA ON FRIDAY AS A JET MAX DROPS INTO THE BASE
OF THE TROUGH OVER NORTHEASTERN ONTARIO. THIS WILL HELP PUSH ANOTHER
WEAK COLD FRONT ACROSS UPSTATE AND WESTERN NEW YORK ON
FRIDAY...POTENTIALLY TRIGGERING A SHOWER OR TWO ACROSS THE NORTH
COUNTRY. HOWEVER...A LACK OF MOISTURE WILL ONCE AGAIN LIMIT POPS TO
A SLIGHT CHANCE AT BEST.
AN EVEN MORE BENIGN PATTERN TAKES SHAPE FOR THE COMING WEEKEND AS
SURFACE HIGH PRESSURE TRACKS OVER THE LOWER GREAT LAKES. THERE WILL
BE PLENTY OF SUNSHINE TO BE HAD FRIDAY AND SATURDAY AS THE HIGH
MOVES OVERHEAD BEFORE MOVING OFF THE EAST COAST SUNDAY. AS THE HIGH
MOVES OFF THE EAST COAST...LOOK FOR RETURN FLOW TO SET UP ACROSS THE
LOWER GREAT LAKES THAT WILL SIGNAL A RETURN TO WARMER CONDITIONS
SUNDAY WITH UNSETTLED WEATHER LIKELY TO FOLLOW BY MONDAY AS A WARM
FRONT LIFTS NORTH ACROSS THE GREAT LAKES.
REGARDING TEMPERATURES...READINGS WILL RUN IN THE 60S ON THURSDAY.
WHILE CERTAINLY WARMER THAN THE CHILLY 50S EXPECTED WEDNESDAY...THE
LOWER GREAT LAKES REGION WILL REMAIN CLOSE ENOUGH TO THE
AFOREMENTIONED UPPER LEVEL LOW TO KEEP TEMPERATURES A FEW DEGREES
BELOW NORMAL. INDEED THE PASSAGE OF THE WEAK COOL FRONT FRIDAY WILL
KNOCK TEMPS BACK A COUPLE OF DEGREES. WITH HIGH PRESSURE MOVING
BUILDING FRIDAY NIGHT AND COOL/DRY AIR IN PLACE...WE SHOULD SEE A
CHILLY NIGHT WITH LOWS IN THE LOW/MID 40S...WITH UPPER 30S IN THE
SOUTHERN TIER AND NORTH COUNTRY. THIS TIME WINDS MAY BE LIGHT ENOUGH
TO POTENTIALLY ALLOW FOR FROST ACROSS THE SHELTERED AREAS OF THE
NORTH COUNTRY AND THE SOUTHERN TIER. THEREAFTER...TEMPERATURES
SHOULD GRADUALLY REBOUND THROUGH THE WEEKEND AS THE HIGH DRIFTS EAST
OF THE REGION AND RETURN FLOW TAKES HOLD WITH WIDESPREAD 70S
EXPECTED ONCE AGAIN BY SUNDAY.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS IN PLACE EARLY THIS MORNING EXCEPT FOR SOME IFR FOG
ACROSS THE HILLTOPS OF THE SOUTHERN TIER. THIS WILL WILL DISSIPATE
IN THE MORNING WITH INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS
FOR KJHW/KROC/KART DURING THE LATE MORNING AND AFTERNOON AS A PRE-
FRONTAL TROUGH CROSSES THE FORECAST AREA. A STABLE FLOW OFF LAKE
ERIE SHOULD KEEP KBUF/KIAG FREE FROM ANY HEAVY STORMS WHICH WILL
DEVELOP FROM THE SOUTHERN TIER TO EAST OF BUFFALO TO ROCHESTER AND
SYRACUSE. STORM ACTIVITY WILL SHIFT EAST LATER THIS EVENING WITH
MAINLY DRY CONDITIONS EXPECTED TONIGHT. SOME LOW CLOUDS/FOG MAY
BRING IFR TO KJHW LATE TONIGHT ESPECIALLY IF HEAVY RAIN FALLS
ACROSS THE SOUTHERN TIER.
OUTLOOK...
TUESDAY THROUGH FRIDAY...VFR.
&&
.MARINE...
LIGHT WINDS AND MINIMAL WAVES WILL CONTINUE ON THE EASTERN GREAT
LAKES TODAY WITH AREAS OF FOG AS A WARM AND HUMID AIRMASS REMAINS
OVER THE COOL LAKE WATERS. CONDITIONS ON THE LAKES SHOULD REMAIN
QUIET OUTSIDE OF ANY THUNDERSTORMS PRODUCING ASSOCIATED HIGHER WINDS
AND WAVES.
A COLD FRONT WILL SWEEP ACROSS THE EASTERN GREAT LAKES LATE
TONIGHT/TUESDAY WITH AN INCREASE IN WIND SPEED AND WAVE ACTION INTO
TUESDAY. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE LAKE ERIE
NEARSHORES COVERING TUESDAY AFTERNOON/EVENING. HIGH PRESSURE WILL
THEN BUILD OVER THE EASTERN GREAT LAKES WEDNESDAY THROUGH THE REST
OF THE WEEK WITH LOW WIND AND WAVE ACTION.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TO 11 PM EDT TUESDAY FOR LEZ040-
041.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...WOOD
LONG TERM...WOOD
AVIATION...SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
515 AM EDT MON MAY 18 2015
.SYNOPSIS...
A WARM AND HUMID AIR MASS WILL REMAIN OVER THE REGION WITH A PERIOD
OF SHOWERS AND THUNDERSTORMS PUSHING ACROSS WESTERN AND CENTRAL NEW
YORK TODAY AHEAD OF A COLD FRONT. SOME OF THESE THUNDERSTORMS MAY
BRING LOCALIZED HEAVY RAIN. THE FRONT WILL CROSS EARLY TUESDAY THEN
A COOLER AND DRIER AIRMASS WILL ARRIVE BEHIND THE FRONT FOR THE
REMAINDER OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE FORECAST AREA LIES BENEATH AN AMPLIFIED 500MB RIDGE THIS MORNING
WITH STACKED SURFACE AND UPPER LEVEL LOW OVER NORTHERN MINNESOTA
CONTINUING TO SPREAD WARM AND MOIST AIR NORTH ACROSS THE GREAT
LAKES. DEWPOINTS RUNNING CLOSE TO 60F ACROSS WESTERN NEW YORK WITH
MID 60S DEWPOINTS FOUND ACROSS MICHIGAN. SPC MESOSCALE ANALYSIS
SHOWS A RIBBON OF HIGH PRECIPITABLE WATER VALUES AROUND 1.7 INCHES
RUNNING FROM NORTH OF GEORGIAN BAY TO LAKE ERIE. PLENTY OF MOISTURE
TO BE FOUND SO FOCUS FOR TIMING OF SHOWER AND THUNDERSTORM ACTIVITY
TODAY WILL BE ON ANY SYNOPTIC/MESOSCALE FEATURES SHIFTING ACROSS
THE EASTERN GREAT LAKES.
A PRE-FRONTAL TROUGH IS ANALYZED ROUGHLY FROM NORTHERN MI SOUTHEAST
TO NEAR KERI. THIS IS FORECAST TO SHIFT ACROSS WESTERN AND CENTRAL
NEW YORK TODAY. LOOKING TO THE MID-LEVELS...FORCING MAY ALSO COME
FROM ANY SUBTLE SHORTWAVES ROLLING UP THE WEST SIDE OF THE RIDGE
AXIS FROM THE MISS VALLEY TOWARD THE EASTERN GREAT LAKES. MESOSCALE
GUIDANCE SUCH AS WRF AND HRRR MODELS SUGGEST A FEW ISOLATED SHOWERS
AND STORMS MAY WORK INTO WNY ALONG THE TROUGH THIS MORNING. BY EARLY
AFTERNOON FORECAST CAPE OF 2-3K J/KG WILL FEED MORE NUMEROUS SHOWERS
AND THUNDERSTORMS DEVELOPING FROM THE SOUTHERN TIER ACROSS THE
GENESEE VALLEY AND FINGER LAKES. A STABLE SOUTHWEST FLOW OFF LAKE
ERIE SHOULD KEEP MUCH OF THE NIAGARA FRONTIER PROTECTED FROM THE
HEAVIER STORMS BUT LAKE BREEZES COULD TRIGGER ADDITIONAL CELLS TO THE
SOUTH AND EAST OF BUFFALO. BULK SHEAR THIS AFTERNOON IS FORECAST
ONLY AROUND 15 KTS SO TOO WEAK TO SUPPORT ANY SIGNIFICANT WIND/HAIL
THREAT. THE DEEP MOISTURE IN PLACE PER PWATS AND SKINNY CAPE
PROFILES WITH SLOW STORM MOTIONS WILL HOWEVER BRING A RISK FOR
LOCALLY HEAVY RAIN AND FLOODING IF ANY TRAINING CELLS DEVELOPS.
TONIGHT...THE SURFACE LOW WILL SHIFT NORTH OF THE GREAT LAKES TO
SOUTHERN QUEBEC. NEAR-TERM MODELS INDICATE THE MAJORITY OF REMAINING
CONVECTION WILL BE LIMITED FROM THE FINGER LAKES EASTWARD ACROSS
CENTRAL AND EASTERN NEW YORK. WESTERN NEW YORK WILL LARGELY REMAIN
DRY. THE COLD FRONT WILL CROSS WNY LATE TONIGHT AND IS FORECAST TO
BE NEAR THE FINGER LAKES BY 12Z TUESDAY WITH SKY COVER THINNING FROM
WEST TO EAST. THE OVERNIGHT TIMING OF THE FRONT SHOULD LIMIT A
SECOND ROUND OF SHOWER/TSTM ACTIVITY.
TEMPERATURES TODAY WILL AGAIN RISE ABOVE NORMAL WITHIN A HUMID
AIRMASS. 850MB TEMPS OF NEAR +15C WILL SUPPORT SURFACE HIGH TEMPS
RANGING FROM THE UPPER 70S TO MID 80S. THE U70S TEMPS WILL ONLY BE
LIMITED BY EARLIER START TO CONVECTION WHILE MORE HEATING ACROSS
FINGER LAKES AND NORTH COUNTRY WILL HELP BOOST TEMPS TO THE M80S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
A STRONG COLD FRONT WILL CROSS THE FORECAST AREA DURING THE DAY ON
TUESDAY. WHILE THE BULK OF THE PRECIPITATION WILL BE ASSOCIATED WITH
THE PRE-FRONTAL TROUGH AND ALREADY WELL TO THE EAST OF THE FORECAST
AREA OVER THE ADIRONDACKS/GREEN MOUNTAINS BY TUESDAY MORNING...A FEW
SHOWERS WILL STILL BE POSSIBLE ALONG/JUST AHEAD OF THE COLD
FRONT...PARTICULARLY ACROSS THE NORTH COUNTRY WHERE THE APPROACH OF
THE COLD FRONT WILL COINCIDE WITH THE AFTERNOON DIURNAL HEATING
MAXIMUM.
OTHERWISE...LOOK FOR BREEZY CONDITIONS WITH FALLING TEMPERATURES
BEHIND THE COLD FRONT. A PERIOD OF POST-FRONTAL SUBSIDENCE AND
SUNSHINE WILL GIVE WAY TO INCREASING CLOUDS LATER IN THE DAY AND
INTO THE EVENING AS THE UPPER LEVEL TROUGH SWINGS THROUGH.
TEMPERATURES WILL CONTINUE TO FALL INTO THE 40S TUESDAY NIGHT...WITH
HIGHER ELEVATIONS DIPPING JUST BELOW THE 40 DEGREE MARK AS THE CORE
OF THE COLD AIR ALOFT MOVES ACROSS THE REGION. WITH 850MB TEMPS
FALLING BELOW -2C...WE MAY EVEN SEE A DECENT AMOUNT OF LAKE-ENHANCED
CLOUD COVER TUESDAY NIGHT AND INTO WEDNESDAY MORNING. THIS COLD AIR
ALOFT AND THE ASSOCIATED CLOUD COVER WILL AID IN MAKING WEDNESDAY
THE COLDEST DAY OF THIS WEEK WITH HIGHS ONLY TOPPING OUT IN THE LOW
TO MID 50S.
BY WEDNESDAY AFTERNOON WE SHOULD SEE AN INCREASE IN SUNSHINE ONCE
MORE AS THE COLDEST AIR ALOFT IS QUICKLY SHUNTED OFF TO THE EAST AS
A FLATTER AND FASTER PATTERN TAKES SHAPE IN THE UPPER LEVELS AND
SURFACE RIDING BEGINS TO CREEP IN ACROSS THE AREA FROM THE UPPER
MIDWEST. A FAST-MOVING SHORTWAVE SHOULD BRING SOME CLOUD COVER TO
THE SOUTHERN TIER WEDNESDAY NIGHT BUT HAVE LITTLE OTHER IMPACT
OWING TO A DEARTH OF MOISTURE. LOWS ONCE AGAIN WILL RUN IN THE
40S...WITH A FEW UPPER 30S IN THE SOUTHERN TIER. IT NOW APPEARS THAT
THERE SHOULD BE ENOUGH OF A BREEZE BOTH TUESDAY AND WEDNESDAY NIGHTS
TO PRECLUDE THE DEVELOPMENT OF FROST IN THE SOUTHERN TIER/NORTH
COUNTRY IN SPITE OF TEMPERATURES THAT WILL BE DIPPING INTO THE 30S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
IT WILL BE A DRY DAY ON THURSDAY WITH PASSING HIGH CLOUDS AS THE
REGION WILL REMAIN UNDERNEATH THE FLATTENED BASE OF A DEEP UPPER
LEVEL LOW CENTERED NEAR JAMES BAY. THE UPPER LEVEL FLOW WILL AMPLIFY
ONCE MORE ACROSS THE AREA ON FRIDAY AS A JET MAX DROPS INTO THE BASE
OF THE TROUGH OVER NORTHEASTERN ONTARIO. THIS WILL HELP PUSH ANOTHER
WEAK COLD FRONT ACROSS UPSTATE AND WESTERN NEW YORK ON
FRIDAY...POTENTIALLY TRIGGERING A SHOWER OR TWO ACROSS THE NORTH
COUNTRY. HOWEVER...A LACK OF MOISTURE WILL ONCE AGAIN LIMIT POPS TO
A SLIGHT CHANCE AT BEST.
AN EVEN MORE BENIGN PATTERN TAKES SHAPE FOR THE COMING WEEKEND AS
SURFACE HIGH PRESSURE TRACKS OVER THE LOWER GREAT LAKES. THERE WILL
BE PLENTY OF SUNSHINE TO BE HAD FRIDAY AND SATURDAY AS THE HIGH
MOVES OVERHEAD BEFORE MOVING OFF THE EAST COAST SUNDAY. AS THE HIGH
MOVES OFF THE EAST COAST...LOOK FOR RETURN FLOW TO SET UP ACROSS THE
LOWER GREAT LAKES THAT WILL SIGNAL A RETURN TO WARMER CONDITIONS
SUNDAY WITH UNSETTLED WEATHER LIKELY TO FOLLOW BY MONDAY AS A WARM
FRONT LIFTS NORTH ACROSS THE GREAT LAKES.
REGARDING TEMPERATURES...READINGS WILL RUN IN THE 60S ON THURSDAY.
WHILE CERTAINLY WARMER THAN THE CHILLY 50S EXPECTED WEDNESDAY...THE
LOWER GREAT LAKES REGION WILL REMAIN CLOSE ENOUGH TO THE
AFOREMENTIONED UPPER LEVEL LOW TO KEEP TEMPERATURES A FEW DEGREES
BELOW NORMAL. INDEED THE PASSAGE OF THE WEAK COOL FRONT FRIDAY WILL
KNOCK TEMPS BACK A COUPLE OF DEGREES. WITH HIGH PRESSURE MOVING
BUILDING FRIDAY NIGHT AND COOL/DRY AIR IN PLACE...WE SHOULD SEE A
CHILLY NIGHT WITH LOWS IN THE LOW/MID 40S...WITH UPPER 30S IN THE
SOUTHERN TIER AND NORTH COUNTRY. THIS TIME WINDS MAY BE LIGHT ENOUGH
TO POTENTIALLY ALLOW FOR FROST ACROSS THE SHELTERED AREAS OF THE
NORTH COUNTRY AND THE SOUTHERN TIER. THEREAFTER...TEMPERATURES
SHOULD GRADUALLY REBOUND THROUGH THE WEEKEND AS THE HIGH DRIFTS EAST
OF THE REGION AND RETURN FLOW TAKES HOLD WITH WIDESPREAD 70S
EXPECTED ONCE AGAIN BY SUNDAY.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS IN PLACE EARLY THIS MORNING EXCEPT FOR SOME IFR FOG
ACROSS THE HILLTOPS OF THE SOUTHERN TIER. THIS WILL WILL DISSIPATE
IN THE MORNING WITH INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS
DURING THE LATE MORNING AND AFTERNOON AS A PRE-FRONTAL TROUGH
CROSSES THE FORECAST AREA. A STABLE FLOW OFF LAKE ERIE SHOULD KEEP
KBUF/KIAG FREE FROM ANY HEAVY STORMS WHICH WILL DEVELOP FROM THE
SOUTHERN TIER TO EAST OF BUFFALO TO ROCHESTER AND SYRACUSE. STORM
ACTIVITY WILL SHIFT EAST LATER THIS EVENING WITH MAINLY DRY
CONDITIONS EXPECTED TONIGHT.
OUTLOOK...
TUESDAY THROUGH FRIDAY...VFR.
&&
.MARINE...
LIGHT WINDS AND MINIMAL WAVES WILL CONTINUE ON THE EASTERN GREAT
LAKES TODAY WITH AREAS OF FOG AS A WARM AND HUMID AIRMASS REMAINS
OVER THE COOL LAKE WATERS. CONDITIONS ON THE LAKES SHOULD REMAIN
QUIET OUTSIDE OF ANY THUNDERSTORMS PRODUCING ASSOCIATED HIGHER WINDS
AND WAVES.
A COLD FRONT WILL SWEEP ACROSS THE EASTERN GREAT LAKES LATE
TONIGHT/TUESDAY WITH AN INCREASE IN WIND SPEED AND WAVE ACTION INTO
TUESDAY. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE LAKE ERIE
NEARSHORES COVERING TUESDAY AFTERNOON/EVENING. HIGH PRESSURE WILL
THEN BUILD OVER THE EASTERN GREAT LAKES WEDNESDAY THROUGH THE REST
OF THE WEEK WITH LOW WIND AND WAVE ACTION.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TO 11 PM EDT TUESDAY FOR LEZ040-
041.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...WOOD
LONG TERM...WOOD
AVIATION...SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
444 AM EDT MON MAY 18 2015
.SYNOPSIS...
A WARM AND HUMID AIR MASS WILL REMAIN OVER THE REGION WITH A PERIOD
OF SHOWERS AND THUNDERSTORMS PUSHING ACROSS WESTERN AND CENTRAL NEW
YORK TODAY AHEAD OF A COLD FRONT. SOME OF THESE THUNDERSTORMS MAY
BRING LOCALIZED HEAVY RAIN. THE FRONT WILL CROSS EARLY TUESDAY THEN
A COOLER AND DRIER AIRMASS WILL ARRIVE BEHIND THE FRONT FOR THE
REMAINDER OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE FORECAST AREA LIES BENEATH AN AMPLIFIED 500MB RIDGE THIS MORNING
WITH STACKED SURFACE AND UPPER LEVEL LOW OVER NORTHERN MINNESOTA
CONTINUING TO SPREAD WARM AND MOIST AIR NORTH ACROSS THE GREAT
LAKES. DEWPOINTS RUNNING CLOSE TO 60F ACROSS WESTERN NEW YORK WITH
MID 60S DEWPOINTS FOUND ACROSS MICHIGAN. SPC MESOSCALE ANALYSIS
SHOWS A RIBBON OF HIGH PRECIPITABLE WATER VALUES AROUND 1.7 INCHES
RUNNING FROM NORTH OF GEORGIAN BAY TO LAKE ERIE. PLENTY OF MOISTURE
TO BE FOUND SO FOCUS FOR TIMING OF SHOWER AND THUNDERSTORM ACTIVITY
TODAY WILL BE ON ANY SYNOPTIC/MESOSCALE FEATURES SHIFTING ACROSS
THE EASTERN GREAT LAKES.
A PRE-FRONTAL TROUGH IS ANALYZED ROUGHLY FROM NORTHERN MI SOUTHEAST
TO NEAR KERI. THIS IS FORECAST TO SHIFT ACROSS WESTERN AND CENTRAL
NEW YORK TODAY. LOOKING TO THE MID-LEVELS...FORCING MAY ALSO COME
FROM ANY SUBTLE SHORTWAVES ROLLING UP THE WEST SIDE OF THE RIDGE
AXIS FROM THE MISS VALLEY TOWARD THE EASTERN GREAT LAKES. MESOSCALE
GUIDANCE SUCH AS WRF AND HRRR MODELS SUGGEST A FEW ISOLATED SHOWERS
AND STORMS MAY WORK INTO WNY ALONG THE TROUGH THIS MORNING. BY EARLY
AFTERNOON FORECAST CAPE OF 2-3K J/KG WILL FEED MORE NUMEROUS SHOWERS
AND THUNDERSTORMS DEVELOPING FROM THE SOUTHERN TIER ACROSS THE
GENESEE VALLEY AND FINGER LAKES. A STABLE SOUTHWEST FLOW OFF LAKE
ERIE SHOULD KEEP MUCH OF THE NIAGARA FRONTIER PROTECTED FROM THE
HEAVIER STORMS BUT LAKE BREEZES COULD TRIGGER ADDITIONAL CELLS TO THE
SOUTH AND EAST OF BUFFALO. BULK SHEAR THIS AFTERNOON IS FORECAST
ONLY AROUND 15 KTS SO TOO WEAK TO SUPPORT ANY SIGNIFICANT WIND/HAIL
THREAT. THE DEEP MOISTURE IN PLACE PER PWATS AND SKINNY CAPE
PROFILES WITH SLOW STORM MOTIONS WILL HOWEVER BRING A RISK FOR
LOCALLY HEAVY RAIN AND FLOODING IF ANY TRAINING CELLS DEVELOPS.
TONIGHT...THE SURFACE LOW WILL SHIFT NORTH OF THE GREAT LAKES TO
SOUTHERN QUEBEC. NEAR-TERM MODELS INDICATE THE MAJORITY OF REMAINING
CONVECTION WILL BE LIMITED FROM THE FINGER LAKES EASTWARD ACROSS
CENTRAL AND EASTERN NEW YORK. WESTERN NEW YORK WILL LARGELY REMAIN
DRY. THE COLD FRONT WILL CROSS WNY LATE TONIGHT AND IS FORECAST TO
BE NEAR THE FINGER LAKES BY 12Z TUESDAY WITH SKY COVER THINNING FROM
WEST TO EAST. THE OVERNIGHT TIMING OF THE FRONT SHOULD LIMIT A
SECOND ROUND OF SHOWER/TSTM ACTIVITY.
TEMPERATURES TODAY WILL AGAIN RISE ABOVE NORMAL WITHIN A HUMID
AIRMASS. 850MB TEMPS OF NEAR +15C WILL SUPPORT SURFACE HIGH TEMPS
RANGING FROM THE UPPER 70S TO MID 80S. THE U70S TEMPS WILL ONLY BE
LIMITED BY EARLIER START TO CONVECTION WHILE MORE HEATING ACROSS
FINGER LAKES AND NORTH COUNTRY WILL HELP BOOST TEMPS TO THE M80S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
A STRONG COLD FRONT WILL CROSS THE FORECAST AREA DURING THE DAY ON
TUESDAY. WHILE THE BULK OF THE PRECIPITATION WILL BE ASSOCIATED WITH
THE PRE-FRONTAL TROUGH AND ALREADY WELL TO THE EAST OF THE FORECAST
AREA OVER THE ADIRONDACKS/GREEN MOUNTAINS BY TUESDAY MORNING...A FEW
SHOWERS WILL STILL BE POSSIBLE ALONG/JUST AHEAD OF THE COLD
FRONT...PARTICULARLY ACROSS THE NORTH COUNTRY WHERE THE APPROACH OF
THE COLD FRONT WILL COINCIDE WITH THE AFTERNOON DIURNAL HEATING
MAXIMUM.
OTHERWISE...LOOK FOR BREEZY CONDITIONS WITH FALLING TEMPERATURES
BEHIND THE COLD FRONT. A PERIOD OF POST-FRONTAL SUBSIDENCE AND
SUNSHINE WILL GIVE WAY TO INCREASING CLOUDS LATER IN THE DAY AND
INTO THE EVENING AS THE UPPER LEVEL TROUGH SWINGS THROUGH.
TEMPERATURES WILL CONTINUE TO FALL INTO THE 40S TUESDAY NIGHT...WITH
HIGHER ELEVATIONS DIPPING JUST BELOW THE 40 DEGREE MARK AS THE CORE
OF THE COLD AIR ALOFT MOVES ACROSS THE REGION. WITH 850MB TEMPS
FALLING BELOW -2C...WE MAY EVEN SEE A DECENT AMOUNT OF LAKE-ENHANCED
CLOUD COVER TUESDAY NIGHT AND INTO WEDNESDAY MORNING. THIS COLD AIR
ALOFT AND THE ASSOCIATED CLOUD COVER WILL AID IN MAKING WEDNESDAY
THE COLDEST DAY OF THIS WEEK WITH HIGHS ONLY TOPPING OUT IN THE LOW
TO MID 50S.
BY WEDNESDAY AFTERNOON WE SHOULD SEE AN INCREASE IN SUNSHINE ONCE
MORE AS THE COLDEST AIR ALOFT IS QUICKLY SHUNTED OFF TO THE EAST AS
A FLATTER AND FASTER PATTERN TAKES SHAPE IN THE UPPER LEVELS AND
SURFACE RIDING BEGINS TO CREEP IN ACROSS THE AREA FROM THE UPPER
MIDWEST. A FAST-MOVING SHORTWAVE SHOULD BRING SOME CLOUD COVER TO
THE SOUTHERN TIER WEDNESDAY NIGHT BUT HAVE LITTLE OTHER IMPACT
OWING TO A DEARTH OF MOISTURE. LOWS ONCE AGAIN WILL RUN IN THE
40S...WITH A FEW UPPER 30S IN THE SOUTHERN TIER. IT NOW APPEARS THAT
THERE SHOULD BE ENOUGH OF A BREEZE BOTH TUESDAY AND WEDNESDAY NIGHTS
TO PRECLUDE THE DEVELOPMENT OF FROST IN THE SOUTHERN TIER/NORTH
COUNTRY IN SPITE OF TEMPERATURES THAT WILL BE DIPPING INTO THE 30S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THURSDAY AND FRIDAY...BROAD/FLAT UPPER LEVEL TROUGHING OVER THE
GREAT LAKES AND NORTHEAST WILL REAMPLIFY AS A PAIR OF SHORTWAVES
DROP THROUGH ITS BACKSIDE AND BASE...WITH AN ATTENDANT SECONDARY
COLD FRONT PIVOTING ACROSS OUR REGION BETWEEN THURSDAY NIGHT AND
FRIDAY. AT THIS JUNCTURE...THIS LATTER FEATURE STILL APPEARS TO BE
TOO WEAK AND STARVED FOR BOTH MOISTURE AND UPPER LEVEL SUPPORT TO
WARRANT THE INCLUSION OF ANY PRECIP CHANCES IN THE FORECAST...SO
HAVE CONTINUED TO LEAVE THINGS DRY WITH SURFACE HIGH PRESSURE AND
DRIER AIR CONTINUING TO DOMINATE OUR WEATHER. IN ADVANCE OF THE
AFOREMENTIONED FRONT...SOME MODEST WARMING OF OUR AIRMASS SHOULD
ALLOW TEMPS TO RECOVER BACK INTO THE LOWER AND MID 60S ON
THURSDAY...BEFORE PULLING BACK AT LEAST A LITTLE BEHIND THE
BOUNDARY ON FRIDAY.
NEXT WEEKEND...SPRAWLING HIGH PRESSURE AND DRY AIR OVER OUR
REGION AT THE START OF SATURDAY WILL SLOWLY DRIFT EASTWARD AND OFF
THE ATLANTIC COASTLINE...WHILE HEIGHTS ALOFT ALSO REBUILD AS THE
UPPER LEVEL TROUGH OVER OUR REGION LIFTS OUT...AND THE NEXT MODEST
TROUGH BEGINS SLIDING EASTWARD ACROSS THE PLAINS STATES. UNDER
THIS REGIME...DRY WEATHER SHOULD PERSIST THROUGH AT LEAST THE
FIRST HALF OF SUNDAY...BEFORE AN APPROACHING WARM FRONT OVER THE
OHIO VALLEY POTENTIALLY BRINGS A RISK OF SHOWERS SUNDAY AFTERNOON.
THIS STATED...HAVE ELECTED TO KEEP THINGS DRY ON SUNDAY FOR NOW
GIVEN BOTH THE DISTANT VANTAGE POINT AND THE LACK OF AGREEMENT
EXHIBITED BY THE MEDIUM RANGE GUIDANCE WITH RESPECT TO THE TIMING
OF THE WARM FRONT...WHICH IS TYPICAL FOR THIS FAR IN ADVANCE. WHAT
IS MORE CERTAIN IS THAT THIS PATTERN SHOULD ALLOW FOR A WARMING
TREND...WITH DAYTIME HIGHS CLIMBING BACK INTO THE 70S BY NEXT
SUNDAY.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS IN PLACE EARLY THIS MORNING EXCEPT FOR SOME IFR FOG
ACROSS THE HILLTOPS OF THE SOUTHERN TIER. THIS WILL WILL DISSIPATE
IN THE MORNING WITH INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS
DURING THE LATE MORNING AND AFTERNOON AS A PRE-FRONTAL TROUGH
CROSSES THE FORECAST AREA. A STABLE FLOW OFF LAKE ERIE SHOULD KEEP
KBUF/KIAG FREE FROM ANY HEAVY STORMS WHICH WILL DEVELOP FROM THE
SOUTHERN TIER TO EAST OF BUFFALO TO ROCHESTER AND SYRACUSE. STORM
ACTIVITY WILL SHIFT EAST LATER THIS EVENING WITH MAINLY DRY
CONDITIONS EXPECTED TONIGHT.
OUTLOOK...
TUESDAY THROUGH FRIDAY...VFR.
&&
.MARINE...
LIGHT WINDS AND MINIMAL WAVES WILL CONTINUE ON THE EASTERN GREAT
LAKES TODAY WITH AREAS OF FOG AS A WARM AND HUMID AIRMASS REMAINS
OVER THE COOL LAKE WATERS. CONDITIONS ON THE LAKES SHOULD REMAIN
QUIET OUTSIDE OF ANY THUNDERSTORMS PRODUCING ASSOCIATED HIGHER WINDS
AND WAVES.
A COLD FRONT WILL SWEEP ACROSS THE EASTERN GREAT LAKES LATE
TONIGHT/TUESDAY WITH AN INCREASE IN WIND SPEED AND WAVE ACTION INTO
TUESDAY. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE LAKE ERIE
NEARSHORES COVERING TUESDAY AFTERNOON/EVENING. HIGH PRESSURE WILL
THEN BUILD OVER THE EASTERN GREAT LAKES WEDNESDAY THROUGH THE REST
OF THE WEEK WITH LOW WIND AND WAVE ACTION.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TO 11 PM EDT TUESDAY FOR LEZ040-
041.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...WOOD
LONG TERM...JJR
AVIATION...SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
749 PM EDT TUE MAY 19 2015
.SYNOPSIS...A COLD FRONT WILL MOVE ACROSS CENTRAL NORTH CAROLINA
TONIGHT...AND THEN STALL OVER SOUTH CAROLINA ON WEDNESDAY. THE
FRONT WILL THEN RETREAT NORTH IN ADVANCE OF AN AREA OF LOW PRESSURE
THAT WILL CROSS THE CAROLINAS ON THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 225 PM TUESDAY...
SCATTERED SHOWERS AND ISOLD TSTMS HAVE BROKEN OUT ACROSS PARTS OF
CENTRAL NC AS EXPECTED...WITH ACTIVITY EXPECTED TO CONTINUE TO
EXPAND AND MOVE EAST THROUGH THE REMAINDER OF THE AFTERNOON. LATEST
MESOANALYSIS STILL SHOWS THE BEST MOISTURE AND INSTABILITY LOCATED
ACROSS OUR EASTERN ZONES...AND SUGGESTS THAT SHOWER/TSTM COVERAGE
SHOULD INCREASE AS THEY EVOLVE EASTWARD LATER THIS AFTERNOON.
ANOTHER NOTABLE FEATURE IS A MID LEVEL VORT CURRENTLY MOVING E
ACROSS NE SC. THIS FEATURE MAY AID THE DEVELOPMENT AND MAINTENANCE
OF SHOWER/TSTM ACTIVITY ACROSS OUR SE ZONES AS IT MOVES EAST THE
REST OF THIS AFTERNOON. OTHERWISE...GIVEN WEAK MID-LEVEL LAPSE RATES
AND WEAK SHEAR...CELL INTENSITY SHOULD BE LIMITED...BUT STILL
CAPABLE OF PRODUCING BRIEF INTENSE DOWNPOURS GIVEN THE ABUNDANT
MOISTURE AND ABOVE-CLIMO PWAT VALUES IN PLACE ACROSS THE AREA.
SHOWER/TSTM ACTIVITY IS THEN EXPECTED TO DIMINISH AND MOVE EAST
TOWARD THE COAST LATER THIS EVENING.
OVERNIGHT...THE COLD FRONT WHICH IS CURRENTLY EXTENDING FROM
PITTSBURGH TO NASHVILLE TO MEMPHIS WILL MOVE S AND E AND ACROSS OUR
CWA. LATEST HRRR SUGGESTS AN ISOLD SHOWER CAN`T BE RULED OUT WITH
PASSAGE OF THE FRONT...BUT MOST PLACES WILL REMAIN DRY AS THE FRONT
MOVES ACROSS. MORE LIKELY WILL BE THE FORMATION OF SOME FOG...ESP
ACROSS AREAS THAT RECEIVE HEAVIER RAINFALL THIS AFTERNOON AND
EVENING. LOW TEMPS WILL BE COOLEST ACROSS THE NW (AROUND 60) WHERE
THE FRONT WILL MOVE THROUGH EARLIER IN THE NIGHT...VERSUS OUR SE
ZONES WHERE THE FROPA WILL OCCUR LATER IN THE NIGHT AND THUS HAVE
LOW IN THE MID TO UPPER 60S.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 225 PM TUESDAY...
THE COLD FRONT WILL STALL TO OUR SOUTH ACROSS SC ON WEDNESDAY. THIS
WILL ALLOW DRIER AND SLIGHTLY COOLER AIR TO MOVE INTO OUR AREA FROM
THE NW. AS SUCH...LOOK FOR FAIR WEATHER WITH HIGHS FROM THE MID 80S
NORTH TO UPPER 80S SOUTH.
WEDNESDAY NIGHT...A SHORT WAVE OVER THE MISS VALLEY WILL MOVE EAST
AND INDUCE A LOW PRESSURE WAVE ALONG THE OLD BOUNDARY TO OUR SOUTH.
THERE ARE STILL MODEL DIFFERENCES REGARDING WHERE (PARTICULARLY HOW
FAR NORTH) THAT WAVE WILL SET UP...BUT EITHER WAY IT APPEARS THAT A
FEW SHOWERS WILL BE POSSIBLE ACROSS OUR PIEDMONT ZONES LATER
OVERNIGHT. LOWS WILL RANGE FROM AROUND 60 NW TO MID 60S SE.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 315 PM TUESDAY...
THURSDAY TROUGH FRIDAY NIGHT: A QUICK MOVING S/W DISTURBANCE IS
EXPECTED TO MOVE FROM THE PLAINS TO OFF THE MID-ATLANTIC/NORTHEAST
U.S. COAST BY FRIDAY MORNING... SPREADING SHOWERS AND SOME STORMS
ACROSS CENTRAL ON THURSDAY. WHILE THE DISTURBANCE WILL TRACK JUST TO
OUR NORTH...AN AREA OF LOW PRESSURE IN RESPONSE WILL DEVELOP/DEEPEN
ALONG THE OLD FRONTAL ZONE NEAR THE NC/SC BORDER... THEN LIFT NORTH
AND EASTWARD ON THURSDAY NIGHT INTO FRIDAY. THIS SHOULD BRING A WIDE
RANGE IN TEMPS ACROSS CENTRAL NC ON THURSDAY... WITH THE POTENTIAL
FOR SOME ROTATING STORMS NEAR THE BOUNDARY... AS DEEP LAYER SHEAR IS
EXPECTED TO INCREASE TO 30 TO 35 KTS WITH A BACKED SURFACE FLOW AS
THE SURFACE APPROACHES. HOWEVER... WITH THE POSSIBILITY OF ON GOING
SHOWERS AND WIDESPREAD CLOUD COVER THERE IS QUITE A BIT OF
UNCERTAINTY WRT HOW MUCH DESTABILIZATION WE WILL SEE IN THE
DEVELOPING WARM SECTOR. THUS...SPC HAS PLACED SOUTHEASTERN/EASTERN
PORTIONS OF CENTRAL NC IN A MARGINAL RISK FOR SEVERE STORMS. FOR NOW
WILL CONTINUE TO MENTION A THREAT FOR ISOLATED SEVERE STORMS ACROSS
OUR SE/E COUNTIES IN THE HWO FOR THURSDAY. WILL GO WITH HIGHS TEMPS
ON THURSDAY RANGING FROM THE UPPER 60S/NEAR 70 (MAYBE NOT COOL
ENOUGH EVEN) NEAR THE NC/VA BORDER TO LOWER TO MID 80S
SOUTH/SOUTHEAST.
THE PRIMARY SURFACE LOW IS EXPECTED TO LIFT OFF TO THE NORTHEAST
LATE THURSDAY NIGHT INTO FRIDAY... BRINGING A RETURN TO DRY AND
QUIET WEATHER... WITH CLEARING/SUNNY SKIES BY FRIDAY AFTERNOON
ONWARD AS SURFACE HIGH PRESSURE BUILDS INTO THE AREA FROM THE
NORTHWEST. EXPECT HIGHS ON FRIDAY WILL BE IN THE UPPER 70S TO LOWER
80S. LOWS FRIDAY MORNING WILL BE DEPENDENT ON THE AMOUNT OF CLEARING
AND ANY LINGERING COOL STABLE AIRMASS. FOR NOW WILL GO WITH LOWS
RANGING FROM THE 50S NORTH TO THE MID 60S SE. LOWS SATURDAY... WITH
SURFACE HIGH PRESSURE TO THE NORTH OF THE REGION... ARE EXPECTED TO
BE IN THE MID TO UPPER 50S.
SATURDAY THROUGH TUESDAY: SURFACE HIGH PRESSURE WILL MOVE ACROSS THE
REGION THIS WEEKEND AND OFFSHORE EARLY NEXT WEEK AS MID LEVEL
RIDGING BEGINS TO BUILD AGAIN. THIS WILL YIELD A WARMING TREND EACH
DAY FROM HIGHS IN THE UPPER 70S TO LOWER 80S ON SATURDAY TO THE
UPPER 80S TO LOWER 90S ON TUESDAY. LOWS WILL FOLLOW A SIMILAR
TREND... 50S THIS WEEKEND TO THE MID TO UPPER 60S BY TUESDAY
MORNING. DRY CONDITIONS ARE GENERALLY EXPECTED FOR THIS PERIOD...
WITH INCREASING CHANCES OF AT LEAST SOME ISOLATED OR WIDELY
SCATTERED SHOWERS AND STORMS BY TUESDAY AFTERNOON (BEST CHANCE
NORTHWEST) AS LOW LEVEL MOISTURE INCREASES IN RETURN FLOW.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 745 PM TUESDAY...
SHOWER AND THUNDERSTORM ACTIVITY WILL CONTINUE TO DIMINISH AS THE
ACTIVITY MOVES EAST. THERE COULD BE A FEW ISOLATED SHOWERS THROUGH
THE FIRST HALF OF THE OVERNIGHT HOURS AS A FRONT CROSSES THE AREA.
HOWEVER...CONFIDENCE IS NOT HIGH OF THIS OCCURRENCE AND REGARDLESS
COVERAGE WOULD BE TOO MINIMAL TO INCLUDE IN THE TAFS NOW. THERE
COULD BE SOME PATCHY FOG OVERNIGHT MAINLY ACROSS THE EAST WHERE THE
DRIER AIR WILL BE LAST TO ARRIVE...AND ESPECIALLY WHERE THE RAIN
OCCURRED (KRDU/KFAY/KRWI). HOWEVER...CONFIDENCE IS STILL TOO LOW TO
INCLUDE IN THE TAFS. THEN...WITH DRIER AIR FILTERING INTO THE AREA
BEHIND THE FRONT...VFR CONDITIONS WILL PERSIST FOR THE REMAINDER OF
THE CURRENT TAF PERIOD.
OUTLOOK: AN AREA OF LOW PRESSURE WILL TRACK ACROSS THE CAROLINAS AND
RESULT IN A CHANCE OF SUB-VFR CEILINGS AND RAIN LATE WED NIGHT AND
EARLY THU...FOLLOWED BY SHOWERS AND STORMS THU AFTERNOON.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RAH
NEAR TERM...RAH
SHORT TERM...RAH
LONG TERM...RAH
AVIATION...RAH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
110 AM CDT MON MAY 18 2015
.UPDATE...
ISSUED AT 109 AM CDT MON MAY 18 2015
ROLLA SUSTAINED WIND AT 37 MPH GUSTING TO 48 MPH AND TURTLE MOUNTAIN
RAWS AT 37 MPH WITH GUSTS TO 57 MPH. THESE VALUES ARE JUST BELOW
HIGH WIND WARNING CRITERIA...AND LOOKING AT THE DECREASING TREND
EXPECTED DURING THE OVERNIGHT HOURS - WILL ALLOW THE HIGH WIND
WARNING FOR ROLETTE AND PIERCE COUNTIES TO EXPIRE. THE STRONG WINDS
ARE IN THE WORDING OF THE WINTER WEATHER ADVISORY THAT IS IN EFFECT
FOR NORTH CENTRAL NORTH DAKOTA - INCLUDING ROLETTE AND PIERCE
COUNTIES. THIS IS IN EFFECT UNTIL 7 AM CDT MONDAY...AND FOR NOW WILL
KEEP THE ADVISORY GOING. PRECIPITATION TRENDS ON REGIONAL RADARS
INDICATE DECREASE IN AREAL COVERAGE AND INTENSITY. SHOULD THIS TREND
CONTINUE THE WINTER WEATHER ADVISORY MAY BE DROPPED/ENDED BEFORE
DAYBREAK. WILL WAIT A FEW HOURS FOR THAT DECISION.
OTHERWISE WINDS ON TRACK WITH THE WIND ADVISORY GOING UNTIL 7
AM...AND WILL RE-EVALUATE IN A FEW HOURS. REST OF FORECAST ELEMENTS
ON TRACK FOR THIS UPDATE.
UPDATE
ISSUED AT 1042 PM CDT SUN MAY 17 2015
ROLLA STILL SUSTAINED AT OVER 40KTS WITH TURTLE MOUNTAIN RAWS
STILL GUSTING TO 61 MPH. WILL EXTEND THE HIGH WIND WARNING A
COUPLE OF HOURS...TILL 1AM CDT. RAP PRESSURE RISES ON THE DECREASE
SO A 1AM EXPIRATION SHOULD BE GOOD.
UPDATE
ISSUED AT 1004 PM CDT SUN MAY 17 2015
HEADLINES WILL REMAIN AS IS. AN ARGUMENT CAN BE MADE FOR A SMALL
AREA FOR BLIZZARD HEADLINES WITH BOTH ROLLA AND HARVEY REPORTING
STRONG WINDS GUSTING 35-45KTS AND 1/4 MILE VIS IN HEAVY SNOW.
HOWEVER...VIS HAVE BEEN JUMPING FROM 1/4 TO 3/4 AND DO NOT FEEL
THE SMALL AREA AND TIME DURATION JUSTIFIES AN UPGRADE. THUS WILL
MAINTAIN THE WINTER WEATHER ADVISORY AS IS WITH NEAR BLIZZARD
WORDING AND OTHER DIRE TERMINOLOGY IN THE OVERVIEW AND SEGMENT.
HIGH WIND WARNING OVER MY FAR NORTHEAST EXPIRES AT 11PM. WILL
REVISIT IN 30-45 MIN FOR A POSSIBLE EXTENSION.
UPDATE
ISSUED AT 710 PM CDT SUN MAY 17 2015
RAIN CHANGING OVER TO SNOW AS TEMPERATURES AT THE SURFACE AND
ALOFT COOL. HAVE HAD A MIX OF SLEET SOUTH CENTRAL WHERE SOUNDINGS
INDICATE A WARM LAYER ALOFT...COLD LAYER AROUND 850MB...AND
SURFACE TEMPERATURES IN THE MIDDLE 30S. THE WARM LAYER WILL COOL
WITH ALL SNOW BY 01-02Z.
HEADLINES ALL STILL VALID...AND WILL STAY THE COURSE WITH THIS
UPDATE.
UPDATE ISSUED AT 608 PM CDT SUN MAY 17 2015
OPTED TO ISSUE A HIGH WIND WARNING OVER ROLETTE AND PIERCE
COUNTIES. WINDS CONTINUE TO GUST OVER 60 MPH AT OBSERVING SITES
ACROSS MY FAR NORTHEAST. CANNOT IGNORE THIS SO WENT WITH A
WARNING. OTHER EDITS MINOR FOR NOW...ANOTHER UPDATE OUT BY 0030Z.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 330 PM CDT SUN MAY 17 2015
SIGNIFICANT STORM IMPACTING NORTH DAKOTA WILL BEGIN TO WANE
TONIGHT AND EXIT THE REGION ON MONDAY. AS COLDER AIR WRAPS UP
INTO THE SYSTEM SNOW WILL START TO ACCUMULATE ACROSS THE NORTH
CENTRAL...WITH 2 TO NEAR 6 INCHES EXPECTED. STRONG WINDS WILL
CONTINUE THROUGH THE NIGHT. WILL KEEP WIND ADVISORY THROUGH 7 PM
NORTH CENTRAL THEN TRANSITION TO A WINTER WEATHER ADVISORY FOR
THE SNOW AND MENTION THE STRONG WINDS IN THE WINTER WEATHER
ADVISORY. WILL MAINTAIN WIND ADVISORY THROUGH THE NIGHT SOUTH
CENTRAL.
THE RAIN WILL SIGNIFICANTLY DECREASE AFTER MIDNIGHT. UNTIL THEN
THERE IS A FLOOD ADVISORY FOR EAST CENTRAL NORTH DAKOTA WHERE
WIDESPREAD WARM CONVEYER BELT PRECIP HAS BEEN QUASI STATIONARY
TODAY.
FINALLY...WIDESPREAD FREEZING TEMPERATURES ARE EXPECTED ACROSS WEST
AND CENTRAL NORTH DAKOTA TONIGHT. WILL LET THE WINTER WEATHER
ADVISORY AND ITS SNOW AMOUNTS STAND IN FOR THE FREEZE WARNING
NORTH CENTRAL. ACROSS THE WEST AND SOUTH WILL ISSUE A FREEZE
WARNING TONIGHT AND EARLY MONDAY.
MONDAY WILL BECOME SUNNY WITH DIMINISHING WINDS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 PM CDT SUN MAY 17 2015
COOL AND DRY WILL CHARACTERIZE THE LONG TERM.
HIGH PRESSURE WILL BUILD IN BEHIND THE DEPARTING WEEKEND STORM
MONDAY NIGHT. THIS WILL LEAD TO CLEAR SKIES AND LIGHT WIND.
TEMPERATURES OVERNIGHT WILL LIKELY FALL INTO THE MID 20S FOR MOST
OF NORTH DAKOTA. A FREEZE WARNING WILL BE POSSIBLE WITH WIDESPREAD
FROST.
THE REST OF THE WEEK LOOKS DRY WITH SURFACE HIGH PRESSURE
REMAINING ENTRENCHED OVER NORTH DAKOTA AND UPPER LEVEL RIDING
BUILDING WEST. THIS WILL KEEP MOST OF THE MOISTURE AND STORM
TRACKS THIS WEEK SOUTH OF NORTH DAKOTA.
TEMPERATURES LOOK TO REBOUND INTO THE 60S BY THURSDAY.
THE NEXT CHANCE FOR PRECIPITATION ARRIVES THIS WEEKEND AS THE
RIDGE BREAKS DOWN AND AN UPPER LEVEL LOW MOVES INTO THE PLAINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 109 AM CDT MON MAY 18 2015
VFR AT KISN SHOULD PREVAIL THROUGH THE TAF PERIOD. KDIK SHOULD BE
IMPROVING BY AROUND 09Z. WIDESPREAD MVFR CONDITIONS IN SNOW AND FOG
AT KMOT/KBIS SHOULD CONTINUE THROUGH AROUND 12Z...THEN IMPROVE TO
VFR. KJMS WILL LIKELY REMAIN AT MVFR AND IFR CONDITIONS UNTIL AROUND
00Z. SNOW SHOULD END AT KJMS BY AROUND 15Z BUT LARGE MVFR CLOUD
SHIELD SHOULD REMAIN EAST OF KMOT/KBIS BUT ENCOMPASS KJMS
THROUGH AROUND 00Z.
&&
.HYDROLOGY...
ISSUED AT 330 PM CDT SUN MAY 17 2015
HAVE ISSUED AN AREAL FLOOD ADVISORY THROUGH THIS EVENING EAST
CENTRAL. RAINFALL AMOUNTS OF TWO TO 4 INCHES WITH SOME ISOLATED
HIGHER AMOUNTS CAUSING PONDING...AND FLOODED FIELDS. CALLS AND
INQUIRIES SO FAR HAVE REVEALED ROADS TO BE OK WITH SOME MINOR
FLOODING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING UNTIL 10 AM CDT /9 AM MDT/ THIS MORNING FOR
NDZ001-009-017>020-031>037-040>048-050-051.
WIND ADVISORY UNTIL 7 AM CDT /6 AM MDT/ THIS MORNING FOR NDZ019-
020-034>037-042-045>048-050-051.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT THIS MORNING FOR
NDZ002>005-010>013-021>023-025.
&&
$$
UPDATE...JV
SHORT TERM...WAA
LONG TERM...AJ
AVIATION...JV
HYDROLOGY...WAA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1135 PM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 1135 PM CDT SUN MAY 17 2015
STILL HAVE WINDS NEAR WARNING CRITERIA WITHIN THE DEVILS LAKE
BASIN...BUT MODEL GUIDANCE INDICATES 925MB WIND SPEEDS DECREASING
10 KNOTS FROM 03Z TO 06Z...SO ALLOWED HIGH WIND WARNING TO EXPIRE
AT 11PM. WILL NEED TO WATCH THE NORTHERN VALLEY WITH DUE NORTH
WINDS AND THE RAP INDICATING INCREASING 925MB WIND SPEEDS. GRAFTON
AWOS IS CLOSE TO WARNING CRITERIA...AND WITH THE SFC PRESSURE
GRADIENT STILL TIGHTENING CANNOT RULE OUT STRONG WINDS HERE.
OTHERWISE...WINTER WEATHER ADVISORY AREA HAS REPORTS OF SNOW AND
SLEET AND SLICK ROADS. ALSO HAD A REPORT OF 2.5 INCHES OF SNOW
JUST N/NE OF ROLLA (IN CANADA). IMAGINE THAT THERE IS SOME SLUSHY
ACCUMULATION INTO THE STATES.
ELSEWHERE...RAIN HAS REDEVELOPED AS EXPECTED ACROSS NW MN (EVEN
INTO THE VALLEY).
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 337 PM CDT SUN MAY 17 2015
FIRST OFF...SFC LOW NEAR SISSETON/WAHPETON AREA AT MID AFTN AND
SFC PRESSURE FALLS ARE NOT CENTERED NEAR FOSSTON MN. SO SFC LOW
WILL TACK NORTHEAST TOWARD THAT AREA THIS EVENING. EAST OF SFC LOW
AREA IN DRY SLOT WHERE HEATING OCCURRED FAVORABLE FOR SOME
THUNDERSTORM TO FORM. FOCUS IS FROM ALEXANDRIA NORTH TO EAST OF
FERGUS FALLS....TO BEMIDJI...PARK RAPIDS AND WADENA. SFC AND UPPER
AIR LOW PLACEMENT FAVORS LOW TOPPED SUPERCELLS WITH POSSIBLE
FUNNEL FORMATION. PER SPC NOT EXPECTING WIDESPREAD STORMS THIS
STRONG....BUT COULD BE THRU 00Z. ANOTHER QUESTION IS NW EDGE OF
DEF ZONE PRECIP. RAIN FALLING PER PUBLIC LANGDON-DEVILS LAKE AREA
STILL. MODELS TAKE DRIER AIR WEST AND WANT TO SHUT OFF DEF ZONE
HEAVY PRECIP THIS EVENING LEAVING LIGHT PRECIP OVERNIGHT INTO
MONDAY MORNING IN THE COLD AIR WHERE IT WILL BE COLD ENOUGH FOR
SNOW. SO JUST HOW MUCH SNOW WILL FALL IS QUESTIONABLE. WILL LEAVE
WSW OUT FOR 1-3 INCHES IN DVL BASIN-LANGDON AREAS OVERNIGHT AS TOO
UNCERTAIN TO TINKER WITH IT.
WINDS WILL BE A BIG FACTOR AND CONTINUE TO GUST IN THE 40-55 MPH
RANGE IN DVL BASIN AND SPREAD INTO THE RRV THIS EVE. STRONG WINDS
OVERNIGHT INTO MONDAY MORNING SO HAVE WIND ADVISORIES OUT.
MOVED PRECIP OUT A BIT FASTER THAN EARLIER FCSTS MONDAY. OTHERWISE
COLD AND WINDY. CLEARING OVERSPREADS AREA MON NIGHT AND LIKELY
FREEZE CONDITIONS IN MANY AREAS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 337 PM CDT SUN MAY 17 2015
WELCOME DRY WEATHER TUESDAY AND WEDNESDAY AS HIGH PRESSURE MOVES
IN AND TEMPS BEGIN TO RECOVER.
FOR WED NIGHT THROUGH SUNDAY...SMALL DISCUSSION TODAY DUE TO SEVERE
WEATHER POTENTIAL. BASICALLY KEPT THE THU/FRI PERIOD DRY AND LEFT
PCPN CHANCES AS THEY WERE FOR SAT/SUN. TEMPS LOOK TO RETURN TO NEAR
NORMAL VALUES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1135 PM CDT SUN MAY 17 2015
LIFR/IFR CONDITIONS WILL CONTINUE THROUGH THE OVERNIGHT
HOURS...WITH CONDITIONS GRADUALLY IMPROVING ON MONDAY. STRONG
NORTH WINDS ALONG AND WEST OF THE VALLEY WILL GRADUALLY DIMINISH
ON MONDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR NDZ008-016-026>030-038-
039-049-052>054.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT MONDAY FOR NDZ006-007-014-
015-024.
MN...WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR MNZ001>004-007-029.
&&
$$
UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM...GODON/RIDDLE
AVIATION...TG
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
309 PM EDT MON MAY 18 2015
.SYNOPSIS...
WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT
IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD
FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON.
&&
.NEAR TERM /THROUGH TUESDAY/...
SCATTERED POPCORN CONVECTION IS BEING SEEN ACROSS THE AREA THIS
AFTERNOON...AS MOIST AIRMASS HEATS UP IN BOUNDARY LAYER HEATING.
OTHERWISE...SLIGHTLY MORE ORGANIZED CONVECTION NOTED OVER EASTERN
KY AND SOUTHERN OH...AS WEAK VORT FEATURE APPROACHES FROM THE
WEST. IT APPEARS THE LATEST RAP RUNS HAVE A FAIR HANDLE ON THE
OVERALL MASS FIELDS AND THE PROGRESSION OF FEATURES ACROSS
TONIGHT. USED A RATHER BROAD BRUSH APPROACH TO COVER POPS THIS
AFTERNOON AND THIS EVENING. HAVE FRONT CROSSING LATE TONIGHT AND
EARLY MORNING. SPEED UP TIMING SLIGHTLY...BY AN HOUR OR TWO...NOT
MUCH TO REALLY MAKE A CHANGE TO THE OVERALL FORECAST.
FOR TEMPS...WILL SEE A FEW DEGREES OF COOLING TUESDAY OVER TODAYS
HIGHS AS COOLER AIRMASS MOVES IN...WITH DRYING OF THE ATMOSPHERIC
COLUMN.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
ZONAL FLOW FOR THE SHORT TERM PART OF THE FORECAST SHOULD PROVIDE
FOR A DRY FORECAST. DO HAVE SLIGHT CHANCE POPS WEDNESDAY NIGHT AS
SEVERAL UPPER LEVEL DISTURBANCES MOVE ACROSS THE NORTHERN OHIO VALLEY
AROUND THE 520+ LOW OVER NEWFOUNDLAND.
WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE
PERIOD...KEEPING THEM BELOW CLIMATOLOGY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
A HIGH BEGINS TO BUILD IN THE GULF OF MEXICO ON SUNDAY...MIGRATES
EAST AND TRIES TO STRENGTHEN. THIS WILL LEAD TO A POTENTIALLY
MESSY FORECAST FOR THE OHIO VALLEY WITH SEVERAL UPPER LEVEL
DISTURBANCES ROTATING AROUND THE CANADIAN LOW PRESSURE SYSTEMS.
HAVE CHANCE POPS ON SUNDAY AND MONDAY AS EXPECT MOISTURE TO BECOME
TRAPPED UNDER THE HIGH. THERE REALLY ISN/T ANYTHING SIGNIFICANT TO
FOCUS ON TO TIME THESE EVENTS.
WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES. TEMPERATURES WILL
RISE THROUGH THE EXTENDED PART OF THE FORECAST.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
ITS DEJA VU ALL OVER AGAIN...AT LEAST FOR ONE MORE DAY. WILL SEE
ISOLD TO SCATTERED CONVECTION THIS AFTERNOON WITH ISOLD IFR IN
MORE INTENSE CONVECTIVE CELLS. IN ADDITION...THERE MAY BE A FEW
ISOLD OUTFLOW BOUNDARIES PRODUCING SOME LOCAL SFC GUSTS IN THE 20
TO 25 KT RANGE. LATEST RADAR SHOWING A SLIGHTLY MORE ORGANIZED
AREA OF...ALBEIT WEAK...CONVECTION MOVING OUT OF EASTERN KY WHICH
SHOULD TRACK ACROSS WESTERN WV AND SE OH THROUGH 23Z. ELSEWHERE
WILL SEE MORE ISOLD DEVELOPMENT FOR THE REMAINING DAYLIGHT HOURS.
AREAS THAT GET RAIN WILL SEE SOME FOG AFTER 10Z AND WILL ALSO SEE
FOG IN AND ALONG THE RIVERS...MUCH THE SAME AS PREVIOUS COUPLE OF
DAYS. LONE EXCEPTION WILL BE KEKN...WHERE FOG SHOULD BE A LITTLE
MORE PREVALENT FOR A SHORT PERIOD OF MORNING IFR.
HOWEVER...A FRONT WILL PASS ON TUESDAY...AND THIS FRONT IS PROGGED
TO BE ALONG THE OH RIVER BY AROUND 12Z. IT WILL SWING THROUGH
DURING THE DAY TUESDAY...HELPING TO SCOUR OUT THE LOW LEVELS FOR
SOME DRIER CONDITIONS TO CLOSE OUT THE PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: COVERAGE OF STORMS COULD HIGHER THAN
EXPECTED...WITH ORE AREAS SEEING IFR OR LOWER CONDITIONS THIS
AFTERNOON AND EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H M M H H H H H H
HTS CONSISTENCY H H H H M H H H H H H H
BKW CONSISTENCY H H M M M M M M M M M H
EKN CONSISTENCY H H M M M M M M M M L L
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H M M M M M H H
AFTER 18Z TUESDAY...
FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT INTO WED MORNING. REDUCE
VISIBILITY POSSIBLE IN AND AROUND THUNDERSTORMS NEXT SUNDAY AND MONDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...FB/KMC
NEAR TERM...KMC
SHORT TERM...FB
LONG TERM...FB
AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
236 PM EDT MON MAY 18 2015
.SYNOPSIS...
WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT
IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD
FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON.
&&
.NEAR TERM /THROUGH TUESDAY/...
SCATTERED POPCORN CONVECTION IS BEING SEEN ACROSS THE AREA THIS
AFTERNOON...AS MOIST AIRMASS HEATS UP IN BOUNDARY LAYER HEATING.
OTHERWISE...SLIGHTLY MORE ORGANIZED CONVECTION NOTED OVER EASTERN
KY AND SOUTHERN OH...AS WEAK VORT FEATURE APPROACHES FROM THE
WEST. IT APPEARS THE LATEST RAP RUNS HAVE A FAIR HANDLE ON THE
OVERALL MASS FIELDS AND THE PROGRESSION OF FEATURES ACROSS
TONIGHT. USED A RATHER BROAD BRUSH APPROACH TO COVER POPS THIS
AFTERNOON AND THIS EVENING. HAVE FRONT CROSSING LATE TONIGHT AND
EARLY MORNING. SPEED UP TIMING SLIGHTLY...BY AN HOUR OR TWO...NOT
MUCH TO REALLY MAKE A CHANGE TO THE OVERALL FORECAST.
FOR TEMPS...WILL SEE A FEW DEGREES OF COOLING TUESDAY OVER TODAYS
HIGHS AS COOLER AIRMASS MOVES IN...WITH DRYING OF THE ATMOSPHERIC
COLUMN.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
MADE NO REAL CHANGES WITH THE SHORT TERM PART OF THE FORECAST.
RAISED POPS A BIT IN THE EAST MONDAY NIGHT AHEAD OF THE COLD
FRONT. PW VALUES ARE IN THE 1.5-1.75 INCHES RANGE AHEAD THE FRONT
SO THE PROSPECT OF HEAVY RAIN OVERNIGHT IS STILL POSSIBLE. EVEN
WITH ALL OF THE RAIN THAT HAS FALLEN UP TO THIS POINT THE GROUND
SHOULD BE ABLE TO HANDLE THE SITUATION SO NO REAL CONCERNS. WILL
CONTINUE TO MONITOR THE SITUATION. IT DRIES OUT QUICKLY BEHIND THE
FRONT STARTING TUESDAY NIGHT.
DRY WEATHER WITH PLEASANT TEMPERATURES SHOULD PREVAIL TUESDAY
NIGHT AND WEDNESDAY AS WEAK HIGH PRESSURE BUILDS TO THE WEST
GIVING ZONAL FLOW FOR THE OHIO VALLEY.
WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE
PERIOD.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
NOTHING SIGNIFICANT TO FOCUS ON IN THE LONG TERM. HIGH PRESSURE
BUILDS OVER THE CENTRAL US AND THAT WILL LEAVE ZONAL FLOW OVER THE
OHIO VALLEY. THE EXTENDED FORECAST WILL BE DRY FOR THE MOST PART
BUT CONFIDENCE IS NOT ALL THAT HIGH AS THERE COULD BE A FEW UPPER
LEVEL RIPPLES CAUSED BY THE WEAK FRONT THAT PASSES TO THE NORTH
NEXT WEEKEND. PRECIPITATION CHANCES INCREASING ON SUNDAY.
WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
ITS DEJA VU ALL OVER AGAIN...AT LEAST FOR ONE MORE DAY. WILL SEE
ISOLD TO SCATTERED CONVECTION THIS AFTERNOON WITH ISOLD IFR IN
MORE INTENSE CONVECTIVE CELLS. IN ADDITION...THERE MAY BE A FEW
ISOLD OUTFLOW BOUNDARIES PRODUCING SOME LOCAL SFC GUSTS IN THE 20
TO 25 KT RANGE. LATEST RADAR SHOWING A SLIGHTLY MORE ORGANIZED
AREA OF...ALBEIT WEAK...CONVECTION MOVING OUT OF EASTERN KY WHICH
SHOULD TRACK ACROSS WESTERN WV AND SE OH THROUGH 23Z. ELSEWHERE
WILL SEE MORE ISOLD DEVELOPMENT FOR THE REMAINING DAYLIGHT HOURS.
AREAS THAT GET RAIN WILL SEE SOME FOG AFTER 10Z AND WILL ALSO SEE
FOG IN AND ALONG THE RIVERS...MUCH THE SAME AS PREVIOUS COUPLE OF
DAYS. LONE EXCEPTION WILL BE KEKN...WHERE FOG SHOULD BE A LITTLE
MORE PREVALENT FOR A SHORT PERIOD OF MORNING IFR.
HOWEVER...A FRONT WILL PASS ON TUESDAY...AND THIS FRONT IS PROGGED
TO BE ALONG THE OH RIVER BY AROUND 12Z. IT WILL SWING THROUGH
DURING THE DAY TUESDAY...HELPING TO SCOUR OUT THE LOW LEVELS FOR
SOME DRIER CONDITIONS TO CLOSE OUT THE PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: COVERAGE OF STORMS COULD HIGHER THAN
EXPECTED...WITH ORE AREAS SEEING IFR OR LOWER CONDITIONS THIS
AFTERNOON AND EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H M M H H H H H H
HTS CONSISTENCY H H H H M H H H H H H H
BKW CONSISTENCY H H M M M M M M M M M H
EKN CONSISTENCY H H M M M M M M M M L L
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H M M M M M H H
AFTER 18Z TUESDAY...
FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT INTO WED MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/ARJ
NEAR TERM...KMC
SHORT TERM...FB
LONG TERM...FB
AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
147 PM EDT MON MAY 18 2015
.SYNOPSIS...
WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT
IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD
FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON.
&&
.NEAR TERM /THROUGH TONIGHT/...
NO UPDATES TO THE NEAR TERM OTHER THAN TO TWEAK POPS BASED ON
CURRENT TRENDS.
PREVIOUS DISCUSSION BELOW...
LATEST RADAR MOSAIC AND SURFACE OBSERVATIONS SUGGEST REGION IS
GENERALLY DRY AT THIS TIME. EXPECT THESE CONDITIONS WILL CONTINUE
THROUGH THE OVERNIGHT HOURS...AND HAVE SLIGHT CHANCE POPS
CONTINUING.
LATEST HRRR SHOWS A SMALL AREA OF SHOWERS...CURRENTLY OVER SOUTHEAST
KENTUCKY...WILL SPREAD NORTHEAST AND INCREASE IN AREAL COVERAGE AS
IT MOVES INTO OUR SOUTHERN COUNTIES LATER THIS MORNING. THE CURRENT
TREND OF THESE SHOWERS HAS BEEN TO WEAKEN. SO NOT SURE HOW MUCH OF
THESE SHOWERS WILL ACTUALLY MAKE IT INTO OUR AREA.
MOST OF THE MODELS THEN INDICATE WEAK DISTURBANCES WILL MOVE ACROSS
THE AREA TODAY INTO TONIGHT. COMBINATION OF THESE DISTURBANCES AND
INCREASING INSTABILITY SHOULD ONCE AGAIN RESULT IN THE DEVELOPMENT
OF SHOWERS AND STORMS TODAY.
LOCALIZED DOWNPOURS ARE ONCE AGAIN POSSIBLE TODAY AND TONIGHT...AND
CAN RESULT IN MINOR FLOODING OF STREETS...CREEKS...LOW LYING AND
POOR DRAINAGE AREAS.
WITH THE LOSS OF DAYTIME HEATING...THE COVERAGE AND INTENSITY OF
THE CONVECTION SHOULD BEGIN TO WANE. HOWEVER...A COLD FRONT...WHICH
IS EXPECTED TO PUSH INTO THE REGION LATE TONIGHT...SHOULD CONTINUE
THE THREAT OF SHOWERS AND STORMS.
CURRENT THINKING IS THAT THE FRONT SHOULD BE LOCATED NEAR OR JUST
EAST OF THE OHIO RIVER AT THE END OF THIS PERIOD.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
MADE NO REAL CHANGES WITH THE SHORT TERM PART OF THE FORECAST.
RAISED POPS A BIT IN THE EAST MONDAY NIGHT AHEAD OF THE COLD
FRONT. PW VALUES ARE IN THE 1.5-1.75 INCHES RANGE AHEAD THE FRONT
SO THE PROSPECT OF HEAVY RAIN OVERNIGHT IS STILL POSSIBLE. EVEN
WITH ALL OF THE RAIN THAT HAS FALLEN UP TO THIS POINT THE GROUND
SHOULD BE ABLE TO HANDLE THE SITUATION SO NO REAL CONCERNS. WILL
CONTINUE TO MONITOR THE SITUATION. IT DRIES OUT QUICKLY BEHIND THE
FRONT STARTING TUESDAY NIGHT.
DRY WEATHER WITH PLEASANT TEMPERATURES SHOULD PREVAIL TUESDAY
NIGHT AND WEDNESDAY AS WEAK HIGH PRESSURE BUILDS TO THE WEST
GIVING ZONAL FLOW FOR THE OHIO VALLEY.
WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE
PERIOD.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
NOTHING SIGNIFICANT TO FOCUS ON IN THE LONG TERM. HIGH PRESSURE
BUILDS OVER THE CENTRAL US AND THAT WILL LEAVE ZONAL FLOW OVER THE
OHIO VALLEY. THE EXTENDED FORECAST WILL BE DRY FOR THE MOST PART
BUT CONFIDENCE IS NOT ALL THAT HIGH AS THERE COULD BE A FEW UPPER
LEVEL RIPPLES CAUSED BY THE WEAK FRONT THAT PASSES TO THE NORTH
NEXT WEEKEND. PRECIPITATION CHANCES INCREASING ON SUNDAY.
WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
ITS DEJA VU ALL OVER AGAIN...AT LEAST FOR ONE MORE DAY. WILL SEE
ISOLD TO SCATTERED CONVECTION THIS AFTERNOON WITH ISOLD IFR IN
MORE INTENSE CONVECTIVE CELLS. IN ADDITION...THERE MAY BE A FEW
ISOLD OUTFLOW BOUNDARIES PRODUCING SOME LOCAL SFC GUSTS IN THE 20
TO 25 KT RANGE. LATEST RADAR SHOWING A SLIGHTLY MORE ORGANIZED
AREA OF...ALBEIT WEAK...CONVECTION MOVING OUT OF EASTERN KY WHICH
SHOULD TRACK ACROSS WESTERN WV AND SE OH THROUGH 23Z. ELSEWHERE
WILL SEE MORE ISOLD DEVELOPMENT FOR THE REMAINING DAYLIGHT HOURS.
AREAS THAT GET RAIN WILL SEE SOME FOG AFTER 10Z AND WILL ALSO SEE
FOG IN AND ALONG THE RIVERS...MUCH THE SAME AS PREVIOUS COUPLE OF
DAYS. LONE EXCEPTION WILL BE KEKN...WHERE FOG SHOULD BE A LITTLE
MORE PREVALENT FOR A SHORT PERIOD OF MORNING IFR.
HOWEVER...A FRONT WILL PASS ON TUESDAY...AND THIS FRONT IS PROGGED
TO BE ALONG THE OH RIVER BY AROUND 12Z. IT WILL SWING THROUGH
DURING THE DAY TUESDAY...HELPING TO SCOUR OUT THE LOW LEVELS FOR
SOME DRIER CONDITIONS TO CLOSE OUT THE PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: COVERAGE OF STORMS COULD HIGHER THAN
EXPECTED...WITH ORE AREAS SEEING IFR OR LOWER CONDITIONS THIS
AFTERNOON AND EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H M M H H H H H H
HTS CONSISTENCY H H H H M H H H H H H H
BKW CONSISTENCY H H M M M M M M M M M H
EKN CONSISTENCY H H M M M M M M M M L L
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H M M M M M H H
AFTER 18Z TUESDAY...
FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT INTO WED MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/ARJ
NEAR TERM...JSH/KMC
SHORT TERM...FB
LONG TERM...FB
AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
140 PM EDT MON MAY 18 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS EVENING. HIGH
PRESSURE WILL BUILD VERY SLOWLY EAST AND SETTLE INTO THE MID
MISSISSIPPI VALLEY REGION BY THURSDAY. THE HIGH WILL EXTEND A RIDGE
EAST ACROSS THE LOCAL AREA DURING THIS TIME. MORE HIGH PRESSURE WILL
BUILD SOUTHEAST OUT OF CANADA AND MERGE WITH THE EXISTING HIGH
PRESSURE AND BECOME CENTERED OVER OHIO BY SATURDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CONVECTIVE DEVELOPMENT IS TAKING PLACE FROM NEAR SANDUSKY BAY
SOUTHWEST TO NEAR FDY. WITH MODEST AMOUNT OF WIND SHEAR WE DON`T
EXPECT MUCH IN THE WAY OF SEVERE POTENTIAL. DCAPE IS LOW GIVEN THE
RATHER HUMID CONDITIONS WITH HIGH PRECIPITABLE WATER AMOUNT NEAR 1.6
INCHES. THE HRRR TIMING OF CONVECTIVE DEVELOPMENT IS SLOW BY A
COUPLE OF HOURS. THE LATEST MESO ANALYSIS DATA SHOW LOW LEVEL CIN
HAS DISSIPATED. EXPECT CONVECTIVE ACTIVITY TO INCREASE IN COVERAGE
AND PROGRESS TO THE NORTHEAST. SHORT RANGE MESOSCALE MODELS
SUGGEST THAT NUMEROUS SHOWERS AND THUNDERSTORMS WILL FORM OVER
NORTHEAST OHIO ESPECIALLY IN THE SNOW BELT COUNTIES EAST OF CLE.
GIVEN THE RATHER DEEP MOISTURE AND LIMITED SHEAR SEVERE POTENTIAL
IS LOW.
HAVE RAISED MAXIMUM TEMPERATURE JUST SLIGHTLY IN SPOTS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
COLD FRONT FINALLY ARRIVES AND IS EXPECTED TO SWEEP EAST ACROSS THE
FORECAST AREA FROM WEST TO EAST BETWEEN 00Z AND 06Z TONIGHT. DRY
SLOT IS EXPECTED TO RACE NORTH AHEAD OF THE FRONT INTO THE AREA AS
WELL LIMITING THE EFFECTS FRONT HAS ON PRODUCING SHOWERS AND
THUNDERSTORMS. FRONT PUSHES EAST LATE TONIGHT DIMINISHING THREAT FOR
SHOWERS AS WELL AS NEGATIVE VORTICITY ADVECTION AND DRIER AIR MOVE
INTO THE REGION.
HIGH PRESSURE RIDGE BUILDS EAST INTO THE AREA TUESDAY THROUGH
WEDNESDAY AND BRINGS A RETURN BACK TO FAIR WEATHER ONCE AGAIN.
NOW...THIS IS WHERE THE MODELS SHOW SOME DIFFERENCES. NAM IS THE
WETTEST WEDNESDAY NIGHT IN FORCING A FAST MOVING UPPER LEVEL
POSITIVE VORTICITY MAXIMUM EAST INTO THE AREA. THIS FEATURE HAS
QUITE A BIT OF MOISTURE WITH IT. THE GFS IS SHOWING A SIMILAR
SOLUTION BUT IS LIMITED IN MOISTURE WHERE AS THE SREF SHUNTS
EVERYTHING SOUTH. SINCE THERE ARE SO MANY DIFFERENCES IN TIMING AND
AREAL EXTENT OF THE PRECIPITATION THREAT...WILL JUST MENTION A
SLIGHT CHANCE FOR SHOWERS AT THIS TIME AND SEE IF THE MODELS CAN
COME TO SOME KIND OF CONSENSUS.
UPPER LEVEL FEATURE PULLS OUT TO THE EAST THURSDAY AND BRINGS A
RETURN BACK TO FAIR WEATHER THURSDAY AFTERNOON AND NIGHT.
THE BAD NEWS IS THAT CHILLY AIR WILL RETURN BEHIND THE COLD FRONT
DROPPING TEMPERATURES BACK INTO THE 50S FOR HIGHS ACROSS THE
NORTHERN TIER COUNTIES BY WEDNESDAY AND LOWER 60S ACROSS THE SOUTH.
OVERNIGHT LOWS WILL DROP INTO THE 40S. A BIT OF A REBOUND WITH MORE
SUN WILL RETURN ON THURSDAY WITH HIGHS IN THE LOWER TO MIDDLE 60S.
YET LOWS WILL STILL BE IN THE 40S THURSDAY NIGHT. NOT EXPECTING ANY
FROST THROUGH THE PERIOD AT THIS TIME.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
THE LONG TERM BEGINS FRIDAY WITH A COLD FRONT HAVING JUST DROPPED
SOUTH ACROSS THE REGION AND AN UNREASONABLE AMOUNT OF COLD AIR JUST
TO OUR NORTH. DURING THE DAY HIGH PRESSURE WILL BUILD IN FROM THE
WEST AND WHILE TEMPS WILL BE ON THE COOL SIDE...BOTH MODELS TAKE THE
CORE OF THE COLD AIR EAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND.
SATURDAY THE HIGH MOVES EAST AND HEIGHTS BEGIN TO RECOVER AS WARMER
AIR BEGINS TO RETURN TO THE REGION. AN UPPER RIDGE WILL BE MOVING
INTO THE MIDWEST HOWEVER A SURFACE LOW IN THE CENTRAL PLAINS WILL
BEING DEEP MOISTURE INTO THE MID MISSISSIPPI VALLEY UNDER THE
RIDGE. BY SATURDAY NIGHT AND SUNDAY THIS MOISTURE WILL LIKELY BE
SPILLING INTO THE AREA WITH DEEP SOUTHERLY FLOW INTO THE AREA AHEAD
OF A DEVELOPING UPPER TROF IN THE PLAINS. WILL KEEP FORECAST DRY
THROUGH SATURDAY NIGHT BUT BRING MID/HIGH CHANCE POPS IN FOR
SUNDAY. WILL HAVE LIKELY POPS NORTHWEST SUNDAY NIGHT AND MONDAY
WHICH MAY NEED TO BE EXPANDED AS THE FORECAST EVOLVES. TEMPS FRIDAY
FROM THE UPPER 50S NORTHEAST LAKESHORE TO THE LOWER 70S SOUTHWEST.
MOST AREAS WILL SEE LOWER AND MID 70S SATURDAY AND SUNDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
STILL WARM AND HUMID AHEAD OF A COLD FRONT THAT WILL BE CROSSING
THE AREA THIS EVENING. SCATTERED SHOWERS HAVE BEEN ABLE TO POP UP
ALREADY THIS AFTERNOON. ANY OF THESE COULD BRING CONDITIONS DOWN
TO IFR/MVFR BRIEFLY. GAVE IT ANOTHER HOUR OR TWO BEFORE ANY
THUNDER MENTIONED IN THE TAF. COLD FRONT LAGS UNTIL THIS EVENING
AND THIS COULD BRING ANOTHER CHANCE FOR SHRA/TS. REALLY UNCERTAIN
WHAT THE COVERAGE OF ANY TS MIGHT BE THEREFORE JUST WENT WITH VCSH
WITH FROPA AND A PERIOD OF MVFR. POST FRONT EXPECT A RETURN TO
VFR ALTHOUGH GIVEN TIMING...INLAND EAST WILL LIKELY HANG ON TO THE
MVFR A BIT LONGER. VFR CU TUESDAY AND A NORTHWEST WIND...WITH ANY
GUSTS 20 KNOTS OR LESS.
.OUTLOOK... NON-VFR POSSIBLE BEHIND A COLD FRONT IN NE OH/NW PA
TUESDAY NIGHT.
&&
.MARINE...
LOW PRESSURE OVER LAKE SUPERIOR WILL MOVE NORTHEAST ACROSS ONTARIO
TO QUEBEC TODAY. A COLD FRONT EXTENDING SOUTHWEST FROM THE LOW WILL
CROSS LAKE ERIE TONIGHT. SOUTH TO SOUTHWEST FLOW TODAY AND TONIGHT
WILL REMAIN FAIRLY LIGHT. TUESDAY WINDS WILL INCREASE FROM THE WEST
AND SOUTHWEST TO 15 TO 25 KNOTS/ WINDS WILL TURN NORTHWEST TUESDAY
NIGHT AS THE COLD AIR DEEPENS ACROSS THE LAKE. A LARGE AREA OF HIGH
PRESSURE WILL BUILD TOWARD THE LAKE MID WEEK AS IT DROPS INTO THE
CENTRAL PLAINS. ANOTHER COLD FRONT HOWEVER WILL APPROACH FROM THE
NORTH THURSDAY LIKELY DROPPING ACROSS THE LAKE THURSDAY NIGHT OR
EARLY FRIDAY. NO GALES ARE EXPECTED THROUGH THE PERIOD HOWEVER A
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED SOMETIME TUESDAY AS WINDS
INCREASE...CONTINUING TUESDAY NIGHT AND MOST OF WEDNESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LAPLANTE
SHORT TERM...LOMBARDY
LONG TERM...TK
AVIATION...OUDEMAN
MARINE...TK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1242 PM EDT MON MAY 18 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS EVENING. HIGH
PRESSURE WILL BUILD VERY SLOWLY EAST AND SETTLE INTO THE MID
MISSISSIPPI VALLEY REGION BY THURSDAY. THE HIGH WILL EXTEND A RIDGE
EAST ACROSS THE LOCAL AREA DURING THIS TIME. MORE HIGH PRESSURE WILL
BUILD SOUTHEAST OUT OF CANADA AND MERGE WITH THE EXISTING HIGH
PRESSURE AND BECOME CENTERED OVER OHIO BY SATURDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CONVECTIVE DEVELOPMENT IS TAKING PLACE FROM NEAR SANDUSKY BAY
SOUTHWEST TO NEAR FDY. WITH MODEST AMOUNT OF WIND SHEAR WE DON`T
EXPECT MUCH IN THE WAY OF SEVERE POTENTIAL. DCAPE IS LOW GIVEN THE
RATHER HUMID CONDITIONS WITH HIGH PRECIPITAL WATER AMOUNT NEAR 1.6
INCHES. THE HRRR TIMING OF CONVECTIVE DEVELOPMENT IS SLOW BY A
COUPLE OF HOURS. THE LATEST MESO ANAYLSIS DATA SHOW LOW LEVEL CIN
HAS DISSIPATED. EXPECT CONVECTIVE ACTIVITY TO INCREASE IN COVERAGE
AND PROGRESS TO THE NORTHEAST. SHORT RANGE MESOSCALE MODELS
SUGGEST THAT NUMEROUS SHOWERS AND THUNDERSTORMS WILL FORM OVER
NORTHEAST OHIO ESPECIALLY IN THE SNOW BELT COUNTIES EAST OF CLE.
GIVEN THE RATHER DEEP MOISTURE AND LIMITED SHEAR SEVERE POTENTIAL
IS LOW.
HAVE RAISED MAXIMUM TEMPERATURE JUST SLIGHTLY IN SPOTS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
COLD FRONT FINALLY ARRIVES AND IS EXPECTED TO SWEEP EAST ACROSS THE
FORECAST AREA FROM WEST TO EAST BETWEEN 00Z AND 06Z TONIGHT. DRY
SLOT IS EXPECTED TO RACE NORTH AHEAD OF THE FRONT INTO THE AREA AS
WELL LIMITING THE EFFECTS FRONT HAS ON PRODUCING SHOWERS AND
THUNDERSTORMS. FRONT PUSHES EAST LATE TONIGHT DIMINISHING THREAT FOR
SHOWERS AS WELL AS NEGATIVE VORTICITY ADVECTION AND DRIER AIR MOVE
INTO THE REGION.
HIGH PRESSURE RIDGE BUILDS EAST INTO THE AREA TUESDAY THROUGH
WEDNESDAY AND BRINGS A RETURN BACK TO FAIR WEATHER ONCE AGAIN.
NOW...THIS IS WHERE THE MODELS SHOW SOME DIFFERENCES. NAM IS THE
WETTEST WEDNESDAY NIGHT IN FORCING A FAST MOVING UPPER LEVEL
POSITIVE VORTICITY MAXIMUM EAST INTO THE AREA. THIS FEATURE HAS
QUITE A BIT OF MOISTURE WITH IT. THE GFS IS SHOWING A SIMILAR
SOLUTION BUT IS LIMITED IN MOISTURE WHERE AS THE SREF SHUNTS
EVERYTHING SOUTH. SINCE THERE ARE SO MANY DIFFERENCES IN TIMING AND
AREAL EXTENT OF THE PRECIPITATION THREAT...WILL JUST MENTION A
SLIGHT CHANCE FOR SHOWERS AT THIS TIME AND SEE IF THE MODELS CAN
COME TO SOME KIND OF CONSENSUS.
UPPER LEVEL FEATURE PULLS OUT TO THE EAST THURSDAY AND BRINGS A
RETURN BACK TO FAIR WEATHER THURSDAY AFTERNOON AND NIGHT.
THE BAD NEWS IS THAT CHILLY AIR WILL RETURN BEHIND THE COLD FRONT
DROPPING TEMPERATURES BACK INTO THE 50S FOR HIGHS ACROSS THE
NORTHERN TIER COUNTIES BY WEDNESDAY AND LOWER 60S ACROSS THE SOUTH.
OVERNIGHT LOWS WILL DROP INTO THE 40S. A BIT OF A REBOUND WITH MORE
SUN WILL RETURN ON THURSDAY WITH HIGHS IN THE LOWER TO MIDDLE 60S.
YET LOWS WILL STILL BE IN THE 40S THURSDAY NIGHT. NOT EXPECTING ANY
FROST THROUGH THE PERIOD AT THIS TIME.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
THE LONG TERM BEGINS FRIDAY WITH A COLD FRONT HAVING JUST DROPPED
SOUTH ACROSS THE REGION AND AN UNREASONABLE AMOUNT OF COLD AIR JUST
TO OUR NORTH. DURING THE DAY HIGH PRESSURE WILL BUILD IN FROM THE
WEST AND WHILE TEMPS WILL BE ON THE COOL SIDE...BOTH MODELS TAKE THE
CORE OF THE COLD AIR EAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND.
SATURDAY THE HIGH MOVES EAST AND HEIGHTS BEGIN TO RECOVER AS WARMER
AIR BEGINS TO RETURN TO THE REGION. AN UPPER RIDGE WILL BE MOVING
INTO THE MIDWEST HOWEVER A SURFACE LOW IN THE CENTRAL PLAINS WILL
BEING DEEP MOISTURE INTO THE MID MISSISSIPPI VALLEY UNDER THE
RIDGE. BY SATURDAY NIGHT AND SUNDAY THIS MOISTURE WILL LIKELY BE
SPILLING INTO THE AREA WITH DEEP SOUTHERLY FLOW INTO THE AREA AHEAD
OF A DEVELOPING UPPER TROF IN THE PLAINS. WILL KEEP FORECAST DRY
THROUGH SATURDAY NIGHT BUT BRING MID/HIGH CHANCE POPS IN FOR
SUNDAY. WILL HAVE LIKELY POPS NORTHWEST SUNDAY NIGHT AND MONDAY
WHICH MAY NEED TO BE EXPANDED AS THE FORECAST EVOLVES. TEMPS FRIDAY
FROM THE UPPER 50S NORTHEAST LAKESHORE TO THE LOWER 70S SOUTHWEST.
MOST AREAS WILL SEE LOWER AND MID 70S SATURDAY AND SUNDAY.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AIRMASS QUITE MOIST THIS MORNING WITH DEWPOINTS IN THE MID 60S
STILL CONDITIONS REMAIN PRIMARILY VFR ACROSS THE AREA. UPPER
RIDGE JUST EAST OF THE AREA CONTINUES TO KEEP A LID ON CONVECTION.
FOR TODAY...ASIDE FROM PATCHY MVFR EARLY...EXPECTING MOSTLY VFR
CONDITIONS INTO THE AFTERNOON. FOLLOWING THE HRRR...DO EXPECT
SCATTERED SHOWERS/POSSIBLY THUNDER TO DEVELOP AND DRIFT ACROSS
CENTRAL AND EASTERN TERMINALS...MAINLY INLAND FROM ABOUT 16-20Z.
WILL LIKELY SEE ANOTHER SHOT OF SHOWERS/TSTMS THROUGH THE EVENING
AND/OR OVERNIGHT WITH MVFR CONDITIONS AHEAD OF THE APPROACHING
COLD FRONT. DRIEST AIR IS IN THE NORTHWEST SO DID NOT BRING
CONVECTION THERE. OTHERWISE VCTS/VCSH. POST FRONT EXPECT A RETURN
TO VFR ALTHOUGH GIVING TIMING INLAND EAST WILL LIKELY END THE
FORECAST PERIOD REMAIN MVFR.
.OUTLOOK... NON-VFR POSSIBLE BEHIND A COLD FRONT IN NE OH/NW PA
TUESDAY NIGHT.
&&
.MARINE...
LOW PRESSURE OVER LAKE SUPERIOR WILL MOVE NORTHEAST ACROSS ONTARIO
TO QUEBEC TODAY. A COLD FRONT EXTENDING SOUTHWEST FROM THE LOW WILL
CROSS LAKE ERIE TONIGHT. SOUTH TO SOUTHWEST FLOW TODAY AND TONIGHT
WILL REMAIN FAIRLY LIGHT. TUESDAY WINDS WILL INCREASE FROM THE WEST
AND SOUTHWEST TO 15 TO 25 KNOTS/ WINDS WILL TURN NORTHWEST TUESDAY
NIGHT AS THE COLD AIR DEEPENS ACROSS THE LAKE. A LARGE AREA OF HIGH
PRESSURE WILL BUILD TOWARD THE LAKE MID WEEK AS IT DROPS INTO THE
CENTRAL PLAINS. ANOTHER COLD FRONT HOWEVER WILL APPROACH FROM THE
NORTH THURSDAY LIKELY DROPPING ACROSS THE LAKE THURSDAY NIGHT OR
EARLY FRIDAY. NO GALES ARE EXPECTED THROUGH THE PERIOD HOWEVER A
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED SOMETIME TUESDAY AS WINDS
INCREASE...CONTINUING TUESDAY NIGHT AND MOST OF WEDNESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LAPLANTE
SHORT TERM...LOMBARDY
LONG TERM...TK
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1108 AM EDT MON MAY 18 2015
.SYNOPSIS...
WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT
IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD
FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON.
&&
.NEAR TERM /THROUGH TONIGHT/...
NO UPDATES TO THE NEAR TERM OTHER THAN TO TWEAK POPS BASED ON
CURRENT TRENDS.
PREVIOUS DISCUSSION BELOW...
LATEST RADAR MOSAIC AND SURFACE OBSERVATIONS SUGGEST REGION IS
GENERALLY DRY AT THIS TIME. EXPECT THESE CONDITIONS WILL CONTINUE
THROUGH THE OVERNIGHT HOURS...AND HAVE SLIGHT CHANCE POPS
CONTINUING.
LATEST HRRR SHOWS A SMALL AREA OF SHOWERS...CURRENTLY OVER SOUTHEAST
KENTUCKY...WILL SPREAD NORTHEAST AND INCREASE IN AREAL COVERAGE AS
IT MOVES INTO OUR SOUTHERN COUNTIES LATER THIS MORNING. THE CURRENT
TREND OF THESE SHOWERS HAS BEEN TO WEAKEN. SO NOT SURE HOW MUCH OF
THESE SHOWERS WILL ACTUALLY MAKE IT INTO OUR AREA.
MOST OF THE MODELS THEN INDICATE WEAK DISTURBANCES WILL MOVE ACROSS
THE AREA TODAY INTO TONIGHT. COMBINATION OF THESE DISTURBANCES AND
INCREASING INSTABILITY SHOULD ONCE AGAIN RESULT IN THE DEVELOPMENT
OF SHOWERS AND STORMS TODAY.
LOCALIZED DOWNPOURS ARE ONCE AGAIN POSSIBLE TODAY AND TONIGHT...AND
CAN RESULT IN MINOR FLOODING OF STREETS...CREEKS...LOW LYING AND
POOR DRAINAGE AREAS.
WITH THE LOSS OF DAYTIME HEATING...THE COVERAGE AND INTENSITY OF
THE CONVECTION SHOULD BEGIN TO WANE. HOWEVER...A COLD FRONT...WHICH
IS EXPECTED TO PUSH INTO THE REGION LATE TONIGHT...SHOULD CONTINUE
THE THREAT OF SHOWERS AND STORMS.
CURRENT THINKING IS THAT THE FRONT SHOULD BE LOCATED NEAR OR JUST
EAST OF THE OHIO RIVER AT THE END OF THIS PERIOD.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
MADE NO REAL CHANGES WITH THE SHORT TERM PART OF THE FORECAST.
RAISED POPS A BIT IN THE EAST MONDAY NIGHT AHEAD OF THE COLD
FRONT. PW VALUES ARE IN THE 1.5-1.75 INCHES RANGE AHEAD THE FRONT
SO THE PROSPECT OF HEAVY RAIN OVERNIGHT IS STILL POSSIBLE. EVEN
WITH ALL OF THE RAIN THAT HAS FALLEN UP TO THIS POINT THE GROUND
SHOULD BE ABLE TO HANDLE THE SITUATION SO NO REAL CONCERNS. WILL
CONTINUE TO MONITOR THE SITUATION. IT DRIES OUT QUICKLY BEHIND THE
FRONT STARTING TUESDAY NIGHT.
DRY WEATHER WITH PLEASANT TEMPERATURES SHOULD PREVAIL TUESDAY
NIGHT AND WEDNESDAY AS WEAK HIGH PRESSURE BUILDS TO THE WEST
GIVING ZONAL FLOW FOR THE OHIO VALLEY.
WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE
PERIOD.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
NOTHING SIGNIFICANT TO FOCUS ON IN THE LONG TERM. HIGH PRESSURE
BUILDS OVER THE CENTRAL US AND THAT WILL LEAVE ZONAL FLOW OVER THE
OHIO VALLEY. THE EXTENDED FORECAST WILL BE DRY FOR THE MOST PART
BUT CONFIDENCE IS NOT ALL THAT HIGH AS THERE COULD BE A FEW UPPER
LEVEL RIPPLES CAUSED BY THE WEAK FRONT THAT PASSES TO THE NORTH
NEXT WEEKEND. PRECIPITATION CHANCES INCREASING ON SUNDAY.
WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
12Z MONDAY THRU 12Z TUESDAY...
CONDITIONS HAVE IMPROVED SINCE 09Z...WITH MOST LOCATIONS MVFR OR
BETTER. HOWEVER...ISOLATED IFR CONDITIONS MAY STILL BE OCCURRING
ALONG RIVER VALLEYS.
LATEST RADAR SHOWS ISOLATED SHOWERS HAVE BEGUN TO DEVELOP ACROSS
PORTIONS OF SOUTHEAST OHIO AND NORTHEAST KENTUCKY. THESE SHOWER
WERE DEVELOPING IN RESPONSE TO AN UPPER LEVEL DISTURBANCE.
EXPECT THESE SHOWERS WILL CONTINUE TO SPREAD ACROSS THE REMAINDER
OF THE STATE...AS THE DISTURBANCE MOVES NORTHEAST..
ADDITIONAL DISTURBANCES ARE EXPECTED TO MOVE ACROSS THE AREA TODAY...
WHICH WILL RESULT IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS...
ESPECIALLY FOR THE AFTERNOON AND EVENING HOURS. WHILE MOST LOCATIONS
WILL SEE VFR OR MVFR CONDITIONS...EXPECT IFR CONDITIONS ARE POSSIBLE
NEAR THE HEAVIER STORMS. GUSTY WINDS ARE ALSO POSSIBLE NEAR THE
STRONGER STORMS.
THE STORMS SHOULD THEN WEAKEN AFTER 23Z. HOWEVER...SCATTERED STORMS
WILL REMAIN POSSIBLE THROUGH THE END OF THE PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: COVERAGE OF STORMS COULD HIGHER THAN
EXPECTED...WITH ORE AREAS SEEING IFR OR LOWER CONDITIONS THIS
AFTERNOON AND EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
CRW CONSISTENCY H H H H H H M M M M H H
HTS CONSISTENCY H H H M M M H H M H H H
BKW CONSISTENCY H H H H H H H H M M M M
EKN CONSISTENCY L M M H M H H H M M M M
PKB CONSISTENCY H H H H H H H H M H H H
CKB CONSISTENCY H H H H H H H H M M M M
AFTER 12Z TUESDAY...
BRIEF IFR IN SHOWERS AND THUNDERSTORMS POSSIBLE IN LOW CLOUDS TUE
MORNING. FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT INTO WED
MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/ARJ
NEAR TERM...JSH/KMC
SHORT TERM...FB
LONG TERM...FB
AVIATION...JSH
AREA FORECAST DISCUSSION...UPDATED
NWS CLEVELAND OH
901 AM EDT MON MAY 18 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS EVENING. HIGH
PRESSURE WILL BUILD VERY SLOWLY EAST AND SETTLE INTO THE MID
MISSISSIPPI VALLEY REGION BY THURSDAY. THE HIGH WILL EXTEND A RIDGE
EAST ACROSS THE LOCAL AREA DURING THIS TIME. MORE HIGH PRESSURE WILL
BUILD SOUTHEAST OUT OF CANADA AND MERGE WITH THE EXISTING HIGH
PRESSURE AND BECOME CENTERED OVER OHIO BY SATURDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
REMOVED ALL POPS FOR REMAINDER OF MORNING. BUMPED UP TEMPS ALONG
THE EASTERN ERIE LAKESHORE DUE TO UPSLOPE FLOW. REMAINDER OF
FORECAST LOOKS REASONABLE.
ORIGINAL DISCUSSION...
WITH SUNRISE...SHOWERS ARE TRYING TO DEVELOP IN THE WESTERN HALF
OF THE FORECAST AREA. WILL KEEP A CHANCE FOR SHOWERS OVER THE
WESTERN HALF THIS MORNING AND THEN EXPAND IT OVER THE REST OF THE
AREA BY THE AFTERNOON. LATEST HRRR MODEL SHOWS THE SHOWER ACTIVITY
OVER SOUTHERN INDIANA GRADUALLY LIFTING NORTHEAST INTO THE REGION
WITH TIME. BUMPED MAX TEMPERATURES UP A COUPLE DEGREES IN THE
CENTRAL PORTIONS AS LATEST GUIDANCE IS COMING IN A COUPLE DEGREES
WARMER.
PREVIOUS DISCUSSION...
NONE OF THE INGREDIENTS APPEAR TO BE IN PHASE TODAY TO PRODUCE
WIDESPREAD SHOWERS AND THUNDERSTORMS. FIRST...UPPER LEVEL POSITIVE
VORTICITY ADVECTION WILL MOVE EAST ACROSS THE AREA TODAY. THERE WILL
BE SOME MOISTURE ASSOCIATED WITH THIS UPPER LEVEL FEATURE.
HOWEVER...THE COLD FRONT IS LAGGING BACK QUITE A BIT AND WILL NOT BE
IN PHASE WITH THE UPPER LEVEL ACTIVITY. SO TIMING OF THE THREAT FOR
SHOWERS AND THUNDERSTORMS COULD BE A BIT ON THE IFFY SIDE THROUGH
THE DAY. WILL KEEP THE MENTION OF SCATTERED SHOWERS AND
THUNDERSTORMS OVER MUCH OF THE AREA. BEST CHANCE WILL LIKELY BE
LATER IN THE DAY IN THE EAST WITH DAY TIME HEATING AND LINGERING
POSITIVE VORTICITY ADVECTION AND APPROACHING COLD FRONT. SO WILL GO
LIKELY POPS OVER THAT AREA FOR THIS AFTERNOON AND EVENING.
WARM AIR ADVECTION STILL TAKING PLACE IN THE WARM SECTOR ACROSS THE
FORECAST AREA. SINCE THE GREATEST THREAT FOR SHOWERS AND
THUNDERSTORMS WILL OCCUR IN THE EAST...TEMPERATURES MAY BE HELD BACK
A TAD COMPARED TO THE WEST. SO WILL LEAN TOWARD AROUND 80 IN THE
EAST AND 80 TO 84 IN THE WEST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
COLD FRONT FINALLY ARRIVES AND IS EXPECTED TO SWEEP EAST ACROSS THE
FORECAST AREA FROM WEST TO EAST BETWEEN 00Z AND 06Z TONIGHT. DRY
SLOT IS EXPECTED TO RACE NORTH AHEAD OF THE FRONT INTO THE AREA AS
WELL LIMITING THE EFFECTS FRONT HAS ON PRODUCING SHOWERS AND
THUNDERSTORMS. FRONT PUSHES EAST LATE TONIGHT DIMINISHING THREAT FOR
SHOWERS AS WELL AS NEGATIVE VORTICITY ADVECTION AND DRIER AIR MOVE
INTO THE REGION.
HIGH PRESSURE RIDGE BUILDS EAST INTO THE AREA TUESDAY THROUGH
WEDNESDAY AND BRINGS A RETURN BACK TO FAIR WEATHER ONCE AGAIN.
NOW...THIS IS WHERE THE MODELS SHOW SOME DIFFERENCES. NAM IS THE
WETTEST WEDNESDAY NIGHT IN FORCING A FAST MOVING UPPER LEVEL
POSITIVE VORTICITY MAXIMUM EAST INTO THE AREA. THIS FEATURE HAS
QUITE A BIT OF MOISTURE WITH IT. THE GFS IS SHOWING A SIMILAR
SOLUTION BUT IS LIMITED IN MOISTURE WHERE AS THE SREF SHUNTS
EVERYTHING SOUTH. SINCE THERE ARE SO MANY DIFFERENCES IN TIMING AND
AREAL EXTENT OF THE PRECIPITATION THREAT...WILL JUST MENTION A
SLIGHT CHANCE FOR SHOWERS AT THIS TIME AND SEE IF THE MODELS CAN
COME TO SOME KIND OF CONSENSUS.
UPPER LEVEL FEATURE PULLS OUT TO THE EAST THURSDAY AND BRINGS A
RETURN BACK TO FAIR WEATHER THURSDAY AFTERNOON AND NIGHT.
THE BAD NEWS IS THAT CHILLY AIR WILL RETURN BEHIND THE COLD FRONT
DROPPING TEMPERATURES BACK INTO THE 50S FOR HIGHS ACROSS THE
NORTHERN TIER COUNTIES BY WEDNESDAY AND LOWER 60S ACROSS THE SOUTH.
OVERNIGHT LOWS WILL DROP INTO THE 40S. A BIT OF A REBOUND WITH MORE
SUN WILL RETURN ON THURSDAY WITH HIGHS IN THE LOWER TO MIDDLE 60S.
YET LOWS WILL STILL BE IN THE 40S THURSDAY NIGHT. NOT EXPECTING ANY
FROST THROUGH THE PERIOD AT THIS TIME.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
THE LONG TERM BEGINS FRIDAY WITH A COLD FRONT HAVING JUST DROPPED
SOUTH ACROSS THE REGION AND AN UNREASONABLE AMOUNT OF COLD AIR JUST
TO OUR NORTH. DURING THE DAY HIGH PRESSURE WILL BUILD IN FROM THE
WEST AND WHILE TEMPS WILL BE ON THE COOL SIDE...BOTH MODELS TAKE THE
CORE OF THE COLD AIR EAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND.
SATURDAY THE HIGH MOVES EAST AND HEIGHTS BEGIN TO RECOVER AS WARMER
AIR BEGINS TO RETURN TO THE REGION. AN UPPER RIDGE WILL BE MOVING
INTO THE MIDWEST HOWEVER A SURFACE LOW IN THE CENTRAL PLAINS WILL
BEING DEEP MOISTURE INTO THE MID MISSISSIPPI VALLEY UNDER THE
RIDGE. BY SATURDAY NIGHT AND SUNDAY THIS MOISTURE WILL LIKELY BE
SPILLING INTO THE AREA WITH DEEP SOUTHERLY FLOW INTO THE AREA AHEAD
OF A DEVELOPING UPPER TROF IN THE PLAINS. WILL KEEP FORECAST DRY
THROUGH SATURDAY NIGHT BUT BRING MID/HIGH CHANCE POPS IN FOR
SUNDAY. WILL HAVE LIKELY POPS NORTHWEST SUNDAY NIGHT AND MONDAY
WHICH MAY NEED TO BE EXPANDED AS THE FORECAST EVOLVES. TEMPS FRIDAY
FROM THE UPPER 50S NORTHEAST LAKESHORE TO THE LOWER 70S SOUTHWEST.
MOST AREAS WILL SEE LOWER AND MID 70S SATURDAY AND SUNDAY.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AIRMASS QUITE MOIST THIS MORNING WITH DEWPOINTS IN THE MID 60S
STILL CONDITIONS REMAIN PRIMARILY VFR ACROSS THE AREA. UPPER
RIDGE JUST EAST OF THE AREA CONTINUES TO KEEP A LID ON CONVECTION.
FOR TODAY...ASIDE FROM PATCHY MVFR EARLY...EXPECTING MOSTLY VFR
CONDITIONS INTO THE AFTERNOON. FOLLOWING THE HRRR...DO EXPECT
SCATTERED SHOWERS/POSSIBLY THUNDER TO DEVELOP AND DRIFT ACROSS
CENTRAL AND EASTERN TERMINALS...MAINLY INLAND FROM ABOUT 16-20Z.
WILL LIKELY SEE ANOTHER SHOT OF SHOWERS/TSTMS THROUGH THE EVENING
AND/OR OVERNIGHT WITH MVFR CONDITIONS AHEAD OF THE APPROACHING
COLD FRONT. DRIEST AIR IS IN THE NORTHWEST SO DID NOT BRING
CONVECTION THERE. OTHERWISE VCTS/VCSH. POST FRONT EXPECT A RETURN
TO VFR ALTHOUGH GIVING TIMING INLAND EAST WILL LIKELY END THE
FORECAST PERIOD REMAIN MVFR.
.OUTLOOK... NON-VFR POSSIBLE BEHIND A COLD FRONT IN NE OH/NW PA
TUESDAY NIGHT.
&&
.MARINE...
LOW PRESSURE OVER LAKE SUPERIOR WILL MOVE NORTHEAST ACROSS ONTARIO
TO QUEBEC TODAY. A COLD FRONT EXTENDING SOUTHWEST FROM THE LOW WILL
CROSS LAKE ERIE TONIGHT. SOUTH TO SOUTHWEST FLOW TODAY AND TONIGHT
WILL REMAIN FAIRLY LIGHT. TUESDAY WINDS WILL INCREASE FROM THE WEST
AND SOUTHWEST TO 15 TO 25 KNOTS/ WINDS WILL TURN NORTHWEST TUESDAY
NIGHT AS THE COLD AIR DEEPENS ACROSS THE LAKE. A LARGE AREA OF HIGH
PRESSURE WILL BUILD TOWARD THE LAKE MID WEEK AS IT DROPS INTO THE
CENTRAL PLAINS. ANOTHER COLD FRONT HOWEVER WILL APPROACH FROM THE
NORTH THURSDAY LIKELY DROPPING ACROSS THE LAKE THURSDAY NIGHT OR
EARLY FRIDAY. NO GALES ARE EXPECTED THROUGH THE PERIOD HOWEVER A
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED SOMETIME TUESDAY AS WINDS
INCREASE...CONTINUING TUESDAY NIGHT AND MOST OF WEDNESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...DJB/LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...TK
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
727 AM EDT MON MAY 18 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS EVENING. HIGH
PRESSURE WILL BUILD VERY SLOWLY EAST AND SETTLE INTO THE MID
MISSISSIPPI VALLEY REGION BY THURSDAY. THE HIGH WILL EXTEND A RIDGE
EAST ACROSS THE LOCAL AREA DURING THIS TIME. MORE HIGH PRESSURE WILL
BUILD SOUTHEAST OUT OF CANADA AND MERGE WITH THE EXISTING HIGH
PRESSURE AND BECOME CENTERED OVER OHIO BY SATURDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WITH SUNRISE...SHOWERS ARE TRYING TO DEVELOP IN THE WESTERN HALF
OF THE FORECAST AREA. WILL KEEP A CHANCE FOR SHOWERS OVER THE
WESTERN HALF THIS MORNING AND THEN EXPAND IT OVER THE REST OF THE
AREA BY THE AFTERNOON. LATEST HRRR MODEL SHOWS THE SHOWER ACTIVITY
OVER SOUTHERN INDIANA GRADUALLY LIFTING NORTHEAST INTO THE REGION
WITH TIME. BUMPED MAX TEMPERATURES UP A COUPLE DEGREES IN THE
CENTRAL PORTIONS AS LATEST GUIDANCE IS COMING IN A COUPLE DEGREES
WARMER.
PREVIOUS DISCUSSION...
NONE OF THE INGREDIENTS APPEAR TO BE IN PHASE TODAY TO PRODUCE
WIDESPREAD SHOWERS AND THUNDERSTORMS. FIRST...UPPER LEVEL POSITIVE
VORTICITY ADVECTION WILL MOVE EAST ACROSS THE AREA TODAY. THERE WILL
BE SOME MOISTURE ASSOCIATED WITH THIS UPPER LEVEL FEATURE.
HOWEVER...THE COLD FRONT IS LAGGING BACK QUITE A BIT AND WILL NOT BE
IN PHASE WITH THE UPPER LEVEL ACTIVITY. SO TIMING OF THE THREAT FOR
SHOWERS AND THUNDERSTORMS COULD BE A BIT ON THE IFFY SIDE THROUGH
THE DAY. WILL KEEP THE MENTION OF SCATTERED SHOWERS AND
THUNDERSTORMS OVER MUCH OF THE AREA. BEST CHANCE WILL LIKELY BE
LATER IN THE DAY IN THE EAST WITH DAY TIME HEATING AND LINGERING
POSITIVE VORTICITY ADVECTION AND APPROACHING COLD FRONT. SO WILL GO
LIKELY POPS OVER THAT AREA FOR THIS AFTERNOON AND EVENING.
WARM AIR ADVECTION STILL TAKING PLACE IN THE WARM SECTOR ACROSS THE
FORECAST AREA. SINCE THE GREATEST THREAT FOR SHOWERS AND
THUNDERSTORMS WILL OCCUR IN THE EAST...TEMPERATURES MAY BE HELD BACK
A TAD COMPARED TO THE WEST. SO WILL LEAN TOWARD AROUND 80 IN THE
EAST AND 80 TO 84 IN THE WEST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
COLD FRONT FINALLY ARRIVES AND IS EXPECTED TO SWEEP EAST ACROSS THE
FORECAST AREA FROM WEST TO EAST BETWEEN 00Z AND 06Z TONIGHT. DRY
SLOT IS EXPECTED TO RACE NORTH AHEAD OF THE FRONT INTO THE AREA AS
WELL LIMITING THE EFFECTS FRONT HAS ON PRODUCING SHOWERS AND
THUNDERSTORMS. FRONT PUSHES EAST LATE TONIGHT DIMINISHING THREAT FOR
SHOWERS AS WELL AS NEGATIVE VORTICITY ADVECTION AND DRIER AIR MOVE
INTO THE REGION.
HIGH PRESSURE RIDGE BUILDS EAST INTO THE AREA TUESDAY THROUGH
WEDNESDAY AND BRINGS A RETURN BACK TO FAIR WEATHER ONCE AGAIN.
NOW...THIS IS WHERE THE MODELS SHOW SOME DIFFERENCES. NAM IS THE
WETTEST WEDNESDAY NIGHT IN FORCING A FAST MOVING UPPER LEVEL
POSITIVE VORTICITY MAXIMUM EAST INTO THE AREA. THIS FEATURE HAS
QUITE A BIT OF MOISTURE WITH IT. THE GFS IS SHOWING A SIMILAR
SOLUTION BUT IS LIMITED IN MOISTURE WHERE AS THE SREF SHUNTS
EVERYTHING SOUTH. SINCE THERE ARE SO MANY DIFFERENCES IN TIMING AND
AREAL EXTENT OF THE PRECIPITATION THREAT...WILL JUST MENTION A
SLIGHT CHANCE FOR SHOWERS AT THIS TIME AND SEE IF THE MODELS CAN
COME TO SOME KIND OF CONSENSUS.
UPPER LEVEL FEATURE PULLS OUT TO THE EAST THURSDAY AND BRINGS A
RETURN BACK TO FAIR WEATHER THURSDAY AFTERNOON AND NIGHT.
THE BAD NEWS IS THAT CHILLY AIR WILL RETURN BEHIND THE COLD FRONT
DROPPING TEMPERATURES BACK INTO THE 50S FOR HIGHS ACROSS THE
NORTHERN TIER COUNTIES BY WEDNESDAY AND LOWER 60S ACROSS THE SOUTH.
OVERNIGHT LOWS WILL DROP INTO THE 40S. A BIT OF A REBOUND WITH MORE
SUN WILL RETURN ON THURSDAY WITH HIGHS IN THE LOWER TO MIDDLE 60S.
YET LOWS WILL STILL BE IN THE 40S THURSDAY NIGHT. NOT EXPECTING ANY
FROST THROUGH THE PERIOD AT THIS TIME.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
THE LONG TERM BEGINS FRIDAY WITH A COLD FRONT HAVING JUST DROPPED
SOUTH ACROSS THE REGION AND AN UNREASONABLE AMOUNT OF COLD AIR JUST
TO OUR NORTH. DURING THE DAY HIGH PRESSURE WILL BUILD IN FROM THE
WEST AND WHILE TEMPS WILL BE ON THE COOL SIDE...BOTH MODELS TAKE THE
CORE OF THE COLD AIR EAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND.
SATURDAY THE HIGH MOVES EAST AND HEIGHTS BEGIN TO RECOVER AS WARMER
AIR BEGINS TO RETURN TO THE REGION. AN UPPER RIDGE WILL BE MOVING
INTO THE MIDWEST HOWEVER A SURFACE LOW IN THE CENTRAL PLAINS WILL
BEING DEEP MOISTURE INTO THE MID MISSISSIPPI VALLEY UNDER THE
RIDGE. BY SATURDAY NIGHT AND SUNDAY THIS MOISTURE WILL LIKELY BE
SPILLING INTO THE AREA WITH DEEP SOUTHERLY FLOW INTO THE AREA AHEAD
OF A DEVELOPING UPPER TROF IN THE PLAINS. WILL KEEP FORECAST DRY
THROUGH SATURDAY NIGHT BUT BRING MID/HIGH CHANCE POPS IN FOR
SUNDAY. WILL HAVE LIKELY POPS NORTHWEST SUNDAY NIGHT AND MONDAY
WHICH MAY NEED TO BE EXPANDED AS THE FORECAST EVOLVES. TEMPS FRIDAY
FROM THE UPPER 50S NORTHEAST LAKESHORE TO THE LOWER 70S SOUTHWEST.
MOST AREAS WILL SEE LOWER AND MID 70S SATURDAY AND SUNDAY.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AIRMASS QUITE MOIST THIS MORNING WITH DEWPOINTS IN THE MID 60S
STILL CONDITIONS REMAIN PRIMARILY VFR ACROSS THE AREA. UPPER
RIDGE JUST EAST OF THE AREA CONTINUES TO KEEP A LID ON CONVECTION.
FOR TODAY...ASIDE FROM PATCHY MVFR EARLY...EXPECTING MOSTLY VFR
CONDITIONS INTO THE AFTERNOON. FOLLOWING THE HRRR...DO EXPECT
SCATTERED SHOWERS/POSSIBLY THUNDER TO DEVELOP AND DRIFT ACROSS
CENTRAL AND EASTERN TERMINALS...MAINLY INLAND FROM ABOUT 16-20Z.
WILL LIKELY SEE ANOTHER SHOT OF SHOWERS/TSTMS THROUGH THE EVENING
AND/OR OVERNIGHT WITH MVFR CONDITIONS AHEAD OF THE APPROACHING
COLD FRONT. DRIEST AIR IS IN THE NORTHWEST SO DID NOT BRING
CONVECTION THERE. OTHERWISE VCTS/VCSH. POST FRONT EXPECT A RETURN
TO VFR ALTHOUGH GIVING TIMING INLAND EAST WILL LIKELY END THE
FORECAST PERIOD REMAIN MVFR.
.OUTLOOK... NON-VFR POSSIBLE BEHIND A COLD FRONT IN NE OH/NW PA
TUESDAY NIGHT.
&&
.MARINE...
LOW PRESSURE OVER LAKE SUPERIOR WILL MOVE NORTHEAST ACROSS ONTARIO
TO QUEBEC TODAY. A COLD FRONT EXTENDING SOUTHWEST FROM THE LOW WILL
CROSS LAKE ERIE TONIGHT. SOUTH TO SOUTHWEST FLOW TODAY AND TONIGHT
WILL REMAIN FAIRLY LIGHT. TUESDAY WINDS WILL INCREASE FROM THE WEST
AND SOUTHWEST TO 15 TO 25 KNOTS/ WINDS WILL TURN NORTHWEST TUESDAY
NIGHT AS THE COLD AIR DEEPENS ACROSS THE LAKE. A LARGE AREA OF HIGH
PRESSURE WILL BUILD TOWARD THE LAKE MID WEEK AS IT DROPS INTO THE
CENTRAL PLAINS. ANOTHER COLD FRONT HOWEVER WILL APPROACH FROM THE
NORTH THURSDAY LIKELY DROPPING ACROSS THE LAKE THURSDAY NIGHT OR
EARLY FRIDAY. NO GALES ARE EXPECTED THROUGH THE PERIOD HOWEVER A
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED SOMETIME TUESDAY AS WINDS
INCREASE...CONTINUING TUESDAY NIGHT AND MOST OF WEDNESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...TK
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
645 AM EDT MON MAY 18 2015
.SYNOPSIS...
WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT
IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD
FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST RADAR MOSAIC AND SURFACE OBSERVATIONS SUGGEST REGION IS
GENERALLY DRY AT THIS TIME. EXPECT THESE CONDITIONS WILL CONTINUE
THROUGH THE OVERNIGHT HOURS...AND HAVE SLIGHT CHANCE POPS CONTINUING.
LATEST HRRR SHOWS A SMALL AREA OF SHOWERS...CURRENTLY OVER SOUTHEAST
KENTUCKY...WILL SPREAD NORTHEAST AND INCREASE IN AREAL COVERAGE AS
IT MOVES INTO OUR SOUTHERN COUNTIES LATER THIS MORNING. THE CURRENT
TREND OF THESE SHOWERS HAS BEEN TO WEAKEN. SO NOT SURE HOW MUCH OF
THESE SHOWERS WILL ACTUALLY MAKE IT INTO OUR AREA.
MOST OF THE MODELS THEN INDICATE WEAK DISTURBANCES WILL MOVE ACROSS
THE AREA TODAY INTO TONIGHT. COMBINATION OF THESE DISTURBANCES AND
INCREASING INSTABILITY SHOULD ONCE AGAIN RESULT IN THE DEVELOPMENT
OF SHOWERS AND STORMS TODAY.
LOCALIZED DOWNPOURS ARE ONCE AGAIN POSSIBLE TODAY AND TONIGHT...AND
CAN RESULT IN MINOR FLOODING OF STREETS...CREEKS...LOW LYING AND
POOR DRAINAGE AREAS.
WITH THE LOSS OF DAYTIME HEATING...THE COVERAGE AND INTENSITY OF
THE CONVECTION SHOULD BEGIN TO WANE. HOWEVER...A COLD FRONT...WHICH
IS EXPECTED TO PUSH INTO THE REGION LATE TONIGHT...SHOULD CONTINUE
THE THREAT OF SHOWERS AND STORMS.
CURRENT THINKING IS THAT THE FRONT SHOULD BE LOCATED NEAR OR JUST
EAST OF THE OHIO RIVER AT THE END OF THIS PERIOD.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
MADE NO REAL CHANGES WITH THE SHORT TERM PART OF THE FORECAST.
RAISED POPS A BIT IN THE EAST MONDAY NIGHT AHEAD OF THE COLD
FRONT. PW VALUES ARE IN THE 1.5-1.75 INCHES RANGE AHEAD THE FRONT
SO THE PROSPECT OF HEAVY RAIN OVERNIGHT IS STILL POSSIBLE. EVEN
WITH ALL OF THE RAIN THAT HAS FALLEN UP TO THIS POINT THE GROUND
SHOULD BE ABLE TO HANDLE THE SITUATION SO NO REAL CONCERNS. WILL
CONTINUE TO MONITOR THE SITUATION. IT DRIES OUT QUICKLY BEHIND THE
FRONT STARTING TUESDAY NIGHT.
DRY WEATHER WITH PLEASANT TEMPERATURES SHOULD PREVAIL TUESDAY
NIGHT AND WEDNESDAY AS WEAK HIGH PRESSURE BUILDS TO THE WEST
GIVING ZONAL FLOW FOR THE OHIO VALLEY.
WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE
PERIOD.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
NOTHING SIGNIFICANT TO FOCUS ON IN THE LONG TERM. HIGH PRESSURE
BUILDS OVER THE CENTRAL US AND THAT WILL LEAVE ZONAL FLOW OVER THE
OHIO VALLEY. THE EXTENDED FORECAST WILL BE DRY FOR THE MOST PART
BUT CONFIDENCE IS NOT ALL THAT HIGH AS THERE COULD BE A FEW UPPER
LEVEL RIPPLES CAUSED BY THE WEAK FRONT THAT PASSES TO THE NORTH
NEXT WEEKEND. PRECIPITATION CHANCES INCREASING ON SUNDAY.
WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
12Z MONDAY THRU 12Z TUESDAY...
CONDITIONS HAVE IMPROVED SINCE 09Z...WITH MOST LOCATIONS MVFR OR
BETTER. HOWEVER...ISOLATED IFR CONDITIONS MAY STILL BE OCCURRING
ALONG RIVER VALLEYS.
LATEST RADAR SHOWS ISOLATED SHOWERS HAVE BEGUN TO DEVELOP ACROSS
PORTIONS OF SOUTHEAST OHIO AND NORTHEAST KENTUCKY. THESE SHOWER
WERE DEVELOPING IN RESPONSE TO AN UPPER LEVEL DISTURBANCE.
EXPECT THESE SHOWERS WILL CONTINUE TO SPREAD ACROSS THE REMAINDER
OF THE STATE...AS THE DISTURBANCE MOVES NORTHEAST..
ADDITIONAL DISTURBANCES ARE EXPECTED TO MOVE ACROSS THE AREA TODAY...
WHICH WILL RESULT IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS...
ESPECIALLY FOR THE AFTERNOON AND EVENING HOURS. WHILE MOST LOCATIONS
WILL SEE VFR OR MVFR CONDITIONS...EXPECT IFR CONDITIONS ARE POSSIBLE
NEAR THE HEAVIER STORMS. GUSTY WINDS ARE ALSO POSSIBLE NEAR THE
STRONGER STORMS.
THE STORMS SHOULD THEN WEAKEN AFTER 23Z. HOWEVER...SCATTERED STORMS
WILL REMAIN POSSIBLE THROUGH THE END OF THE PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: COVERAGE OF STORMS COULD HIGHER THAN
EXPECTED...WITH ORE AREAS SEEING IFR OR LOWER CONDITIONS THIS
AFTERNOON AND EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS
CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY L H H H H H H H H M M M
HTS CONSISTENCY H H H H H H M M M H H M
BKW CONSISTENCY H H H H H H H H H H H M
EKN CONSISTENCY L M L L H H H M H H H M
PKB CONSISTENCY H H H H H H H H H H H M
CKB CONSISTENCY H H H H M H H H H H H M
AFTER 12Z TUESDAY...
BRIEF IFR IN SHOWERS AND THUNDERSTORMS POSSIBLE IN LOW CLOUDS TUE
MORNING. FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT INTO WED
MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/ARJ
NEAR TERM...JSH
SHORT TERM...FB
LONG TERM...FB
AVIATION...JSH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
635 AM EDT MON MAY 18 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS EVENING. HIGH
PRESSURE WILL BUILD VERY SLOWLY EAST AND SETTLE INTO THE MID
MISSISSIPPI VALLEY REGION BY THURSDAY. THE HIGH WILL EXTEND A RIDGE
EAST ACROSS THE LOCAL AREA DURING THIS TIME. MORE HIGH PRESSURE WILL
BUILD SOUTHEAST OUT OF CANADA AND MERGE WITH THE EXISTING HIGH
PRESSURE AND BECOME CENTERED OVER OHIO BY SATURDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WITH SUNRISE...SHOWERS ARE TRYING TO DEVELOP IN THE WESTERN HALF
OF THE FORECAST AREA. WILL KEEP A CHANCE FOR SHOWERS OVER THE
WESTERN HALF THIS MORNING AND THEN EXPAND IT OVER THE REST OF THE
AREA BY THE AFTERNOON. LATEST HRRR MODEL SHOWS THE SHOWER ACTIVITY
OVER SOUTHERN INDIANA GRADUALLY LIFTING NORTHEAST INTO THE REGION
WITH TIME. BUMPED MAX TEMPERATURES UP A COUPLE DEGREES IN THE
CENTRAL PORTIONS AS LATEST GUIDANCE IS COMING IN A COUPLE DEGREES
WARMER.
PREVIOUS DISCUSSION...
NONE OF THE INGREDIENTS APPEAR TO BE IN PHASE TODAY TO PRODUCE
WIDESPREAD SHOWERS AND THUNDERSTORMS. FIRST...UPPER LEVEL POSITIVE
VORTICITY ADVECTION WILL MOVE EAST ACROSS THE AREA TODAY. THERE WILL
BE SOME MOISTURE ASSOCIATED WITH THIS UPPER LEVEL FEATURE.
HOWEVER...THE COLD FRONT IS LAGGING BACK QUITE A BIT AND WILL NOT BE
IN PHASE WITH THE UPPER LEVEL ACTIVITY. SO TIMING OF THE THREAT FOR
SHOWERS AND THUNDERSTORMS COULD BE A BIT ON THE IFFY SIDE THROUGH
THE DAY. WILL KEEP THE MENTION OF SCATTERED SHOWERS AND
THUNDERSTORMS OVER MUCH OF THE AREA. BEST CHANCE WILL LIKELY BE
LATER IN THE DAY IN THE EAST WITH DAY TIME HEATING AND LINGERING
POSITIVE VORTICITY ADVECTION AND APPROACHING COLD FRONT. SO WILL GO
LIKELY POPS OVER THAT AREA FOR THIS AFTERNOON AND EVENING.
WARM AIR ADVECTION STILL TAKING PLACE IN THE WARM SECTOR ACROSS THE
FORECAST AREA. SINCE THE GREATEST THREAT FOR SHOWERS AND
THUNDERSTORMS WILL OCCUR IN THE EAST...TEMPERATURES MAY BE HELD BACK
A TAD COMPARED TO THE WEST. SO WILL LEAN TOWARD AROUND 80 IN THE
EAST AND 80 TO 84 IN THE WEST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
COLD FRONT FINALLY ARRIVES AND IS EXPECTED TO SWEEP EAST ACROSS THE
FORECAST AREA FROM WEST TO EAST BETWEEN 00Z AND 06Z TONIGHT. DRY
SLOT IS EXPECTED TO RACE NORTH AHEAD OF THE FRONT INTO THE AREA AS
WELL LIMITING THE EFFECTS FRONT HAS ON PRODUCING SHOWERS AND
THUNDERSTORMS. FRONT PUSHES EAST LATE TONIGHT DIMINISHING THREAT FOR
SHOWERS AS WELL AS NEGATIVE VORTICITY ADVECTION AND DRIER AIR MOVE
INTO THE REGION.
HIGH PRESSURE RIDGE BUILDS EAST INTO THE AREA TUESDAY THROUGH
WEDNESDAY AND BRINGS A RETURN BACK TO FAIR WEATHER ONCE AGAIN.
NOW...THIS IS WHERE THE MODELS SHOW SOME DIFFERENCES. NAM IS THE
WETTEST WEDNESDAY NIGHT IN FORCING A FAST MOVING UPPER LEVEL
POSITIVE VORTICITY MAXIMUM EAST INTO THE AREA. THIS FEATURE HAS
QUITE A BIT OF MOISTURE WITH IT. THE GFS IS SHOWING A SIMILAR
SOLUTION BUT IS LIMITED IN MOISTURE WHERE AS THE SREF SHUNTS
EVERYTHING SOUTH. SINCE THERE ARE SO MANY DIFFERENCES IN TIMING AND
AREAL EXTENT OF THE PRECIPITATION THREAT...WILL JUST MENTION A
SLIGHT CHANCE FOR SHOWERS AT THIS TIME AND SEE IF THE MODELS CAN
COME TO SOME KIND OF CONSENSUS.
UPPER LEVEL FEATURE PULLS OUT TO THE EAST THURSDAY AND BRINGS A
RETURN BACK TO FAIR WEATHER THURSDAY AFTERNOON AND NIGHT.
THE BAD NEWS IS THAT CHILLY AIR WILL RETURN BEHIND THE COLD FRONT
DROPPING TEMPERATURES BACK INTO THE 50S FOR HIGHS ACROSS THE
NORTHERN TIER COUNTIES BY WEDNESDAY AND LOWER 60S ACROSS THE SOUTH.
OVERNIGHT LOWS WILL DROP INTO THE 40S. A BIT OF A REBOUND WITH MORE
SUN WILL RETURN ON THURSDAY WITH HIGHS IN THE LOWER TO MIDDLE 60S.
YET LOWS WILL STILL BE IN THE 40S THURSDAY NIGHT. NOT EXPECTING ANY
FROST THROUGH THE PERIOD AT THIS TIME.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
THE LONG TERM BEGINS FRIDAY WITH A COLD FRONT HAVING JUST DROPPED
SOUTH ACROSS THE REGION AND AN UNREASONABLE AMOUNT OF COLD AIR JUST
TO OUR NORTH. DURING THE DAY HIGH PRESSURE WILL BUILD IN FROM THE
WEST AND WHILE TEMPS WILL BE ON THE COOL SIDE...BOTH MODELS TAKE THE
CORE OF THE COLD AIR EAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND.
SATURDAY THE HIGH MOVES EAST AND HEIGHTS BEGIN TO RECOVER AS WARMER
AIR BEGINS TO RETURN TO THE REGION. AN UPPER RIDGE WILL BE MOVING
INTO THE MIDWEST HOWEVER A SURFACE LOW IN THE CENTRAL PLAINS WILL
BEING DEEP MOISTURE INTO THE MID MISSISSIPPI VALLEY UNDER THE
RIDGE. BY SATURDAY NIGHT AND SUNDAY THIS MOISTURE WILL LIKELY BE
SPILLING INTO THE AREA WITH DEEP SOUTHERLY FLOW INTO THE AREA AHEAD
OF A DEVELOPING UPPER TROF IN THE PLAINS. WILL KEEP FORECAST DRY
THROUGH SATURDAY NIGHT BUT BRING MID/HIGH CHANCE POPS IN FOR
SUNDAY. WILL HAVE LIKELY POPS NORTHWEST SUNDAY NIGHT AND MONDAY
WHICH MAY NEED TO BE EXPANDED AS THE FORECAST EVOLVES. TEMPS FRIDAY
FROM THE UPPER 50S NORTHEAST LAKESHORE TO THE LOWER 70S SOUTHWEST.
MOST AREAS WILL SEE LOWER AND MID 70S SATURDAY AND SUNDAY.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
CONDITIONS VFR ACROSS NRN OHIO AND NWRN PA AT 05Z. AIRMASS QUITE
MOIST BUT UPPER RIDGE JUST EAST OF THE AREA MOSTLY KEEPING A LID
ON CONVECTION. GUIDANCE SUGGESTS OVERNIGHT AND INTO THE EARLY
MORNING HOURS CIGS AND VISIBILITIES SHOULD GO DOWN TO IFR IN
STRATUS AND FOG. AM IN AGREEMENT WITH MVFR VISIBILITIES IN A
MORNING FOG/MIST HAVE OPTED TO REMAIN MORE CONSERVATIVE THAN
GUIDANCE WHICH MAY BE TOO PESSIMISTIC AS STRATUS THAT HAS
DEVELOPED HAS BEEN AT 5 TO 7 KFT. TIME WILL TELL. AS FOR MONDAY
GIVEN MOISTURE AND THE APPROACHING COLD FRONT FROM THE WEST WILL
CONTINUE WITH VCTS FOR THE AFTERNOON ACROSS THE AREA IN DIURNAL
CONVECTION. COULD ALSO HAVE ANOTHER LINE APPROACHING WESTERN
TERMINALS TOWARD THE END OF THE PERIOD WITH THE FRONT.
.OUTLOOK...NON VFR AT TIMES IN SCATTERED SHOWERS OR THUNDERSTORMS
TONIGHT. NON-VFR POSSIBLE BEHIND A COLD FRONT IN NE OH/NW PA
TUESDAY AFTERNOON/EVENING.
&&
.MARINE...
LOW PRESSURE OVER LAKE SUPERIOR WILL MOVE NORTHEAST ACROSS ONTARIO
TO QUEBEC TODAY. A COLD FRONT EXTENDING SOUTHWEST FROM THE LOW WILL
CROSS LAKE ERIE TONIGHT. SOUTH TO SOUTHWEST FLOW TODAY AND TONIGHT
WILL REMAIN FAIRLY LIGHT. TUESDAY WINDS WILL INCREASE FROM THE WEST
AND SOUTHWEST TO 15 TO 25 KNOTS/ WINDS WILL TURN NORTHWEST TUESDAY
NIGHT AS THE COLD AIR DEEPENS ACROSS THE LAKE. A LARGE AREA OF HIGH
PRESSURE WILL BUILD TOWARD THE LAKE MID WEEK AS IT DROPS INTO THE
CENTRAL PLAINS. ANOTHER COLD FRONT HOWEVER WILL APPROACH FROM THE
NORTH THURSDAY LIKELY DROPPING ACROSS THE LAKE THURSDAY NIGHT OR
EARLY FRIDAY. NO GALES ARE EXPECTED THROUGH THE PERIOD HOWEVER A
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED SOMETIME TUESDAY AS WINDS
INCREASE...CONTINUING TUESDAY NIGHT AND MOST OF WEDNESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...TK
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
213 AM EDT MON MAY 18 2015
.SYNOPSIS...
WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT
IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD
FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST RADAR MOSAIC AND SURFACE OBSERVATIONS SUGGEST REGION IS
GENERALLY DRY AT THIS TIME. EXPECT THESE CONDITIONS WILL CONTINUE
THROUGH THE OVERNIGHT HOURS...AND HAVE SLIGHT CHANCE POPS CONTINUING.
LATEST HRRR SHOWS A SMALL AREA OF SHOWERS...CURRENTLY OVER SOUTHEAST
KENTUCKY...WILL SPREAD NORTHEAST AND INCREASE IN AREAL COVERAGE AS
IT MOVES INTO OUR SOUTHERN COUNTIES LATER THIS MORNING. THE CURRENT
TREND OF THESE SHOWERS HAS BEEN TO WEAKEN. SO NOT SURE HOW MUCH OF
THESE SHOWERS WILL ACTUALLY MAKE IT INTO OUR AREA.
MOST OF THE MODELS THEN INDICATE WEAK DISTURBANCES WILL MOVE ACROSS
THE AREA TODAY INTO TONIGHT. COMBINATION OF THESE DISTURBANCES AND
INCREASING INSTABILITY SHOULD ONCE AGAIN RESULT IN THE DEVELOPMENT
OF SHOWERS AND STORMS TODAY.
LOCALIZED DOWNPOURS ARE ONCE AGAIN POSSIBLE TODAY AND TONIGHT...AND
CAN RESULT IN MINOR FLOODING OF STREETS...CREEKS...LOW LYING AND
POOR DRAINAGE AREAS.
WITH THE LOSS OF DAYTIME HEATING...THE COVERAGE AND INTENSITY OF
THE CONVECTION SHOULD BEGIN TO WANE. HOWEVER...A COLD FRONT...WHICH
IS EXPECTED TO PUSH INTO THE REGION LATE TONIGHT...SHOULD CONTINUE
THE THREAT OF SHOWERS AND STORMS.
CURRENT THINKING IS THAT THE FRONT SHOULD BE LOCATED NEAR OR JUST
EAST OF THE OHIO RIVER AT THE END OF THIS PERIOD.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
MADE NO REAL CHANGES WITH THE SHORT TERM PART OF THE FORECAST.
RAISED POPS A BIT IN THE EAST MONDAY NIGHT AHEAD OF THE COLD
FRONT. PW VALUES ARE IN THE 1.5-1.75 INCHES RANGE AHEAD THE FRONT
SO THE PROSPECT OF HEAVY RAIN OVERNIGHT IS STILL POSSIBLE. EVEN
WITH ALL OF THE RAIN THAT HAS FALLEN UP TO THIS POINT THE GROUND
SHOULD BE ABLE TO HANDLE THE SITUATION SO NO REAL CONCERNS. WILL
CONTINUE TO MONITOR THE SITUATION. IT DRIES OUT QUICKLY BEHIND THE
FRONT STARTING TUESDAY NIGHT.
DRY WEATHER WITH PLEASANT TEMPERATURES SHOULD PREVAIL TUESDAY
NIGHT AND WEDNESDAY AS WEAK HIGH PRESSURE BUILDS TO THE WEST
GIVING ZONAL FLOW FOR THE OHIO VALLEY.
WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE
PERIOD.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
NOTHING SIGNIFICANT TO FOCUS ON IN THE LONG TERM. HIGH PRESSURE
BUILDS OVER THE CENTRAL US AND THAT WILL LEAVE ZONAL FLOW OVER THE
OHIO VALLEY. THE EXTENDED FORECAST WILL BE DRY FOR THE MOST PART
BUT CONFIDENCE IS NOT ALL THAT HIGH AS THERE COULD BE A FEW UPPER
LEVEL RIPPLES CAUSED BY THE WEAK FRONT THAT PASSES TO THE NORTH
NEXT WEEKEND. PRECIPITATION CHANCES INCREASING ON SUNDAY.
WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
06Z MONDAY THRU 06Z TUESDAY...
ALL OF THE SHOWERS AND STORMS HAVE MOVED OUT OF THE REGION...OR
HAVE DISSIPATED. A FEW SHOWERS ARE STILL POSSIBLE DURING THE
OVERNIGHT HOURS.
VFR CONDITIONS PREVAILED IN MOST LOCATIONS. HOWEVER...MVFR/IFR
CONDITIONS WERE OCCURRING ALONG SOME RIVER VALLEYS.
CONDITIONS SHOULD REMAIN ROUGHLY ABOUT THE SAME THRU 12Z...WHEN
CONDITIONS SHOULD IMPROVE AFTER SUNRISE.
SEVERAL DISTURBANCES ARE EXPECTED TO MOVE ACROSS THE AREA
TODAY...WHICH WILL RESULT IN THE REDEVELOPMENT OF SHOWERS AND
THUNDERSTORMS FOR THE AFTERNOON AND EVENING HOURS. WHILE MOST
LOCATIONS WILL SEE VFR OR MVFR CONDITIONS...EXPECT IFR CONDITIONS
ARE POSSIBLE NEAR THE HEAVIER STORMS. GUSTY WINDS ARE ALSO
POSSIBLE NEAR THE STRONGER STORMS.
THE STORMS SHOULD THEN WEAKEN AFTER 23Z. HOWEVER...SCATTERED
STORMS WILL REMAIN POSSIBLE THROUGH THE END OF THE PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: COVERAGE OF FOG REMAINS IN QUESTION OVER
WEST VIRGINIA THROUGH 12Z MON. HIGHLY VARIABLE CONDITIONS IN THE
SHOWERS AND STORMS TODAY WITH CONDITIONS GOING LOWER THAN
FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE MON 05/18/15
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY H H L L L L H H H M M H
HTS CONSISTENCY H H H H H H H H H M H H
BKW CONSISTENCY M H H H H H H H H M H H
EKN CONSISTENCY L L L L L L H M H H M M
PKB CONSISTENCY H H H H H H H H M M M H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 06Z TUESDAY...
BRIEF IFR IN SHOWERS AND THUNDERSTORMS POSSIBLE MON NIGHT...AND IN
LOW CLOUDS TUE MORNING. FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT
INTO WED MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/ARJ
NEAR TERM...JSH
SHORT TERM...FB
LONG TERM...FB
AVIATION...JSH
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
955 PM CDT TUE MAY 19 2015
.UPDATE...
INCREASED RAIN CHANCES OVER MUCH OF THE AREA TONIGHT.
LOWERED OVERNIGHT LOWS.
&&
.DISCUSSION...
HEAVY RAINFALL...FLOODING...AND SEVERE WEATHER WILL CONTINUE
TONIGHT IN SOUTHERN OKLAHOMA AND NORTH TEXAS.
THE ENVIRONMENT SUPPORTS MORE HEAVY RAIN AND SEVERE WEATHER. THINK
THE TORNADO THREAT WILL CONTINUE IN SOUTHERN OKLAHOMA AND NORTH
TEXAS WHERE SURFACE DEWPOINTS ARE 70 DEGREES OR HIGHER AND DUE TO
HIGH LOW LEVEL SHEAR.
THE FLOODING THREAT WILL CONTINUE TO INCREASE ACROSS SOUTHERN
OKLAHOMA AND NORTH TEXAS WHERE SEVERAL INCHES OF RAINFALL MAY
OCCUR TONIGHT...THAT WILL ONLY AGGRAVATE ONGOING FLOODING.
THE CONVECTION IN SOUTHWEST OKLAHOMA AND FAR WESTERN NORTH TEXAS
FROM HOBART TO ALTUS TO QUANAH AT 950 PM APPEARS TO BE DEVELOPING
A STRONG LOW LEVEL COLD POOL. WITH THIS THOUGHT AND LOOKING AT
LATEST HRRR RUNS...THINK THIS LINE WILL GROW UPSCALE...BECOME A
LARGE ORGANIZED COMPLEX AND MOVE EAST SOUTHEAST THROUGH THE
NIGHT...BRINGING SOME WIND AND HAIL REPORTS. A FEW BRIEF TORNADOES
COULD OCCUR ALONG THIS LINE AS WELL. THIS LINE MAY ACCELERATE
THROUGH THE NIGHT.
MOST OF THE HEAVY RAIN AND SEVERE WEATHER THREAT IS EXPECTED TO
STAY SOUTH OF THE OKLAHOMA CITY METRO AREA FOR THE REST OF TONIGHT.
A FEW NON SEVERE AND LIGHTER SHOWERS AND STORMS MAY AFFECT
NORTHERN OKLAHOMA FOR THE REST OF TONIGHT. COLD FRONT WILL MOVE
SOUTH THROUGH THE NIGHT AS WELL.
PRODUCTS HAVE BEEN UPDATED.
MBS
&&
.PREV DISCUSSION... /ISSUED 657 PM CDT TUE MAY 19 2015/
DISCUSSION...
THE 00Z AVIATION DISCUSSION FOLLOWS....
AVIATION...
SHORT-TERM MODELS ARE IN REASONABLY GOOD AGREEMENT THAT THE
CURRENT MASS OF TSRA FROM THE TX PANHANDLE E INTO CENTRAL OK WILL
FILL IN AND BECOME A SINGLE LARGE STORM COMPLEX TOWARD MIDNIGHT...AS
A COLD FRONT ADVANCES S FROM KS. UNTIL THAT HAPPENS...CEILINGS
AND VISIBILITIES WILL BE EXTREMELY VARIABLE OVER SPACE AND TIME.
IN ADDITION...SCT +TSRA OVER S OK AND N TX WILL CONTINUE THIS
EVENING...AND SOME OF THEM WILL BE SEVERE. AFTER MIDNIGHT...A
SINGLE LARGE STORM COMPLEX SHOULD ADVANCE SE ACROSS ALL OUR TAF
SITES EXCEPT KGAG...KWWR...AND KPNC...WHICH SHOULD BE N OF THE
AREA OF DEVELOPMENT. THERE WILL BE ABOUT 2 HOURS OF
+TSRA...FOLLOWED BY MAYBE AN HOUR OF -RA AS THE STORMS ADVANCE
SOUTH OF EACH SITE. AS THE STORMS DEPART TO THE S/SE...N WINDS
WILL BEGIN...AND COOLER AIR WILL FLOW IN. VISIBILITIES SHOULD BE
UNLIMITED ONCE THE RAIN STOPS...BUT LOW CEILINGS WILL PERSIST INTO
WEDNESDAY MORNING. ONLY SLOW INCREASES IN CEILINGS ARE EXPECTED
TOMORROW...BUT IF THE POST-FRONTAL MOISTURE LAYER IS THIN
ENOUGH...THERE MAY BE BREAKS IN THE CLOUDS TOMORROW AFTERNOON.
CMS
PREV DISCUSSION... /ISSUED 444 PM CDT TUE MAY 19 2015/
DISCUSSION...
EXISTING CONVECTION WILL LIKELY CONTINUE THROUGH THE
EVENING...THEN MERGE INTO A SINGLE CONVECTIVE SYSTEM TOWARD
MIDNIGHT AS A COLD FRONT MOVES INTO OKLAHOMA. THE FRONT WILL
ADVANCE SOUTHEAST OVERNIGHT...TAKING THE STORMS WITH
IT...TEMPORARILY.
IN ADDITION TO THE SEVERE WEATHER POTENTIAL...HEAVY RAIN HAS
CAUSED...AND WILL CONTINUE TO CAUSE...AREAS OF FLOODING. VERY
HEAVY RAINFALL RATES WILL CONTINUE TO CAUSE FLOODING OF STREETS
AND HIGHWAYS IN URBANIZED AREAS UNTIL EARLY TOMORROW MORNING. WE
HAVE EXPANDED OUR FLOOD WATCH TO INCLUDE ALL OF OUR SOUTH-CENTRAL
AND SOUTHEAST OKLAHOMA COUNTIES.
RAIN/THUNDERSTORM CHANCES WILL CONTINUE...ALTHOUGH MAINLY OVER OUR
SOUTHERN COUNTIES...THROUGH THURSDAY...AS THE FRONT AND LOW-LEVEL
MOISTURE REMAIN IN/NEAR OUR FORECAST AREA.
ANOTHER UPPER-LEVEL WAVE WILL APPROACH FRIDAY AND THIS WEEKEND.
UNLIKE THE LAST TWO WEEKENDS...THIS SYSTEM DOES NOT HAVE THE
CLASSIC SEVERE-WEATHER LOOK TO IT. IT LOOKS LESS ORGANIZED.
NEVERTHELESS...IF WE DO NOT HAVE WIDESPREAD RAIN ON FRIDAY AND
SATURDAY...SEVERE WEATHER WILL BE A DEFINITE POSSIBILITY.
DRIER AIR IS FORECAST TO ARRIVE EARLY NEXT WEEK...ALONG WITH
SHORTWAVE RIDGING ALOFT. THIS MAY BRING US A FEW DAYS OF DRY
WEATHER...BUT THAT IS CERTAINLY NOT GUARANTEED.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 53 68 53 66 / 70 40 20 10
HOBART OK 53 67 52 66 / 100 20 20 20
WICHITA FALLS TX 60 76 57 69 / 100 40 50 30
GAGE OK 45 62 47 64 / 40 10 10 10
PONCA CITY OK 51 66 50 66 / 60 30 10 10
DURANT OK 62 80 59 71 / 100 50 50 40
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLOOD WATCH UNTIL 7 AM CDT WEDNESDAY FOR OKZ007-008-012>014-
016>048-050>052.
TX...FLOOD WATCH UNTIL 7 AM CDT WEDNESDAY FOR TXZ085-086-089-090.
&&
$$
MBS
AREA FORECAST DISCUSSION
NWS TULSA OK
1139 PM CDT SUN MAY 17 2015
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
PATCHY FOG STILL EXPECTED LATE TONIGHT AS WINDS SUBSIDE AHEAD OF
COLD FRONT...WHICH WILL MOVE INTO NORTHEAST OKLAHOMA MONDAY
MORNING. THUNDERSTORM CHANCES APPEAR TO LOW AT THIS POINT TO
MENTION ALONG/AHEAD OF FROPA.
&&
.PREV DISCUSSION... /ISSUED 935 PM CDT SUN MAY 17 2015/
DISCUSSION...
A MUCH QUIETER EVENING AS THE AREA HAS REMAINED PRECIP FREE FOR
THE DURATION. BOUNDARY SEPARATING DEW POINTS IN UPPER 60S TO NEAR
70S FROM DRIER AIR EXTENDS FROM SOUTH CENTRAL OK INTO WESTERN
OSAGE COUNTY AND NEAR THIS INTERFACE WITH LIGHT WINDS SOME FOG
DEVELOPMENT REMAINS POSSIBLE. WARM MOIST SECTOR OVER WESTERN OK
AND WESTERN AR REMAINS CAPPED AND SHORT RANGE GUIDANCE INCLUDING
THE 00Z NAM TRENDING TOWARD A DRIER SOLUTION FOR TONIGHT. WILL
KEEP SLIGHT CHANCE ACROSS FAR EASTERN/SOUTHERN AREAS AS A SUBTLE
WAVER MOVES ACROSS TONIGHT AND MAY HAVE JUST ENOUGH LIFT TO SPARK
A FEW SHOWERS LATE TONIGHT OR EARLY MON MORNING. UPDATED PRODUCTS
WILL BE OUT SHORTLY.
PREV DISCUSSION... /ISSUED 634 PM CDT SUN MAY 17 2015/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
SCATTERED TO BROKEN MID/HIGH CLOUDS WILL CONTINUE OVERNIGHT AS
WEAK UPPER DISTURBANCE TRAVERSES THE AREA. COULD SEE SOME
LIGHT FOG TOWARDS MORNING AS WINDS BECOME LIGHT AHEAD OF APPROACHING
FRONTAL BOUNDARY. OTHERWISE...VFR CONDITIONS EXPECTED THROUGH
THE FORECAST PERIOD.
PREV DISCUSSION... /ISSUED 359 PM CDT SUN MAY 17 2015/
DISCUSSION...
NEXT COUPLE OF DAYS MARGINAL CHANCE FOR SHOWERS
THUNDERSTORMS MAINLY SOUTH WHERE BETTER MOISTURE
RESIDES. WRF MODEL AN OUTLIER REGARDING PRECIP
AND POP SOUTHEAST AND NORTHWEST ARKANSAS. DRIER
SHORT TERM HRRR LOOKS GOOD TONIGHT.
NEXT BIG RAIN TUESDAY NIGHT WEDNESDAY WHEN THE
NEXT SHOT OF ENERGY EJECTED FROM THE SOUTHWEST.
CHANCE POPS THURSDAY INTO FRIDAY.
UPPER LOW OVER THE SOUTHWEST FRIDAY MOVES ACROSS
THE ROCKIES AND INTO THE CENTRAL PLAINS...SUNDAY.
ANOTHER SLUG WET WEATHER FOR THE HOLIDAY WEEKEND.
GW
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...12
AREA FORECAST DISCUSSION
NWS PORTLAND
249 PM PDT MON MAY 18 2015
.SYNOPSIS...ONSHORE FLOW RETURNS TONIGHT AND TUESDAY WITH PLENTY
OF CLOUDS AND SOMEWHAT COOLER TEMPERATURES. THIS SHOULD RESULT IN
GREATER STABILITY AND CONFINE THE THUNDERSTORM THREAT CLOSER TO THE
CASCADE CREST TUESDAY WITH POTENTIAL TO SPREAD A LITTLE WESTWARD
WEDNESDAY AND THURSDAY. TEMPERATURES SHOULD BE WITHIN A FEW DEGREES
OF NORMAL FOR THE REMAINDER OF THE WEEK.
&&
.SHORT TERM...TONIGHT THROUGH THURSDAY...DEEP CONVECTION AND
THUNDERSTORMS HAVE DEVELOPED OVER THE CASCADES ABOUT ON SCHEDULE.
THEY HAVE TAKEN ON A VERY SLIGHT WESTWARD DRIFT WHICH HAS ALLOWED
THE STORMS A BIT OF LONGEVITY. STRONGEST ACTION HAS BEEN AROUND
DETROIT WITH RADAR INDICATED RAIN RATES AS HIGH AS A COUPLE INCHES
PER HOUR. THERE HAS BEEN ADDITIONAL FORMATION AROUND AND NORTH OF MT
ST HELENS FORTUNATELY...THE WEAK MOVEMENT HAS LIMITED ACCUMULATIONS
TO 0.75 TO 1.00 INCHES OVER AN HOUR. THE NORTHERN END OF THE
CONVECTIVE LINE NEAR DETROIT HAS WEAKENED A BIT AS IT MOVED OVER THE
EASTERN BOUNDARY OF THE FOOTHILL ZONE. LATEST HRRR RUNS STILL
MAINTAIN A PRIMARY THREAT FOR THE STORMS TO CONTINUE OVER THE
CASCADES THIS EVENING BUT IT WILL BE INTERESTING TO SEE HOW LONG
THE VALLEY LASTS BEFORE STARTING CONVECTION. TEMPERATURES ONLY NEED
TO RISE 4 TO 5 DEGREES BEFORE POTENTIALLY BREAKING THE 12Z SLE
SOUNDING MID LEVEL CAP. STILL EXPECT STORMS WILL FORM...WHEREVER
THEY DO...THROUGH THE EARLY EVENING BEFORE WEAKENING CONSIDERABLY
WITH THE LOSS OF HEATING. THEN EXPECT SOME CONVECTIVE DEBRIS SHOWERS
TO LINGER WEST ACROSS THE VALLEY BEFORE DISSIPATING AND DRIFTING
INTO SOUTHWEST OREGON OVERNIGHT.
THE VERY BROAD UPPER TROUGH WILL MOVE LITTLE WITH FAIRLY NON-DESCRIPT
MID AND UPPER LEVEL FLOW PATTERNS REMAINING OVERHEAD MAKING TUESDAY
THROUGH THURSDAY LARGELY A BROKEN RECORD. TUESDAY WILL SEE A BIT OF
A COOL OFF FOR THE LOWER ELEVATIONS AS DEEPENING SURFACE LOW ACROSS
THE COLUMBIA BASIN WILL EVENTUALLY DRAW THE MARINE LAYER BACK IN
ACROSS THE LOWER ELEVATIONS. SEEMS UNLIKELY THE LAYER WILL BE
SUBSTANTIALLY DEEP AND SHOULD SEE SOME AFTERNOON/EVENING CONVECTION
ACROSS CASCADES ONCE AGAIN AND PROBABLY STAYING CLOSER TO THE CREST.
WILL GET A LITTLE WARMER WEDNESDAY AND THURSDAY WITH A LITTLE BIT OF
EASTERLY COMPONENT STORM MOTION TO AT LEAST BRING A THREAT OF THE
HIGH CASCADE STORMS DRIFTING WEST TOWARD THE FOOTHILLS. MAY SEE SOME
LIGHT SHOWER ACTIVITY OVER THE COAST RANGE AND VALLEY AS WELL. /JBONK
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY...PACIFIC NORTHWEST
REMAINS UNDER LONGWAVE TROUGHING THROUGH THE WEEKEND INTO EARLY NEXT
WEEK KEEPING WEATHER AND TEMPERATURES FAIRLY CONSISTENT. EXPECT
AFTERNOON/EVENING SHOWERS IN THE CASCADES FRIDAY AND SATURDAY.
FRIDAY MAY SEE SHOWERS SPILL WESTWARD INTO THE WILLAMETTE
VALLEY...BUT CONFIDENCE IS LOW. HIGH PRESSURE ATTEMPTS TO BUILD
ONSHORE SUNDAY...WHICH COULD PUSH MOST OF THE MOISTURE OFF TO THE
EAST...THOUGH AS MODELS CONTINUE TO TREND WEAKER WITH THIS RIDGE
SUNDAY IS LOOKING MORE LIKELY TO BE SIMILAR TO SATURDAY WITH SHOWERS
IN THE CASCADES. MONDAY WILL SEE A RETURN TO THE PATTERN FAVORABLE
FOR SHOWERS IN THE CASCADES. -MCCOY
&&
.AVIATION...SHOWERS AND THUNDERSTORMS ARE DEVELOPING OVER THE
CASCADES THIS AFTERNOON. THERE IS A CHANCE A FEW OF THESE THUNDERSTORMS
WILL DRIFT WESTWARD AND IMPACT A WILLAMETTE VALLEY TAF SITE OR TWO
LATER TODAY...MOST LIKELY BETWEEN 00Z AND 03Z TUESDAY. CONFIDENCE
IN WHICH SITES WILL BE IMPACTED REMAINS LOW SO WILL KEEP A VCSH IN
THE TAF FOR NOW.
OTHERWISE...INCREASING ONSHORE PRESSURE GRADIENTS THIS AFTERNOON
AND EVENING SHOULD RESULT IN MVFR STRATUS PUSHING BACK SOLIDLY
ONTO THE COAST AND INTO THE COASTAL GAPS OVERNIGHT. THERE IS A
GOOD CHANCE THESE LOWER FLIGHT CONDITIONS WILL IMPACT A FEW
INTERIOR TAF SITES AS WELL.
KPDX AND APPROACHES...SHOWERS AND THUNDERSTORMS ARE DEVELOPING
OVER THE CASCADES THIS AFTERNOON AND WILL LIKELY IMPACT EASTERN
APPROACHES. THERE IS A CHANCE A STORM COULD DRIFT WESTWARD AND
IMPACT THE TERMINAL...MOST LIKELY BETWEEN 00Z AND 03Z
TUESDAY...BUT CONFIDENCE IN THIS SCENARIO PANNING OUT REMAINS
LOW. MVFR CONDITIONS SHOULD RETURN TO THE TERMINAL BETWEEN 12Z AND
18Z TUESDAY. /NEUMAN
&&
.MARINE...SURFACE HIGH PRESSURE AND THERMAL LOW PRESSURE OVER THE
INLAND NORTHWEST WILL MAINTAIN RELATIVELY LIGHT NORTHWESTERLY
WINDS THROUGH THE UPCOMING WEEKEND.
VERY STRONG EBBS WILL LIKELY PRODUCE STEEP EBB CHOP THE NEXT
SEVERAL MORNINGS ON THE COLUMBIA RIVER BAR...BUT SEAS SHOULD
REMAIN SMALL ENOUGH THAT SMALL CRAFT ADVISORIES FOR ROUGH BARS DO
NOT APPEAR NECESSARY. /NEUMAN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS MEDFORD OR
207 PM PDT MON MAY 18 2015
.SHORT TERM...MOISTURE CONTINUES TO ROTATE IN OVER OUR AREA FROM
THE EAST AS AN UPPER LOW MOVES INTO THE GREAT BASIN. DYNAMICS ARE
WEAK, BUT THERE IS PLENTY OF INSTABILITY PRESENT FROM THE CASCADE
CREST AND SISKIYOUS EASTWARD, AND NUMEROUS SHOWERS AND ISOLATED
THUNDERSTORMS HAVE ALREADY DEVELOPED. THIS CONVECTION WILL
INCREASE IN COVERAGE AND MIGRATE TOWARD THE WEST THROUGH THE
AFTERNOON. CONVECTION IS ALREADY TRYING TO SPILL OVER ONTO THE
WEST SIDE, BUT IT IS BEING INHIBITED BY THE LITTLE REMAINING CAP.
THE SUN IS PEAKING THROUGH IN THE WEST SIDE VALLEYS AND THE
SURFACE HEATING WILL BREAK THE CAP PRETTY SOON. MESOANALYSIS
INDICATES WE`VE BUILT 500-1000 J/KG OF SURFACE BASED CAPE
OVER JACKSON AND JOSEPHINE COUNTIES ALREADY, WHICH SHOULD BE
RELEASED EVENTUALLY, AND RESULT IN SHOWERS AND THUNDERSTORMS THERE
AS WELL. LATEST RAP AND HRRR GUIDANCE ACTUALLY SHOWS QUITE A LOT
OF CONVECTION OVER THE ROGUE AND ILLINOIS VALLEYS LATER THIS
AFTERNOON. THEY MAY BE A BIT OVERDONE, BUT PEOPLE IN THESE AREAS
SHOULD KEEP AN EYE ON THE SKY. AS OPPOSED TO YESTERDAY, THE SUN IS
ALSO POKING OUT IN THE UMPQUA, AND THEY DO STAND A BETTER CHANCE
OF SEEING SOME THUNDERSTORMS THIS AFTERNOON AS WELL. THERE IS A
LOT OF MOISTURE IN THE PROFILE (PRECIPITABLE WATER IS NEAR AN
INCH) AND THUS ANY OF THESE STORMS WILL BE CAPABLE OF PRODUCING
SMALL HAIL AND HEAVY DOWNPOURS. WITH LITTLE WIND ALOFT TO SPEAK
OF, STRONG WINDS SHOULDN`T BE MUCH OF A CONCERN, BUT WE COULD SEE
GUSTY WINDS AROUND STORMS.
THINGS WILL STABILIZE TONIGHT AS THE BOUNDARY LAYER COOLS, BUT
SHOWERS ARE LIKELY TO CONTINUE OVERNIGHT ALONG THE MOUNTAINS AND
EAST SIDE. AS BROAD TROUGHING REMAINS OVER THE REGION, WE EXPECT
TO REPEAT THIS BASIC DIURNAL PATTERN OF NIGHT TIME SHOWERS AND
MORE WIDESPREAD SHOWERS AND THUNDERSTORMS IN THE AFTERNOONS
TOMORROW THROUGH THURSDAY. WE SHOULD GRADUALLY BECOME MORE STABLE
ON THE WEST SIDE, SO THUNDERSTORMS BECOME LESS OF AN ISSUE. ONE
BIGGER CHANGE I MADE WAS TO INCREASE POPS OVER THE WEST SIDE
TUESDAY NIGHT INTO WEDNESDAY MORNING AS ALL THE MODELS ARE SHOWING
A DEFORMATION BAND FORMING OVER THE AREA. -WRIGHT
.LONG TERM...THE MODELS SHOW THE WEAK UPPER LOW MOVING INTO
ARIZONA WITH WEAK RIDGING BUILDING OFFSHORE. THE GFS SHOWS MORE
RIDGING COMPARED TO THE EC AND BOTH CONTINUE TO SHOW QPF OVER MOST
OF THE AREA. I SUSPECT THE QPF MAY BE OVERDONE NOT ONLY WITH
AMOUNTS, BUT ALSO THE COVERAGE. THUS HAVE SCALED BACK ON POPS FOR
FRIDAY. ANOTHER WEAK UPPER LOW MOVES INTO THE AREA SATURDAY, BUT
THIS ONE WILL BE COMING IN FROM THE NORTHWEST AND IS NOT EXPECTED
TO HAVE ANY OVER WATER TRAJECTORY, THEREFORE MOISTURE WILL BE
LIMITED AND ANY SHOWERS SHOULD BE ISOLATED AND EAST OF THE
CASCADES. THE EC AND GFS DISAGREE WITH THE PROGRESSION OF THE
UPPER LOW SUNDAY AND THE UPSTREAM UPPER LOW. THE GFS KEEPS THE
UPPER LOW OVER THE AREA SUNDAY WHILE THE EC MOVES IT INTO NORTHERN
CAL. FOR NOW WE`LL GO WITH A BLEND BETWEEN THE TWO AND KEEP A
SLIGHT CHANCE OF SHOWERS EAST OF THE CASCADES. THE ENSEMBLE MEAN
SHOWS A LARGE SPREAD IN THIS TIME PERIOD WHICH YIELDS LOWER
CONFIDENCE IN THE FORECAST. -PETRUCELLI
&&
.AVIATION...FOR THE 18/18Z TAF CYCLE...THE MAIN CONCERN INTO THIS
EVENING WILL BE GUSTY AND ERRATIC WINDS NEAR THUNDERSTORMS. A FEW
STORMS COULD ALSO PRODUCE SMALL HAIL. VFR CIGS WILL BE THE DOMINATE
CONDITION INTO THIS EVENING FOR ALL TERMINALS, EXCEPT FOR TEMPORARY
MVFR CIGS WITH PARTIAL MOUNTAIN OBSCURATION AND REDUCED VISIBILITY
IN SHOWERS AND THUNDERSTORMS. THE ATMOSPHERE WILL STABILIZE TONIGHT
AND CIGS WILL LOWER TO MVFR, THEN IFR AT THE COAST. MODELS ALSO SHOW
PLENTY OF LOW LEVEL MOISTURE INLAND TONIGHT AND IT`S POSSIBLE MVFR
CIGS WILL ALSO DEVELOP FOR INLAND LOCATIONS BETWEEN 4-6Z WITH LOCAL
IFR CIGS IN THE UMPQUA BASIN LATE TONIGHT. -PETRUCELLI
&&
.MARINE...UPDATED 200 PM PDT, MONDAY 18 MAY 2015...A PATTERN OF
WEAK HIGH PRESSURE OFFSHORE AND WEAK LOW PRESSURE INLAND WILL
PERSIST MOST OF THIS WEEK WITH LIGHT TO MODERATE NORTH WINDS AND
NORTHWEST SWELL OVER THE WATERS. WINDS WILL APPROACH SMALL CRAFT
ADVISORY LEVELS ON TUESDAY EVENING AND WEDNESDAY MORNING SOUTH OF
CAPE BLANCO. AFTER THIS NORTH WINDS AROUND 10-20 KTS WILL CONTINUE
INTO THE WEEKEND. /CS
&&
.FIRE WEATHER...UPDATED 200 PM PDT, MONDAY 18 MAY 2015...AN UPPER
LOW CENTERED JUST EAST OF THE BAY AREA IS SENDING MOISTURE NORTHEAST
TOWARDS THE AREA. SO FAR ISOLATED STORMS HAVE BEEN CONFINED TO THE
CASCADES EAST, BUT THEY ARE EXPECTED TO BECOME MORE FREQUENT AS THE
AFTERNOON PROGRESSES INTO THIS EVENING. THE LATEST MESOSCALE ANALYSIS
SHOWS HIGHER CAPE VALUES WEST OF THE CASCADES COMPARED TO YESTERDAY
AND THE MOIST LAYER IS MUCH DEEPER ALL THE WAY UP TO 400 MB BASED IN
THIS MORNINGS SOUNDING. THE 700 MB FLOW WILL BE FROM THE EAST TO
NORTHEAST, THERE IS A BETTER CHANCE FOR SHOWERS AND ISOLATED STORMS
TO MAKE THEIR WAY WEST OF THE CASCADES. WITH PLENTY OF MOISTURE
AVAILABLE, THUNDERSTORMS ARE LIKELY TO BE RAIN PRODUCERS AND THEY
WILL BE SLOW MOVERS. SO HEAVY RAINFALL IS POSSIBLE.
THUNDERSTORMS WILL DECREASE THIS EVENING AND END TONIGHT, BUT WE`LL
CONTINUE TO GET MUCH NEEDED RAIN SHOWERS OVERNIGHT TONIGHT.
THE UPPER LOW WILL MOVE EAST AND WEAKEN TUESDAY WITH THE BEST CHANCE
FOR THUNDERSTORMS ALONG AND EAST OF THE CASCADES. THE ATMOSPHERE IS
EXPECTED TO BE MORE STABLE WEST OF THE CASCADES DUE TO A MARINE
INFLUENCE, SO WERE ONLY EXPECTING SHOWERS. -PETRUCELLI
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
AREA FORECAST DISCUSSION
NWS PORTLAND
942 AM PDT MON MAY 18 2015
.SYNOPSIS...BROAD BUT ILL-DEFINED UPPER LEVEL LOW PRESSURE WILL
REMAIN OVER MUCH OF THE WESTERN UNITED STATES THE NEXT SEVERAL
DAYS...KEEPING THE WEATHER UNSETTLED IN GENERAL ACROSS THE REGION.
WEAK HIGH PRESSURE OVER EASTERN WASHINGTON HAS WEAKENED ONSHORE FLOW
CONSIDERABLY. WITHOUT THE STRONG MARINE INFLUENCE...TEMPERATURES
WILL BE A FEW DEGREES WARMER INLAND THAN THE PAST FEW DAYS. THIS
WILL DESTABILIZE THE ATMOSPHERE TO THE POINT WHERE THUNDERSTORMS
COULD DEVELOP FROM THE COAST RANGE EASTWARD THIS AFTERNOON AND
EVENING. THE OVERALL AIR MASS IS RATHER MOIST AND STORMS WILL BE
SLOW MOVING...SO THE POTENTIAL IS THERE FOR LOCALLY HEAVY RAIN.
ONSHORE FLOW RETURNS IN FULL FORCE TONIGHT AND TUESDAY WITH PLENTY
OF CLOUDS AND A RETURN TO COOLER TEMPERATURES. THIS SHOULD RESULT IN
GREATER STABILITY AND CONFINE THE THUNDERSTORM THREAT TO AREAS ALONG
AND EAST OF THE CASCADE CREST FOR MUCH OF THE WEEK. AFTER
TODAY...TEMPERATURES SHOULD BE WITHIN A FEW DEGREES OF NORMAL FOR
THE REMAINDER OF THE WEEK.
&&
.UPDATE...SOME CHANGES TO THE FORECAST PACKAGE FOR TODAY AND
TONIGHT...BUT THE OVERALL MESSAGE WILL BE THE SAME. 12Z SALEM
SOUNDING SHOWED A LITTLE STRONGER MID LEVEL CAP WITH TEMPERATURES
FEW DEGREES WARMER THAN THE EARLIER MODEL RUNS INDICATED. LOOKS LIKE
THE 12Z NAM/GFS AND LAST COUPLE HRRR RUNS PICKED UP ON THIS AND HAVE
SOMEWHAT DIMINISHED THE THUNDER THREAT FROM THE WILLAMETTE
VALLEY/PORTLAND METRO AND AREAS WEST. FORECASTED HIGH TEMPS TODAY
WILL STILL BE AROUND THE CONVECTIVE TEMPS SO CONTINUE TO EXPECT A
THUNDERSTORM ALONG THE I-5 CORRIDOR AND WILL LIMIT COVERAGE TO
ISOLATED. THE CASCADES AND FOOTHILLS STILL APPEAR TO HAVE THE FAR
BETTER CHANCE OF SEEING SCATTERED COVERAGE WITH THE HIGHER TERRAIN
ACTING AS THE ELEVATED HEAT SOURCE. THAT WILL MAKE IT EASIER TO
BREAK THROUGH THAT CAP.
THE BIG UNKNOWN WILL BE THE AMOUNT OF STORM MOTION. MODELED STORM
MOTIONS FOR YESTERDAY PRODUCED NORTHERLY DRIFT OF AROUND 5 KTS WHICH
WAS JUST ENOUGH TO KEEP THE DOWNDRAFT AWAY FROM THE UPDRAFT AND GIVE
SOME LONGEVITY TO THE CELLS. MODELED STORM MOTIONS FOR TODAY BROADLY
SHOW ZERO MOVEMENT ACROSS THE AREA. MENTAL MODEL OF THIS PROVIDES
FOR MORE OF A PULSE STORM SITUATION WHERE STORMS MAY PUT OUR A BRIEF
HEAVY RAIN AND SEVERAL LIGHTNING STRIKES BUT THEN COLLAPSE AS THE
UPDRAFT IS CUT OFF BY THE DOWNDRAFT. ENVISION SOMETHING LIKE AN OLD
SCHOOL PINBALL MACHINE EFFECT WHERE COLLIDING OUTFLOW BOUNDARIES
CONVERGE TO PRODUCE A NEW UPDRAFT AS A TRIGGER FOR A NEW CELL.
THUNDERSTORM INITIATION TIMING STILL FAVORS EARLY AFTERNOON FOR THE
CASCADES AND FOOTHILLS WITH IT TAKING UNTIL MID TO LATE AFTERNOON
FOR THE I-5 CORRIDOR. GIVEN THIS WILL BE MORE OF AN AIR MASS
THUNDERSTORM DAY WHERE GROUND HEATING IS THE TRIGGER...FEEL MOST
DEEP CONVECTIVE ACTION SHOULD QUICKLY DIMINISH TOWARDS THE 7 TO 8 PM
HOURS WITH WEAKER NON-THUNDERSTORM SHOWERS CONTINUING TOWARD
MIDNIGHT. LINGERING CONVECTIVE DEBRIS SHOWERS MAY ULTIMATELY HANG ON
AFTER MIDNIGHT BUT MAINLY CLOSER TO LANE COUNTY.
UPDATES SHOULD BE AVAILABLE NOW. /JBONK
&&
.AVIATION...MARINE STRATUS IS CURRENTLY PRODUCING HIGH END IFR TO
LOW MVFR CONDITIONS ALONG THE COAST AND ALONG THE COLUMBIA RIVER.
EXPECT INTERIOR LOCATIONS TO TURN VFR BETWEEN 17Z AND 18Z TODAY.
CONFIDENCE IN TIMING STRATUS BREAKUP ALONG THE COAST IS
LOWER...BUT BASED ON SATELLITE AND MODEL GUIDANCE IT APPEARS VFR
CONDITIONS WILL BE LONGER LIVED AT KONP THAN KAST TODAY.
SHOWERS AND THUNDERSTORMS WILL LIKELY DEVELOP OVER THE CASCADES
THIS AFTERNOON. THERE IS A CHANCE A FEW THUNDERSTORMS WILL DRIFT
WESTWARD AND IMPACT A WILLAMETTE VALLEY TAF SITE OR TWO LATER
TODAY...MOST LIKELY BETWEEN 00Z AND 03Z TUESDAY...BUT LATEST MODEL
GUIDANCE HAS BACKED OFF ON THIS IDEA A BIT. AS A RESULT...CONFIDENCE
IN DETAILS REMAINS LOW AND WILL KEEP A VCSH IN THE TAFS FOR NOW.
OTHERWISE...HEALTHY ONSHORE FLOW THIS AFTERNOON AND EVENING SHOULD
RESULT IN MVFR STRATUS PUSHING BACK SOLIDLY ONTO THE COAST AND
INTO THE COASTAL GAPS OVERNIGHT. THERE IS A GOOD CHANCE THESE
LOWER FLIGHT CONDITIONS WILL IMPACT AT LEAST KPDX AND KTTD BY 15Z
TUESDAY.
KPDX AND APPROACHES...TEMPORARY LOW END MVFR CONDITIONS CURRENTLY
AT THE TERMINAL WILL END BETWEEN 17Z AND 18Z MONDAY. SHOWERS AND
THUNDERSTORMS WILL LIKELY DEVELOP OVER THE CASCADES LATER TODAY
AND COULD DRIFT WESTWARD AND IMPACT THE TERMINAL...MOST LIKELY
BETWEEN 00Z AND 03Z TUESDAY...BUT CONFIDENCE IN THIS SCENARIO
REMAINS LOW. MVFR CONDITIONS SHOULD RETURN TO THE TERMINAL BETWEEN
12Z AND 18Z TUESDAY AS MARINE STRATUS PUSHES UP THE COLUMBIA
RIVER. /NEUMAN
&&
.MARINE...SURFACE HIGH PRESSURE AND THERMAL LOW PRESSURE OVER THE
INLAND NORTHWEST WILL MAINTAIN RELATIVELY LIGHT NORTHWESTERLY
WINDS THROUGH THE UPCOMING WEEKEND. A WEAK UPPER LEVEL LOW
PRESSURE SYSTEM MAY TEMPORARILY SHIFT WINDS OUT OF THE
SOUTH OVER THE WEEKEND...BUT IMPACTS TO WIND SPEEDS APPEAR
NEGLIGIBLE.
VERY STRONG EBBS WILL LIKELY PRODUCE STEEP EBB CHOP THE NEXT
SEVERAL MORNINGS ON THE COLUMBIA RIVER BAR...BUT SEAS SHOULD
REMAIN SMALL ENOUGH THAT SMALL CRAFT ADVISORIES FOR ROUGH BARS DO
NOT APPEAR NECESSARY. /NEUMAN
&&
.PREV DISCUSSION... /ISSUED 307 AM PDT MON MAY 18 2015/
SHORT TERM...TODAY THROUGH WEDNESDAY...AS ADVERTISED FOR SEVERAL
DAYS NOW...TODAY CONTINUES TO BE THE BEST THREAT IN QUITE SOME TIME
FOR SEVERAL NON-SEVERE THUNDERSTORMS TO DEVELOP COAST RANGE EASTWARD.
MAIN THREAT FROM THESE STORMS WILL BE LOCALLY HEAVY RAIN AND POSSIBLY
SMALL HAIL. SOME HIGHLY LOCALIZED AND BRIEF URBAN AND SMALL STREAM
FLOODING ISSUES ARE POSSIBLE IF ANY OF THESE STORMS DEVELOP OVER POOR
DRAINAGE AREAS...ESPECIALLY IF THEY MOVE THROUGH THE DENSER URBAN
AREAS. TODAY WILL BE AN INTERESTING DAY TO WATCH THE RADAR ACROSS
WESTERN OREGON...AND POSSIBLY SOUTHWEST WASHINGTON.
THE INGREDIENTS COMING TOGETHER TODAY TO SUPPORT DEEP CONVECTION AND
THUNDERSTORMS...1. WEAK HIGH PRESSURE OVER EASTERN WASHINGTON HAS
WEAKENED ONSHORE FLOW ACROSS THE FORECAST AREA...LIMITING THE
STABILIZING MARINE INFLUENCE TO MAINLY THE COASTAL AREAS. THIS WILL
CAUSE INLAND TEMPS TO WARM THROUGH THE 70S...POSSIBLY EVEN UPPER 70S
IN THE PORTLAND METRO AREA. 2. SKIES HAVE GENERALLY CLEARED ACROSS
THE FORECAST AREA ASIDE FROM SOME THIN HIGH CLOUDS. THIS SHOULD
REMAIN THE CASE FOR THE FIRST HALF OF THE DAY. THIS WILL ALSO HELP
SFC TEMPS REACH THE CONVECTIVE TEMPS INDICATED ON MODEL SOUNDINGS
COAST RANGE EASTWARD. 3. NAM/GFS BUFR SOUNDINGS AGREE THAT THERE WILL
BE LITTLE TO NO CAP IN THE ATMOSPHERE UP TO THE TROPOPAUSE. IF
SURFACE TEMPS CAN REACH THE CONVECTIVE TEMP OF AROUND 75 DEG F...
THERE IS LITTLE TO STOP PARCELS FROM REACHING THE TROPOPAUSE. DEEP
BUT FAIRLY SKINNY SBCAPE ON THE ORDER OF 750-1500 J/KG IS BEING SHOWN
UP AND DOWN THE WILLAMETTE VALLEY AND CASCADES THIS AFTERNOON WITH
LIFTED INDICES OF -1 TO -4 DEG C. AS A RESULT...EQUILIBRIUM LEVELS
ARE 30-35 KFT...PLENTY DEEP FOR CHARGE SEPARATION AND LIGHTNING TO
DEVELOP.
AS USUAL FOR OUR AREA...THERE ARE AT LEAST A COUPLE CONS FOR THUNDER
TODAY...AT LEAST FOR AREAS WILLAMETTE VALLEY EASTWARD... 1. MODELS
ARE ALREADY OVERESTIMATING THE SFC DEWPOINTS...FORECASTING LOWER 50S
THIS MORNING WHILE DEWPOINTS ARE ACTUALLY IN THE MID TO UPPER 40S. IF
THIS TREND HOLDS...MODEL CAPE/LI VALUES WILL LIKELY BE EXAGGERATED.
2. LITTLE TO NO SHEAR. UPDRAFTS MAY QUICKLY BE OVERWHELMED BY
DOWNDRAFTS...POSSIBLY BEFORE THUNDERSTORMS CAN MATURE. 3. WEAK
FORCING. WITH LITTLE FLOW IN OUR VERY BROAD UPPER LEVEL
LOW...VORTICITY IS HARD TO COME BY. EXPECT VERY LITTLE HELP FROM ANY
SYNOPTIC FEATURES TODAY...DESPITE A WEAK SHORTWAVE DRIFTING WEST
ACROSS THE SOUTHERN PORTION OF OUR CWA.
GIVEN THE CONVECTION WHICH DEVELOPED IN THE CASCADES SUNDAY IN A LESS
FAVORABLE ENVIRONMENT...CONFIDENCE IS HIGHER THAN USUAL THAT
SCATTERED THUNDERSTORMS WILL DEVELOP ALONG THE CASCADES TODAY. THE
SAME ENVIRONMENT FAVORING THUNDER IN THE CASCADES TODAY SHOULD
SUPPORT SCATTERED THUNDERSTORMS POPPING OFF IN THE WILLAMETTE VALLEY
BY MID-AFTERNOON...ASSUMING DEBRIS FROM THE EARLIER CASCADE
THUNDERSTORMS DO NOT LIMIT SFC HEATING TOO MUCH. ADDITIONALLY SPC
SREF CALIBRATED THUNDERSTORM PROBABILITY IS 50-60 PCT ACROSS PORTIONS
OF OUR INTERIOR LOWLANDS...THE HIGHEST I HAVE SEEN IT. THEREFORE WE
ADDED SCATTERED THUNDERSTORM WORDING TO ALL AREAS COAST RANGE
EASTWARD.
GIVEN THE WEAK SHEAR ENVIRONMENT...IT IS DOUBTFUL ANY THUNDERSTORMS
WILL REACH SEVERE LIMITS. MOST CELLS SHOULD BE PULSE-LIKE...ONLY
LASTING FOR A SHORT PERIOD OF TIME WITH LITTLE ORGANIZATION. HOWEVER
WITH PRECIPITABLE WATER VALUES APPROACHING 1 INCH AND VERY WEAK
STEERING FLOW...THERE IS THE POTENTIAL FOR RAINFALL HEAVY ENOUGH TO
CAUSE BRIEF AND LOCALIZED URBAN/SMALL STREAM FLOODING ISSUES. SOME
LOCATIONS WILL RECEIVE NO RAIN AT ALL...WHILE SOME MAY SEE UPWARDS OF
A HALF INCH OF RAIN IN A VERY SHORT PERIOD OF TIME. HIGHLIGHTED THIS
THREAT IN THE GRIDS AND WILL ISSUE A SPECIAL WEATHER STATEMENT
MENTIONING THIS POSSIBILITY FOR THE AFTERNOON/EVENING COMMUTE.
MEANWHILE SEMI-THERMALLY INDUCED LOW PRESSURE WILL DEVELOP OVER THE
COLUMBIA BASIN THIS AFTERNOON...INCREASING THE ONSHORE COMPONENT OF
THE LOW LEVEL FLOW. THIS SHOULD CAUSE A SURGE OF MARINE AIR TONIGHT
WHICH WILL CUT OFF THE THUNDERSTORM THREAT AND YIELD A MOSTLY
CLOUDY...COOLER DAY TUESDAY. TUESDAY HAS SOME POTENTIAL TO BE A LOT
LIKE LAST FRI/SAT...SO DECIDED TO UNDERCUT MOS GUIDANCE BY A FEW
DEGREES FOR HIGH TEMPS. THE STABLE MARINE AIR WILL LIKELY CONFINE ANY
THUNDERSTORMS TO AREAS ALONG AND EAST OF THE CASCADE CREST.
WEDNESDAY IS A BIT OF A TOUGH TEMPERATURE FORECAST AS MODELS SHOW
GOOD AGREEMENT ON HIGHS ONCE AGAIN REACHING THE MID-UPPER 70S FOR THE
INLAND VALLEYS DESPITE CONTINUED ONSHORE PRESSURE GRADIENTS. THE
MARINE LAYER APPEARS A BIT SHALLOWER THAN IT WAS FRI/SAT...SO THERE
IS BETTER CHANCE OF IT MIXING OUT FOR THE AFTERNOON. NONETHELESS WE
DECIDED TO KEEP FCST TEMPS ON THE LOW SIDE OF GUIDANCE FOR WEDNESDAY.
THE SHALLOWER MARINE LAYER MAY LEAD TO A BETTER CHANCE OF THUNDER IN
THE CASCADES WED AFTN/EVE...ESPECIALLY WITH SOME MODELS SUGGESTING
ANOTHER WEAK SHORTWAVE PIVOTING WESTWARD ACROSS OREGON AT THAT TIME.
WEAGLE
LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
WEDNESDAY NIGHT THROUGH SUNDAY...BROAD UPPER-LEVEL TROUGHING REMAINS
IN PLACE THROUGH THE END OF WEEK...WITH SHORTWAVES BRINGING CHANCES
OF RAIN THURSDAY AND FRIDAY AND MAYBE SOME THUNDERSTORMS IN THE
CASCADES. RIDGING SHOWN YESTERDAY IN MODELS FOR THE WEEKEND IS
LOOKING WEAKER...AND LIKELY WON`T PULL US OUT OF THE OVERALL LONGWAVE
TROUGH PATTERN. THAT SAID...WITH WEAK HIGH PRESSURE OVER THE REGION
SATURDAY AND SUNDAY WEATHER COULD DRY OUT FOR THE WEEKEND WITH MOSTLY
SUNNY SKIES. CONFIDENCE IS STILL LOW AS OF NOW DUE TO HOW FAR OUT IN
THE FORECAST PERIOD THIS IS AS WELL AS THE WEAKENING TREND IN THE
MODELS. -MCCOY
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
657 PM EDT MON MAY 18 2015
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE AREA TONIGHT AND EARLY
TUESDAY...PRECEDED BY SHOWERS AND THUNDERSTORMS. THE FRONT WILL
USHER IN A COOL...DRY AIRMASS FOR THE MIDDLE OF THE WEEK.
MUGGINESS WILL RETURN OVER THE HOLIDAY WEEKEND.
&&
.NEAR TERM /UNTIL 1 AM TUESDAY MORNING/...
VERY HIGH PWAT AIR SITTING OVER THE AREA. CAPE HAS BEEN SOMEWHAT
LIMITED UNTIL THE LAST 30 TO 60 MINUTES. THE CAP IS BROKEN AND TC
HAS BEEN PASSED. SHOWERS AND THUNDERSTORMS HAVE GROWN OVER ALMOST
ALL OF THE CWA WITH LITTLE TO NO PATTERN OR ORGANIZATION. THERE
HAS BEEN ONE BACK-BUILDING STORM IN SRN LANC CO. BUT THE HIGH
MOISTURE WILL TIELD SOME VERY HIGH RAIN RATES. WILL NEED TO KEEP
AN EYE ON AREAS WHICH RECEIVE MULTIPLE STORMS/BACKBUILD. THESE
SHOWERS WILL CONTINUE INTO THE EVENING. LATEST NAM RUN PUSHES
MOST OF THE RAIN OFF TO THE EAST OF THE SUSQ RIVER SHORTLY AFTER
1 AM.
&&
.SHORT TERM /1 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
THE FIRST NUDGE OF DRY AIR COMES IN UNDER A SHORT WAVE CURRENTLY
OVER KCVG. THIS SHOULD EFFECTIVELY END MOST OF THE SHOWERS. BUT
THE REAL COLD/DRY AIR DOES NOT ARRIVE IN THE WEST UNTIL CLOSE TO
SUNRISE TUES. THUS...A SLIGHT CHC OF A SHOWER WILL BE MENTIONED
FOR MUCH OF THE AREA OVERNIGHT - ESP IN THE EAST. DEWPOINTS DROP
THROUGH THE DAY IN THE NW HALF OF THE AREA...BUT THE SE COULD STAY
MUGGY AND THE SKY SHOULD BREAK UP LATER TONIGHT. SO SUNSHINE WILL
HEAT UP THE ERN VALLEYS. A STORM OR TWO WILL PROBABLY POP UP IN
THE HEATING OF THE DAY THERE...BUT ARRIVAL OF THE DRY AIR WILL
MAKE IT DIFFICULT TO ALLOW ANYTHING TO GROW ENOUGH IN THE WEST TO
PRECIPITATE. FOG AND LOW CLOUDS ARE AGAIN EXPECTED OVER MOST/ALL
OF THE AREA. PERHAPS ONLY THE PLACES WHICH CAN KEEP WIND OVER
5-6KTS THROUGH THE NIGHT - MAINLY HIGHER ELEVS IN THE WEST - CAN
STAY AWAY FROM BAD VISBYS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
AREA OF SHOWERS/TSTMS WILL BE DEPARTING LATE TUE/EARLY TUE
EVE...ASSOCIATED WITH A COLD FRONT CLEARING THE REGION.
IN IT/S WAKE...RESPECTABLE ANTICYCLONE WILL BUILD IN FROM THE WEST
WITH A PUSH OF NOTICEABLY COOLER AND DRIER AIR FILTERING IN FOR
MIDWEEK. A WEAK WAVE EJECTS EASTWARD FROM THE S PLAINS TOWARD THE
CAROLINA/S ON THU...WHILE TROUGH CONTINUES TO SPIN OVER EASTERN
CANADA. CENTRAL PA REMAINS BETWEEN THESE TWO FEATURES...WHICH WILL
KEEP US DRY. EVEN WITH NW FLOW...DAYTIME TEMPS WILL REBOUND A BIT
WARMER EACH DAY. BUT DIURNAL TEMP RANGES WILL BE FAIRLY LARGE
THANKS TO THE DRIER AIRMASS...WHICH WILL BRING CHILLY MORNINGS.
THE COLDEST CONTINUES TO LOOK LIKE THURSDAY MORNING WHERE THERE
REMAINS A RISK FOR PATCHY FROST...MAINLY OVER THE NORTH-CENTRAL
ZONES WHERE GUIDANCE IS SHOWING POSS FOR MID 30S AOA BFD /JUST IN
TIME FOR THE START OF THE GROWING SEASON/.
THE WEAK LOW OVER CAROLINAS/MID ATLANTIC REGION SLIDES OFFSHORE
FRI...WITH SPRAWLING HIGH PRESSURE AREA BUILDING IN FOR SAT/SUN.
ONCE RIDGE AXIS SLIDES BY SAT NIGHT...HUMIDITY WILL BEGIN TO
INCREASE ON SUNDAY WITH RISING TEMPS /AND ISOLATED CONVECTION
POSS/. EVEN WARMER AND MUGGIER ON MEMORIAL DAY...WITH SCATTERED TO
EVEN NUMEROUS SHOWERS/TSTMS IN THE FORECAST.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
SCT SHRA/TSRA WILL CONTINUE TO FORM ACROSS CENTRAL PA THIS EVENING
IN UNSTABLE AIR MASS AHEAD OF APPROACHING COLD FRONT OVR THE
MIDWEST. ANY OF THESE SHRA/TSRA COULD PRODUCE BRIEF VIS
REDUCTIONS. HOWEVER...THE MAIN AVIATION CONCERN THIS EVENING WILL
BE THE DEVELOPING LOW CIGS ACROSS EASTERN PA...THE RESULT OF
MARINE AIR FLOWING OFF THE ATLANTIC OCEAN. LOWER CIGS ALREADY
NOTED ACROSS NJ AT 22Z AND NEAR TERM MDL DATA SUPPORT IFR CIGS
MOVING INTO KLNS/KMDT BTWN 00Z-02Z. THE IFR MARINE STRATUS DECK
COULD WORK AS FAR WEST AS KIPT OVERNIGHT. FURTHER WEST...EXPECT
IFR CIGS TO DEVELOP AFTER 06Z AT KBFD/KJST...WHERE A PLUME OF
MOISTURE AHEAD OF COLD FRONT WILL ASCEND THE ALLEGHENY
MTNS...PRODUCING THE LOW CIGS. BOTH SREF AND LATEST HRRR SUPPORT
THIS SCENARIO. MOST FAVORABLE CONDS SHOULD BE AT KAOO/KUNV
OVERNIGHT...WHERE SIG REDUCTIONS APPEAR UNLIKELY.
LOW CIGS ACROSS THE W MTNS AND EASTERN PA SHOULD LIFT BY LATE AM.
CAN/T RULE OUT AN ISOLD SHRA/TSRA ACROSS EASTERN PA ARND MIDDAY
WITH PASSAGE OF COLD FRONT. OTHERWISE...EXPECT A RETURN TO
WIDESPREAD VFR CONDS...AS A MUCH DRIER WEST WIND FLOWS IN BEHIND
THE COLD FRONT.
OUTLOOK...
WED-SAT...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...RXR
AVIATION...DANGELO/FITZGERALD
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
118 PM CDT MON MAY 18 2015
.UPDATE...
UPDATED FOR 18Z AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 1100 AM CDT MON MAY 18 2015/
DISCUSSION...
THE MCS THAT MOVED THROUGH OVERNIGHT HAS STABILIZED MUCH OF
THE MIDSOUTH AND THE MAIN FOCUS FOR HEAVY RAIN HAS SHIFTED SOUTH
OF THE AREA. LATEST HRRR INDICATES THAT SCT REDEVELOPMENT WILL
OCCUR THIS AFTERNOON AS AIRMASS TRIES TO DESTABILIZE AGAIN DUE TO
SURFACE HEATING BUT COVERAGE WILL BE LIMITED AND THE WIDESPREAD
HEAVY RAIN THREAT HAS DIMINISHED. AS A RESULT DECIDED TO CANCEL
FLASH FLOOD WATCH EARLY.
SJM
PREV DISCUSSION... /ISSUED 422 AM CDT MON MAY 18 2015/
A WEAKENING MESOSCALE CONVECTIVE SYSTEM (MCS) WAS LOCATED ALONG
THE TN RIVER OF WEST TN INTO NORTHEAST MS EARLY THIS MORNING. THE
MCS WAS PUSHING TO THE NORTHEAST. ANOTHER MCS WAS STRENGTHENING
OVER NORTH LA AND LOOKS LIKE IT MIGHT SKIRT SOUTHERN PORTIONS OF
NORTH MS WITH THE POSSIBILITY OF VERY HEAVY RAINFALL. WITH THE
HEAVIER STORMS EARLIER TONIGHT ACROSS NORTH MS...VERY HEAVY
RAINFALL WAS INDICATED IN SOME SPOTS...IN EXCESS OF 2 INCHES PLUS
PER HOUR AS SHOWN BY DUAL POL RADAR. WILL KEEP THE FLASH FLOOD
WATCH GOING FOR TODAY. LATEST MODELS DID COME IN WITH POPS A
LITTLE LOWER FOR TODAY ESPECIALLY ACROSS AREAS TO THE NORTHWEST
INCLUDING NORTHEAST AR AND THE MO BOOTHEEL. ALSO...MODELS ARE
SHOWING PRECIPITABLE WATER VALUES DECREASING SLIGHTLY FROM THE
NORTHWEST DURING THE DAY. NEVERTHELESS...A COLD FRONT WILL
APPROACH THE REGION FROM THE NORTH TODAY MOVING INTO NORTHEAST AR
LATE THIS AFTERNOON OR EARLY EVENING. INSTABILITY WILL INCREASE
ACROSS THE AREA ALLOWING FOR SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS TO DEVELOP AHEAD OF THE FRONT. PRECIPITABLE WATER
VALUES WILL BE BETWEEN 1.5 AND 2.1 INCHES ACROSS MOST OF THE AREA.
WITH STORMS BEING VERY EFFICIENT RAIN PRODUCERS...THINK LOCALLY
HEAVY RAINFALL COULD STILL BE A PROBLEM LEADING TO FLASH FLOODING.
ALSO... THINK INSTABILITY WILL BE SUFFICIENT TO SUPPORT A FEW
STRONG THUNDERSTORMS WITH STRONG GUSTY WINDS AND SMALL HAIL.
THE COLD FRONT IS FORECAST TO MOVE THROUGH THE MIDSOUTH TONIGHT AND
TUESDAY...ALTHOUGH THE NAM AND ECWMF ARE SLOWER WITH THE PASSAGE OF
THE FRONT THAN THE GFS. THINK THE CHANCE OF SHOWERS AND
THUNDERSTORMS TUESDAY WILL BE MAINLY ACROSS EAST CENTRAL AR INTO
PORTIONS OF NORTH MS. DRIER AND A LITTLE COOLER AIR WILL SPREAD INTO
THE REGION NORTH OF THE FRONT. THUS MUCH OF THE REGION WILL HAVE A
VERY NICE SPRING DAY TUESDAY.
FOR TUESDAY NIGHT INTO THURSDAY...FOLLOWED THE ECMWF / NAM SOLUTION
VERSUS THE GFS. THE ECMWF AND NAM INDICATE THAT THE FRONTAL SYSTEM
WILL PUSH BACK TO NORTH TUESDAY NIGHT WITH THE MIDSOUTH ONCE AGAIN IN
THE WARM SECTOR WEDNESDAY. SURFACE HIGH PRESSURE WILL THEN PUSH THE
FRONT BACK THROUGH THE REGION WEDNESDAY NIGHT AS A COLD FRONT. THIS
WOULD RESULT IN ANOTHER THREAT OF HEAVY RAINFALL AND POSSIBLY A FEW
STRONG TO SEVERE THUNDERSTORMS WEDNESDAY. HOWEVER...CONFIDENCE IS
LOW AND DID NOT MENTION IN THE HAZARDOUS WEATHER OUTLOOK WITH THE
GFS KEEPING THE FRONTAL SYSTEM MORE TO OUR SOUTH AND MOST OF OUR
FORECAST AREA NOT GETTING BACK INTO THE WARM SECTOR.
MODELS DO AGREE THAT DURING THE DAY THURSDAY DRIER AND A LITTLE
COOLER AIR WILL SPREAD IN FROM THE NORTH ENCOMPASSING THE ENTIRE AREA
BY THURSDAY NIGHT. PLEASANT AND DRY SPRING WEATHER WILL OCCUR FRIDAY
AND FOR MOST OF THE AREA SATURDAY. ANOTHER LARGE SCALE UPPER LEVEL
TROUGH WILL APPROACH FROM THE WEST BY THE LATTER HALF OF THE WEEKEND
BRINGING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS...BUT ONCE AGAIN
AS OBSERVED MUCH OF THIS SPRING...THE TROUGH IS FORECAST TO LIFT TO
THE NORTHEAST AS STRONG UPPER LEVEL HIGH PRESSURE IS LOCATED ALONG
THE SOUTHEASTERN UNITED STATES COAST.
JCL
.AVIATION...
18Z TAFS
VFR..MVFR...AND POSSIBLY IFR CONDITIONS ARE EXPECTED THROUGHOUT
THE 24 HR TAF CYCLE. SCATTERED SHOWERS AND THUNDERSTORMS HAVE
STARTED TO FORM NEAR ALL FOUR TAF SITES THIS AFTERNOON. COVERAGE
WILL CONTINUE TO INCREASE THROUGHOUT THE EVENING AND THUNDERSTORMS
COULD DEVELOP AS THE ATMOSPHERE CONTINUES TO DESTABILIZE...
HOWEVER WE WILL NOT SEE COVERAGE LIKE YESTERDAY. CIGS WILL REMAIN
MVFR AND VFR THIS AFTERNOON BEFORE LIFTING AND CLEARING TO VFR
LEVELS OVERNIGHT AT ALL SITES EXCEPT KTUP. FROPA WILL CAUSE WINDS
TO SHIFT TO THE NORTH AROUND MIDNIGHT FOR KJBR...KMEM...AND KMKL.
IFR CONDITIONS WILL BE POSSIBLE AT KTUP OVERNIGHT AND TOMORROW
MORNING.
JPM3
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1100 AM CDT MON MAY 18 2015
.DISCUSSION...
THE MCS THAT MOVED THROUGH OVERNIGHT HAS STABILIZED MUCH OF
THE MIDSOUTH AND THE MAIN FOCUS FOR HEAVY RAIN HAS SHIFTED SOUTH
OF THE AREA. LATEST HRRR INDICATES THAT SCT REDEVELOPMENT WILL
OCCUR THIS AFTERNOON AS AIRMASS TRIES TO DESTABILIZE AGAIN DUE TO
SURFACE HEATING BUT COVERAGE WILL BE LIMITED AND THE WIDESPREAD
HEAVY RAIN THREAT HAS DIMINISHED. AS A RESULT DECIDED TO CANCEL
FLASH FLOOD WATCH EARLY.
SJM
&&
PREV DISCUSSION... /ISSUED 422 AM CDT MON MAY 18 2015/
A WEAKENING MESOSCALE CONVECTIVE SYSTEM (MCS) WAS LOCATED ALONG
THE TN RIVER OF WEST TN INTO NORTHEAST MS EARLY THIS MORNING. THE
MCS WAS PUSHING TO THE NORTHEAST. ANOTHER MCS WAS STRENGTHENING
OVER NORTH LA AND LOOKS LIKE IT MIGHT SKIRT SOUTHERN PORTIONS OF
NORTH MS WITH THE POSSIBILITY OF VERY HEAVY RAINFALL. WITH THE
HEAVIER STORMS EARLIER TONIGHT ACROSS NORTH MS...VERY HEAVY
RAINFALL WAS INDICATED IN SOME SPOTS...IN EXCESS OF 2 INCHES PLUS
PER HOUR AS SHOWN BY DUAL POL RADAR. WILL KEEP THE FLASH FLOOD
WATCH GOING FOR TODAY. LATEST MODELS DID COME IN WITH POPS A
LITTLE LOWER FOR TODAY ESPECIALLY ACROSS AREAS TO THE NORTHWEST
INCLUDING NORTHEAST AR AND THE MO BOOTHEEL. ALSO...MODELS ARE
SHOWING PRECIPITABLE WATER VALUES DECREASING SLIGHTLY FROM THE
NORTHWEST DURING THE DAY. NEVERTHELESS...A COLD FRONT WILL
APPROACH THE REGION FROM THE NORTH TODAY MOVING INTO NORTHEAST AR
LATE THIS AFTERNOON OR EARLY EVENING. INSTABILITY WILL INCREASE
ACROSS THE AREA ALLOWING FOR SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS TO DEVELOP AHEAD OF THE FRONT. PRECIPITABLE WATER
VALUES WILL BE BETWEEN 1.5 AND 2.1 INCHES ACROSS MOST OF THE AREA.
WITH STORMS BEING VERY EFFICIENT RAIN PRODUCERS...THINK LOCALLY
HEAVY RAINFALL COULD STILL BE A PROBLEM LEADING TO FLASH FLOODING.
ALSO... THINK INSTABILITY WILL BE SUFFICIENT TO SUPPORT A FEW
STRONG THUNDERSTORMS WITH STRONG GUSTY WINDS AND SMALL HAIL.
THE COLD FRONT IS FORECAST TO MOVE THROUGH THE MIDSOUTH TONIGHT AND
TUESDAY...ALTHOUGH THE NAM AND ECWMF ARE SLOWER WITH THE PASSAGE OF
THE FRONT THAN THE GFS. THINK THE CHANCE OF SHOWERS AND
THUNDERSTORMS TUESDAY WILL BE MAINLY ACROSS EAST CENTRAL AR INTO
PORTIONS OF NORTH MS. DRIER AND A LITTLE COOLER AIR WILL SPREAD INTO
THE REGION NORTH OF THE FRONT. THUS MUCH OF THE REGION WILL HAVE A
VERY NICE SPRING DAY TUESDAY.
FOR TUESDAY NIGHT INTO THURSDAY...FOLLOWED THE ECMWF / NAM SOLUTION
VERSUS THE GFS. THE ECMWF AND NAM INDICATE THAT THE FRONTAL SYSTEM
WILL PUSH BACK TO NORTH TUESDAY NIGHT WITH THE MIDSOUTH ONCE AGAIN IN
THE WARM SECTOR WEDNESDAY. SURFACE HIGH PRESSURE WILL THEN PUSH THE
FRONT BACK THROUGH THE REGION WEDNESDAY NIGHT AS A COLD FRONT. THIS
WOULD RESULT IN ANOTHER THREAT OF HEAVY RAINFALL AND POSSIBLY A FEW
STRONG TO SEVERE THUNDERSTORMS WEDNESDAY. HOWEVER...CONFIDENCE IS
LOW AND DID NOT MENTION IN THE HAZARDOUS WEATHER OUTLOOK WITH THE
GFS KEEPING THE FRONTAL SYSTEM MORE TO OUR SOUTH AND MOST OF OUR
FORECAST AREA NOT GETTING BACK INTO THE WARM SECTOR.
MODELS DO AGREE THAT DURING THE DAY THURSDAY DRIER AND A LITTLE
COOLER AIR WILL SPREAD IN FROM THE NORTH ENCOMPASSING THE ENTIRE AREA
BY THURSDAY NIGHT. PLEASANT AND DRY SPRING WEATHER WILL OCCUR FRIDAY
AND FOR MOST OF THE AREA SATURDAY. ANOTHER LARGE SCALE UPPER LEVEL
TROUGH WILL APPROACH FROM THE WEST BY THE LATTER HALF OF THE WEEKEND
BRINGING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS...BUT ONCE AGAIN
AS OBSERVED MUCH OF THIS SPRING...THE TROUGH IS FORECAST TO LIFT TO
THE NORTHEAST AS STRONG UPPER LEVEL HIGH PRESSURE IS LOCATED ALONG
THE SOUTHEASTERN UNITED STATES COAST.
JCL
&&
.AVIATION...
12Z TAFS
WIDESPREAD LIGHT RAINFALL WITH A FEW EMBEDDED LIGHTNING STRIKES
THIS MORNING ACROSS MOST TERMINALS EXCEPT JBR...WHICH HAS MANAGED
TO CLEAR. SIMILAR TO THE PAST FEW DAYS...SHOWERS AND
THUNDERSTORMS ARE FORECAST TO REDEVELOP TOWARD 17Z ACROSS ALL
TERMINALS. COVERAGE OF STORMS SHOULD BE LESS TODAY AND THERE IS A
LITTLE MORE UNCERTAINTY IN THAT ASPECT...BUT VCTS IS IN THE
FORECAST AT ALL TERMINALS TO ACCOUNT FOR THIS AS OF NOW. CLOUD
COVER SHOULD ALSO BE ABUNDANT TODAY...WITH A PERSISTENT BKN TO
OVC DECK. A FRONTAL BOUNDARY SHOULD BRING AN END TO THE PRECIP
LATE THIS AFTERNOON WITH CIGS LIFTING AFTER 00Z. THE EXCEPTION TO
THIS WILL BE TUP WHERE GUIDANCE IS AGGRESSIVE ON DEVELOPING AN
IFR DECK AFTER 06Z. DID NOT BRING CIGS DOWN THAT LOW YET BUT
TRENDED DOWNWARD...SO THIS WILL NEED TO BE WATCHED.
WINDS SHOULD MAINLY BE SOUTH-SOUTHWESTERLY AROUND 10 MPH THROUGH
THE DAY.
TVT
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1123 PM CDT SUN MAY 17 2015
.UPDATE...
&&
.PREV DISCUSSION... /ISSUED 856 PM CDT SUN MAY 17 2015/
DISCUSSION...WATER VAPOR SATELLITE/WSR-88D VAD WIND PROFILES
INDICATE A MESOSCALE CONVECTIVE VORTEX /MCV/ OVER LOUISIANA. THIS
MCV ALONG WITH A SUBTLE 700 MB SHORTWAVE TROUGH OVER THE LOWER
MISSISSIPPI HAD RESULTED IN ADDITIONAL SHOWERS AND THUNDERSTORMS
DEVELOPING ACROSS THE MID SOUTH THIS EVENING...MAINLY WEST OF THE
MISSISSIPPI RIVER. AS OF 8 PM CDT...TEMPERATURES ACROSS THE
MID SOUTH ARE IN THE LOWER 70S AT MOST LOCATIONS.
LATEST HRRR ALONG WITH THE 00Z WRF INDICATE POTENTIAL FOR RE-
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS THE MID SOUTH
OVERNIGHT. WILL MAKE SOME ADJUSTMENTS TO POPS AND ALL OTHER
ELEMENTS AS NEEDED FOR THE REMAINDER OF THE NIGHT.
UPDATED GRIDS WILL BE AVAILABLE SHORTLY.
CJC
PREV DISCUSSION... /ISSUED 639 PM CDT SUN MAY 17 2015/
UPDATE...AVIATION DISCUSSION.
PREV DISCUSSION... /ISSUED 304 PM CDT SUN MAY 17 2015/
THE MIDSOUTH REMAINS STUCK UNDERNEATH SOUTHWEST FLOW ALOFT. THE
SOUTHWEST FLOW ALOFT HAS BROUGHT THIS WET PATTERN TO THE REGION AS
THE COMBINATION OF SHORTWAVES MOVING THROUGH THE FLOW AND AN
ABUNDANCE OF MOISTURE FROM THE GULF OF MEXICO HAS PRODUCED ROUND
AFTER ROUND OF SHOWERS AND THUNDERSTORMS.
LOOKING AT LATEST RADAR IMAGES...MOST OF THE SHOWER AND
THUNDERSTORM ACTIVITY HAS NOW PUSHED EAST OF THE MISSISSIPPI
RIVER. MOST OF THIS CONVECTION WILL LIKELY PUSH EAST OF THE CWA BY
7 PM. HOWEVER...LATEST HRRR SHOWS REDEVELOPMENT OCCURRING OVER
NORTHEAST ARKANSAS BY THAT TIME. THE CORRIDOR FROM NORTHEAST
ARKANSAS AND THE MISSOURI BOOTHEEL MAY SEE MOST OF THE CONVECTION
DURING THE LATE EVENING INTO THE OVERNIGHT HOURS BEFORE IT SHIFTS
SOUTHWARD ON MONDAY. HAVE ADJUSTED POPS ACCORDINGLY. IN
ADDITION...SINCE THERE ARE PORTIONS OF NORTHEAST MISSISSIPPI THAT
HAS SEEN SEVERAL ROUNDS OF HEAVY SHOWERS TODAY...WILL GO AHEAD AND
EXPAND THE FLASH FLOOD WATCH SOUTHWARD TO COVER THE ENTIRE CWA
THROUGH MONDAY.
MONDAY WILL BE ANOTHER RAINY DAY FOR THE MIDSOUTH WITH OFF AND ON
PERIODS OF HEAVY SHOWERS AND THUNDERSTORMS. EXPECT HIGHS IN THE
UPPER 70S TO LOWER 80S.
THE COLD FRONT WILL FINALLY BEGIN TO PUSH INTO THE AREA MONDAY
NIGHT INTO TUESDAY. MODELS ARE COMING INTO TO CLOSER AGREEMENT
THAT THE FRONT WILL STALL OUT JUST SOUTH OF THE CWA AND BEGIN
LIFTING BACK NORTHWARD AS A WARM FRONT LATE TUESDAY NIGHT INTO
WEDNESDAY. THIS WILL KEEP SMALL CHANCES FOR SHOWERS AND
THUNDERSTORMS IN THE FORECAST FOR PORTIONS OF EAST-CENTRAL
ARKANSAS AND NORTH MISSISSIPPI WHILE GIVING THE REST OF THE CWA
ONLY A BRIEF REPRIEVE ON TUESDAY NIGHT.
BY WEDNESDAY...THE ENTIRE MIDSOUTH WILL SEE CHANCES FOR SHOWERS
AND THUNDERSTORMS AGAIN AS A WEAK SHORTWAVE MOVES ACROSS THE CWA.
BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS WILL COME WEDNESDAY
NIGHT INTO THURSDAY AS THE FRONT MOVES BACK THROUGH THE AREA AS A
COLD FRONT.
HIGH PRESSURE WILL BUILD INTO THE AREA THURSDAY NIGHT THROUGH
SATURDAY. NO PRECIPITATION IS EXPECTED AS A RESULT. HIGHS WILL BE
IN THE MID 70S TO LOWER 80S. LOWS WILL BE IN THE MID 50S TO LOWER
60S.
LOOKS LIKE THE MIDSOUTH COULD BE UNDERNEATH SOUTHWEST FLOW ALOFT
AGAIN BY SATURDAY NIGHT CONTINUING INTO EARLY NEXT WEEK. THIS
COULD BRING ANOTHER EXTENDED WET PERIOD TO THE REGION.
KRM
&&
.AVIATION...06Z TAFS
MORE OF THE SAME OVER THE NEXT 24 HOURS....ALTHOUGH THIS LOOKS
LIKE THE END OF SEVERAL DAYS OF DEALING WITH STORMS. PERIODS OF
THUNDERSTORMS WILL RESULT IN BRIEF IFR VIS AND VARIABLE GUSTY
WINDS.
THE NEXT ROUND OF THUNDERSTORMS IS DEVELOPING IN SOUTHEAST
ARKANSAS AND NORTHWEST MISSISSIPPI...TRACKING TOWARD THE
NORTHEAST. FEEL CONFIDENT ENOUGH THAT THEY WILL IMPACT MEM AND MKL
TO ADD A PREVAILING THUNDER GROUP FOR A COUPLE OF HOURS STARTING
AT 06 AND 0730Z RESPECTIVELY.
SHORT RANGE MODELS INDICATE ANOTHER YET ROUND OF TSRAS WILL FIRE
UP AFTER MIDNIGHT...SHIFTING ACROSS JBR...MEM...AND MKL PRIOR TO
SUNRISE. MODELS DISAGREE ON HOW WIDESPREAD LOW CLOUDS LATER
TONIGHT AND MON MORNING. BEST CHANCES APPEAR TO BE AT KTUP AND
PLACED A MVFR CIG THERE MONDAY MORNING OTRW WILL GO WITH
OPTIMISTIC FORECAST. ANOTHER ROUND OF DAYTIME HEATING DRIVEN
STORMS IS EXPECTED TOMORROW. WILL CARRY TEMPO VCTS AT ALL SITES
FOR MOST OF THE AFTERNOON.
SOUTH WINDS 10-12 KTS WITH HIGHER GUSTS THIS AFTN...8-10 KTS
TONIGHT. WINDS SHOULD BEGIN TO SHIFT MORE WESTERLY OR
NORTHWESTERLY BY SUNSET TOMORROW...AND PRECIPITATION SHOULD COME
TO AN END AFTER SUNSET.
30
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR CLAY-CRAIGHEAD-
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.
MO...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR DUNKLIN-PEMISCOT.
MS...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR ALCORN-BENTON MS-
CALHOUN-CHICKASAW-COAHOMA-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS-
MARSHALL-MONROE-PANOLA-PONTOTOC-PRENTISS-QUITMAN-
TALLAHATCHIE-TATE-TIPPAH-TISHOMINGO-TUNICA-UNION-YALOBUSHA.
TN...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR BENTON TN-CARROLL-
CHESTER-CROCKETT-DECATUR-DYER-FAYETTE-GIBSON-HARDEMAN-
HARDIN-HAYWOOD-HENDERSON-HENRY-LAKE-LAUDERDALE-MADISON-
MCNAIRY-OBION-SHELBY-TIPTON-WEAKLEY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
914 PM CDT TUE MAY 19 2015
.UPDATE...
UPDATED TO LOWER MIN TEMPS CONSIDERABLY TONIGHT FOR A STRONG COLD
FRONT NOW ENTERING THE FAR SOUTHERN TX PANHANDLE. ABUNDANT
STRATUS AND FOG AS LOW AS 1/2 MILE WAS NOTED BEHIND THIS FRONT AND
THE VISIBILITY AT HEREFORD PLUMMETED FROM 10 MILES TO JUST OVER 1
MILE IN 20 MINUTES. TEMPS IN THE 40S ALREADY ACROSS THE NORTHERN
PANHANDLE CONFIRM THE MAGNITUDE OF COLD ADVECTION...SO HAVE
UPDATED GRIDS LARGELY IN LINE WITH THE LATEST RAP AND HRRR
SOLUTIONS WHICH HAVE A GOOD HANDLE ON THESE TRENDS.
POP-WISE...DROPPED MOST PRECIP MENTION FROM THE CAPROCK
TONIGHT...HOWEVER WE STILL EXPECT SOME STORMS TO RE-DEVELOP WWD
TO NEAR THE I-27 AND HWY 87 CORRIDOR LATER TONIGHT AS THE COLD
FRONT AND TRAILING FRONT ALOFT INTERSECT DEEPER MOISTURE EAST OF
THE RETREATING DRYLINE.
&&
.PREV DISCUSSION... /ISSUED 643 PM CDT TUE MAY 19 2015/
AVIATION...
DETERIORATING CONDITIONS FROM N-S TONIGHT. CDS STANDS THE BEST
CHANCE OF TSRA THIS EVENING BEHIND A RECENT COLD FROPA. THIS
FRONT SHOULD IMPACT PVW AND LBB FROM 11PM-1AM FOLLOWED BY IFR
CIGS AND LIGHT FOG/MIST ON NE WINDS. COULD SEE TS REDEVELOP WWD
ALONG THIS FRONT TONIGHT...BUT THE CHANCES OF THESE IMPACTING LBB
AND PVW NOW APPEAR LESS. IFR CIGS MAY LINGER WELL INTO THE
AFTERNOON IN THIS COOL AND MOIST POST-FRONTAL FLOW...BUT MODELS
FAVOR MVFR BY LATE MORNING.
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1255 PM CDT MON MAY 18 2015
.AVIATION...
VFR DETERIORATING TO IFR TONIGHT AT ALL SITES. SURGE OF MOISTURE
INTO THE REGION WILL BREED SCT TSRA SW OF LBB LATER THIS AFTN
BEFORE REACHING LBB AND PVW THIS EVENING. MUCH BETTER CHANCE FOR
WIDESPREAD TSRA DEVELOPMENT SHOULD OCCUR EARLY TUE MORNING FROM
W-E AS AN UPPER TROUGH REACHES THE AREA. IFR CIGS ARE LIKELY TO
PERSIST THRU 18Z TUE AS MOIST E-SE UPSLOPE WINDS PERSIST.
&&
PREV DISCUSSION... /ISSUED 340 AM CDT MON MAY 18 2015/
SHORT TERM...
THE SHORT TERM PERIOD WILL FOCUS ON THE RETURN OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS...THAT COULD COMMENCE AS EARLY
AS LATE THIS AFTN.
THE PACIFIC FRONT/DRYLINE THAT AFFECTED THE SOUTHERN PLAINS
YESTERDAY WAS WELL SOUTH AND EAST OF THE CWA EARLY THIS MORNING...AS
HINTED AT BY DEWPOINTS IN THE 60S AND 70S ACROSS THE CONCHO
VALLEY...BIG COUNTRY AND EDWARDS PLATEAU AREAS. AS SUCH...SOME FOG
AND/OR LOW CLOUDS HAVE DEVELOPED ACROSS PORTIONS OF THE SAID AREAS.
COMPUTER MODELS HINT AT THE BOUNDARY RETREATING TO NEAR THE FAR SRN
SOUTH PLAINS AND LOW ROLLING PLAINS BY AOA DAYBREAK...BRINGING WITH
IT RICH LOW LEVEL MOISTURE AND A CHANCE FOR THE FOG AND/OR STRATUS
DECK TO MAKE HEADWAY TOWARDS THE FA. HOWEVER...MODEL SOLUTIONS SUCH
AS THE HRRR AND THE NAM EXHIBIT THE FOG AND LOW CLOUDS TO STOP JUST
SHORT OF THE FA AND DISSIPATE...GIVEN SFC WINDS VEERING TO THE W-SW
THROUGHOUT DAYBREAK AND THUS MITIGATING THE TRANSPORT OF THE LOW
LEVEL MOISTURE. WE WILL CONTINUE TO MONITOR AND SEE IF THIS DOES
INDEED OCCUR.
ATTENTION WILL TURN TO AN UA LOW THAT WAS IMPINGING ON CNTRL/SRN
CALI PER 07Z SATELLITE WATER VAPOR IMAGERY...AND IS PROGGED TO
TRANSLATE ENE TO NEAR THE FOUR-CORNERS REGION BY TONIGHT. AS
SUCH...SW FLOW ALOFT WILL SHARPEN. EMBEDDED WITHIN THIS SW FLOW IS
AN IMPULSE THAT MODEL SOLUTIONS SHOW EJECTING OUT AHEAD OF THE
PARENT UA LOW...AND NEAR THE SWRN ZONES LATE THIS AFTN/EARLY EVENING
AND PROGRESS TO THE NE TO ACROSS THE NERN ZONES BY TONIGHT. WITH SFC
LEE TROUGHING DEEPENING DUE TO THE APPROACHING UA LOW...THIS WILL
AID TO BACK SFC WINDS TO THE S-SE AND PWATS WILL SOAR INTO THE 1.00-
1.50 INCH RANGE BY TONIGHT...WHILST THE LLJ CRANKS UP TO 20-40 KTS.
WITH ALL THAT SAID...CONVECTION IS STILL EXPECTED TO INITIATE ACROSS
THE FAR SW SOUTH PLAINS AS EARLY AS LATE THIS AFTN/EARLY THIS
EVENING...ESPECIALLY IF THE TIMING OF THE ANTICIPATED EMBEDDED
IMPULSE STAYS TRUE. PRECIP WILL BECOME SCATTERED TO PERHAPS
WIDESPREAD AS IT PROGRESSES NE TO ACROSS THE REMAINDER OF THE CWA
THROUGH THE NIGHT. TO ADD FUEL TO THE PROVERBIAL FIRE...A COLD FRONT
WILL BACKDOOR INTO THE REGION THIS EVENING/TONIGHT...WHICH COULD
SERVE AS ANOTHER FOCUS FOR STORM DEVELOPMENT. WITH SUCH HIGH
PWATS...MODERATE-HEAVY RAINFALL CAN NOT BE RULED OUT WHICH RAISES
CONCERNS FOR LOCALIZED FLOODED. WE ALSO NEED TO KEEP AN EYE OUT FOR
SOME STORMS BECOMING STRONG TO SEVERE...ESPECIALLY ACROSS THE SWRN
ZONES LATE THIS AFTN AS PROGGED MUCAPE VALUES OF 2-3 KJ/KG...30-40
KTS OF 0-6 KM BULK SHEAR...STEEPENED LAPSE RATES AND VEERING WIND
PROFILES SAYS AS MUCH /HAIL AND GUSTY WINDS WILL BE THE PRIMARY
THREATS/.
A SEASONABLY WARM DAY WILL PREVAIL WITH HIGHS IN THE 70S AND
80S...FOLLOWED BY OVERNIGHT LOWS IN THE 50S AND 60S.
LONG TERM...
THE WEATHER FOR THE PAST SEVERAL WEEKS /MINUS THE WIND AND LACK
OF 70+ DEGREE DEW POINTS/ HAVE MADE IT FEEL LIKE I AM BACK IN MY
OLD STOMPING GROUNDS IN SOUTH MS...AND IT DOESN/T LOOK LIKE THE
PATTERN WILL CHANGE ANY OVER THE NEXT 7 DAYS AND BEYOND. FOR
STARTERS WPC QPF GUIDANCE PRE 00Z SHOWS UPWARDS OF 5 INCHES OF
RAIN OVER THE NEXT 7 DAYS. TUESDAY MORNING WILL START VERY WET
WITH AN UPPER LEVEL LOW WITH A SLIGHT NEG TILT MOVES OVER NV TOWARDS
THE REGION. MODEL OMEGA FIELDS/SOUNDING PROFILES ALL SHOW LIFT AND
NO SUBSIDENCE BY 7AM THOUGH THEY DO VARY ON THE AMOUNT OF LIFT. THE
GFS HAS THE LEAST AMOUNT OF LIFT WITH THE LEAST AMOUNT OF QPF WHILE
THE NAM/ECMWF ARE FAIRLY IN LINE WITH EACH OTHER. PWAT VALUES WILL
BE RELATIVELY HIGH...1.25 TO 1.5 INCHES ON THE CAPROCK WHILE
APPROACHING 2 INCHES ACROSS THE EASTER ROLLING PLAINS. THIS IS IN
PART DUE TO MOIST SURFACE CONDITIONS AS WELL AS A 40KT LLJ PUMPING
IN MOISTURE FROM THE GOMEX. ONE CONCERN WITH TUESDAY MORNING WILL BE
FLOODING. WITH ALREADY SATURATED SOILS AND FULL PLAYA LAKES RUN
OFF...MAINLY IN URBAN AREAS...WILL BE ALL BUT GUARANTEED WITH A
QUICK 1 INCH RAINFALL CAUSING PROBLEMS. WHILE ACTUAL RAINFALL
AMOUNTS AS WELL AS THE LOCATION OF THE HEAVIEST RAIN IS HARD TO
PINPOINT NEARLY 24 HOURS OUT...THE EXPECTED WIDESPREAD DYNAMIC LIFT
IN ADDITION TO THE RICH MOISTURE TRANSPORT VIA THE LLJ SHOWS THAT
HEAVY RAIN MAY BE FAIRLY WIDESPREAD. GIVEN THAT THIS IS EXPECTED TO
HAPPEN DURING THE MORNING TRAFFIC RUSH AN AREAL FLOOD WATCH MAY BE
WARRANTED. FOR NOW WE WILL DEFER THE WATCH DECISION TO THE NEXT
SHIFT FOR FURTHER EVALUATION OF MORE UP TO DATE INFO. THERE IS A
POSSIBLE SEVERE THREAT LATER TOMORROW AFTERNOON/EVENING DEPENDING ON
HOW MUCH SURFACE HEATING CAN BE ACHIEVED. THIS WILL BE DEPENDENT ON
CLOUD COVER. AS OF NOW OUR WESTERN ZONES HAVE SOMEWHAT HIGHER
CHANCES TO SEE SEVERE STORMS THAN THE REST OF THE FA AS CLOUDS WILL
BEGIN TO THIN FROM WEST TO EAST.
WE SHOULD SEE PRECIP MOVE OFF TO THE EAST BY WED MORNING AS A FRONT
APPROACHES FROM THE NORTH. MODEL TIMING WITH THE FROPA DIFFERS WITH
THE GFS /FRONT PUSHING INTO OUR NORTHERN ZONES BY 00Z THURS/ BEING
SLOWER THAN THE ECMWF /FRONT THRU THE FA BY 00Z/. OTHER THAN A WIND
SHIFT AND CLOUD COVER THIS SHOULDN/T CREATE MUCH OF A HEADACHE AS
FAR AS THE FORECAST IS CONCERNED. THE FROPA WILL BE ACCOMPANIED BY A
LOW STRATUS DECK THAT WILL STICK AROUND FOR MUCH OF WED NIGHT INTO
THURS AFTERNOON. RAIN WILL BE POSSIBLE MAINLY DUE TO ISENTROPIC
LIFTING. THE BIGGEST CHANGE TO THE FORECAST DURING THIS PERIOD IS
MAKING THE PRECIP MAINLY IN THE FORM OF RAIN WITH A MENTION OF ISO
THUNDER AS THE CHANCE EXISTS FOR SOME ELEVATED CAPE. ANOTHER LOW IS
PROGGED TO MOVE INLAND ACROSS SOCAL WHICH WILL RETURN SURFACE FLOW
OUT OF THE SOUTH/SOUTHEAST AND SET UP A DRYLINE OVER CENTRAL NM.
THIS WILL BE OUR NEXT BIG RAIN MAKER AS THE DRYLINE PUSHES EASTWARD
AND THEN RETREATS FRIDAY AND SATURDAY.
TEMPS WILL CONTINUE TO REMAIN BELOW SEASONAL AVERAGE AS CLOUD COVER
WILL BE ABUNDANT THRU THE WEEK AND SURFACE MOISTURE WILL HELP
MODERATE SURFACE TEMPS. THURS WILL BE PARTICULARLY CHILLY WITH TEMPS
AVERAGING 20 DEGREES BELOW SEASONAL AVERAGE /MID 60S/ DUE TO SURFACE
CAA ASSOCIATED WITH THE FROPA. ALDRICH
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
620 AM CDT MON MAY 18 2015
.AVIATION...
VFR CONDITIONS EXPECTED DURING THE DAY...BUT WILL DETERIORATE TO
MVFR DECKS AND VIS COURTESY OF INCREASING CHANCES OF THUNDERSTORMS
THIS EVENING THROUGH TONIGHT. HAVE INSERTING A PREVAILING TSRA AT
ALL THREE TAF SITES...COMMENCING THIS EVENING AT KLBB AND
KPVW...AND MORE SO BY TONIGHT AT KCDS. RAINFALL COULD BECOME HEAVY
AT TIMES. OTHERWISE...LIGHT SOUTHWEST WINDS EARLY THIS MORNING
WILL BACK TO THE SOUTH SOUTHEAST THIS AFTERNOON AT 10-15 KTS.
&&
.PREV DISCUSSION... /ISSUED 340 AM CDT MON MAY 18 2015/
SHORT TERM...
THE SHORT TERM PERIOD WILL FOCUS ON THE RETURN OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS...THAT COULD COMMENCE AS EARLY
AS LATE THIS AFTN.
THE PACIFIC FRONT/DRYLINE THAT AFFECTED THE SOUTHERN PLAINS
YESTERDAY WAS WELL SOUTH AND EAST OF THE CWA EARLY THIS MORNING...AS
HINTED AT BY DEWPOINTS IN THE 60S AND 70S ACROSS THE CONCHO
VALLEY...BIG COUNTRY AND EDWARDS PLATEAU AREAS. AS SUCH...SOME FOG
AND/OR LOW CLOUDS HAVE DEVELOPED ACROSS PORTIONS OF THE SAID AREAS.
COMPUTER MODELS HINT AT THE BOUNDARY RETREATING TO NEAR THE FAR SRN
SOUTH PLAINS AND LOW ROLLING PLAINS BY AOA DAYBREAK...BRINGING WITH
IT RICH LOW LEVEL MOISTURE AND A CHANCE FOR THE FOG AND/OR STRATUS
DECK TO MAKE HEADWAY TOWARDS THE FA. HOWEVER...MODEL SOLUTIONS SUCH
AS THE HRRR AND THE NAM EXHIBIT THE FOG AND LOW CLOUDS TO STOP JUST
SHORT OF THE FA AND DISSIPATE...GIVEN SFC WINDS VEERING TO THE W-SW
THROUGHOUT DAYBREAK AND THUS MITIGATING THE TRANSPORT OF THE LOW
LEVEL MOISTURE. WE WILL CONTINUE TO MONITOR AND SEE IF THIS DOES
INDEED OCCUR.
ATTENTION WILL TURN TO AN UA LOW THAT WAS IMPINGING ON CNTRL/SRN
CALI PER 07Z SATELLITE WATER VAPOR IMAGERY...AND IS PROGGED TO
TRANSLATE ENE TO NEAR THE FOUR-CORNERS REGION BY TONIGHT. AS
SUCH...SW FLOW ALOFT WILL SHARPEN. EMBEDDED WITHIN THIS SW FLOW IS
AN IMPULSE THAT MODEL SOLUTIONS SHOW EJECTING OUT AHEAD OF THE
PARENT UA LOW...AND NEAR THE SWRN ZONES LATE THIS AFTN/EARLY EVENING
AND PROGRESS TO THE NE TO ACROSS THE NERN ZONES BY TONIGHT. WITH SFC
LEE TROUGHING DEEPENING DUE TO THE APPROACHING UA LOW...THIS WILL
AID TO BACK SFC WINDS TO THE S-SE AND PWATS WILL SOAR INTO THE 1.00-
1.50 INCH RANGE BY TONIGHT...WHILST THE LLJ CRANKS UP TO 20-40 KTS.
WITH ALL THAT SAID...CONVECTION IS STILL EXPECTED TO INITIATE ACROSS
THE FAR SW SOUTH PLAINS AS EARLY AS LATE THIS AFTN/EARLY THIS
EVENING...ESPECIALLY IF THE TIMING OF THE ANTICIPATED EMBEDDED
IMPULSE STAYS TRUE. PRECIP WILL BECOME SCATTERED TO PERHAPS
WIDESPREAD AS IT PROGRESSES NE TO ACROSS THE REMAINDER OF THE CWA
THROUGH THE NIGHT. TO ADD FUEL TO THE PROVERBIAL FIRE...A COLD FRONT
WILL BACKDOOR INTO THE REGION THIS EVENING/TONIGHT...WHICH COULD
SERVE AS ANOTHER FOCUS FOR STORM DEVELOPMENT. WITH SUCH HIGH
PWATS...MODERATE-HEAVY RAINFALL CAN NOT BE RULED OUT WHICH RAISES
CONCERNS FOR LOCALIZED FLOODED. WE ALSO NEED TO KEEP AN EYE OUT FOR
SOME STORMS BECOMING STRONG TO SEVERE...ESPECIALLY ACROSS THE SWRN
ZONES LATE THIS AFTN AS PROGGED MUCAPE VALUES OF 2-3 KJ/KG...30-40
KTS OF 0-6 KM BULK SHEAR...STEEPENED LAPSE RATES AND VEERING WIND
PROFILES SAYS AS MUCH /HAIL AND GUSTY WINDS WILL BE THE PRIMARY
THREATS/.
A SEASONABLY WARM DAY WILL PREVAIL WITH HIGHS IN THE 70S AND
80S...FOLLOWED BY OVERNIGHT LOWS IN THE 50S AND 60S.
LONG TERM...
THE WEATHER FOR THE PAST SEVERAL WEEKS /MINUS THE WIND AND LACK
OF 70+ DEGREE DEW POINTS/ HAVE MADE IT FEEL LIKE I AM BACK IN MY
OLD STOMPING GROUNDS IN SOUTH MS...AND IT DOESN/T LOOK LIKE THE
PATTERN WILL CHANGE ANY OVER THE NEXT 7 DAYS AND BEYOND. FOR
STARTERS WPC QPF GUIDANCE PRE 00Z SHOWS UPWARDS OF 5 INCHES OF
RAIN OVER THE NEXT 7 DAYS. TUESDAY MORNING WILL START VERY WET
WITH AN UPPER LEVEL LOW WITH A SLIGHT NEG TILT MOVES OVER NV TOWARDS
THE REGION. MODEL OMEGA FIELDS/SOUNDING PROFILES ALL SHOW LIFT AND
NO SUBSIDENCE BY 7AM THOUGH THEY DO VARY ON THE AMOUNT OF LIFT. THE
GFS HAS THE LEAST AMOUNT OF LIFT WITH THE LEAST AMOUNT OF QPF WHILE
THE NAM/ECMWF ARE FAIRLY IN LINE WITH EACH OTHER. PWAT VALUES WILL
BE RELATIVELY HIGH...1.25 TO 1.5 INCHES ON THE CAPROCK WHILE
APPROACHING 2 INCHES ACROSS THE EASTER ROLLING PLAINS. THIS IS IN
PART DUE TO MOIST SURFACE CONDITIONS AS WELL AS A 40KT LLJ PUMPING
IN MOISTURE FROM THE GOMEX. ONE CONCERN WITH TUESDAY MORNING WILL BE
FLOODING. WITH ALREADY SATURATED SOILS AND FULL PLAYA LAKES RUN
OFF...MAINLY IN URBAN AREAS...WILL BE ALL BUT GUARANTEED WITH A
QUICK 1 INCH RAINFALL CAUSING PROBLEMS. WHILE ACTUAL RAINFALL
AMOUNTS AS WELL AS THE LOCATION OF THE HEAVIEST RAIN IS HARD TO
PINPOINT NEARLY 24 HOURS OUT...THE EXPECTED WIDESPREAD DYNAMIC LIFT
IN ADDITION TO THE RICH MOISTURE TRANSPORT VIA THE LLJ SHOWS THAT
HEAVY RAIN MAY BE FAIRLY WIDESPREAD. GIVEN THAT THIS IS EXPECTED TO
HAPPEN DURING THE MORNING TRAFFIC RUSH AN AREAL FLOOD WATCH MAY BE
WARRANTED. FOR NOW WE WILL DEFER THE WATCH DECISION TO THE NEXT
SHIFT FOR FURTHER EVALUATION OF MORE UP TO DATE INFO. THERE IS A
POSSIBLE SEVERE THREAT LATER TOMORROW AFTERNOON/EVENING DEPENDING ON
HOW MUCH SURFACE HEATING CAN BE ACHIEVED. THIS WILL BE DEPENDENT ON
CLOUD COVER. AS OF NOW OUR WESTERN ZONES HAVE SOMEWHAT HIGHER
CHANCES TO SEE SEVERE STORMS THAN THE REST OF THE FA AS CLOUDS WILL
BEGIN TO THIN FROM WEST TO EAST.
WE SHOULD SEE PRECIP MOVE OFF TO THE EAST BY WED MORNING AS A FRONT
APPROACHES FROM THE NORTH. MODEL TIMING WITH THE FROPA DIFFERS WITH
THE GFS /FRONT PUSHING INTO OUR NORTHERN ZONES BY 00Z THURS/ BEING
SLOWER THAN THE ECMWF /FRONT THRU THE FA BY 00Z/. OTHER THAN A WIND
SHIFT AND CLOUD COVER THIS SHOULDN/T CREATE MUCH OF A HEADACHE AS
FAR AS THE FORECAST IS CONCERNED. THE FROPA WILL BE ACCOMPANIED BY A
LOW STRATUS DECK THAT WILL STICK AROUND FOR MUCH OF WED NIGHT INTO
THURS AFTERNOON. RAIN WILL BE POSSIBLE MAINLY DUE TO ISENTROPIC
LIFTING. THE BIGGEST CHANGE TO THE FORECAST DURING THIS PERIOD IS
MAKING THE PRECIP MAINLY IN THE FORM OF RAIN WITH A MENTION OF ISO
THUNDER AS THE CHANCE EXISTS FOR SOME ELEVATED CAPE. ANOTHER LOW IS
PROGGED TO MOVE INLAND ACROSS SOCAL WHICH WILL RETURN SURFACE FLOW
OUT OF THE SOUTH/SOUTHEAST AND SET UP A DRYLINE OVER CENTRAL NM.
THIS WILL BE OUR NEXT BIG RAIN MAKER AS THE DRYLINE PUSHES EASTWARD
AND THEN RETREATS FRIDAY AND SATURDAY.
TEMPS WILL CONTINUE TO REMAIN BELOW SEASONAL AVERAGE AS CLOUD COVER
WILL BE ABUNDANT THRU THE WEEK AND SURFACE MOISTURE WILL HELP
MODERATE SURFACE TEMPS. THURS WILL BE PARTICULARLY CHILLY WITH TEMPS
AVERAGING 20 DEGREES BELOW SEASONAL AVERAGE /MID 60S/ DUE TO SURFACE
CAA ASSOCIATED WITH THE FROPA. ALDRICH
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 78 55 71 49 / 10 80 90 20
TULIA 79 57 69 51 / 10 80 90 40
PLAINVIEW 79 58 70 53 / 10 80 90 40
LEVELLAND 83 60 74 56 / 20 80 90 30
LUBBOCK 83 61 73 57 / 10 80 90 40
DENVER CITY 82 61 76 60 / 30 80 80 20
BROWNFIELD 84 61 74 59 / 20 80 90 30
CHILDRESS 86 63 71 60 / 10 60 90 60
SPUR 84 63 73 61 / 10 70 90 50
ASPERMONT 87 66 75 64 / 10 70 90 50
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
29
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
340 AM CDT MON MAY 18 2015
.SHORT TERM...
THE SHORT TERM PERIOD WILL FOCUS ON THE RETURN OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS...THAT COULD COMMENCE AS EARLY
AS LATE THIS AFTN.
THE PACIFIC FRONT/DRYLINE THAT AFFECTED THE SOUTHERN PLAINS
YESTERDAY WAS WELL SOUTH AND EAST OF THE CWA EARLY THIS MORNING...AS
HINTED AT BY DEWPOINTS IN THE 60S AND 70S ACROSS THE CONCHO
VALLEY...BIG COUNTRY AND EDWARDS PLATEAU AREAS. AS SUCH...SOME FOG
AND/OR LOW CLOUDS HAVE DEVELOPED ACROSS PORTIONS OF THE SAID AREAS.
COMPUTER MODELS HINT AT THE BOUNDARY RETREATING TO NEAR THE FAR SRN
SOUTH PLAINS AND LOW ROLLING PLAINS BY AOA DAYBREAK...BRINGING WITH
IT RICH LOW LEVEL MOISTURE AND A CHANCE FOR THE FOG AND/OR STRATUS
DECK TO MAKE HEADWAY TOWARDS THE FA. HOWEVER...MODEL SOLUTIONS SUCH
AS THE HRRR AND THE NAM EXHIBIT THE FOG AND LOW CLOUDS TO STOP JUST
SHORT OF THE FA AND DISSIPATE...GIVEN SFC WINDS VEERING TO THE W-SW
THROUGHOUT DAYBREAK AND THUS MITIGATING THE TRANSPORT OF THE LOW
LEVEL MOISTURE. WE WILL CONTINUE TO MONITOR AND SEE IF THIS DOES
INDEED OCCUR.
ATTENTION WILL TURN TO AN UA LOW THAT WAS IMPINGING ON CNTRL/SRN
CALI PER 07Z SATELLITE WATER VAPOR IMAGERY...AND IS PROGGED TO
TRANSLATE ENE TO NEAR THE FOUR-CORNERS REGION BY TONIGHT. AS
SUCH...SW FLOW ALOFT WILL SHARPEN. EMBEDDED WITHIN THIS SW FLOW IS
AN IMPULSE THAT MODEL SOLUTIONS SHOW EJECTING OUT AHEAD OF THE
PARENT UA LOW...AND NEAR THE SWRN ZONES LATE THIS AFTN/EARLY EVENING
AND PROGRESS TO THE NE TO ACROSS THE NERN ZONES BY TONIGHT. WITH SFC
LEE TROUGHING DEEPENING DUE TO THE APPROACHING UA LOW...THIS WILL
AID TO BACK SFC WINDS TO THE S-SE AND PWATS WILL SOAR INTO THE 1.00-
1.50 INCH RANGE BY TONIGHT...WHILST THE LLJ CRANKS UP TO 20-40 KTS.
WITH ALL THAT SAID...CONVECTION IS STILL EXPECTED TO INITIATE ACROSS
THE FAR SW SOUTH PLAINS AS EARLY AS LATE THIS AFTN/EARLY THIS
EVENING...ESPECIALLY IF THE TIMING OF THE ANTICIPATED EMBEDDED
IMPULSE STAYS TRUE. PRECIP WILL BECOME SCATTERED TO PERHAPS
WIDESPREAD AS IT PROGRESSES NE TO ACROSS THE REMAINDER OF THE CWA
THROUGH THE NIGHT. TO ADD FUEL TO THE PROVERBIAL FIRE...A COLD FRONT
WILL BACKDOOR INTO THE REGION THIS EVENING/TONIGHT...WHICH COULD
SERVE AS ANOTHER FOCUS FOR STORM DEVELOPMENT. WITH SUCH HIGH
PWATS...MODERATE-HEAVY RAINFALL CAN NOT BE RULED OUT WHICH RAISES
CONCERNS FOR LOCALIZED FLOODED. WE ALSO NEED TO KEEP AN EYE OUT FOR
SOME STORMS BECOMING STRONG TO SEVERE...ESPECIALLY ACROSS THE SWRN
ZONES LATE THIS AFTN AS PROGGED MUCAPE VALUES OF 2-3 KJ/KG...30-40
KTS OF 0-6 KM BULK SHEAR...STEEPENED LAPSE RATES AND VEERING WIND
PROFILES SAYS AS MUCH /HAIL AND GUSTY WINDS WILL BE THE PRIMARY
THREATS/.
A SEASONABLY WARM DAY WILL PREVAIL WITH HIGHS IN THE 70S AND
80S...FOLLOWED BY OVERNIGHT LOWS IN THE 50S AND 60S.
.LONG TERM...
THE WEATHER FOR THE PAST SEVERAL WEEKS /MINUS THE WIND AND LACK
OF 70+ DEGREE DEW POINTS/ HAVE MADE IT FEEL LIKE I AM BACK IN MY
OLD STOMPING GROUNDS IN SOUTH MS...AND IT DOESN/T LOOK LIKE THE
PATTERN WILL CHANGE ANY OVER THE NEXT 7 DAYS AND BEYOND. FOR
STARTERS WPC QPF GUIDANCE PRE 00Z SHOWS UPWARDS OF 5 INCHES OF
RAIN OVER THE NEXT 7 DAYS. TUESDAY MORNING WILL START VERY WET
WITH AN UPPER LEVEL LOW WITH A SLIGHT NEG TILT MOVES OVER NV TOWARDS
THE REGION. MODEL OMEGA FIELDS/SOUNDING PROFILES ALL SHOW LIFT AND
NO SUBSIDENCE BY 7AM THOUGH THEY DO VARY ON THE AMOUNT OF LIFT. THE
GFS HAS THE LEAST AMOUNT OF LIFT WITH THE LEAST AMOUNT OF QPF WHILE
THE NAM/ECMWF ARE FAIRLY IN LINE WITH EACH OTHER. PWAT VALUES WILL
BE RELATIVELY HIGH...1.25 TO 1.5 INCHES ON THE CAPROCK WHILE
APPROACHING 2 INCHES ACROSS THE EASTER ROLLING PLAINS. THIS IS IN
PART DUE TO MOIST SURFACE CONDITIONS AS WELL AS A 40KT LLJ PUMPING
IN MOISTURE FROM THE GOMEX. ONE CONCERN WITH TUESDAY MORNING WILL BE
FLOODING. WITH ALREADY SATURATED SOILS AND FULL PLAYA LAKES RUN
OFF...MAINLY IN URBAN AREAS...WILL BE ALL BUT GUARANTEED WITH A
QUICK 1 INCH RAINFALL CAUSING PROBLEMS. WHILE ACTUAL RAINFALL
AMOUNTS AS WELL AS THE LOCATION OF THE HEAVIEST RAIN IS HARD TO
PINPOINT NEARLY 24 HOURS OUT...THE EXPECTED WIDESPREAD DYNAMIC LIFT
IN ADDITION TO THE RICH MOISTURE TRANSPORT VIA THE LLJ SHOWS THAT
HEAVY RAIN MAY BE FAIRLY WIDESPREAD. GIVEN THAT THIS IS EXPECTED TO
HAPPEN DURING THE MORNING TRAFFIC RUSH AN AREAL FLOOD WATCH MAY BE
WARRANTED. FOR NOW WE WILL DEFER THE WATCH DECISION TO THE NEXT
SHIFT FOR FURTHER EVALUATION OF MORE UP TO DATE INFO. THERE IS A
POSSIBLE SEVERE THREAT LATER TOMORROW AFTERNOON/EVENING DEPENDING ON
HOW MUCH SURFACE HEATING CAN BE ACHIEVED. THIS WILL BE DEPENDENT ON
CLOUD COVER. AS OF NOW OUR WESTERN ZONES HAVE SOMEWHAT HIGHER
CHANCES TO SEE SEVERE STORMS THAN THE REST OF THE FA AS CLOUDS WILL
BEGIN TO THIN FROM WEST TO EAST.
WE SHOULD SEE PRECIP MOVE OFF TO THE EAST BY WED MORNING AS A FRONT
APPROACHES FROM THE NORTH. MODEL TIMING WITH THE FROPA DIFFERS WITH
THE GFS /FRONT PUSHING INTO OUR NORTHERN ZONES BY 00Z THURS/ BEING
SLOWER THAN THE ECMWF /FRONT THRU THE FA BY 00Z/. OTHER THAN A WIND
SHIFT AND CLOUD COVER THIS SHOULDN/T CREATE MUCH OF A HEADACHE AS
FAR AS THE FORECAST IS CONCERNED. THE FROPA WILL BE ACCOMPANIED BY A
LOW STRATUS DECK THAT WILL STICK AROUND FOR MUCH OF WED NIGHT INTO
THURS AFTERNOON. RAIN WILL BE POSSIBLE MAINLY DUE TO ISENTROPIC
LIFTING. THE BIGGEST CHANGE TO THE FORECAST DURING THIS PERIOD IS
MAKING THE PRECIP MAINLY IN THE FORM OF RAIN WITH A MENTION OF ISO
THUNDER AS THE CHANCE EXISTS FOR SOME ELEVATED CAPE. ANOTHER LOW IS
PROGGED TO MOVE INLAND ACROSS SOCAL WHICH WILL RETURN SURFACE FLOW
OUT OF THE SOUTH/SOUTHEAST AND SET UP A DRYLINE OVER CENTRAL NM.
THIS WILL BE OUR NEXT BIG RAIN MAKER AS THE DRYLINE PUSHES EASTWARD
AND THEN RETREATS FRIDAY AND SATURDAY.
TEMPS WILL CONTINUE TO REMAIN BELOW SEASONAL AVERAGE AS CLOUD COVER
WILL BE ABUNDANT THRU THE WEEK AND SURFACE MOISTURE WILL HELP
MODERATE SURFACE TEMPS. THURS WILL BE PARTICULARLY CHILLY WITH TEMPS
AVERAGING 20 DEGREES BELOW SEASONAL AVERAGE /MID 60S/ DUE TO SURFACE
CAA ASSOCIATED WITH THE FROPA. ALDRICH
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 78 55 71 49 / 10 80 90 20
TULIA 79 57 69 51 / 10 80 90 40
PLAINVIEW 79 58 70 53 / 10 80 90 40
LEVELLAND 83 60 74 56 / 20 80 90 30
LUBBOCK 83 61 73 57 / 10 80 90 40
DENVER CITY 82 61 76 60 / 30 80 80 20
BROWNFIELD 84 61 74 59 / 20 80 90 30
CHILDRESS 86 63 71 60 / 10 60 90 60
SPUR 84 63 73 61 / 10 70 90 50
ASPERMONT 87 66 75 64 / 10 70 90 50
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
29/51
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
329 AM CDT MON MAY 18 2015
.SHORT TERM...
THE SHORT TERM PERIOD WILL FOCUS ON THE RETURN OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS...THAT COULD COMMENCE AS EARLY
AS LATE THIS AFTN.
THE PACIFIC FRONT/DRYLINE THAT AFFECTED THE SOUTHERN PLAINS
YESTERDAY WAS WELL SOUTH AND EAST OF THE CWA EARLY THIS MORNING...AS
HINTED AT BY DEWPOINTS IN THE 60S AND 70S ACROSS THE CONCHO
VALLEY...BIG COUNTRY AND EDWARDS PLATEAU AREAS. AS SUCH...SOME FOG
AND/OR LOW CLOUDS HAVE DEVELOPED ACROSS PORTIONS OF THE SAID AREAS.
COMPUTER MODELS HINT AT THE BOUNDARY RETREATING TO NEAR THE FAR SRN
SOUTH PLAINS AND LOW ROLLING PLAINS BY AOA DAYBREAK...BRINGING WITH
IT RICH LOW LEVEL MOISTURE AND A CHANCE FOR THE FOG AND/OR STRATUS
DECK TO MAKE HEADWAY TOWARDS THE FA. HOWEVER...MODEL SOLUTIONS SUCH
AS THE HRRR AND THE NAM EXHIBIT THE FOG AND LOW CLOUDS TO STOP JUST
SHORT OF THE FA AND DISSIPATE...GIVEN SFC WINDS VEERING TO THE W-SW
THROUGHOUT DAYBREAK AND THUS MITIGATING THE TRANSPORT OF THE LOW
LEVEL MOISTURE. WE WILL CONTINUE TO MONITOR AND SEE IF THIS DOES
INDEED OCCUR.
ATTENTION WILL TURN TO AN UA LOW THAT WAS IMPINGING ON CNTRL/SRN
CALI PER 07Z SATELLITE WATER VAPOR IMAGERY...AND IS PROGGED TO
TRANSLATE ENE TO NEAR THE FOUR-CORNERS REGION BY TONIGHT. AS
SUCH...SW FLOW ALOFT WILL SHARPEN. EMBEDDED WITHIN THIS SW FLOW IS
AN IMPULSE THAT MODEL SOLUTIONS SHOW EJECTING OUT AHEAD OF THE
PARENT UA LOW...AND NEAR THE SWRN ZONES LATE THIS AFTN/EARLY EVENING
AND PROGRESS TO THE NE TO ACROSS THE NERN ZONES BY TONIGHT. WITH SFC
LEE TROUGHING DEEPENING DUE TO THE APPROACHING UA LOW...THIS WILL
AID TO BACK SFC WINDS TO THE S-SE AND PWATS WILL SOAR INTO THE 1.00-
1.50 INCH RANGE BY TONIGHT...WHILST THE LLJ CRANKS UP TO 20-40 KTS.
WITH ALL THAT SAID...CONVECTION IS STILL EXPECTED TO INITIATE ACROSS
THE FAR SW SOUTH PLAINS AS EARLY AS LATE THIS AFTN/EARLY THIS
EVENING...ESPECIALLY IF THE TIMING OF THE ANTICIPATED EMBEDDED
IMPULSE STAYS TRUE. PRECIP WILL BECOME SCATTERED TO PERHAPS
WIDESPREAD AS IT PROGRESSES NE TO ACROSS THE REMAINDER OF THE CWA
THROUGH THE NIGHT. TO ADD FUEL TO THE PROVERBIAL FIRE...A COLD FRONT
WILL BACKDOOR INTO THE REGION THIS EVENING/TONIGHT...WHICH COULD
SERVE AS ANOTHER FOCUS FOR STORM DEVELOPMENT. WITH SUCH HIGH
PWATS...MODERATE-HEAVY RAINFALL CAN NOT BE RULED OUT WHICH RAISES
CONCERNS FOR LOCALIZED FLOODED. WE ALSO NEED TO KEEP AN EYE OUT FOR
SOME STORMS BECOMING STRONG TO SEVERE...ESPECIALLY ACROSS THE SWRN
ZONES LATE THIS AFTN AS PROGGED MUCAPE VALUES OF 2-3 KJ/KG...30-40
KTS OF 0-6 KM BULK SHEAR...STEEPENED LAPSE RATES AND VEERING WIND
PROFILES SAYS AS MUCH
/HAIL AND GUSTY WINDS WILL BE THE PRIMARY THREATS/.
A SEASONABLY WARM DAY WILL PREVAIL WITH HIGHS IN THE 70S AND
80S...FOLLOWED BY OVERNIGHT LOWS IN THE 50S AND 60S.
.LONG TERM...
THE WEATHER FOR THE PAST SEVERAL WEEKS /MINUS THE WIND AND LACK
OF 70+ DEGREE DEW POINTS/ HAVE MADE IT FEEL LIKE I AM BACK IN MY
OLD STOMPING GROUNDS IN SOUTH MS...AND IT DOESN/T LOOK LIKE THE
PATTERN WILL CHANGE ANY OVER THE NEXT 7 DAYS AND BEYOND. FOR
STARTERS WPC QPF GUIDANCE PRE 00Z SHOWS UPWARDS OF 5 INCHES OF
RAIN OVER THE NEXT 7 DAYS. TUESDAY MORNING WILL START VERY WET
WITH AN UPPER LEVEL LOW WITH A SLIGHT NEG TILT MOVES OVER NV
TOWARDS THE REGION. MODEL OMEGA FIELDS/SOUNDING PROFILES SHOW ALL
LIFT AND NO SUBSIDENCE BY 7AM THOUGH THEY DO VARY ON THE AMOUNT OF
LIFT. THE GFS HAS THE LEAST AMOUNT OF LIFT WITH THE LEAST AMOUNT
OF QPF WHILE THE NAM/ECMWF ARE FAIRLY IN LINE WITH EACH OTHER.
PWAT VALUES WILL BE RELATIVELY HIGH...1.25 TO 1.5 INCHES ON THE
CAPROCK WHILE APPROACHING 2 INCHES ACROSS THE EASTER ROLLING
PLAINS. THIS IS IN PART DUE TO MOIST SURFACE CONDITIONS AS WELL AS
A 40KT LLJ PUMPING IN MOISTURE FROM THE GOMEX. ONE CONCERN WITH
TUESDAY MORNING WILL BE FLOODING. WITH ALREADY SATURATED SOILS AND
FULL PLAYA LAKES RUN OFF...MAINLY IN URBAN AREAS...WILL BE ALL BUT
GUARANTEED WITH A QUICK 1 INCH RAINFALL CAUSING PROBLEMS. WHILE
ACTUAL RAINFALL AMOUNTS AS WELL AS THE LOCATION OF THE HEAVIEST
RAIN IS HARD TO PINPOINT NEARLY 24 HOURS OUT...THE EXPECTED
WIDESPREAD DYNAMIC LIFT IN ADDITION TO THE RICH MOISTURE TRANSPORT
VIA THE LLJ SHOWS THAT HEAVY RAIN MAY BE FAIRLY WIDESPREAD. GIVEN
THAT THIS IS EXPECTED TO HAPPEN DURING THE MORNING TRAFFIC RUSH AN
AREAL FLOOD WATCH MAY BE WARRANTED. FOR NOW WE WILL DEFER THE
WATCH DECISION TO THE NEXT SHIFT FOR FURTHER EVALUATION OF MORE UP
TO DATE INFO. THERE IS A POSSIBLE SEVERE THREAT LATER TOMORROW
AFTERNOON/EVENING DEPENDING ON HOW MUCH SURFACE HEATING CAN BE
ACHIEVED. THIS WILL BE DEPENDENT ON CLOUD COVER. AS OF NOW OUR
WESTERN ZONES HAVE SOMEWHAT HIGHER CHANCES TO SEE SEVERE STORMS
THAN THE REST OF THE FA AS CLOUDS WILL BEGIN TO THIN FROM WEST TO
EAST.
WE SHOULD SEE PRECIP MOVE OFF THE THE EAST BY WED MORNING AS A FRONT
APPROACHES FROM THE NORTH. MODEL TIMING WITH THE FROPA DIFFERS WITH
THE GFS /FRONT PUSHING INTO OUR NORTHERN ZONES BY 00Z THURS/ BEING
SLOWER THAN THE ECMWF /FRONT THRU THE FA BY 00Z/. OTHER THAN WIND
SHIFT AND CLOUD COVER THIS SHOULDN/T CREATE MUCH OF A HEADACHE AS
FAR AS THE FORECAST IS CONCERNED. THE FROPA WILL BE ACCOMPANIED BY A
LOW STRATUS DECK THAT WILL STICK AROUND FOR MUCH OF WED NIGHT INTO
THURS AFTERNOON. RAIN WILL BE POSSIBLE MAINLY DUE TO ISENTROPIC
LIFTING. THE BIGGEST CHANGE TO THE FORECAST DURING THIS PERIOD IS
MAKING THE PRECIP MAINLY IN THE FORM OF RAIN WITH A MENTION OF ISO
THUNDER AS THE CHANCE EXISTS FOR SOME ELEVATED CAPE. ANOTHER LOW IS
PROGGED TO MOVE INLAND ACROSS SOCAL WHICH WILL RETURN SURFACE FLOW
TO OUT OF THE SOUTH/SOUTHEAST AND SET UP A DRYLINE OVER CENTRAL NM.
THIS WILL BE OUR NEXT BIG RAIN MAKER AS THE DRYLINE PUSHES EASTWARD
AND THEN RETREATS FRIDAY AND SATURDAY.
TEMPS WILL CONTINUE TO REMAIN BELOW SEASONAL AVERAGE AS CLOUD COVER
WILL BE ABUNDANT THRU THE WEEK AND SURFACE MOISTURE WILL HELP
MODERATE SURFACE TEMPS. THURS WILL BE PARTICULARLY CHILLY WITH TEMPS
AVERAGING 20 DEGREES BELOW SEASONAL AVERAGE /MID 60S/ DUE TO SURFACE
CAA ASSOCIATED WITH THE FROPA. ALDRICH
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 78 55 71 49 / 10 80 90 20
TULIA 79 57 69 51 / 10 80 90 40
PLAINVIEW 79 58 70 53 / 10 80 90 40
LEVELLAND 83 60 74 56 / 20 80 90 30
LUBBOCK 83 61 73 57 / 10 80 90 40
DENVER CITY 82 61 76 60 / 30 80 80 20
BROWNFIELD 84 61 74 59 / 20 80 90 30
CHILDRESS 86 63 71 60 / 10 60 90 60
SPUR 84 63 73 61 / 10 70 90 50
ASPERMONT 87 66 75 64 / 10 70 90 50
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
29/51
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
648 PM EDT MON MAY 18 2015
.SYNOPSIS...
A COLD FRONT EXTENDS FROM MICHIGAN TO SOUTHERN MISSOURI. THIS
FRONT WILL MOVE EAST ACROSS THE OHIO VALLEY OVERNIGHT...CROSSING
THE MID ATLANTIC REGION TUESDAY. MOIST SOUTHERLY FLOW AHEAD OF THE
FRONT WILL HELP FUEL SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
ONCE THE FRONT PASSES EAST OF THE AREA TUESDAY...COOLER...DRIER
AIR WILL FILTER INTO THE REGION FOR MID WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 640 PM EDT MONDAY...
NO MAJOR CHANGES TO THE FORECAST AS WE HEAD INTO THE EVENING
HOURS. WE STILL EXPECT SCATTERED SHOWERS AND SOME STORMS ACROSS
MUCH OF THE REGION. WHAT DID CHANGE WAS THE FOCUS FOR WHERE THE
BEST CHANCES WOULD BE IN THE NEXT COUPLE OF HOURS BASED UPON WHERE
THE GREATEST CONCENTRATION IS CURRENTLY LOCATED...FROM FRANKLIN
COUNTY VA SOUTHWEST TO AROUND PILOT MOUNTAIN IN NORTH
CAROLINA...AND WEST TO THE GRAYSON HIGHLANDS OF SOUTHWEST
VIRGINIA. ALSO...ANOTHER GENEROUS REGION OF PRECIPITATION WAS
MOVING THROUGH ROCKBRIDGE COUNTY VA...AND THERE WAS ANOTHER ONE
APPROACHING WESTERN GREENBRIER COUNTY AND SUMMERS COUNTY IN
SOUTHEAST WEST VIRGINIA. AS WE PROGRESS INTO THE LATE EVENING AND
TOWARDS MIDNIGHT....FORECAST CHANGES WERE A LITTLE MORE EXPANSIVE.
BASED UPON THE LATEST HRRR AND RNK WRF. THE FORECAST WILL NOW
REFLECT LITTLE OR NO COVERAGE OF PRECIPITATION OUTSIDE SOUTHEAST
WEST VIRGINIA AND NEIGHBORING PORTIONS OF SOUTHWEST VIRGINIA ONCE
WE REACH THAT TIME TONIGHT.
AS OF 330 PM EDT MONDAY...
PWATS 2-3 STANDARD DEVIATIONS ABOVE NORMAL WILL HELP FUEL
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THIS EVENING.
THE AIRMASS IS UNSEASONABLY JUICY BUT LACK OF ANY GOOD DYNAMICS
SHOULD KEEP ACTIVITY UNORGANIZED. NEVER THE LESS...SLOW MOVEMENT
WILL YIELD HEAVY DOWNPOURS FOR ANY PASSING SHOWER/STORM.
FORECAST AREA REMAINS UNDERNEATH A VERY SHARP UPPER LEVEL
RIDGE...WHICH IS PROMOTING VERY LIGHT STEERING WINDS...0-8KM MEAN
WIND OF ONLY 11 KTS...FROM 290 DEGREES. THIS UPPER RIDGE IS
EXPECTED TO WEAKEN AS WE TRANSITION THROUGH THE NEXT 12-18
HOURS...AS LOW PRESSURE MOVES ACROSS THE GREAT LAKES AND INTO
ONTARIO CANADA. AT THE SURFACE...A COLD FRONT WILL TRAIL SOUTH
FROM THE LOW...CROSSING THE OHIO VALLEY TONIGHT. AS THE FRONT
APPROACHES...IT WILL FOCUS THE DEEPER MOISTURE FROM THE OH/TN
VALLEYS INTO THE WEST SIDE OF THE APPALACHIANS. THIS SQUEEZE PLAY
OF DEEPER MOISTURE IN ADDITION TO LINGERING INSTABILITY OVER THE
MOUNTAINS WILL RESULT IN GOOD COVERAGE OF SHOWER ACTIVITY THROUGH
THIS EVENING.
COVERAGE AND INTENSITY OF SHOWER AND THUNDERSTORM ACTIVITY WILL
DECREASE WITH THE LOSS OF DAYTIME HEATING. HOWEVER...WITH THE
COLD FRONT CONTINUING ITS APPROACH OVERNIGHT...SHOWER THREAT WILL
NOT SUBSIDE ALTOGETHER. MOISTURE TRANSPORT AND CONVERGENCE PER
SOUTHWEST WIND FLOW AHEAD OF THE FRONT WILL CONTINUE TO GENERATE
ACTIVITY INTO THE LATE NIGHT.
SURFACE FRONT IS EXPECTED TO REACH THE WESTERN SLOPES OF THE
APPALACHIANS BY DAYBREAK TUESDAY...THEN MOVE OVER AND EAST OF THE
MTNS MID-DAY...CLEARING THE CWA BY TUESDAY EVENING. WILL MAINTAIN
THREAT FOR SHOWERS UNTIL THE PASSAGE OF THE FRONT...FOLLOWED BY
CLEARING AND DRYING WITH FROPA.
MET/MAV TEMPERATURE GUIDANCE LOOKS GOOD...AND USED A BLEND FOR
TONIGHT`S LOWS AND TUESDAYS HIGHS...READINGS REMAINING QUITE MILD
TONIGHT...AOA 60 FOR LOWS...FOLLOWED BY ANOTHER WARM DAY TUESDAY
WITH HIGHS RANGING IN THE 70S MTNS TO THE 80S IN THE LOWER
ELEVATIONS.
ANY SIGNIFICANT COOLING/DRYING WILL NOT TAKE PLACE UNTIL WE CHANGE
AIRMASSES LATER TUESDAY...BECOMING NOTICEABLE ONCE THE SUN GOES
DOWN TUESDAY EVENING.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 300 PM EDT MONDAY...
ANY LINGERING CONVECTION IN THE FAR SOUTHEAST PORTIONS OF FORECAST
AREA WILL TAPER OFF BY 06Z WEDNESDAY. LOW TEMPERATURES TUESDAY NIGHT
WILL RANGE FROM THE UPPER 40S IN THE NORTHWEST MOUNTAINS TO
THE LOWER 60S IN THE PIEDMONT.
HIGH PRESSURE IN THE MIDWEST WILL RIDGE SOUTHEAST INTO OUR AREA FOR
WEDNESDAY PROVIDING A BREAK FROM THE ACTIVE CONVECTION. THE COOLER
HIGH TEMPERATURES ON WEDNESDAY WILL ALSO BE A WELCOME CHANGE WITH
READINGS FROM THE LOWER 60S IN THE NORTHWEST MOUNTAINS TO THE MID
80S IN THE PIEDMONT. WITH A WEAK SHORTWAVE ROTATING EAST ACROSS THE
REGION WEDNESDAY NIGHT...ALLOW FOR SOME LIGHT POPS IN THE WEST.
LOW TEMPERATURES WEDNESDAY NIGHT WILL VARY FROM THE UPPER 40S IN
THE WEST TO THE UPPER 50S IN THE EAST.
THURSDAYS FORECAST REMAINS A CHALLENGE WITH THE LATEST MODEL RUNS
ALL DEPICT A STRONGER SHORTWAVE TRACKING ACROSS THE AREA...BUT WITH
WIDELY VARYING DEGREES OF INTENSITY AND RESULTANT
MOISTURE/PRECIPITATION. WITH CAUTION...ELECTED TO USE A BLEND OF
SUPERBLEND AND HPCGUIDE WITH SCATTERED POPS FOR THURSDAY. HIGH
TEMPERATURES THURSDAY WILL WARM TO AROUND 60 DEGREES IN THE
NORTHWEST TO AROUND 80 DEGREES ALONG THE SOUTHERN BLUE RIDGE.
SHORTWAVE WILL EXIT TO THE SOUTHEAST THURSDAY NIGHT AS SFC HIGH
PRESSURE SLIDES FROM THE PLAINS TO THE GREAT LAKES. OVERALL...THE
AIRMASS APPEARS TO BE TOO STABLE AND DRY IN THE LOWER LEVELS TO
SUPPORT MUCH THUNDER WITH THIS EVENT. HOWEVER...A NOSE OF
INSTABILITY SUPPORT ISOLATED THUNDERSTORM ACROSS SOUTHERN PORTIONS
OF FORECAST AREA. DIURNAL CONVECTION TAPERS OFF QUICKLY THURSDAY
NIGHT. LOW TEMPERATURES THURSDAY NIGHT WILL GENERALLY VARY FROM THE
UPPER 40S IN THE MOUNTAINS TO THE UPPER 50S IN THE PIEDMONT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 300 PM EDT MONDAY...
MOISTURE...WARMTH...AND HUMIDITY ARE POISED TO RETURN BY EARLY NEXT
WEEK AS YET ANOTHER DEEP UPPER LOW BUILDS INTO THE SOUTHWEST UNITED
STATE...THE NORTHEAST TROUGH PUSHES EASTWARD INTO THE NORTHERN
ATLANTIC...AND AN ELONGATED RIDGE BETWEEN THESE TWO FEATURES DRIFTS
INTO OUR REGION. HIGH TEMPERATURES FRIDAY WARM INTO THE MID 60S IN
THE MOUNTAINS TO THE MID 70S IN THE PIEDMONT. LOW TEMPERATURES WILL
DROP INTO THE MID 40S TO THE 50S IN GENERAL.
ON SATURDAY...CANADIAN HIGH PRESSURE SHIFTS OFF THE MID-ATLANTIC
COAST...AS FRONTAL BOUNDARY IS CENTRAL U.S. LIFTS NORTHEAST. KEPT
SATURDAY DRY...WITH HIGH TEMPERATURES RANGING FROM THE MID 60S IN
THE NORTHWEST MOUNTAINS TO THE UPPER 70S IN THE PIEDMONT.
AS THE HIGH CENTER MOVES EAST...AN EAST TO SOUTHEAST RETURN FLOW ON
THE BACKSIDE MAY DEVELOP A WEDGE ACROSS THE REGION OVER THE WEEKEND.
WITH THE POTENTIAL OF OVERRUNNING PRECIPITATION DEVELOPING FROM THE
WEST. ADDED A SLIGHT CHANCE OF SHOWERS IN THE NORTHWEST MOUNTAINS OF
NORTH CAROLINA. MODERATED LOW TEMPERATURES SATURDAY NIGHT WITH
VALUES MAINLY IN THE 50S...WITH INCREASED CLOUD COVER. SCATTERED
SHOWERS CONTINUED ON SUNDAY WITH THE BEST CHANCES IN THE NORTHWEST.
THE UPPER RIDGE WILL SHIFT SOUTHEAST BY MONDAY...ALLOWING AN ACTIVE
BAROCLINIC ZONE TO SHIFT SOUTH AND EAST INTO THE REGION FROM THE
OH/TN VALLEY. CONTINUED THE POTENTIAL FOR SCATTERED CONVECTION ON
TUESDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 200 PM EDT MONDAY...
A VERY MOIST AIR MASS REMAINS ACROSS THE REGION STUCK UNDER AN
UPPER RIDGE AS THE PAST SEVERAL DAYS. HOWEVER...THE PATTERN IS
FINALLY ABOUT TO CHANGE. THE UPPER LOW THAT HAS PLAGUED THE
CENTRAL U.S. THE PAST SEVERAL DAYS IS SHEARING OUT AND MOVING
TOWARD THE GREAT LAKES WHERE IT WILL AID IN THE DEVELOPMENT OF A
DEEP UPPER LOW ACROSS SOUTHEAST CANADA BY MIDWEEK. THIS WILL PUSH
A FRONT INTO OUR REGION BY EARLY TUESDAY...THEN EAST OF THE REGION
BY TUE EVENING.
FOR THIS AFTERNOON AND EVENING...SCATTERED TO NUMEROUS SHOWERS
AND THUNDERSTORMS ARE EXPECTED IN ADVANCE OF THE UPPER
TROUGH/FRONT. THE ACTIVITY WILL EXTEND FROM THE OH/TN VALLEYS
EASTWARD INTO THE MID ATLANTIC...AND FARTHER EAST INTO THE
PIEDMONT AS COMPARED TO THE PAST FEW AFTERNOONS. DURING THE
AFTERNOON/EVENING...THUNDERSTORMS SHOULD BE MOST NUMEROUS WEST OF
THE BLUE RIDGE...SOME WITH LOCALLY HEAVY RAINFALL. THE STRONGER
STORMS WILL CONTAIN LOCALIZED OUTFLOW WINDS OF 25-30KTS IN
ADDITION TO MVFR CIGS AND BRIEF PERIODS OF MVFR-IFR VSBYS. LACK OF
ORGANIZATION MAKES IT DIFFICULT TO PINPOINT TIMING AT ANY OF THE
TERMINALS...ESP THOSE EAST OF THE BLUE RIDGE. AS SUCH...WILL
CONTINUE TO MENTION VCNTY SHRA/TSRA AND AMEND TAFS PER RADAR
TRENDS.
COVERAGE OF THE SHOWERS/THUNDERSTORMS WILL DECREASE AFTER
SUNSET...BUT GIVEN THE SYNOPTIC PATTERN WOULD EXPECT SOME ACTIVITY
TO LINGER ALL NIGHT ACROSS MUCH OF THE CWA. WITH WINDS BECOMING
NW...UPSLOPE MVFR CIGS APPEAR LIKELY ACROSS EASTERN WV INTO FAR
SOUTHWEST VA...WITH MODELS SUGGESTING PERIOD OF IFR CIGS PRIOR TO
DAYBREAK TUESDAY AT KBLF/KLWB. MVFR VSBYS WILL ALSO PREVAIL IN
MANY AREAS OVERNIGHT IN A NEAR SATURATED BOUNDARY LAYER WITH
MOIST/WET GROUND AND LIGHT WSW-WNW WINDS.
ANY LOW CIG/VSBY ELEMENTS SHOULD QUICKLY IMPROVE AFTER 13Z/9AM
TUESDAY WITH RETURN OF VFR FOR THE AFTERNOON. SURFACE FRONT WILL
PASS THROUGH ALL TERMINALS TUESDAY WITH SKIES CLEARING AND WINDS
BECOMING NORTHWEST 6 TO 12 KTS.
EXTENDED AVIATION DISCUSSION...
DRIER/COOLER CONDITIONS ARE EXPECTED TUESDAY NIGHT AND WEDNESDAY.
AN UPPER DISTURBANCE WILL LIKELY BRING SOME MVFR CIGS AND -SHRA
BACK INTO THE AREA THU...MOVING OUT FRIDAY WITH VFR CONDITIONS
RETURNING FRI-SAT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PM
NEAR TERM...DS/PM
SHORT TERM...KK
LONG TERM...KK
AVIATION...PM
Area Forecast Discussion
National Weather Service Spokane WA
725 PM PDT TUE MAY 19 2015
.SYNOPSIS...
A mild, occasionally unsettled pattern will persist over the
region through the week. While most of the region will remain
dry, scattered showers and a few afternoon and evening
thunderstorms will be possible mainly over a small portion of
southeast Washington, north-central Idaho and near the Cascade
crest. The chances of showers and thunderstorms will increase by
Friday as a weak low pressure system drops into northwest
Washington. Some of these thunderstorms could produce locally
heavy rain near the Cascades. A shift toward cooler and wetter
weather will move into the region for the upcoming holiday
weekend.
&&
.DISCUSSION...
An update has been sent to make minor adjustments to the forecast.
The majority of Eastern Washington and north Idaho is under the
influence of dry easterly flow courtesy of a large blocking upper
ridge over western Canada. The only exceptions is over extreme
southeast Washington and the Lewiston area, as well as along the
Washington Cascade crest where moisture wrapping around a broad
low south of the region is clipping these areas. The best
instability this evening is along the Washington Cascade crest,
especially western Chelan county including the Methow Valley.
Uncapped CAPE values as high as 500-1000 J/KG will lead to the
potential for isolated thunderstorms mainly near the Cascade crest
although can`t completely rule out a storm in the Methow Valley
with radar showing a few cells in this area. Easterly flow will
tend to steer most of these storms near the crest towards the west
slopes of the Cascades. Brief heavy rain and gusty winds are the
main threats with these storms. Elsewhere most of the instability
around the Lewiston area is capped...however just enough moisture
and instability is present that a few light showers are expected
through the evening. JW
&&
.AVIATION...
00Z TAFS: Expect a near repeat of weather tomorrow as what
happened today as a persistent weather pattern continues. This
will mean a continuation of VFR conditions at all TAF sites.
Isolated thunderstorms will be focused mainly south of the region across
Oregon, and in the Cascades...mainly along and west of the Cascade
crest. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 50 77 52 79 54 80 / 0 0 10 20 10 20
Coeur d`Alene 48 77 51 78 52 79 / 0 0 10 20 20 20
Pullman 48 76 51 76 50 74 / 10 10 10 30 40 40
Lewiston 54 81 56 81 57 80 / 20 10 20 30 40 50
Colville 49 80 51 83 51 84 / 0 0 10 10 10 10
Sandpoint 49 75 45 78 47 79 / 0 0 10 10 10 10
Kellogg 46 76 48 77 48 77 / 0 10 10 30 20 30
Moses Lake 55 83 56 85 56 83 / 0 0 10 10 20 30
Wenatchee 56 83 60 84 59 82 / 0 10 10 10 20 50
Omak 49 83 50 84 53 83 / 0 0 10 10 10 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
Area Forecast Discussion
National Weather Service Spokane WA
725 PM PDT TUE MAY 19 2015
.SYNOPSIS...
A mild, occasionally unsettled pattern will persist over the
region through the week. While most of the region will remain
dry, scattered showers and a few afternoon and evening
thunderstorms will be possible mainly over a small portion of
southeast Washington, north-central Idaho and near the Cascade
crest. The chances of showers and thunderstorms will increase by
Friday as a weak low pressure system drops into northwest
Washington. Some of these thunderstorms could produce locally
heavy rain near the Cascades. A shift toward cooler and wetter
weather will move into the region for the upcoming holiday
weekend.
&&
.DISCUSSION...
An update has been sent to make minor adjustments to the forecast.
The majority of Eastern Washington and north Idaho is under the
influence of dry easterly flow courtesy of a large blocking upper
ridge over western Canada. The only exceptions is over extreme
southeast Washington and the Lewiston area, as well as along the
Washington Cascade crest where moisture wrapping around a broad
low south of the region is clipping these areas. The best
instability this evening is along the Washington Cascade crest,
especially western Chelan county including the Methow Valley.
Uncapped CAPE values as high as 500-1000 J/KG will lead to the
potential for isolated thunderstorms mainly near the Cascade crest
although can`t completely rule out a storm in the Methow Valley
with radar showing a few cells in this area. Easterly flow will
tend to steer most of these storms near the crest towards the west
slopes of the Cascades. Brief heavy rain and gusty winds are the
main threats with these storms. Elsewhere most of the instability
around the Lewiston area is capped...however just enough moisture
and instability is present that a few light showers are expected
through the evening. JW
&&
.AVIATION...
00Z TAFS: Expect a near repeat of weather tomorrow as what
happened today as a persistent weather pattern continues. This
will mean a continuation of VFR conditions at all TAF sites.
Isolated thunderstorms will be focused mainly south of the region across
Oregon, and in the Cascades...mainly along and west of the Cascade
crest. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 50 77 52 79 54 80 / 0 0 10 20 10 20
Coeur d`Alene 48 77 51 78 52 79 / 0 0 10 20 20 20
Pullman 48 76 51 76 50 74 / 10 10 10 30 40 40
Lewiston 54 81 56 81 57 80 / 20 10 20 30 40 50
Colville 49 80 51 83 51 84 / 0 0 10 10 10 10
Sandpoint 49 75 45 78 47 79 / 0 0 10 10 10 10
Kellogg 46 76 48 77 48 77 / 0 10 10 30 20 30
Moses Lake 55 83 56 85 56 83 / 0 0 10 10 20 30
Wenatchee 56 83 60 84 59 82 / 0 10 10 10 20 50
Omak 49 83 50 84 53 83 / 0 0 10 10 10 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
Area Forecast Discussion
National Weather Service Spokane WA
725 PM PDT TUE MAY 19 2015
.SYNOPSIS...
A mild, occasionally unsettled pattern will persist over the
region through the week. While most of the region will remain
dry, scattered showers and a few afternoon and evening
thunderstorms will be possible mainly over a small portion of
southeast Washington, north-central Idaho and near the Cascade
crest. The chances of showers and thunderstorms will increase by
Friday as a weak low pressure system drops into northwest
Washington. Some of these thunderstorms could produce locally
heavy rain near the Cascades. A shift toward cooler and wetter
weather will move into the region for the upcoming holiday
weekend.
&&
.DISCUSSION...
An update has been sent to make minor adjustments to the forecast.
The majority of Eastern Washington and north Idaho is under the
influence of dry easterly flow courtesy of a large blocking upper
ridge over western Canada. The only exceptions is over extreme
southeast Washington and the Lewiston area, as well as along the
Washington Cascade crest where moisture wrapping around a broad
low south of the region is clipping these areas. The best
instability this evening is along the Washington Cascade crest,
especially western Chelan county including the Methow Valley.
Uncapped CAPE values as high as 500-1000 J/KG will lead to the
potential for isolated thunderstorms mainly near the Cascade crest
although can`t completely rule out a storm in the Methow Valley
with radar showing a few cells in this area. Easterly flow will
tend to steer most of these storms near the crest towards the west
slopes of the Cascades. Brief heavy rain and gusty winds are the
main threats with these storms. Elsewhere most of the instability
around the Lewiston area is capped...however just enough moisture
and instability is present that a few light showers are expected
through the evening. JW
&&
.AVIATION...
00Z TAFS: Expect a near repeat of weather tomorrow as what
happened today as a persistent weather pattern continues. This
will mean a continuation of VFR conditions at all TAF sites.
Isolated thunderstorms will be focused mainly south of the region across
Oregon, and in the Cascades...mainly along and west of the Cascade
crest. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 50 77 52 79 54 80 / 0 0 10 20 10 20
Coeur d`Alene 48 77 51 78 52 79 / 0 0 10 20 20 20
Pullman 48 76 51 76 50 74 / 10 10 10 30 40 40
Lewiston 54 81 56 81 57 80 / 20 10 20 30 40 50
Colville 49 80 51 83 51 84 / 0 0 10 10 10 10
Sandpoint 49 75 45 78 47 79 / 0 0 10 10 10 10
Kellogg 46 76 48 77 48 77 / 0 10 10 30 20 30
Moses Lake 55 83 56 85 56 83 / 0 0 10 10 20 30
Wenatchee 56 83 60 84 59 82 / 0 10 10 10 20 50
Omak 49 83 50 84 53 83 / 0 0 10 10 10 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
Area Forecast Discussion
National Weather Service Spokane WA
725 PM PDT TUE MAY 19 2015
.SYNOPSIS...
A mild, occasionally unsettled pattern will persist over the
region through the week. While most of the region will remain
dry, scattered showers and a few afternoon and evening
thunderstorms will be possible mainly over a small portion of
southeast Washington, north-central Idaho and near the Cascade
crest. The chances of showers and thunderstorms will increase by
Friday as a weak low pressure system drops into northwest
Washington. Some of these thunderstorms could produce locally
heavy rain near the Cascades. A shift toward cooler and wetter
weather will move into the region for the upcoming holiday
weekend.
&&
.DISCUSSION...
An update has been sent to make minor adjustments to the forecast.
The majority of Eastern Washington and north Idaho is under the
influence of dry easterly flow courtesy of a large blocking upper
ridge over western Canada. The only exceptions is over extreme
southeast Washington and the Lewiston area, as well as along the
Washington Cascade crest where moisture wrapping around a broad
low south of the region is clipping these areas. The best
instability this evening is along the Washington Cascade crest,
especially western Chelan county including the Methow Valley.
Uncapped CAPE values as high as 500-1000 J/KG will lead to the
potential for isolated thunderstorms mainly near the Cascade crest
although can`t completely rule out a storm in the Methow Valley
with radar showing a few cells in this area. Easterly flow will
tend to steer most of these storms near the crest towards the west
slopes of the Cascades. Brief heavy rain and gusty winds are the
main threats with these storms. Elsewhere most of the instability
around the Lewiston area is capped...however just enough moisture
and instability is present that a few light showers are expected
through the evening. JW
&&
.AVIATION...
00Z TAFS: Expect a near repeat of weather tomorrow as what
happened today as a persistent weather pattern continues. This
will mean a continuation of VFR conditions at all TAF sites.
Isolated thunderstorms will be focused mainly south of the region across
Oregon, and in the Cascades...mainly along and west of the Cascade
crest. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 50 77 52 79 54 80 / 0 0 10 20 10 20
Coeur d`Alene 48 77 51 78 52 79 / 0 0 10 20 20 20
Pullman 48 76 51 76 50 74 / 10 10 10 30 40 40
Lewiston 54 81 56 81 57 80 / 20 10 20 30 40 50
Colville 49 80 51 83 51 84 / 0 0 10 10 10 10
Sandpoint 49 75 45 78 47 79 / 0 0 10 10 10 10
Kellogg 46 76 48 77 48 77 / 0 10 10 30 20 30
Moses Lake 55 83 56 85 56 83 / 0 0 10 10 20 30
Wenatchee 56 83 60 84 59 82 / 0 10 10 10 20 50
Omak 49 83 50 84 53 83 / 0 0 10 10 10 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
Area Forecast Discussion
National Weather Service Spokane WA
434 PM PDT TUE MAY 19 2015
.SYNOPSIS...
A mild, occasionally unsettled pattern will persist over the
region through the week. While most of the region will remain
dry, scattered showers and a few afternoon and evening
thunderstorms will be possible mainly over a small portion of
southeast Washington, north-central Idaho and near the Cascade
crest. The chances of showers and thunderstorms will increase by
Friday as a weak low pressure system drops into northwest
Washington. Some of these thunderstorms could produce locally
heavy rain near the Cascades. A shift toward cooler and wetter
weather will move into the region for the upcoming holiday
weekend.
&&
.DISCUSSION...
Tonight through Wednesday evening...A complex of upper level lows
centered between the northern California Coast and northern Utah
will persist through this period. Meanwhile a strong upper level
high will remain fixed over eastern Montana. Most of our forecast
area will feel the effects of the latter system with relatively
dry air continuing to surge into our area from the northeast. This
drier air will continue inhibit any deep convection over most of
the Inland NW. The exceptions will continue to occur near the
Cascade Crest and over extreme SE Washington and adjacent portions
of the Idaho Panhandle. The latest visible and IR satellite
imagery is showing convection over these areas as of early
afternoon. The most developed convection was over extreme western
Chelan County, near Stevens Pass, with a slow southwest movement
exhibited. The HRRR has consistently suggested this activity will
not become any more widespread with a tapering off by early
evening. The other area where we could see some convection develop
this evening would be over extreme southern Garfield and eastern
Asotin Counties however satellite trends do not look promising.
Once the convection dies off this evening it will remain dry
through early Wednesday afternoon. Once again any convective
activity will fire over the same areas we are seeing it today. The
model instability parameters are on par with what we are seeing
today, however the lack of significant upper level support will
ensure that any convection we see will be spotty. Temperatures
will remain above seasonal normals with most locations climbing
into the mid 70s to mid 80s. fx
Wednesday night through Friday evening: Little in the way of big
changes are anticipated Wednesday and Thursday. Low pressure over
the southwest portion of the U.S. will continue to draw up
moisture into portions of southern WA and the southern and central
ID Panhandle. This will keep the atmosphere unstable with the best
instability over the northern Cascade Mtns, southeast WA and into
the Central Panhandle Mtns. Even though the instability looks to
be present there is a question of a trigger to get convection
going either Wednesday or Thursday. Higher elevations will have
less CIN to overcome and will see a better chance for convection
to fire during the afternoon. The basin will have a harder time
overcoming the capping inversion without kicker pushing through to
generate lift. Thunderstorms that do develop will be slow moving
and will likely contain heavy rainfall.
By Friday: A shortwave trough of lower pressure will approach the
region off of the eastern Pacific. This disturbance will provide
good synoptic scale lift. The proximity of this disturbance to
the northern Cascade Mtns will give this area the best chance for
convection to fire off through the afternoon and into the evening.
CAPE values off of the NAM and GFS top out at around 700-1000
J/KG; P-Wats will be up around 0.90 inches; and the steering flow
will be 5-10 kts out of the south-southeast. All these factors
coming together would pose a threat for slow moving and wet
thunderstorms. There are some model differences, but the GFS, NAM,
and Canadian models show general agreement with the potential for
heavy rain along the east slopes of the Northern Cascades. The
ECMWF is less unstable and does not show as high of a threat. I
decided to lean more away from the 12Z ECMWF model guidance in
favor of the better agreement between the GFS, NAM and Canadian
model guidance. The main concern will be for the possibility of
Flash Flooding and/or Debris Flows. Recent burn scar locations
will be most susceptible, but the threat will not only be limited
to these locations. Specifics in where the heaviest rain will
fall is uncertain at this time. This leads to moderate to high
confidence in the possibility for scattered thunderstorm activity
over this area, but low confidence in any actual impacts
occurring. This situation will need to be monitored with future
updates as the event approaches.
The threat of thunderstorms will spread eastward into Friday
evening. The southeast portion of the the forecast area will be
another prime location for instability and will see a good chance
for thunderstorms. Models are more uncertain about the
northwestern portion of the region with questions regarding instability
and lift. Temperatures will be warm and above normal through the
latter half of the work week. Temperatures are expected to peak
Thursday and Friday with some locations potentially reaching 80s
for the first time this season. /SVH
Friday night through Tuesday...Confidence is growing that there
will be a wet event during the holiday weekend but medium range
models are not playing well with others. Both the GFS and ECMWF
show an upper level low moving through the region but there remain
significant differences in the track of the low as well as some
timing issues. The GFS seems to have more run-to-run consistency
so for now the forecast will lean toward that solution. PoPs have
been raised to likely category for a chunk of the forecast area
for the Friday night/Saturday period. Until models show a trend
toward consensus, the Saturday night/Sunday period will stay
within the chance category and the remainder of the extended
period will trend near climo PoPs. The eventual track of the low
will determine where the heaviest precipitation will fall but with
Pwats hovering around an inch, it should be a decent wetting rain.
Some afternoon/evening thunderstorms will be possible through the
weekend, but for now we will keep a broad brush slight chance
thunder across the entire forecast area during peak heating.
Temperatures will be on a cooling trend for the weekend, with
areas of precipitation dictating where the coolest daytime temps
will be. /Kelch
&&
.AVIATION...
00Z TAFS: Expect a near repeat of weather tomorrow as what
happened today as a persistent weather pattern continues. This
will mean a continuation of VFR conditions at all TAF sites.
Isolated thunderstorms will be focused mainly south of the region across
Oregon, and in the Cascades...mainly along and west of the Cascade
crest. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 50 77 52 79 54 80 / 0 0 10 20 10 20
Coeur d`Alene 48 77 51 78 52 79 / 0 0 10 20 20 20
Pullman 48 76 51 76 50 74 / 10 10 10 30 40 40
Lewiston 54 81 56 81 57 80 / 20 10 20 30 40 50
Colville 49 80 51 83 51 84 / 0 0 10 10 10 10
Sandpoint 46 75 45 78 47 79 / 0 0 10 10 10 10
Kellogg 46 76 48 77 48 77 / 10 10 10 30 20 30
Moses Lake 55 83 56 85 56 83 / 0 0 10 10 20 30
Wenatchee 56 83 60 84 59 82 / 10 10 10 10 20 50
Omak 49 83 50 84 53 83 / 0 0 10 10 10 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
Area Forecast Discussion
National Weather Service Spokane WA
256 PM PDT TUE MAY 19 2015
.SYNOPSIS...
A mild, occasionally unsettled pattern will persist over the
region through the week. While most of the region will remain
dry, scattered showers and a few afternoon and evening
thunderstorms will be possible mainly over a small portion of
southeast Washington, north-central Idaho and near the Cascade
crest. The chances of showers and thunderstorms will increase by
Friday as a weak low pressure system drops into northwest
Washington. Some of these thunderstorms could produce locally
heavy rain near the Cascades. A shift toward cooler and wetter
weather will move into the region for the upcoming holiday
weekend.
&&
.DISCUSSION...
Tonight through Wednesday evening...A complex of upper level lows
centered between the northern California Coast and northern Utah
will persist through this period. Meanwhile a strong upper level
high will remain fixed over eastern Montana. Most of our forecast
area will feel the effects of the latter system with relatively
dry air continuing to surge into our area from the northeast. This
drier air will continue inhibit any deep convection over most of
the Inland NW. The exceptions will continue to occur near the
Cascade Crest and over extreme SE Washington and adjacent portions
of the Idaho Panhandle. The latest visible and IR satellite
imagery is showing convection over these areas as of early
afternoon. The most developed convection was over extreme western
Chelan County, near Stevens Pass, with a slow southwest movement
exhibited. The HRRR has consistently suggested this activity will
not become any more widespread with a tapering off by early
evening. The other area where we could see some convection develop
this evening would be over extreme southern Garfield and eastern
Asotin Counties however satellite trends do not look promising.
Once the convection dies off this evening it will remain dry
through early Wednesday afternoon. Once again any convective
activity will fire over the same areas we are seeing it today. The
model instability parameters are on par with what we are seeing
today, however the lack of significant upper level support will
ensure that any convection we see will be spotty. Temperatures
will remain above seasonal normals with most locations climbing
into the mid 70s to mid 80s. fx
Wednesday night through Friday evening: Little in the way of big
changes are anticipated Wednesday and Thursday. Low pressure over
the southwest portion of the U.S. will continue to draw up
moisture into portions of southern WA and the southern and central
ID Panhandle. This will keep the atmosphere unstable with the best
instability over the northern Cascade Mtns, southeast WA and into
the Central Panhandle Mtns. Even though the instability looks to
be present there is a question of a trigger to get convection
going either Wednesday or Thursday. Higher elevations will have
less CIN to overcome and will see a better chance for convection
to fire during the afternoon. The basin will have a harder time
overcoming the capping inversion without kicker pushing through to
generate lift. Thunderstorms that do develop will be slow moving
and will likely contain heavy rainfall.
By Friday: A shortwave trough of lower pressure will approach the
region off of the eastern Pacific. This disturbance will provide
good synoptic scale lift. The proximity of this disturbance to
the northern Cascade Mtns will give this area the best chance for
convection to fire off through the afternoon and into the evening.
CAPE values off of the NAM and GFS top out at around 700-1000
J/KG; P-Wats will be up around 0.90 inches; and the steering flow
will be 5-10 kts out of the south-southeast. All these factors
coming together would pose a threat for slow moving and wet
thunderstorms. There are some model differences, but the GFS, NAM,
and Canadian models show general agreement with the potential for
heavy rain along the east slopes of the Northern Cascades. The
ECMWF is less unstable and does not show as high of a threat. I
decided to lean more away from the 12Z ECMWF model guidance in
favor of the better agreement between the GFS, NAM and Canadian
model guidance. The main concern will be for the possibility of
Flash Flooding and/or Debris Flows. Recent burn scar locations
will be most susceptible, but the threat will not only be limited
to these locations. Specifics in where the heaviest rain will
fall is uncertain at this time. This leads to moderate to high
confidence in the possibility for scattered thunderstorm activity
over this area, but low confidence in any actual impacts
occurring. This situation will need to be monitored with future
updates as the event approaches.
The threat of thunderstorms will spread eastward into Friday
evening. The southeast portion of the the forecast area will be
another prime location for instability and will see a good chance
for thunderstorms. Models are more uncertain about the
northwestern portion of the region with questions regarding instability
and lift. Temperatures will be warm and above normal through the
latter half of the work week. Temperatures are expected to peak
Thursday and Friday with some locations potentially reaching 80s
for the first time this season. /SVH
Friday night through Tuesday...Confidence is growing that there
will be a wet event during the holiday weekend but medium range
models are not playing well with others. Both the GFS and ECMWF
show an upper level low moving through the region but there remain
significant differences in the track of the low as well as some
timing issues. The GFS seems to have more run-to-run consistency
so for now the forecast will lean toward that solution. PoPs have
been raised to likely category for a chunk of the forecast area
for the Friday night/Saturday period. Until models show a trend
toward consensus, the Saturday night/Sunday period will stay
within the chance category and the remainder of the extended
period will trend near climo PoPs. The eventual track of the low
will determine where the heaviest precipitation will fall but with
Pwats hovering around an inch, it should be a decent wetting rain.
Some afternoon/evening thunderstorms will be possible through the
weekend, but for now we will keep a broad brush slight chance
thunder across the entire forecast area during peak heating.
Temperatures will be on a cooling trend for the weekend, with
areas of precipitation dictating where the coolest daytime temps
will be. /Kelch
&&
.AVIATION...
18Z TAFS: Dry northeast flow will deliver VFR conditions to all
forecast sites. There will be a small chance of -shra that could
develop over extreme SE WA/NC ID and an westward drift could move
them close enough to LWS to warrant the mention of vcsh in their
forecast. The HRRR keeps this threat through 04-06z or so. After
that we should see any chance of convection move out of that area
with VFR conditions prevailing. fx
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 50 77 52 79 54 80 / 0 0 10 20 10 20
Coeur d`Alene 48 77 51 78 52 79 / 0 0 10 20 20 20
Pullman 48 76 51 76 50 74 / 10 10 10 30 40 40
Lewiston 54 81 56 81 57 80 / 20 10 20 30 40 50
Colville 49 80 51 83 51 84 / 0 0 10 10 10 10
Sandpoint 46 75 45 78 47 79 / 0 0 10 10 10 10
Kellogg 46 76 48 77 48 77 / 10 10 10 30 20 30
Moses Lake 55 83 56 85 56 83 / 0 0 10 10 20 30
Wenatchee 56 83 60 84 59 82 / 10 10 10 10 20 50
Omak 49 83 50 84 53 83 / 0 0 10 10 10 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
550 PM CDT MON MAY 18 2015
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 235 PM CDT MON MAY 18 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW OCCLUDED
LOW PRESSURE MOVING EAST OVER WESTERN LAKE SUPERIOR. A VERY CHILLY
AIRMASS FOR THIS TIME OF THE YEAR IS WRAPPING AROUND THE LOW AND
GRADUALLY MOVING EAST OVER THE WESTERN HALF OF WISCONSIN. THE LOW
STRATUS HAS MOVED VERY LITTLE EASTWARD SO FAR TODAY...BUT SHOULD
GAIN SOME MOMENTUM THROUGH THE AFTERNOON AS THE COLDER AIR AT 850MB
OVER TAKES IT. PLENTY OF OBS ARE REPORTING LIGHT RAIN/DRIZZLE...AND
EVEN A FEW FLAKES UPSTREAM OVER NORTHWEST WISCONSIN AND NORTHERN
MINNESOTA. AS THE COLDER AIR AND LIGHT PRECIP SPREAD ACROSS THE
REGION...TEMPS AND PRECIP TRENDS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...OCCLUDED LOW PRESSURE WILL MOVE EAST OVER LAKE SUPERIOR
AND NORTHERN ONTARIO AND WEAKEN AT THE SAME TIME. AS WINDS SHIFT TO
THE NORTHWEST...COLD ADVECTION WILL CONTINUE ACROSS THE STATE
THROUGH THE NIGHT...DROPPING 850MB TEMPS TO AROUND -8C TO -10C.
DEEPER MOISTURE WILL BE ROTATING ACROSS NORTHERN WISCONSIN AND
COMBINED WITH UPSLOPE FLOW OFF LAKE SUPERIOR AND UNSTABLE
CONDITIONS...SHOULD SEE PERIODS OF LIGHT RAIN/DRIZZLE...MIXED WITH
SNOW AT TIMES. TEMPERATURES WILL BE FALLING INTO THE 30-32 DEGREE
RANGE OVER NORTHERN WISCONSIN FOR A FEW HOURS LATE TONIGHT. BUT
AREAS OVER THE UPPER PENINSULA AND NORTHWEST WISCONSIN HAVE NOT
OFFICIALLY STARTED THEIR GROWING SEASONS...SO WILL HIGHLIGHT THE
COLD IN A SPECIAL WEATHER STATEMENT. ELSEWHERE...LOOK FOR A CLOUDY
AND BLUSTERY NIGHT.
TUESDAY...THERMAL TROUGHING AND FLOW OFF LAKE SUPERIOR ARGUE FOR A
CLOUDY/MOSTLY CLOUDY START TO THE DAY. BUT SHOULD SEE CLOUDS
GRADUALLY ERODE FROM SOUTHWEST THROUGH NORTHEAST THROUGH THE DAY AS
CYCLONIC FLOW ABATES AND LOW LEVEL TEMPS MODERATE. LOWERED MAX
TEMPS A DEGREE...AND WENT WITH HIGHS RANGING FROM THE MID 40S NORTH
TO MID 50S SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 235 PM CDT MON MAY 18 2015
FROST/FREEZE HEADLINE POTENTIAL TUESDAY NIGHT AND WEDNESDAY NIGHT...
AND PCPN TRENDS FOR THE MEMORIAL DAY WEEKEND...ARE THE MAIN FCST
CONCERNS.
CANADIAN HIGH PRESSURE WILL BE RIDGED OVER THE WSTRN GREAT LAKES
ON TUESDAY NIGHT...AND WILL BRING LIGHT WINDS TO THE FORECAST AREA.
EXPECT SKIES TO BE MOSTLY CLEAR OVER NORTHERN WI...LEADING TO
WIDESPREAD SUB-FREEZING TEMPERATURES. AVERAGE MIXING RATIOS OF
2.5 TO 3 G/KG SUPPORT THE POTENTIAL FOR MIN TEMPS AS COLD AS
20 TO 25 AT THE CLIMATOLOGICALLY FAVORED COLD SPOTS. HIGH CLOUDS
ARE EXPECTED TO INCREASE OVER C/EC WI...ON THE ANTICYCLONIC SHEAR
SIDE...AND WITHIN THE RRQ...OF A STRONG UPPER JET STREAK. WHILE
THIS LIKELY WILL NOT PREVENT FROST DEVELOPMENT IN OUR SOUTHERN
COUNTIES...IT SHOULD AT LEAST KEEP MOST PLACES ABOVE FREEZING.
WILL NOT ISSUE ANY HEADLINES WITH THIS FORECAST PACKAGE...BUT
FROST/FREEZE HEADLINES APPEAR IMMINENT.
THE POTENTIAL FOR FROST WILL CONTINUE INTO WEDNESDAY NIGHT...
BUT SHOULD SHIFT TO MAINLY NORTHERN WI...WHERE MIN TEMPS ARE
EXPECTED TO DROP INTO THE LOWER TO MIDDLE 30S.
A WEAK BACK DOOR COLD FRONT IS EXPECTED TO DROP SOUTH THROUGH
THE REGION SOMETIME DURING THE WEDS NGT TO THU NGT PERIOD. THE
GFS IS FOCUSING ON WEDS NGT/THU...WHILE THE ECMWF IS SLOWER
AND BRINGS THE FRONT THROUGH THU AND EARLY THU NGT. A VERY
DRY AIR MASS SHOULD PRECLUDE ANY PCPN DEVELOPMENT.
CANADIAN HIGH PRESSURE WILL RETURN TO THE WSTRN GREAT LAKES
FRIDAY...AND SHOULD HOLD ANY PCPN AT BAY THROUGH AT LEAST
SATURDAY.
A COLD FRONT/INVERTED SFC TROF AND UPPER TROF WILL IMPACT THE
REGION FOR THE LATTER HALF OF THE MEMORIAL DAY WEEKEND...BUT
TIMING DIFFERENCES ARE SIGNIFICANT BETWEEN THE MODELS. THE GFS
HAS PCPN OVER THE REGION FROM SAT NGT THROUGH MONDAY...WITH THE
HEAVIEST QPF FCST ON SUNDAY. THE ECMWF IS SLOWER...AND FOCUSES
MOST OF THE PCPN DURING THE SUNDAY NIGHT AND MONDAY PERIODS.
DUE TO THE TIMING DIFFERENCES...HAVE BACKED OFF ON LIKELY POPS
FOR ANY SPECIFIC PERIOD...BUT OVERALL TRENDS SUPPORT AT LEAST
A PERIOD OR TWO OF MODERATE RAINFALL.
SLIGHTLY BLO NORMAL TEMPERATURES ARE EXPECTED AT THE BEGINNING
AND END OF THE EXTENDED PERIOD...WITH NEAR NORMAL READINGS FOR
THE REST OF THE DAYS.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 548 PM CDT MON MAY 18 2015
A MUCH COLDER AIR MASS WILL POUR ACROSS THE TAF SITES OVER THE
NEXT 24 HOURS. OCCASIONAL RAIN SHOWERS...DRIZZLE AND A SNOW SHOWER
OR TWO ARE LIKELY ACROSS NORTH-CENTRAL WISCONSIN TONIGHT AS DEEPER
MOISTURE MOVES OVERHEAD. OTHERWISE...WINDS WILL VEER TO THE
NORTHWEST TONIGHT AND REMAIN GUSTY. BROKEN MVFR CIGS WILL SPREAD
EAST INTO EASTERN WISCONSIN LATER THIS EVENING AND HANG AROUND
INTO TUESDAY MORNING. COOL DRY HIGH PRESSURE SETTLING INTO THE
GREAT LAKES REGION WILL PRODUCE VFR CIGS LATER TUESDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......TDH
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 235 PM CDT MON MAY 18 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW OCCLUDED
LOW PRESSURE MOVING EAST OVER WESTERN LAKE SUPERIOR. A VERY CHILLY
AIRMASS FOR THIS TIME OF THE YEAR IS WRAPPING AROUND THE LOW AND
GRADUALLY MOVING EAST OVER THE WESTERN HALF OF WISCONSIN. THE LOW
STRATUS HAS MOVED VERY LITTLE EASTWARD SO FAR TODAY...BUT SHOULD
GAIN SOME MOMENTUM THROUGH THE AFTERNOON AS THE COLDER AIR AT 850MB
OVER TAKES IT. PLENTY OF OBS ARE REPORTING LIGHT RAIN/DRIZZLE...AND
EVEN A FEW FLAKES UPSTREAM OVER NORTHWEST WISCONSIN AND NORTHERN
MINNESOTA. AS THE COLDER AIR AND LIGHT PRECIP SPREAD ACROSS THE
REGION...TEMPS AND PRECIP TRENDS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...OCCLUDED LOW PRESSURE WILL MOVE EAST OVER LAKE SUPERIOR
AND NORTHERN ONTARIO AND WEAKEN AT THE SAME TIME. AS WINDS SHIFT TO
THE NORTHWEST...COLD ADVECTION WILL CONTINUE ACROSS THE STATE
THROUGH THE NIGHT...DROPPING 850MB TEMPS TO AROUND -8C TO -10C.
DEEPER MOISTURE WILL BE ROTATING ACROSS NORTHERN WISCONSIN AND
COMBINED WITH UPSLOPE FLOW OFF LAKE SUPERIOR AND UNSTABLE
CONDITIONS...SHOULD SEE PERIODS OF LIGHT RAIN/DRIZZLE...MIXED WITH
SNOW AT TIMES. TEMPERATURES WILL BE FALLING INTO THE 30-32 DEGREE
RANGE OVER NORTHERN WISCONSIN FOR A FEW HOURS LATE TONIGHT. BUT
AREAS OVER THE UPPER PENINSULA AND NORTHWEST WISCONSIN HAVE NOT
OFFICIALLY STARTED THEIR GROWING SEASONS...SO WILL HIGHLIGHT THE
COLD IN A SPECIAL WEATHER STATEMENT. ELSEWHERE...LOOK FOR A CLOUDY
AND BLUSTERY NIGHT.
TUESDAY...THERMAL TROUGHING AND FLOW OFF LAKE SUPERIOR ARGUE FOR A
CLOUDY/MOSTLY CLOUDY START TO THE DAY. BUT SHOULD SEE CLOUDS
GRADUALLY ERODE FROM SOUTHWEST THROUGH NORTHEAST THROUGH THE DAY AS
CYCLONIC FLOW ABATES AND LOW LEVEL TEMPS MODERATE. LOWERED MAX
TEMPS A DEGREE...AND WENT WITH HIGHS RANGING FROM THE MID 40S NORTH
TO MID 50S SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 235 PM CDT MON MAY 18 2015
FROST/FREEZE HEADLINE POTENTIAL TUESDAY NIGHT AND WEDNESDAY NIGHT...
AND PCPN TRENDS FOR THE MEMORIAL DAY WEEKEND...ARE THE MAIN FCST
CONCERNS.
CANADIAN HIGH PRESSURE WILL BE RIDGED OVER THE WSTRN GREAT LAKES
ON TUESDAY NIGHT...AND WILL BRING LIGHT WINDS TO THE FORECAST AREA.
EXPECT SKIES TO BE MOSTLY CLEAR OVER NORTHERN WI...LEADING TO
WIDESPREAD SUB-FREEZING TEMPERATURES. AVERAGE MIXING RATIOS OF
2.5 TO 3 G/KG SUPPORT THE POTENTIAL FOR MIN TEMPS AS COLD AS
20 TO 25 AT THE CLIMATOLOGICALLY FAVORED COLD SPOTS. HIGH CLOUDS
ARE EXPECTED TO INCREASE OVER C/EC WI...ON THE ANTICYCLONIC SHEAR
SIDE...AND WITHIN THE RRQ...OF A STRONG UPPER JET STREAK. WHILE
THIS LIKELY WILL NOT PREVENT FROST DEVELOPMENT IN OUR SOUTHERN
COUNTIES...IT SHOULD AT LEAST KEEP MOST PLACES ABOVE FREEZING.
WILL NOT ISSUE ANY HEADLINES WITH THIS FORECAST PACKAGE...BUT
FROST/FREEZE HEADLINES APPEAR IMMINENT.
THE POTENTIAL FOR FROST WILL CONTINUE INTO WEDNESDAY NIGHT...
BUT SHOULD SHIFT TO MAINLY NORTHERN WI...WHERE MIN TEMPS ARE
EXPECTED TO DROP INTO THE LOWER TO MIDDLE 30S.
A WEAK BACK DOOR COLD FRONT IS EXPECTED TO DROP SOUTH THROUGH
THE REGION SOMETIME DURING THE WEDS NGT TO THU NGT PERIOD. THE
GFS IS FOCUSING ON WEDS NGT/THU...WHILE THE ECMWF IS SLOWER
AND BRINGS THE FRONT THROUGH THU AND EARLY THU NGT. A VERY
DRY AIR MASS SHOULD PRECLUDE ANY PCPN DEVELOPMENT.
CANADIAN HIGH PRESSURE WILL RETURN TO THE WSTRN GREAT LAKES
FRIDAY...AND SHOULD HOLD ANY PCPN AT BAY THROUGH AT LEAST
SATURDAY.
A COLD FRONT/INVERTED SFC TROF AND UPPER TROF WILL IMPACT THE
REGION FOR THE LATTER HALF OF THE MEMORIAL DAY WEEKEND...BUT
TIMING DIFFERENCES ARE SIGNIFICANT BETWEEN THE MODELS. THE GFS
HAS PCPN OVER THE REGION FROM SAT NGT THROUGH MONDAY...WITH THE
HEAVIEST QPF FCST ON SUNDAY. THE ECMWF IS SLOWER...AND FOCUSES
MOST OF THE PCPN DURING THE SUNDAY NIGHT AND MONDAY PERIODS.
DUE TO THE TIMING DIFFERENCES...HAVE BACKED OFF ON LIKELY POPS
FOR ANY SPECIFIC PERIOD...BUT OVERALL TRENDS SUPPORT AT LEAST
A PERIOD OR TWO OF MODERATE RAINFALL.
SLIGHTLY BLO NORMAL TEMPERATURES ARE EXPECTED AT THE BEGINNING
AND END OF THE EXTENDED PERIOD...WITH NEAR NORMAL READINGS FOR
THE REST OF THE DAYS.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1207 PM CDT MON MAY 18 2015
A MUCH COLDER AIRMASS WILL FILTER ACROSS THE TAF SITES OVER THE
NEXT 24 HOURS. OCCASIONAL RAIN SHOWERS...DRIZZLE...AND A SNOW
SHOWER OR TWO ARE LIKELY ACROSS NORTH-CENTRAL WISCONSIN TONIGHT AS
DEEPER MOISTURE MOVES OVERHEAD. OTHERWISE...WINDS WILL VEER TO THE
NORTHWEST TONIGHT AND REMAIN GUSTY. BROKEN MVFR CIGS WILL SPREAD
EAST INTO EASTERN WISCONSIN THIS EVENING AND LOOK TO HANG AROUND
THROUGH THE END OF THE TAF PERIOD.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1136 PM CDT SUN MAY 17 2015
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.UPDATE...
ISSUED AT 608 PM CDT SUN MAY 17 2015
STORMS HAVE DIMINISHED IN INTENSITY AND COVERAGE THE
LAST FEW HOURS OVER THE FORECAST AREA. MESO DATA SUGGESTS THE
REGION OF POTENTIAL NEW DEVELOPMENT OF STORMS LIKELY OVER THE
NORTHWEST HALF OF THE STATE...INCLUDING PARTS OF CENTRAL AND
NORTH CENTRAL WISCONSIN WITH THE BEST SHEAR VALUES...AND STEEP
SURFACE LAPSE RATES. ANTICIPATE THE SURFACE LAPSE RATES TO BE ON
THE DECLINE THE NEXT FEW HOURS...SO THE THREAT OF STRONG TO SEVERE
STORMS SHOULD LESSON. SPIRALING BANDS OF CONVECTION OVER EASTERN
MINNESOTA AND FAR WESTERN WISCONSIN CLOSER TO THE LOW PRESSURE
AREA OVER NORTHERN MINNESOTA MAY ROTATE INTO THIS ENVIRONMENT AND
INTENSIFY OVER NORTH CENTRAL WISCONSIN THIS EVENING.
&&
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 229 PM CDT SUN MAY 17 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN OCCLUDED
LOW PRESSURE SYSTEM SPINNING OVER THE EASTERN DAKOTAS. SHORTWAVES
ARE ROTATING NORTHWARD AHEAD OF THIS OCCLUDED CYCLONE...THE
STRONGEST OF WHICH IS LOCATED OVER EASTERN IOWA. A PWAT AXIS IS
MOVING ACROSS WISCONSIN EARLY THIS AFTERNOON...WHICH COMBINED WITH
MOISTURE CONVERGENCE...IS CONTRIBUTING TO SCATTERED SHOWER
DEVELOPMENT OVER CENTRAL WISCONSIN. CLOUD COVER HAS SIGNIFICANTLY
SLOWED THE HEATING CURVE SO FAR TODAY...KEEPING ML CAPES BELOW 200
J/KG. WITH SHOWER COVERAGE EXPECT TO INCREASE THROUGH THE
AFTERNOON...IT WILL BE TOUGH TO SEE MUCH OF AN INCREASE OF
INSTABILITY. STILL THOUGH...RADAR ECHOES SUGGEST SOME THUNDERSTORMS
WILL BE POSSIBLE...AND ANY STORMS COULD BRING DOWN STRONG WINDS FROM
ALOFT. WILL HAVE TO KEEP A MENTION OF ISOLATED DAMAGING WINDS
THROUGH EARLY THIS EVENING. OTHERWISE...THE LATEST HRRR CONGEALS THE
SHOWER ACTIVITY INTO BAND AND PROGRESSES IT ACROSS THE FORECAST AREA
FOR THE REST OF THE AFTERNOON.
TONIGHT...LOW PRESSURE WILL MOVE EAST ACROSS NORTHERN
MINNESOTA...WHILE A COLD FRONT WILL PUSH EAST THROUGH ALL BUT FAR
EASTERN WISCONSIN OVERNIGHT. THOUGH SHORTWAVE ENERGY WILL BE
ROTATING NORTHEAST OVER NORTHWEST WISCONSIN THROUGH THE
EVENING...CONCERNED THAT STRONG DRYING AND INCREASING CAPPING IN THE
MID-LEVELS WILL EVEN FURTHER LIMIT THUNDERSTORM POTENTIAL FOR THE
FIRST COUPLE HOURS IN THE EVENING. WILL KEEP A MENTION OF ISOLATED
DAMAGING WINDS THROUGH 02Z IN CASE SOME THUNDERSTORMS MAKE A RUN
INTO N-C WISCONSIN FROM MINNESOTA. ONCE THE THREAT OF STORMS ENDS...MODELS
SHOW CLEARING TAKING PLACE UNTIL LOW CLOUDS FLOOD EAST BEHIND THE
COLD FRONT LATE TONIGHT. LOW TEMPS NEAR 60 OVER THE EAST...BUT
COOLING TO NEAR 50 OVER THE WEST.
MONDAY...OCCLUDED LOW PRESSURE WILL BE WEAKENING AS IT MOVES TO THE
EAST ACROSS LAKE SUPERIOR. WEST WINDS ON THE SOUTHERN FLANK OF THE
LOW WILL BE COLD ADVECTING THROUGH THE DAY...WHILE PUSHING IN WRAP
AROUND MOISTURE. SHOULD SEE AMPLE CLOUD COVER OVER CENTRAL AND
NORTH-CENTRAL WISCONSIN THROUGH THE DAY...BUT EAST-CENTRAL WISCONSIN
WILL LIKELY SEE SOME SUN IN THE MORNING BEFORE CLOUDS INCREASE IN
THE AFTERNOON. WITH THE SUNSHINE...TEMPS SHOULD WARM TO NEAR 70 IN
THE EAST...BUT ONLY INTO THE MID AND UPPER 50S OVER THE WEST.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 229 PM CDT SUN MAY 17 2015
MUCH COOLER TEMPERATURES FOR THE FIRST HALF OF THE WORK WEEK...DRY
AND MILDER CONDITIONS FOR THE LATTER HALF...AND A POSSIBLE RETURN
TO WET WEATHER LATER IN THE MEMORIAL DAY WEEKEND...ARE THE MAIN
FCST CONCERNS.
THE REMNANTS OF THE UPPER LOW WILL TRACK ACROSS NORTHERN LAKE SUPERIOR
ON MONDAY NIGHT...FOLLOWED BY A S/W TROF PASSING NORTH OF WI ON TUESDAY.
UNSEASONABLY COLD AIR (H8 TEMPS -8 TO -10 C) WILL FLOW INTO THE REGION
ON NNW WINDS...SETTING THE STAGE FOR SOME LAKE-ENHANCED SHOWERS OVER
NC WI. LOW-LEVEL TEMPS AND THICKNESSES SUPPORT A MIX THEN CHANGEOVER
TO SNOW LATE MONDAY NIGHT INTO TUESDAY MORNING...WITH LITTLE OR NO
ACCUMULATION EXPECTED. ANY LINGERING PCPN SHOULD END TUESDAY AFTERNOON
AS CANADIAN HIGH PRESSURE BUILDS INTO THE REGION.
HIGH PRESSURE WILL COVER THE AREA TUESDAY NIGHT INTO WEDNESDAY. STILL
EXPECTING FROST TUESDAY NIGHT...BUT GETTING A LITTLE CONCERNED ABOUT
THE POSSIBILITY OF THICKER HIGH LEVEL CLOUDS...DUE TO THE PRESENCE
OF A STRONG JET STREAK OVER THE REGION. RIGHT NOW...HAVE JUST
BUMPED UP CLOUD COVER A BIT OVER C/EC WI...BUT KEPT MOSTLY CLEAR
SKIES OVER NORTHERN WI. WILL CONTINUE TO CARRY WIDESPREAD FROST OR
FREEZE CONDITIONS OVER NORTHERN WI...AND PATCHY FROST OVER MOST OF
C/EC WI.
A WEAK BACK DOOR COLD FRONT WILL SAG THROUGH THE FORECAST AREA THURSDAY
INTO THURSDAY NIGHT...BUT WILL NOT HAVE ANY MOISTURE TO WORK WITH...SO
DRY WEATHER WILL PREVAIL. BEHIND THE FRONT...CANADIAN HIGH PRESSURE
WILL REESTABLISH ITSELF OVER THE WESTERN GREAT LAKES...AND IS EXPECTED
TO LINGER INTO SATURDAY. ABUNDANT SUNSHINE SHOULD BRING A RETURN TO
NEAR NORMAL TEMPERATURES FOR THE LATTER HALF OF THE WEEK.
AN UPPER TROF...LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL
IMPACT THE REGION FROM SATURDAY NIGHT INTO SUNDAY. GULF MOISTURE
IS EXPECTED TO FLOW INTO THE REGION AHEAD OF THE FRONT...WITH
PRECIPITABLE WATER VALUES REACHING 1.00-1.25 INCHES. HAVE RAMPED
POPS UP TO LIKELY FOR SUNDAY. THE ECMWF PULLS MOST OF THE PCPN OUT
OF THE REGION SUNDAY EVG...WHILE THE GFS HANGS ONTO SIGNIFICANT
QPF INTO MEMORIAL DAY...SO FCST CONFIDENCE WANES BEYOND SUNDAY.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1135 PM CDT SUN MAY 17 2015
LAST OF THE SHOWERS WERE DEPARTING FAR NORTH CENTRAL
WISCONSIN LATE THIS EVENING. OTHERWISE VFR CONDITIONS TO PREVAIL
OVERNIGHT ALONG WITH LLWS CONDITIONS. LLWS CONDITIONS WILL END
MONDAY MORNING BUT BLUSTERY WEST SURFACE WINDS WILL DEVELOP.
WRAP AROUND MVFR CIGS DUE TO THE DEPARTING UPPER LOW SYSTEM WILL
BEGIN TO WORK INTO CENTRAL AND NORTH CENTRAL WISCONSIN MONDAY
MORNING. CIGS WILL CONTINUE TO WORK INTO EASTERN AREAS BUT WILL
MORE OF THE LOWER END VFR CIGS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE.........TDH
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
417 AM CDT WED MAY 20 2015
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
AN AREA OF SHOWERS AND THUNDERSTORMS HAS CONTINUED TO PUSH EASTWARD
AND INTO THE AREA DURING THE OVERNIGHT HOURS. SO FAR RAINFALL RATES
EXCEEDING ONE TO TWO INCHES PER HOUR HAVE BEEN SEEN ACROSS WESTERN
PORTIONS OF THE CWA. HRRR...ARW...NMM HAVE ALL HAD A GOOD HANDLE ON
THE SYSTEM TONIGHT AND DO AGREE THAT THE SYSTEM WILL WEAKEN BY
MIDMORNING. DO BELIEVE SOME DRIER AIR WILL FILTER INTO WESTERN
ARKANSAS...BUT AT THIS TIME ONLY THE HRRR COMPLETELY DRIES THINGS
OUT DURING THE AFTERNOON HOURS. DID CONTINUE WITH CHANCE POPS DURING
THE AFTERNOON HOURS FOR MUCH OF THE CWA...BUT THIS WILL NEED TO
CONTINUE TO BE MONITORED AND UPDATED AS NEEDED.
FRONT IS EXPECTED TO CLEAR THE STATE BY 00Z AND WILL CONTINUE TO
PUSH SOUTH AND REMAIN ACROSS LOUISIANA. FOR THE MOST PART...THURSDAY
WILL REMAIN DRY FOR MUCH OF THE STATE...WITH SOME PRECIP CHANCES
REMAINING ACROSS SOUTHERN ARKANSAS. HIGH PRESSURE WILL BUILD IN
BRIEFLY BEFORE PRECIPITATION CHANCES RETURN TO THE FORECAST ON
FRIDAY. MODELS HAVE COME IN BETTER AGREEMENT WITH THE PRECIP ON
FRIDAY...BUT IT LOOKS LIKE PRECIPITATION CHANCES WILL REMAIN
GENERALLY ACROSS WESTERN ARKANSAS. UNSETTLED WEATHER WILL CONTINUE
THROUGH THE WEEKEND WITH A LONGWAVE TROUGH ACROSS THE WESTERN CONUS.
&&
.LONG TERM...SUNDAY THROUGH TUESDAY
MODEL DATA THIS MRNG CONT TO INDC AN UNSETTLED WX PATTERN WL PERSIST
ACRS THE REGION TO CLOSE OUT THE HOLIDAY WEEKEND. AN UPR RDG WL SET
UP OVR THE SOUTHEASTERN STATES...RESULTING IN A SWLY FLOW ALOFT ACRS
AR. A SERIES OF IMPULSES WL TRACK NEWD AND BRING CONTD CHCS OF
SHRA/TSRA EACH DAY. KEPT POPS IN THE CHC CAT FOR NOW AS TIMING OF
EACH SHRTWV WL RMN DIFFICULT THIS FAR IN ADVANCE. HVY RAIN POTENTIAL
WL ALSO BE A CONCERN THRU THE PD...ALONG WITH THE CONTD THREAT OF
FLOODING.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 68 52 68 51 / 70 30 10 10
CAMDEN AR 86 63 73 59 / 70 40 20 10
HARRISON AR 70 49 66 50 / 70 20 10 10
HOT SPRINGS AR 83 62 71 56 / 70 30 20 10
LITTLE ROCK AR 81 60 71 56 / 70 30 20 10
MONTICELLO AR 85 63 71 57 / 70 30 20 10
MOUNT IDA AR 83 59 70 54 / 70 30 20 10
MOUNTAIN HOME AR 67 49 68 51 / 70 20 10 10
NEWPORT AR 70 52 67 51 / 70 40 10 10
PINE BLUFF AR 83 61 70 56 / 70 30 20 10
RUSSELLVILLE AR 80 58 71 55 / 70 20 20 10
SEARCY AR 76 57 69 51 / 70 40 10 10
STUTTGART AR 79 58 70 54 / 70 40 20 10
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...65 / LONG TERM...44
AREA FORECAST DISCUSSION
NWS TOPEKA KS
332 AM CDT Wed May 20 2015
.SHORT TERM...(Today and Tonight)
Issued at 331 AM CDT WED MAY 20 2015
Mid/upper level trough currently lifting northeastward over SD and
NE, and will eventually merge with energy tracking over the upper
Midwest. An expansive area of light to moderate rain will move
across northeast KS early this morning, which is supported by upper
level forcing associated with the trough and low level
frontogenesis. Most of the forcing is forecast to continue eastward
and mainly exiting the area around 12Z. There are indications that
light rain showers and or drizzle could linger through the early
afternoon hours after the mid/upper levels dry out. Both RAP and NAM
soundings show steep low level lapse rates coinciding with
saturation along with weak lift. This could be enough to generate
these light showers and or drizzle. Although these models also
suggest isentropic downglide on the backside of the wave so very
little precip accumulations are expected after 12Z. Clouds will
stick around most of the day and northerly flow will keep
temperatures from warming up much, therefore highs will generally be
in the mid 50s. Surface high pressure will build into the region
tonight and clouds may begin to scatter out as the drier air filters
southward. As surface winds begin to lighten and temperatures cool
there is a chance fog could develop especially given the recent
rainfall. Temperatures are expected to drop into the low to mid 40s
with a few isolated locations in the upper 30s.
.LONG TERM...(Thursday through Tuesday)
Issued at 331 AM CDT WED MAY 20 2015
Thursday through Thursday night, A surface ridge of high pressure
over eastern KS will shift east into MO by Friday morning. An upper
level trough will move onshore across southern CA. Expect mostly
sunny skies on Thursday with highs reaching the mid 60s. Thursday
night will be a bit warmer as the center of the surface ridge moves
east into MO, allowing light winds to become southerly. Lows Friday
morning will only drop into the mid to upper 40s. High and mid level
clouds will increase late Thursday night.
Friday through Monday, The upper trough over southern CA will slowly
drift northeast into western CO and slowly fill. Southwest flow
aloft across the central Rockies will cause a surface lee trough to
deepen across the central and southern high plains. Deeper gulf
moisture will gradually be advected northward into the southern
plains Friday afternoon. The resulting isentropic lift ahead of the
deeper moisture return combined with any ascent from minor H5
troughs embedded within the southern stream of the H5 jet will
provide an increasing chance for showers and isolated thunderstorms
during the day Friday and into the Friday evening. The ECMWF shows a
brief amplification of the main H5 trough across AZ. This may
amplify a downstream H5 ridge across the southern plains which may
provide a break from the showers and thunderstorms across eastern KS
on Saturday. Due to cloud cover and increasing rain chances on
Friday, highs will only reach the mid 60s. If we see more insolation
on Saturday highs will reach the lower 70s.
Saturday night through Sunday night, the Upper trough will fill as
it lifts northeast into western CO. The southern stream H5 ridge
will shift east across the Gulf coast states. Embedded shortwave
trough combined with deeper moisture advection will cause periods of
showers and thunderstorms to develop. The mid level flow will weaken
below 40 KTS. The weaker vertical wind shear should prevent
organized storms updrafts. Also, the instability may be lower due to
the cloud cover. I don`t expect severe thunderstorms this weekend.
The primary hazard may be occasional heavy rainfall. Highs on Sunday
will reach the mid 70s
Monday (Memorial Day), The ECMWF and GEM forecast a slightly more
amplified H5 trough to move northeast from southwest TX into central
OK. The better ascent ahead of this trough will be across northern
TX and southern OK. Both models do not forecast much in the way of
QPF during the day. The showers and thunderstorms may increase
Monday night as the H5 trough lifts northeast into western MO. Highs
on Monday should reach the mid 70s
Tuesday, the H5 trough across western MO will lift northeast into
eastern IA and IL. We may see a break in the precip. The GFS is
slower moving the H5 trough northeast across MO and forecast higher
QPF across eastern KS on Tuesday. Looks a bit warmer on Tuesday as
16 to 18 degree C 850mb temps advect northeast across the CWA. Highs
should reach into the upper 70s to around 80.
&&
.AVIATION...(For the 06Z TAFs through 06Z Wednesday Night)
Issued at 1127 PM CDT TUE MAY 19 2015
Drier air behind the departing wave has allowed the lower categories
to remain west of terminals thus far. Short term guidance is still
trending with the showers west of KMHK to track east through 11Z.
Confidence is decent in MVFR ceilings, however IFR is a bit more
uncertain at KTOP/KFOE, with the better chances for a heavier
shower and therefore the lower ceilings to impact KMHK. Ceilings
gradually recover back to high end MVFR by the afternoon as
northerly winds hover near 10 kts throughout the period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Sanders
LONG TERM...Gargan
AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS PADUCAH KY
318 AM CDT WED MAY 20 2015
.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 316 AM CDT WED MAY 20 2015
TIGHTER ZONAL GRADIENT DEVELOPS TODAY IN THE WAKE OF THE DEPARTING
AND DAMPENING LOW/MIDDLE LEVEL RIDGE. COMBINED WITH SLIGHTLY
STRONGER VORTICITY IN MINOR LOW AMPLITUDE NORTH-SOUTH SHORTWAVE
SHOULD PROVIDE SUFFICIENT LIFT FOR SHOWER ACTIVITY. STILL BELIEVE
THE ANTECEDENT CLOUD COVER AND COOLER BOUNDARY LAYER TEMPERATURES
IN NORTHERLY/NORTHEASTERLY WOULD PROVIDE SUFFICIENT LIFT FOR
SHOWER GENERATION. OVERALL INSTABILITY ALOFT WILL BE ENOUGH TO
SUPPORTED LIMITED THUNDERSTORM CHANCES ALONG THE SOUTHERN 1/3 OF
THE WFO PAH FORECAST AREA.
THE EXTENT OF CLOUD COVER AND NORTH/NORTHEASTERLY COOL/DRY FLOW
FROM THE DEPARTING RIDGE WILL DETERMINE THE EASTWARD MOVEMENT OF
THE PRECIPITATION TODAY AND THIS EVENING ACROSS THE WFO PAH
FORECAST AREA. THE HRRR AND GFS GUIDANCE SUPPORT A MORE
PROGRESSIVE AND FASTER SCENARIO, BUT WITH LESSER RESIDENCE TIME
FOR INSTABILITY ACROSS THE AREA. BLENDED THIS GUIDANCE WITH
EXISTING FORECAST.
BEYOND TONIGHT...DRY CONDITIONS SHOULD RETURN TO THE FORECAST AREA
THROUGH NEARLY ALL OF FRIDAY NIGHT.
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 316 AM CDT WED MAY 20 2015
ABOVE AVERAGE FORECAST CONFIDENCE IN THE LONG TERM WITH MODELS
SHOWING MINOR DISAGREEMENTS.
AT THE BEGINNING OF THE LONG TERM PERIOD...AN H5 RIDGE IN PLACE OVER
THE REGION BEGINS TO FLATTEN AND SHIFT EASTWARD ALLOWING DEEPER
MOISTURE AND A SERIES OF UPPER LEVEL DISTURBANCES TO SPREAD
PRECIPITATION CHANCES EASTWARD ACROSS THE REGION. AS THE RIDGE AXIS
SHIFTS FARTHER EASTWARD...PRECIPITATION CHANCES WILL GENERALLY
INCREASE THROUGH THE LONG TERM PERIOD.
TEMPERATURES SHOULD REMAIN AT OR ABOVE NORMAL THROUGH THE PERIOD.
&&
.AVIATION...
ISSUED AT 1157 PM CDT TUE MAY 19 2015
NORTH/NORTHEAST WINDS AND VFR CONDITIONS INTO WEDNESDAY MORNING. A
WEAKENING SURFACE LOW/TROUGH WILL PASS EAST TO THE SOUTH OF THE
AREA THROUGH THE AFTERNOON AND EVENING HOURS. SHRA/RA WILL BE
ACCOMPANY IT THROUGH THE REGION. NOT SURE HOW FAST SATURATION WILL
OCCUR...BUT IT SHOULD BE QUICKER AND RESULT IN LOWER CONDITIONS AT KCGI
AND KPAH THAN AT KEVV AND KOWB. THE WORST CONDITIONS IN BR/DZ WILL
BE BEHIND THE MORE SIGNIFICANT RAINS INTO THE EVENING. WENT AS
LOW AS IFR CONDITIONS IN THE EVENING IN THE SOUTHWEST...BUT KEPT
IT AT MVFR IN THE NORTHEAST. TRIED TO STAY ON THE OPTIMISTIC SIDE
OF GUIDANCE...SO LOWER CONDITIONS CANNOT BE RULED OUT.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...SMITH
LONG TERM...JP
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
258 AM EDT WED MAY 20 2015
.SYNOPSIS...
A SEASONABLY COOL AND MAINLY DRY WEATHER PATTERN WILL CONTINUE
INTO WEEKEND...FOLLOWED BY A GRADUAL WARMING TREND WITH UNSETTLED
CONDITIONS RETURNING EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
IR STLT SHOWS A PRETTY SOLID STRATOCUMULS CLOUD SHIELD COVERING
THE WRN 1/2 OF THE CWA EARLY THIS MORNING. THERE HAS EVEN BEEN
SOME LIGHT RAIN/SPRINKLES REPORTED AT BFD/OLE IN COOL UPSLOPE NW
FLOW REGIME. THE LOW CLOUDS ARE ASSOCIATED WITH A 850MB COOL POOL
ALOFT WHICH IS FCST TO MODERATE THROUGH THE AFTERNOON. WITH NO
SIGNIFICANT WX EXPECTED ON DAY 1 THE SENSIBLE WX FCST CHALLENGES
INVOLVE T/TD...SKY...WINDS AND RH VALUES WITH PERHAPS SOME
MARGINAL FIRE WX CONCERNS. WILL TAKE CLOSER LOOK AT THIS WITH THE
NEXT UPDATE...BUT FOR NOW LEANED ON THE HRRR WHICH HAS SUBJECTIVELY
PERFORMED BETTER THAN THE BLENDED MODEL DATA WITH DEWPOINTS AND
SUBSEQUENT RH/S. CLOUD COVER MAY BE CRITICAL KEEPING TEMPS LOWER
AND THUS RH/S HIGHER. BREEZY AND NOTICEABLY COOLER WILL DESCRIBE
TODAY QUITE WELL WITH HIGHS RUNNING 15 TO 20 DEGREES LOWER THAN
YESTERDAY...AND ABOUT 5 TO 15 DEGREES BELOW LATE MAY CLIMATOLOGY.
LOOK FOR CLOUDS TO INCREASE BY EARLY TONIGHT IN ADVANCE OF
SHORTWAVE TROUGH TRACKING THROUGH THE GREAT LAKES EMBEDDED WITHIN
LARGE SCALE UPPER TROUGH ANCHORING THE NORTHEASTERN SECTOR OF THE
CONTINENT. THE MODELS SEEM TO BE IN SLIGHTLY BETTER AGREEMENT IN
POSSIBLE SHOWERS DEVELOPING OVER SOUTH-CENTRAL PA LATE TONIGHT
INTO THURSDAY. THE PCPN ACTIVITY APPEARS TO BE TIED TO WAA
DOWNSTREAM OF HEIGHT FALL CENTER REACHING THE UPPER OH VLY. AS A
RESULT HAVE INCREASED POPS INTO THE LOW-MID CHC RANGE FOR THE
SOUTH-CENTRAL ZONES WITH THE HIGHEST POPS ALONG THE MD BORDER.
FINALLY...BLENDED MIN TEMPS ARE IN THE UPPER 30S OVER THE NW MTNS
BUT THE OVERALL PATTERN AND EXPECTED CLOUD COVER DOES NOT REALLY
SUPPORT FROST FORMATION.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
DAY 2/THURSDAY MAY END UP BEING THE COOLEST DAY OF THE WEEK AS
LOW CLOUDS PERSIST FOR MUCH OF THE DAY ACROSS SOUTH-CENTRAL PA.
GUIDANCE BLEND SUGGEST DAYTIME READINGS HOLDING IN THE 50S IN THE
LAUREL HIGHLANDS. PCPN CHANCES SHOULD LINGER ALONG THE SRN TIER
DURING THE DAY BEFORE DRIER AIR RETURNS TO CENTRAL PA BEHIND A
WEAK FRONTAL PASSAGE THU NGT. WINDS SHOULD PICK UP SOME THU NIGHT
BUT OVERALL EXPECT CLEARING SKIES FROM NW TO SE AND NO SIG WX.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
A WEAK SFC LOW IS FCST TO EMERGE OFF THE CAROLINAS INTO FRIDAY
WITH SOME SPREAD IN THE GUIDANCE...OWING TO VARIABILITY IN THE
HANDLING OF THE PARENT SHORTWAVE. A SECONDARY COLD FRONT SHOULD
CROSS THE AREA ON FRIDAY FOLLOWED BY A REINFORCING SHOT OF COOL
AIR. CONFIDENCE REMAINS ON THE LOW SIDE FOR FROST THU MORNING IN
THE NORTH AS THE PATTERN DOES NOT LOOK FAVORABLE OR CONDUCIVE.
CONFIDENCE IN FROST POTENTIAL IS MUCH HIGHER ON SATURDAY MORNING
OVER THE NORTH-CNTRL ZONES WITH A LARGE AREA OF HIGH PRESSURE
FCST TO SETTLE OVER CENTRAL PA. MAINTAINED FROST WORDING IN SOME
NORTHERN ZONES. DRY WX SHOULD HOLD ON UNTIL EARLY NEXT WEEK AS
THE UPPER RIDGE BUILDS AGAIN OVER THE ERN U.S.
AN E-W FRONTAL BOUNDARY LOOKS TO BECOME A FOCUS FOR PCPN MON-TUE
AS IT PIVOTS AND LIFTS NWD IN A SIMILAR FASHION TO THIS PAST
WEEKEND. ALL GUIDANCE POINTS TO A GRADUAL WARMING TREND OVER THE
WEEKEND...WITH EVEN MILDER AND MORE MUGGY CONDITIONS STARTING
MEMORIAL DAY AND CONTINUING INTO NEXT WEEK.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
11 PM UPDATE...
THE AVIATION CONCERN OVERNIGHT AND INTO THE MONRING IS THE SHIELD
OF MVFR CEILINGS THAT ARE SPREADING OVER CENTRAL AND NORTHWEST PA.
CURRENTLY BFD AND JST ARE AT MVFR WITH BFD AT TIMES DOWN TO IFR IN
LOW STRATOCU. EXPECT MVFR TO SPREAD TO AOO...UNV AND IPT. HOWEVER
IFR IS LESS LIKELY CONSIDERING THE WINDS...BUT THIS DOWNSLOPE FLOW
TO THE LOWER SUSQ SHOULD KEEP SKIES MAINLY SCATTERED AND VFR. THE
PERSISTENT NORTHWESTERLY FLOW SHOULD KEEP ANY REDUCTION IN VSBYS.
LOW CEILINGS WILL MIX OUT AND LIFT QUICKLY THIS MORNING LEAVING
VFR CONDITIONS AT ALL SITES BY MID DAY. GUSTY WINDS WILL CONTINUE
IN THE NEIGHBORHOOD OF 10-15 KT OVERNIGHT BEFORE INCREASING ONCE
AGAIN WED TO 15-25 KT. HOWEVER AS THE WINDS SHIFT TO THE NORTH
LATER IN THE DAY...THE GUSTS WILL SUBSIDE AND WINDS WILL DECREASE
TO NEAR CALM BETWEEN 23Z TO 02Z THURSDAY.
OUTLOOK...
THU-FRI...NO SIG WX.
SUN...MAINLY VFR...MVFR POSS IN SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...RXR/STEINBUGL
AVIATION...LA CORTE/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
209 AM EDT WED MAY 20 2015
.SYNOPSIS...
A SEASONABLY COOL AND MAINLY DRY WEATHER PATTERN WILL CONTINUE
INTO WEEKEND...FOLLOWED BY A GRADUAL WARMING TREND WITH UNSETTLED
CONDITIONS RETURNING EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
IR STLT SHOWS A PRETTY SOLID STRATOCUMULS CLOUD SHIELD COVERING
THE WRN 1/2 OF THE CWA EARLY THIS MORNING. THERE HAS EVEN BEEN
SOME LIGHT RAIN/SPRINKLES REPORTED AT BFD/OLE IN COOL UPSLOPE NW
FLOW REGIME. THE LOW CLOUDS ARE ASSOCIATED WITH A 850MB COOL POOL
ALOFT WHICH IS FCST TO MODERATE THROUGH THE AFTERNOON. WITH NO
SIGNIFICANT WX EXPECTED ON DAY 1 THE SENSIBLE WX FCST CHALLENGES
INVOLVE T/TD...SKY...WINDS AND RH VALUES WITH PERHAPS SOME
MARGINAL FIRE WX CONCERNS. WILL TAKE CLOSER LOOK AT THIS WITH THE
NEXT UPDATE...BUT FOR NOW LEANED ON THE HRRR WHICH HAS SUBJECTIVELY
PERFORMED BETTER THAN THE BLENDED MODEL DATA WITH DEWPOINTS AND
SUBSEQUENT RH/S. CLOUD COVER MAY BE CRITICAL KEEPING TEMPS LOWER
AND THUS RH/S HIGHER. BREEZY AND NOTICEABLY COOLER WILL DESCRIBE
TODAY QUITE WELL WITH HIGHS RUNNING 15 TO 20 DEGREES LOWER THAN
YESTERDAY...AND ABOUT 5 TO 15 DEGREES BELOW LATE MAY CLIMATOLOGY.
LOOK FOR CLOUDS TO INCREASE BY EARLY TONIGHT IN ADVANCE OF
SHORTWAVE TROUGH TRACKING THROUGH THE GREAT LAKES EMBEDDED WITHIN
LARGE SCALE UPPER TROUGH ANCHORING THE NORTHEASTERN SECTOR OF THE
CONTINENT. THE MODELS SEEM TO BE IN SLIGHTLY BETTER AGREEMENT IN
POSSIBLE SHOWERS DEVELOPING OVER SOUTH-CENTRAL PA LATE TONIGHT
INTO THURSDAY. THE PCPN ACTIVITY APPEARS TO BE TIED TO WAA
DOWNSTREAM OF HEIGHT FALL CENTER REACHING THE UPPER OH VLY. AS A
RESULT HAVE INCREASED POPS INTO THE LOW-MID CHC RANGE FOR THE
SOUTH-CENTRAL ZONES WITH THE HIGHEST POPS ALONG THE MD BORDER.
FINALLY...BLENDED MIN TEMPS ARE IN THE UPPER 30S OVER THE NW MTNS
BUT THE OVERALL PATTERN AND EXPECTED CLOUD COVER DOES NOT REALLY
SUPPORT FROST FORMATION.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
DAY 2/THURSDAY MAY END UP BEING THE COOLEST DAY OF THE WEEK AS
LOW CLOUDS PERSIST FOR MUCH OF THE DAY ACROSS SOUTH-CENTRAL PA.
GUIDANCE BLEND SUGGEST DAYTIME READINGS HOLDING IN THE 50S IN THE
LAUREL HIGHLANDS. PCPN CHANCES SHOULD LINGER ALONG THE SRN TIER
DURING THE DAY BEFORE DRIER AIR RETURNS TO CENTRAL PA BEHIND A
WEAK FRONTAL PASSAGE THU NGT. WINDS SHOULD PICK UP SOME THU NIGHT
BUT OVERALL EXPECT CLEARING SKIES FROM NW TO SE AND NO SIG WX.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
A WEAK SFC LOW IS FCST TO EMERGE OFF THE CAROLINAS INTO FRIDAY
WITH SOME SPREAD IN THE GUIDANCE...OWING TO VARIABILITY IN THE
HANDLING OF THE PARENT SHORTWAVE. A SECONDARY COLD FRONT SHOULD
CROSS THE AREA ON FRIDAY FOLLOWED BY A REINFORCING SHOT OF COOL
AIR. CONFIDENCE REMAINS ON THE LOW SIDE FOR FROST THU MORNING IN
THE NORTH AS THE PATTERN DOES NOT LOOK FAVORABLE OR CONDUCIVE.
CONFIDENCE IN FROST POTENTIAL IS MUCH HIGHER ON SATURDAY MORNING
OVER THE NORTH-CNTRL ZONES WITH A LARGE AREA OF HIGH PRESSURE
FCST TO SETTLE OVER CENTRAL PA. MAINTAINED FROST WORDING IN SOME
NORTHERN ZONES. DRY WX SHOULD HOLD ON UNTIL EARLY NEXT WEEK AS
THE UPPER RIDGE BUILDS AGAIN OVER THE ERN U.S.
AN E-W FRONTAL BOUNDARY LOOKS TO BECOME A FOCUS FOR PCPN MON-TUE
AS IT PIVOTS AND LIFTS NWD IN A SIMILAR FASHION TO THIS PAST
WEEKEND. ALL GUIDANCE POINTS TO A GRADUAL WARMING TREND OVER THE
WEEKEND...WITH EVEN MILDER AND MORE MUGGY CONDITIONS STARTING
MEMORIAL DAY AND CONTINUING INTO NEXT WEEK.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
11 PM UPDATE...
A SHIELD OF MVFR CEILINGS HAS MOVED INTO THE LAURELS UP INTO THE NW
MOUNTAINS...AND WILL KEEP CEILINGS IN THE 1500-4000` RANGE IN
PLACE FOR MUCH OF THE OVERNIGHT. CEILINGS OF 3000-5000` MAY MAKE
IT DOWN INTO THE AREA FROM ALTOONA TO STATE COLLEGE AND
WILLIAMSPORT BUT DOWNSLOPE FLOW INTO THE LOWER SUSQ VALLEY SHOULD
FAVOR MAINLY SCATTERED SKIES.
LOW CEILINGS WILL MIX OUT AND LIFT QUICKLY WEDNESDAY MORNING
LEAVING VFR CONDITIONS AT ALL SITES BY MID DAY.
A GUSTY WIND WILL CONTINUE IN THE NEIGHBORHOOD OF 10-15 KT
OVERNIGHT BEFORE INCREASING ONCE AGAIN WED TO 15-25 KT.
OUTLOOK...
THU-FRI...NO SIG WX.
SUN...MAINLY VFR...MVFR POSS IN SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...RXR/STEINBUGL
AVIATION...LA CORTE
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
252 AM MDT WED MAY 20 2015
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 250 AM MDT WED MAY 20 2015
08Z SURFACE ANALYSIS HAD HIGH PRESSURE OVER THE DAKOTAS. WATER
VAPOUR LOOP HAD UPPER LOW SPINNING OVER NORTH CENTRAL NE.
DEFORMATION ZONE -RASN ACROSS SOUTHERN SD STARTING TO WANE AS
MOISTURE PLUME IS CUTOFF AND MAIN FORCING SHIFTS NORTHEAST ON 90KT
JET STREAK ACROSS THE MIDDLE MO RIVER VALLEY. FEW INCHES OF SNOW
OVER THE HIGHER ELEVATIONS PER WEB CAMS/ROAD REPORTS SINCE TUESDAY
AFTERNOON. 00Z NAM/GFS AND LATEST RAP SHOW PRECIPITATION WANING
THROUGH THE MORNING HOURS WITH MOST SYNOPTIC SCALE ACTIVITY/LIFT
DONE BY 18Z. LOW LEVEL INSTABILITY SUGGESTS A FEW POPCORN SHOWERS
POSSIBLE THIS AFTERNOON ACROSS THE FAR SOUTH GIVEN RESIDUAL LOW
LEVEL MOISTURE...BUT DRIER AIR INFILTRATING BOUNDARY LAYER UNDER
SURFACE HIGH MAY LIMIT ACTIVITY TO SPRINKLES/VIRGA. TEMPERATURES
WILL COOL AND BE BELOW GUIDANCE ACROSS THE SOUTH BUT NEAR
GUIDANCE ACROSS THE NORTH WHERE CLEARING SKIES WILL MAKE FOR A
PLEASANT DAY...ALBEIT BELOW NORMAL.
TONIGHT/THURSDAY...WEAK UPPER RIDGE BUILDS INTO THE NORTHERN PLAINS
AS SURFACE HIGH SHIFTS INTO THE MIDDLE MS RIVER VALLEY. FROST MAY
OCCUR OVER PARTS OF THE SD PLAINS AND LATER SHIFTS WILL NEED TO
ASSESS FOR HEADLINES. WEAK RETURN FLOW EXPECTED THURSDAY WITH WARM
AIR ADVECTION PUSHING TEMPERATURES INTO THE 60S ON THE PLAINS AND
50S IN THE BLACK HILLS.
THURSDAY NIGHT...UPPER FLOW BECOMES SOUTHWEST IN RESPONSE TO UPPER
LOW/TROUGH OVER THE WEST COAST. SHORTWAVE MOVING THROUGH WY MAY
PRODUCE SMALL POPS OVER THE FAR SOUTHWEST LATE. TEMPERATURES WILL BE
NEAR GUIDANCE.
.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 250 AM MDT WED MAY 20 2015
THE NEXT LOW PRESSURE SYSTEM TO EJECT OUT OF THE WESTERN CONUS
TROF WILL BEGIN TO IMPACT THE AREA ON FRIDAY...WITH CHANCES FOR
SHOWERS AND THUNDERSTORMS INCREASING FROM SOUTHWEST TO NORTHEAST
ACROSS THE CWA INTO FRIDAY EVENING. MEDIUM RANGE MODELS SEEM TO BE
IN BETTER AGREEMENT ON THE TRACK OF THE SYSTEM...WITH SOME
DIFFERENCES ON TIMING AND WHERE HEAVIER RAINFALL MAY DEVELOP. THE
BEST CHANCES FOR MORE WIDESPREAD PCPN STILL LOOK TO BE FROM LATE
FRIDAY INTO SUNDAY MORNING...WITH THE THREAT FOR HEAVIEST RAINFALL
GENERALLY BEING SATURDAY AFTERNOON AND NIGHT. SATURDAY LOOKS TO BE
THE MOST FAVORABLE DAY FOR STRONGER THUNDERSTORMS AS WELL...
ESPECIALLY FROM THE BLACK HILLS AREA AND EASTWARD. AS THE SYSTEM
WEAKENS TO THE NORTH AND EAST OF THE AREA LATE IN THE
WEEKEND...SOUTHWEST FLOW ALOFT WILL REMAIN OVER THE REGION. THIS
WILL KEEP THE UNSETTLED PATTERN CONTINUING INTO EARLY NEXT WEEK.
TEMPERATURES WILL STAY BELOW AVERAGE THROUGH THE WEEKEND WITH
CLOUDS AND MOISTURE ACROSS THE AREA. WILL LIKELY SEE A WARMING
TREND TO NEAR AVERAGE TEMPERATURES EARLY NEXT WEEK.
&&
.AVIATION...FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT
ISSUED AT 250 AM MDT WED MAY 20 2015
LOW PRESSURE ALOFT WILL WEAKEN AND SHIFT EAST OF THE REGION THIS
MORNING. LIGHT RAIN/SNOW WITH MVFR/IFR CONDITIONS OVER SOUTHERN SD
AND PORTIONS OF NORTHEAST WY WILL CONTINUE EARLY THIS
MORNING...WITH PCPN TAPERING OFF AND CONDITIONS IMPROVING TO VFR
FROM NORTH TO SOUTH THROUGH THE REST OF THE MORNING AND MIDDAY
HOURS. VFR CONDITIONS WILL PERSIST ACROSS NORTHWEST SD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...HELGESON
LONG TERM...26
AVIATION...26
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
450 AM CDT Wed May 20 2015
.SHORT TERM...
(Today and Tonight)
This morning, a cool front extended across central and southwest
Oklahoma and southwest to south of Lubbock. Also, a complex of
thunderstorms (latest IR indicating warming cloud tops) was
located across north Texas and southern Oklahoma or mainly along
the Red River valley. Scattered showers and storms extended back
west into Haskell and Throckmorton counties. For today, the cool
front will make some progress south across West Central Texas to
probably along a San Angelo to Brownwood line by 00Z. Looks like
the best potential for thunderstorms will be in the warm sector
across the southern half of the area, along and ahead of the
front. All the models indicate at least scattered thunderstorms
developing, with the high res HRRR the most aggressive. The
combination of moderate instability and 0-6km shear values of
30-35 knots will lead to a few storms becoming severe during
mainly this afternoon and evening. the main hazards will be large
hail and damaging winds. The Big Country will probably see more
stable conditions behind the front, so the severe weather concern
is mainly low for the next 24 hours. Highs today will range from
the upper 60s to lower 70s across the Northern Big Country to
lower 80s along the I-10 corridor.
For tonight, the scattered afternoon storms may form into an
organized complex during this evening. However, there is some
uncertainty on how and where the storms will organize. For now,
will keep the likely Pops going across the southeast half of the
area and chance Pops elsewhere. Locally heavy rainfall will be
possible mainly due to PW values of 1.25 to 1.5 inches. Again, A few
storms may be severe during the evening. The cool front should move
south of the area after midnight and convection should begin to
weaken some.
.LONG TERM...
(Thursday through Tuesday)
...Unsettled weather will continue through the Memorial Day
Weekend...
Cloudy and cool conditions will start off the extended period on
Thursday, as the cold front remains stalled south of the area
during the day. Temperatures will be well below normal for this
time of year, with highs ranging from the upper 60s across the Big
Country, to the middle 70s along the I-10 corridor. Best rain
chances will be across the southern half of the forecast area
during the day, but will ramp up areawide by Thursday night as a
shortwave lifts northeast across the area.
Southerly flow returns on Friday as the stalled front lifts back
north as a warm front during the day. Temperatures will be warmer
but still below normal, with highs mainly in the upper 70s and
lower 80s. There will be a continued chance for showers and
thunderstorms on Friday, with highest POPs across northern
sections where aformentioned front is expected to lift north
during the afternoon hours.
Maintaining high POPs for next weekend as a short wave trough
moves east from the Four Corners region on Saturday and across
the southern Rockies by Sunday. This system will bring a threat
of strong to severe storms and heavy rainfall potential to the
area for the Memorial Day weekend. Precipitation chances will
start to wane by early next week as weak short wave ridging
develops in the wake of the departing upper trough.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 74 59 68 58 77 / 40 50 40 60 50
San Angelo 80 63 71 61 81 / 40 60 40 60 40
Junction 83 67 75 64 83 / 20 60 50 50 40
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21/24
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
426 AM CDT WED MAY 20 2015
.SHORT TERM (TODAY THROUGH THURSDAY)...
AREA STREAMS AND RIVERS ARE HAVING A BRIEF PERIOD TO RECOVER
THROUGH EARLY TODAY BEFORE A COLD FRONT ARRIVES TO TRIGGER NEW
CONVECTION AND POSSIBLY RIVER RISES. MOST OF THE HIGHER RES MODELS
GENERATE WHAT LOOKS TO BE STRONG TO SEVERE STORMS OVER THE WESTERN
HALF OF THE FORECAST AREA WHERE THE COLD FRONT INTERACTS WITH HIGH
EVENING CAPE VALUES AND LIGHT TO MODERATE SHEAR. WITH SPC MESO-
ANALYSIS SHOWING HIGH PWAT VALUES OVER THE COMPLEX RIDING ALONG
THE COLD FRONT OVER THE RED RIVER VALLEY EARLY THIS MORNING...WILL
EXPECT A SIMILAR ENVIRONMENT SETTING UP FOR CENTRAL TX INTO THE
WESTERN HILL COUNTRY THIS EVENING. THE PAST COUPLE RUNS OF THE NAM
MODEL SEEM TO REFLECT A GOOD MIDDLE GROUND FROM THE HIGH RES CAMPS
THAT SHOW EXTRA EMPHASIS OVER WESTERN COUNTIES AND OTHERS...
INCLUDING RECENT HRRR RUNS...THAT KEEP THE CURRENT COMPLEX ALIVE
AND MOVE IT INTO MAINLY CENTRAL AND EASTERN COUNTIES IN THE LATE
AFTERNOON HOURS.
IN THE FIRST OPERATIONAL PERIOD FOR TODAY...WILL FOLLOW A PORTION
OF THE EASTERN SOLUTIONS OF HIGHER RES RUNS WITH THE EXPECTATION
THAT SOME GRAVITY WAVE INDUCED SHOWER ACTIVITY TAPS INTO LOCALLY
HIGHER PWAT VALUES. SLIGHTLY HIGHER POPS ARE SHOWN OVER CENTRAL
TX FOR THIS AFTERNOON. HOWEVER...EXPECT THE SURFACE FRONTAL
BOUNDARY TO MIX OUT...AND MID LEVEL STABILITY TO HOLD BACK MOST
DEEP CONVECTION. WILL NEED TO MONITOR THE CONVECTIVE DEVELOPMENT
CLOSELY OVER CENTRAL TX SHOULD THE CONVECTIVE OUTFLOW BE MORE
ROBUST OVER NORTH TX IN THE LATE MORNING HOURS.
BY THIS EVENING...THE NAM COMPROMISE SOLUTION SHOWS ITS HIGHEST
IMPACT OVER THE NORTHERN HILL COUNTRY AND COULD MEAN A THREAT FOR
BOTH SEVERE WEATHER AND FLASH FLOODING WITH SLOW SOUTHWARD
PROPAGATING CELLS MOVING DOWN HIGHWAY 281. WHILE THIS SIGNAL WAS
SIMILAR IN TWO STRAIGHT NAM RUNS...LOWER RES SOLUTIONS SHOW
HIGHEST RAIN POTENTIAL MUCH FARTHER TO THE WEST WITH FRONTAL
FORCING LIMITED OVER EASTERN COUNTIES. THUS WILL BALK AT ISSUING
AN FFA...AS FLOODING THREATS SHOULD BE SOMEWHAT ISOLATED SHOULD
THE WESTERN SOLUTIONS PREVAIL. TOWARD DAYBREAK...MUCH OF THE AREA
SHOULD SHOW SOME LOW LEVEL STABILITY FROM THE FRONT...WITH MOST OF
THE ELEVATED RAINS EXPECTED TO BE LIGHT TO MODERATE INTO THURSDAY.
THE FRONT IS EXPECTED TO BE WEAK AND SHALLOW...SO WILL SHOW CHANCE
CATEGORY POPS WHICH SIDE WITH THE LOWER RES MODELS OVER THE DRIER
SOLUTIONS OF MOST HIGHER RES RUNS.
&&
.LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)...
ASSUMING WE GET THROUGH TONIGHTS SITUATIONAL HEAVY RAIN THREAT
WITHOUT A MAJOR ORDEAL...THE HEAVY RAIN EMPHASIS WE ARE MOST
CONCERNED ABOUT IS OVER THE WEEKEND. A SHARPENING AND HIGH
AMPLITUDE UPPER TROUGH TO THE SOUTHWEST WILL INCREASE POPS
GRADUALLY FRIDAY INTO SATURDAY...AND THEN AGRESSIVELY SATURDAY
NIGHT THROUGH SUNDAY EVENING. A WIDESPREAD HEAVY RAIN OF 1 TO 3
INCHES IS EXPECTED FOR THIS ENHANCED PERIOD WITH ISOLATED HIGHER
AMOUNTS OF 4 TO 6 INCHES POSSIBLE. THE ECMWF AND CANADIAN EVEN
CARRY THE EVENT INTO MEMORIAL DAY...WHICH COULD SEND PROJECTIONS
EVEN HIGHER. FOR NOW...WILL ASSUME THAT A WIDESPREAD MCS OVER THE
WEEKEND SHOULD TEMPORARILY STABILIZE THE AIR FOR MONDAY WHICH
FAVORS THE MORE CONSERVATIVE GFS SOLUTION.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 86 69 79 66 83 / 30 50 30 40 40
AUSTIN BERGSTROM INTL AIRPORT 85 68 79 66 83 / 30 50 30 40 40
NEW BRAUNFELS MUNI AIRPORT 86 70 81 67 83 / 30 40 40 40 40
BURNET MUNI AIRPORT 83 66 75 63 80 / 30 60 30 40 40
DEL RIO INTL AIRPORT 86 71 82 69 85 / 20 60 50 60 40
GEORGETOWN MUNI AIRPORT 84 66 76 64 82 / 30 60 30 40 40
HONDO MUNI AIRPORT 86 71 82 68 84 / 20 50 40 50 40
SAN MARCOS MUNI AIRPORT 85 69 79 66 82 / 30 40 30 40 40
LA GRANGE - FAYETTE REGIONAL 86 70 81 69 83 / 30 20 40 30 40
SAN ANTONIO INTL AIRPORT 86 71 81 69 83 / 20 40 40 40 40
STINSON MUNI AIRPORT 87 72 82 69 84 / 20 30 40 40 40
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...76
SYNOPTIC/GRIDS...18
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1224 AM CDT WED MAY 20 2015
.AVIATION...
HIGH CONFIDENCE OF IFR CIGS PREVAILING FOR MOST/IF NOT ALL/ OF
THIS TAF CYCLE. STRONG COLD FRONT IS ON SCHEDULE TO CLEAR LBB
SHORTLY BEFORE 06Z AHEAD OF A SHIELD OF IFR STRATUS AND SOME FOG.
VISBYS HAVE FALLEN TO AS LOW AS 1/2SM AT TIMES BEHIND THE FRONT
AND THIS THREAT SEEMS MOST PRUDENT AT LBB AND PVW WHEREAS NEARBY
SHRA/TSRA AT CDS FOR ANOTHER HOUR SHOULD KEEP THE LOW LEVELS MIXED
TO AVOID POOR VISBYS.
EXTENT OF LOW CIGS AS FAR NORTH AS KANSAS SUGGEST IFR WILL PREVAIL
ALL MORNING AND LIKELY THE AFTERNOON...THOUGH A FEW MODELS
INDICATE CIGS RISING TO MVFR FOR A COUPLE HOURS THIS AFTN BEFORE
RESUMING IFR THEREAFTER.
&&
.PREV DISCUSSION... /ISSUED 914 PM CDT TUE MAY 19 2015/
UPDATE...
UPDATED TO LOWER MIN TEMPS CONSIDERABLY TONIGHT FOR A STRONG COLD
FRONT NOW ENTERING THE FAR SOUTHERN TX PANHANDLE. ABUNDANT
STRATUS AND FOG AS LOW AS 1/2 MILE WAS NOTED BEHIND THIS FRONT AND
THE VISIBILITY AT HEREFORD PLUMMETED FROM 10 MILES TO JUST OVER 1
MILE IN 20 MINUTES. TEMPS IN THE 40S ALREADY ACROSS THE NORTHERN
PANHANDLE CONFIRM THE MAGNITUDE OF COLD ADVECTION...SO HAVE
UPDATED GRIDS LARGELY IN LINE WITH THE LATEST RAP AND HRRR
SOLUTIONS WHICH HAVE A GOOD HANDLE ON THESE TRENDS.
POP-WISE...DROPPED MOST PRECIP MENTION FROM THE CAPROCK
TONIGHT...HOWEVER WE STILL EXPECT SOME STORMS TO RE-DEVELOP WWD
TO NEAR THE I-27 AND HWY 87 CORRIDOR LATER TONIGHT AS THE COLD
FRONT AND TRAILING FRONT ALOFT INTERSECT DEEPER MOISTURE EAST OF
THE RETREATING DRYLINE.
&&
.PREV DISCUSSION... /ISSUED 349 PM CDT TUE MAY 19 2015/
SHORT TERM...
THE MORNING SHOWER AND THUNDER ACTIVITY HAS CLEARED AWAY LEAVING
PLENTY OF SUN TO WARM THE SURFACE. BY MID AFTERNOON WITH RECOVERY
AND WEAK SURFACE PRESSURE FALLS UNDERWAY...SURFACE BASED CAPES HAD
INCREASED TO OVER 3000 JOULES PER KILOGRAM WHILE SURFACE FLOW WAS
MOSTLY SOUTHERLY AND BULK SHEAR VALUES 40+ KNOTS. MOST SHORT RANGE
SOLUTIONS SHOWED SOME DEGREE OF THUNDERSTORM INITIATION WITH THESE
FAVORABLE CONDITIONS LATE THIS AFTERNOON. SEVERAL SHORT CUMULUS
STREETS OVER THE WESTERN SOUTH PLAINS WITHIN A WEAK SURFACE
CONVERGENCE ZONE/DRYLINE...WERE BUBBLING WITH NORTHERN END OF THIS
AREA OVER THE NORTHWESTERN SOUTH PLAINS APPEARING CLOSEST TO
BREAKING OUT ALTHOUGH AS OF YET UNSUCCESSFUL. WITH ABOVE INDICES AND
CURRENT CONDITIONS WE WILL RETAIN A SOLID CHANCE FOR THUNDERSTORMS
AND A POTENTIAL SEVERE THREAT INTO THE EARLY EVENING.
A STATIONARY FRONTAL BOUNDARY ACROSS THE CENTRAL PANHANDLE INTO
WESTERN OKLAHOMA ALSO APPEARS WILL GET SHOVED SOUTHWARD THIS EVENING
AS A SHORT-WAVE UPPER TROUGH ROTATES NORTHWARD THROUGH THE CENTRAL
PLAINS. THIS FRONT MAY LEAD TO MORE ORGANIZED THUNDERSTORMS
SPREADING OUT OF THE PANHANDLE FAVORING NORTH CENTRAL TO NORTHEAST
ZONES...ALTHOUGH SHORT RANGE SOLUTIONS HAVE BEEN TRENDING FURTHER
WEST WITH DEVELOPMENT RECENTLY. AND THIS ACTIVITY WOULD THEN FOLLOW
THE FRONT SOUTHWARD LATER TONIGHT AND EARLY WEDNESDAY...WITH WESTERN
DEVELOPMENT STILL LESS CERTAIN THAN EAST THOUGH ALSO TRENDING MORE
FAVORABLE. BOUNDARY SHOULD MOVE SOUTH OF THE AREA EARLY WEDNESDAY
AND REMAINING THUNDER CHANCES WILL BECOME INCREASINGLY MOST
FAVORABLE SOUTH OF OUR AREA DURING THE DAY WEDNESDAY. TEMPERATURES
HAVE TRENDED SLIGHTLY COOLER FOR MUCH OF THE AREA WEDNESDAY AS WELL.
ANYWAY...WITH SOMEWHAT MARGINAL CONFIDENCE ABOVE IS OUR LATEST
THINKING AND WE HAVE MADE A NUMBER OF ADJUSTMENTS TO MATCH. THE
HEAVY RAIN THREAT MAY REDEVELOP AS WELL OVERNIGHT SHOULD A WELL-
ORGANIZED CONVECTIVE COMPLEX COME TOGETHER BUT SIGNALS TOO MIXED TO
JUMP ALL-IN JUST YET. SO...BE READY FOR POTENTIALLY FAST-BREAKING
WEATHER THROUGH THE NIGHT WITH A BONA-FIDE THOUGH NOT AT ALL CERTAIN
RISK FOR SEVERE STORMS AND STILL AT LEAST LOCALLY HEAVY RAIN
LEADING TO A MINOR FLOODING THREAT. RMCQUEEN
LONG TERM...
THE ACTIVE MAY WEATHER SHOWS NO SIGN OF LETTING UP THROUGH AT LEAST
THIS WEEKEND. THIS WILL OCCUR AS SOME FORM OF SOUTHWESTERLY FLOW
ALOFT PERSISTS OVER WEST TEXAS DOWNSTREAM OF WESTERN CONUS
TROUGHING. THIS UNSETTLED PATTERN WILL PROVIDE MORE OPPORTUNITIES
FOR SEVERE WEATHER AS WELL AS HEAVY RAINFALL.
TO KICK OFF THE EXTENDED...THE SOUTH PLAINS REGION SHOULD FIND
ITSELF NORTH OF A COLD FRONT WITH SURFACE RIDGING AND ABUNDANT CLOUD
COVER PROVIDING COOL AND MOIST CONDITIONS WEDNESDAY NIGHT INTO
THURSDAY. THAT SAID...THERE WILL BE ENOUGH ELEVATED INSTABILITY AND
RETURNING SOUTHEASTERLY FLOW OFF THE DECK THAT ISOLATED TO SCATTERED
SHOWERS/STORMS WILL BE POSSIBLE. A FEW STRONGER ELEVATED STORMS COULD
EVEN OCCUR THOUGH MUTED SURFACE-BASED HEATING/INSTABILITY SHOULD KEEP
THE OVERALL SEVERE THREAT RELATIVELY LOW.
THE COVERAGE AND INTENSITY OF THE CONVECTION MAY TREND UPWARD LATE
THURSDAY INTO EARLY FRIDAY AS A LEAD SHORTWAVE TROUGH IS PROGGED TO
EJECT THROUGH THE SOUTHWEST FLOW OVER THE SOUTHERN HIGH PLAINS.
EVENTUALLY THE WARM FRONT AND WARM SECTOR IS FORECAST TO LIFT NORTH
ACROSS THE AREA OPENING THE DOOR FOR BETTER CHANCES FOR SURFACE-
BASED CONVECTION BY FRIDAY AFTERNOON...THOUGH WHETHER THERE WILL BE
ANY FORCING FOR LARGE-SCALE ASCENT IS UNCLEAR. THAT MAY CHANGE BY
LATE FRIDAY NIGHT INTO EARLY SATURDAY WHEN ANOTHER WEAK UPPER-LEVEL
DISTURBANCE MAY RACE THROUGH THE FLOW. THE WESTERN TROUGH IS THEN
PROGGED TO APPROACH FROM THE WEST ON SATURDAY WITH THE DRYLINE
LIKELY SOMEWHERE NEAR THE TX/NM LINE BY LATE IN THE DAY WHERE IT
WILL PROVIDE A FOCUS FOR CONVECTIVE INITIATION. MODERATE TO STRONG
INSTABILITY AND DEEP-LAYER SHEAR WILL BRING THE RISK FOR SEVERE
STORMS. THIS SAME PATTERN WILL CONTINUE INTO SUNDAY THOUGH THE
DRYLINE AND BEST LARGE-SCALE ASCENT MAY SHIFT EASTWARD A BIT.
A WEAK FRONT MAY SNEAK INTO THE AREA BEHIND THE WEEKEND TROUGH EARLY
MONDAY...BUT IT IS NOT EXPECTED TO HAVE A STRONG PUSH WHICH SHOULD
ALLOW GOOD MOISTURE AND INSTABILITY TO CONTINUE TO RESIDE NEARBY
INTO MUCH OF NEXT WEEK. IT DOES APPEAR THE UPPER FLOW MAY FLATTEN
AND WEAKEN NEXT WEEK...BUT GIVEN THE MAGNITUDE OF THE PROGGED
INSTABILITY AT LEAST ISOLATED LATE DAY STORMS MAY BE POSSIBLE AND
WE HAVE RETAINED SLIGHT CHANCE POPS FROM MONDAY ONWARD.
HIGHS ON THURSDAY WILL ONLY BE IN THE 50S AND 60S...BUT SHOULD
MODERATE INTO THE UPPER 60S TO UPPER 70S FRIDAY BEFORE FURTHER
WARMING INTO THE 70S AND LOWER 80S SATURDAY...WHERE HIGHS WILL
GENERALLY REMAIN THROUGH THE REST OF THE EXTENDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 50 59 49 69 / 30 50 60 40
TULIA 50 58 49 67 / 30 40 70 60
PLAINVIEW 51 59 51 68 / 30 40 70 60
LEVELLAND 52 60 52 72 / 40 60 60 50
LUBBOCK 51 61 52 71 / 40 50 70 60
DENVER CITY 54 61 52 75 / 40 60 60 50
BROWNFIELD 54 61 52 74 / 40 60 60 50
CHILDRESS 53 64 55 71 / 30 20 60 60
SPUR 53 62 53 72 / 40 40 60 60
ASPERMONT 56 65 56 77 / 50 40 60 60
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93/31
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1200 AM CDT Wed May 20 2015
.AVIATION...
/06Z TAFS/
Look for challenging flight weather during the next 24 hours.
Stratus is already return to our southern terminals. Others will
follow soon. Another cold front will push into the Big Country
before noon tomorrow. This front may stall somewhere across the
Concho Valley. Thunderstorms will likely develop along and near
this boundary.
&&
.PREV DISCUSSION... /ISSUED 602 PM CDT Tue May 19 2015/
AVIATION...
/00Z TAFS/
Scattered showers and thunderstorms are affecting mainly the KABI
TAF this evening, where a VCTS group was included. Elsewhere,
convection should remain isolated. Stratus will move back into all
of the TAF sites after 06z, resulting in MVFR/IFR ceilings. VFR
ceilings should return to all sites by late morning or early
afternoon Wednesday. A cold front will approach KABI around 17z,
then slowly move south. Scattered showers and thunderstorms will
be possible along and behind the front, along with a wind shift to
the north at 8 to 12 knots.
PREV DISCUSSION... /ISSUED 353 PM CDT Tue May 19 2015/
SHORT TERM...
(Today and Tonight)
.Flash flood Watch has been extended until 10 PM CDT tonight for
the Big Country, Concho Valley, and Heartland...
The atmosphere is unstable this afternoon with RUC SB CAPES of
4000 J/KG. Severe storms are certainly possible this afternoon and
evening with the very strong instability. Strong storms were
already developing in the Trans Pecos and eastern Permian basin,
where less stratus was bringing more heating and instability.
These will likely move eastward into the Concho Valley this
evening. Scattered showers and thunderstorms were also developing
from Robert Lee to Brownwood, then northward into the Big Country.
With saturated soil conditions from Wednesday storms, the flash
flood watch has been extended to 10 PM CDT to catch the evening
storms. While coverage is expected to be less, excessive rainfall
rates from slow moving storms will likely cause localized flash
flooding on saturated soils. The atmosphere remains very moist,
with the SPC mesoanalysis page indicating very high precipitable
waters of 1.5 to 1.7 inches, which could bring very efficient
rainfall production.
Wednesday, a cold front will move into the Big Country in the
afternoon, and through the rest of West Central Texas overnight.
The atmosphere will remain unstable, and the front may be a
focus for severe thunderstorm development and localized flooding.
04
LONG TERM...
(Wednesday night through Tuesday)
The slow moving cold front is forecast to be near the I-20
corridor by Wednesday evening. A potent shortwave trough is
progged to be lifting northeast across Far West TX by this time,
increasing large scale forcing for ascent. Precipitable water
values will be in the 1.4 to 1.6" range, providing ample moisture
for convective development. As thunderstorms develop along/north
of this cold front, southerly winds above the boundary layer will
feed Gulf moisture into the complex. This will help propagate the
cold front slowly south across the CWA through Thursday morning,
with east to northeast surface winds developing across West
Central TX. Relatively weak winds aloft will result in slower
storm motions, enhancing the potential for locally heavy rainfall.
Another Flash Flood Watch may be required for this period.
The best rain chances shift to the southern zones on Thursday as
slightly drier air advects into the area behind this cold front.
Cooler temperatures are anticipated on Thursday, with highs in the
mid/upper 60s across the Big Country to the mid 70s along the I-10
corridor. The next shortwave trough is progged to approach West TX
Thursday and Thursday night. Rain chances ramp up accordingly, as
fairly widespread convection is anticipated across West Central
TX. Additional locally heavy rainfall will be possible during the
overnight hours.
Southerly winds are forecast to resume on Friday as the
aforementioned surface boundary washes out. Temperatures are
expected to respond by warming into the upper 70s to lower 80s.
Again, showers and thunderstorms will be possible, especially
during the afternoon and evening hours as thunderstorms over the
Permian Basin drift east into West Central TX.
The weather pattern over the weekend suggests a potential not only
for heavy rainfall, but also for severe weather. Southwest flow
aloft increases as a strong shortwave trough moves slowly east
across the Four Corners. Warmer surface temperatures, rich Gulf
moisture, and steepening mid-level lapse rates will increase the
potential for strong to severe thunderstorms.
In summary, showers and thunderstorms will be possible areawide
through Monday. The severe weather threat will be relatively low,
albeit still present. The potential for severe thunderstorms will
increase this weekend. Heavy rainfall will be the primary concern
through the period. Total rainfall amounts exceeding 4 inches are
possible.
Johnson
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 68 78 59 69 60 / 30 40 50 30 60
San Angelo 68 83 63 73 63 / 20 30 60 40 60
Junction 69 83 67 77 65 / 20 20 60 50 50
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1147 PM CDT TUE MAY 19 2015
.AVIATION...
HIGH CONFIDENCE OF IFR CIGS PREVAILING FOR MOST/IF NOT ALL/ OF
THIS TAF CYCLE. STRONG COLD FRONT IS ON SCHEDULE TO CLEAR LBB
SHORTLY BEFORE 06Z AHEAD OF A SHIELD OF IFR STRATUS AND SOME FOG.
VISBYS HAVE FALLEN TO AS LOW AS 1/2SM AT TIMES BEHIND THE FRONT
AND THIS THREAT SEEMS MOST PRUDENT AT LBB AND PVW WHEREAS NEARBY
SHRA/TSRA AT CDS FOR ANOTHER HOUR SHOULD KEEP THE LOW LEVELS MIXED
TO AVOID POOR VISBYS.
EXTENT OF LOW CIGS AS FAR NORTH AS KANSAS SUGGEST IFR WILL PREVAIL
ALL MORNING AND LIKELY THE AFTERNOON...THOUGH A FEW MODELS
INDICATE CIGS RISING TO MVFR FOR A COUPLE HOURS THIS AFTN BEFORE
RESUMING IFR THEREAFTER.
&&
.PREV DISCUSSION... /ISSUED 914 PM CDT TUE MAY 19 2015/
UPDATE...
UPDATED TO LOWER MIN TEMPS CONSIDERABLY TONIGHT FOR A STRONG COLD
FRONT NOW ENTERING THE FAR SOUTHERN TX PANHANDLE. ABUNDANT
STRATUS AND FOG AS LOW AS 1/2 MILE WAS NOTED BEHIND THIS FRONT AND
THE VISIBILITY AT HEREFORD PLUMMETED FROM 10 MILES TO JUST OVER 1
MILE IN 20 MINUTES. TEMPS IN THE 40S ALREADY ACROSS THE NORTHERN
PANHANDLE CONFIRM THE MAGNITUDE OF COLD ADVECTION...SO HAVE
UPDATED GRIDS LARGELY IN LINE WITH THE LATEST RAP AND HRRR
SOLUTIONS WHICH HAVE A GOOD HANDLE ON THESE TRENDS.
POP-WISE...DROPPED MOST PRECIP MENTION FROM THE CAPROCK
TONIGHT...HOWEVER WE STILL EXPECT SOME STORMS TO RE-DEVELOP WWD
TO NEAR THE I-27 AND HWY 87 CORRIDOR LATER TONIGHT AS THE COLD
FRONT AND TRAILING FRONT ALOFT INTERSECT DEEPER MOISTURE EAST OF
THE RETREATING DRYLINE.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
153 AM EDT WED MAY 20 2015
.SYNOPSIS...
HIGH PRESSURE OVER THE GREAT LAKES WILL MOVE EAST TODAY...FOLLOWED
BY AN AREA OF LOW PRESSURE THAT WILL AFFECT THE REGION
THURSDAY. DRY AND TRANQUIL WEATHER EXPECTED FOR FRIDAY AND
SATURDAY COURTESY OF DRY HIGH PRESSURE.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 145 AM EDT WEDNESDAY...
FAIR/DRY WEATHER TODAY AND AS HIGH PRESSURE WHICH IS BUILDS INTO
THE MID ATLANTIC REGION FROM THE NORTHWEST. TEMPERATURES NEAR
NORMAL WITH 70S TO AROUND 80 FOR HIGHS. OVERNIGHT LOWS WILL BE
HELD UP SOMEWHAT..GENERALLY IN THE 50S TO NEAR 60 BY ADVANCING
HIGH CLOUDS AHEAD OF NEXT WEATHER SYSTEM WHICH WILL AFFECT AREA ON
THURSDAY.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
AS OF 330 PM EDT TUESDAY...
A GOOD DEGREE OF UNCERTAINTY IN THE FORECAST EARLY IN THE SHORT TERM
PERIOD AS GUIDANCE DIFFERENCES ON HANDLING OF SURFACE FEATURES...
WHICH WILL HAVE AN IMPACT ON RAIN CHANCES WEDNESDAY NIGHT THROUGH
THURSDAY. SHORT WAVE ENERGY EJECTING OUT OF AN WESTERN UPPER LEVEL
RIDGE WILL COMBINE WITH SOME SHORT WAVE ENERGY ROTATING AROUND AN
UPPER TROF OVER THE GREAT LAKES AND HEAD IN OUR DIRECTION. THIS
WILL HELP DRIVE DEVELOPMENT OF A SURFACE LOW OVER THE SOUTHEAST US
LATE WEDNESDAY NIGHT...WHICH WILL THEN MOVE OFF THE MIDDLE ATLANTIC
COAST BY THURSDAY NIGHT. THE OPERATIONAL GFS RUN IS ON BOARD WITH
OTHER MODELS IN HANDLING OF DYNAMICS BUT IS MUCH LESS AGGRESSIVE AND
FURTHER EAST IN DEVELOPING PRECIPITATION OVER THE AREA. OTHER
OPERATIONAL RUNS AND ENSEMBLES DO GENERATE A MUCH MORE COHESIVE
PRECIPITATION SHIELD NORTH AND WEST OF THE LOW ASSOCIATED WITH
ENHANCED LIFT IN DEFORMATION AREAS AND RR QUAD OF UPPER JET WHERE WE
NORMALLY EXPECT TO SEE THESE FEATURES. THUS WILL LEAN TOWARD THE
WETTER GUIDANCE AND RAMP POPS UP TO HIGH CHANCE FOR MOST AREAS BY
LATE WED NIGHT AND THROUGH THURSDAY. BELIEVE THUNDER CHANCES WILL
STAY JUST SOUTH OF THE FOOTHILLS/PIEDMONT OF NC SINCE WE WILL BE IN
A COOLER AND MORE STABLE ENVIRONMENT WITH THE LOW TRACKING TO OUR
SOUTH. AS THE LOW DEPARTS THURSDAY NIGHT...HIGH PRESSURE WILL BUILD
IN FROM THE UPPER MIDWEST AND WE WILL SEE STEADILY IMPROVING
CONDITIONS WITH QUIET WEATHER EXPECTED AS WE HEAD INTO THE WEEKEND.
TEMPERATURES WILL START OFF A BIT COOL ON THURSDAY WITH
PRECIPITATION ON THE COOL SIDE OF THE LOW...BUT VALUES WILL REBOUND
TO SEASONAL LEVELS WITH GENERALLY UPPER 60S/AROUND 70 BLUE RIDGE
WEST AND LOW TO MID 70S EAST.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 330 PM EDT TUESDAY...
UPPER PATTERN WILL BE DEVELOPING A LARGE TROF OVER THE EASTERN US
DURING THE EXTENDED PERIOD...WITH A BERMUDA HIGH OFF THE COAST. THIS
WILL GIVE US A VERY COMFORTABLE AND PLEASANT SATURDAY FOLLOWED BY
HEAT AND HUMIDITY MOVING BACK INTO THE REGION BY SUNDAY...WITH THE
TRULY UNCOMFORTABLE CONDITIONS HOLDING OFF UNTIL THE FIRST PART OF
NEXT WEEK. HOWEVER THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE
ONLY MODEST AS SIGNIFICANT DYNAMIC FORCING WILL BE ABSENT...LEAVING
US TO RELY ON OROGRAPHIC FORCING FROM THE BLUE RIDGE WEST TO FOCUS
LIFT AND GENERATE SOME CONVECTIVE ACTIVITY. PWATS WILL ONCE AGAIN BE
RISING ABOVE ONE INCH SO THE POSSIBILITY OF LOCAL DOWNPOURS WILL BE
INCREASING. BY TUESDAY A COLD FRONT WILL BE APPROACHING FROM THE
WEST AND LOOKS TO BRING GREATER COVERAGE OF PRECIPITATION TO THE
REGION TUESDAY AFTERNOON AND EVENING. AFTER A COMFORTABLE
SATURDAY...EXPECT RISING TEMPERATURES TO BE ABOUT 10 DEGREES ABOVE
NORMAL AS WE HEAD INTO NEXT WEEK.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 145 AM EDT WEDNESDAY...
VFR CONDITIONS EXPECTED TO PREVAIL IN REST OF THE OVERNIGHT AND
EARLY MORNING AS HIGH PRESSURE OVER THE GREAT LAKES RIDGES INTO
CENTRAL MID-ATLANTIC REGION. EVEN KLWB MAINTAINING LIGHT NW WINDS
AT THIS TIME AND A WIDE T-TD SPREAD WITH LITTLE LIKELIHOOD OF FOG
DEVELOPMENT. HIGH OVERCAST IN ADVANCE OF FAST-MOVING SYSTEM
EXPECTED BY THE EVENING BUT NO IMPACT TO AVIATION.
EXTENDED AVIATION DISCUSSION...
AN UPPER LEVEL DISTURBANCE WILL LIKELY BRING SOME MVFR CEILINGS
AND SHOWERS BACK INTO THE AREA THURSDAY...MOVING OUT FRIDAY
MORNING...WITH VFR CONDITIONS RETURNING FRIDAY AFTERNOON AND
SATURDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PM
NEAR TERM...PM
SHORT TERM...MBS
LONG TERM...MBS
AVIATION...AMS/PC
AREA FORECAST DISCUSSION...UPDATE
NWS LITTLE ROCK AR
1035 AM CDT WED MAY 20 2015
.DISCUSSION...
MID MORNING UPDATE LOWERED POPS IN THE WEST TO CENTRAL AR...WHILE
THE HIGHEST IN THE EAST. RADAR TRENDS ARE TAKING MUCH OF THE RAIN
OUT OF THE CWA BY NOON...THEN SHORT RANGE MODELS ONLY SHOW LOW
AMOUNTS OVER THE STATE THE REST OF TODAY. UNTIL THE SURFACE LOW
PULLS EAST AND THE COLD FRONT IS TOTALLY THROUGH AR...WILL HAVE TO
KEEP SOME CHANCES OF RAIN...ISOLATED THUNDER...IN THE FORECAST. AT
MID MORNING THE SURFACE LOW WAS OVER SW MO...WITH THE COLD FRONT
SOUTHWEST TO EASTERN OK. WILL SEE IT GRADUALLY MOVE THROUGH AR TODAY
TO THIS EVENING...WITH A WIND SHIFT TO THE W TO NW BEHIND THE FRONT.
LATER THIS EVENING...THE FRONT IS EXPECTED IN SOUTHERN AR...BUT
LOCATION WILL BE A BIT UNCERTAIN...ESPECIALLY HOW FAR SOUTH IT GOES.
AT SOME POINT OVER SOUTHERN AR THE STEERING FLOW WILL BECOME
PARALLEL AND BOUNDARY WILL STALL...MORE LIKELY NEAR THE AR AND LA
STATE LINE. LATE MORNING UPDATE WILL ADJUST POPS THIS
AFTERNOON...CLOUDS...TEMPS AND WINDS. (59)
&&
.PREV DISCUSSION... /ISSUED 656 AM CDT WED MAY 20 2015/
.AVIATION...20/12Z TAF CYCLE
VFR CONDS WL CONT ACRS SERN AR UNTIL CONVECTION ARRIVES THERE
TOWARDS MID MRNG. ELSEWHERE...MVFR/IFR CONDS WL PREVAIL THIS MRNG
AS A COMPLEX OF SHRA/TSRA CONTS TO AFFECT MUCH OF AR. THE ENTIRE
SYS WL EVENTUALLY SHIFT EWD...WITH ASSOCD PRECIP TAPERING OFF ACRS
WRN AR LATER THIS MRNG. THIS TREND WL CONT OVR CNTRL AND ERN AR
EARLY THIS AFTN. EXPECT VFR/MVFR CIGS TO LINGER OVR THE AREA INTO
THIS EVENING...WITH MVFR CIGS BCMG MORE PREVALENT AFT 21/06Z. /44/
&&
.PREV DISCUSSION... /ISSUED 417 AM CDT WED MAY 20 2015/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT
AN AREA OF SHOWERS AND THUNDERSTORMS HAS CONTINUED TO PUSH EASTWARD
AND INTO THE AREA DURING THE OVERNIGHT HOURS. SO FAR RAINFALL RATES
EXCEEDING ONE TO TWO INCHES PER HOUR HAVE BEEN SEEN ACROSS WESTERN
PORTIONS OF THE CWA. HRRR...ARW...NMM HAVE ALL HAD A GOOD HANDLE ON
THE SYSTEM TONIGHT AND DO AGREE THAT THE SYSTEM WILL WEAKEN BY
MIDMORNING. DO BELIEVE SOME DRIER AIR WILL FILTER INTO WESTERN
ARKANSAS...BUT AT THIS TIME ONLY THE HRRR COMPLETELY DRIES THINGS
OUT DURING THE AFTERNOON HOURS. DID CONTINUE WITH CHANCE POPS DURING
THE AFTERNOON HOURS FOR MUCH OF THE CWA...BUT THIS WILL NEED TO
CONTINUE TO BE MONITORED AND UPDATED AS NEEDED.
FRONT IS EXPECTED TO CLEAR THE STATE BY 00Z AND WILL CONTINUE TO
PUSH SOUTH AND REMAIN ACROSS LOUISIANA. FOR THE MOST PART...THURSDAY
WILL REMAIN DRY FOR MUCH OF THE STATE...WITH SOME PRECIP CHANCES
REMAINING ACROSS SOUTHERN ARKANSAS. HIGH PRESSURE WILL BUILD IN
BRIEFLY BEFORE PRECIPITATION CHANCES RETURN TO THE FORECAST ON
FRIDAY. MODELS HAVE COME IN BETTER AGREEMENT WITH THE PRECIP ON
FRIDAY...BUT IT LOOKS LIKE PRECIPITATION CHANCES WILL REMAIN
GENERALLY ACROSS WESTERN ARKANSAS. UNSETTLED WEATHER WILL CONTINUE
THROUGH THE WEEKEND WITH A LONGWAVE TROUGH ACROSS THE WESTERN CONUS.
LONG TERM...SUNDAY THROUGH TUESDAY
MODEL DATA THIS MRNG CONT TO INDC AN UNSETTLED WX PATTERN WL PERSIST
ACRS THE REGION TO CLOSE OUT THE HOLIDAY WEEKEND. AN UPR RDG WL SET
UP OVR THE SOUTHEASTERN STATES...RESULTING IN A SWLY FLOW ALOFT ACRS
AR. A SERIES OF IMPULSES WL TRACK NEWD AND BRING CONTD CHCS OF
SHRA/TSRA EACH DAY. KEPT POPS IN THE CHC CAT FOR NOW AS TIMING OF
EACH SHRTWV WL RMN DIFFICULT THIS FAR IN ADVANCE. HVY RAIN POTENTIAL
WL ALSO BE A CONCERN THRU THE PD...ALONG WITH THE CONTD THREAT OF
FLOODING.
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
656 AM CDT WED MAY 20 2015
.AVIATION...20/12Z TAF CYCLE
VFR CONDS WL CONT ACRS SERN AR UNTIL CONVECTION ARRIVES THERE
TOWARDS MID MRNG. ELSEWHERE...MVFR/IFR CONDS WL PREVAIL THIS MRNG
AS A COMPLEX OF SHRA/TSRA CONTS TO AFFECT MUCH OF AR. THE ENTIRE
SYS WL EVENTUALLY SHIFT EWD...WITH ASSOCD PRECIP TAPERING OFF ACRS
WRN AR LATER THIS MRNG. THIS TREND WL CONT OVR CNTRL AND ERN AR
EARLY THIS AFTN. EXPECT VFR/MVFR CIGS TO LINGER OVR THE AREA INTO
THIS EVENING...WITH MVFR CIGS BCMG MORE PREVALENT AFT 21/06Z. /44/
&&
.PREV DISCUSSION... /ISSUED 417 AM CDT WED MAY 20 2015/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT
AN AREA OF SHOWERS AND THUNDERSTORMS HAS CONTINUED TO PUSH EASTWARD
AND INTO THE AREA DURING THE OVERNIGHT HOURS. SO FAR RAINFALL RATES
EXCEEDING ONE TO TWO INCHES PER HOUR HAVE BEEN SEEN ACROSS WESTERN
PORTIONS OF THE CWA. HRRR...ARW...NMM HAVE ALL HAD A GOOD HANDLE ON
THE SYSTEM TONIGHT AND DO AGREE THAT THE SYSTEM WILL WEAKEN BY
MIDMORNING. DO BELIEVE SOME DRIER AIR WILL FILTER INTO WESTERN
ARKANSAS...BUT AT THIS TIME ONLY THE HRRR COMPLETELY DRIES THINGS
OUT DURING THE AFTERNOON HOURS. DID CONTINUE WITH CHANCE POPS DURING
THE AFTERNOON HOURS FOR MUCH OF THE CWA...BUT THIS WILL NEED TO
CONTINUE TO BE MONITORED AND UPDATED AS NEEDED.
FRONT IS EXPECTED TO CLEAR THE STATE BY 00Z AND WILL CONTINUE TO
PUSH SOUTH AND REMAIN ACROSS LOUISIANA. FOR THE MOST PART...THURSDAY
WILL REMAIN DRY FOR MUCH OF THE STATE...WITH SOME PRECIP CHANCES
REMAINING ACROSS SOUTHERN ARKANSAS. HIGH PRESSURE WILL BUILD IN
BRIEFLY BEFORE PRECIPITATION CHANCES RETURN TO THE FORECAST ON
FRIDAY. MODELS HAVE COME IN BETTER AGREEMENT WITH THE PRECIP ON
FRIDAY...BUT IT LOOKS LIKE PRECIPITATION CHANCES WILL REMAIN
GENERALLY ACROSS WESTERN ARKANSAS. UNSETTLED WEATHER WILL CONTINUE
THROUGH THE WEEKEND WITH A LONGWAVE TROUGH ACROSS THE WESTERN CONUS.
LONG TERM...SUNDAY THROUGH TUESDAY
MODEL DATA THIS MRNG CONT TO INDC AN UNSETTLED WX PATTERN WL PERSIST
ACRS THE REGION TO CLOSE OUT THE HOLIDAY WEEKEND. AN UPR RDG WL SET
UP OVR THE SOUTHEASTERN STATES...RESULTING IN A SWLY FLOW ALOFT ACRS
AR. A SERIES OF IMPULSES WL TRACK NEWD AND BRING CONTD CHCS OF
SHRA/TSRA EACH DAY. KEPT POPS IN THE CHC CAT FOR NOW AS TIMING OF
EACH SHRTWV WL RMN DIFFICULT THIS FAR IN ADVANCE. HVY RAIN POTENTIAL
WL ALSO BE A CONCERN THRU THE PD...ALONG WITH THE CONTD THREAT OF
FLOODING.
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
930 AM EDT WED MAY 20 2015
.DISCUSSION...
CURRENT...TAILEND OF A FRONT JUST SKIRTING ST JOHN AND FLAGLER
COUNTIES AND APPROACHING NORTHEAST VOLUSIA COUNTY. DIURNAL CUMULUS
FIELD SHOULD START FORMING WITHIN THE HOUR WITH THE INCREASING
TEMPERATURES AND THE INCREASING MOISTURE PER THE MORNING CAPE
CANAVERAL SOUNDING. THE VERTICAL WIND PROFILER(S) AT KSC WERE
DETECTING SOUTHWEST TO WEST WINDS TO 10 KNOTS THROUGH ABOUT 4000
FEET THEN A QUICK SHIFT TO THE NORTH THEN NORTHEAST THROUGH ABOUT
10000 FEET. THE LOW LEVEL SOUTHWEST TO WEST WIND COULD DELAY THE
EAST COAST SEA BREEZE BY AN HOUR OR TWO THIS AFTERNOON. LIGHT NORTH
TO SOUTH WINDS ABOVE THE BOUNDARY LAYER AN INDICATOR OF A SLOW SOUTH
TO SOUTHWEST STORM MOTION THIS AFTERNOON. COOLER TEMPERATURES
ALOFT...-10C AT CAPE CANAVERAL AND -8C AT JACKSONVILLE...A GOOD
INDICATOR FOR STRONG WIND GUSTS AND HAIL IN ANY OF THE STRONGER
STORMS THAT DEVELOP THIS AFTERNOON. LATEST HRRR MODEL RUN SUGGESTING
SEA BREEZES FORMING EARLY AFTERNOON AND MOVING SLOWLY INLAND AS IT
PUSHES AGAINST THE PREVAILING LOW LEVEL SOUTHWEST TO WEST WINDFLOW.
THE HRRR ALSO IS SUGGESTING THE BEST TIME FRAME FOR STORMS ALONG A
LINE FROM FROM AROUND DAYTONA BEACH TO OKEECHOBEE COUNTY WITH A SLOW
SOUTHEAST TO SOUTH MOTION ALONG THE SEA BREEZE.
THE MORNING ZONES UPDATE WILL TAKE A LOOK AT AMENDING WIND FIELDS AND
THE TIMING OF THE AFTERNOON STORMS.
&&
.AVIATION...PREVIOUS...PREVAILING VFR THROUGH 18Z WITH LCL MVFR CIGS
BKN025-030 DURING ONSET OF DIURNAL CU FIELD ~14Z-16Z. AFT
18Z...ISOLD SHRA/TS INCREASING IN COVERAGE 22Z-02Z. G30KT/1SM +TSRA
IN LOCALES WHERE CELL CORES MOVE OVHD...TYPICAL OF SUMMER CONVECTION.
&&
.MARINE...PREVIOUS...LIGHT S-SWRLY FLOW WILL GIVE WAY TO ONSHORE
ESE/SERLY SEA BREEZE AROUND 10KT NEAR THE COAST. SEAS 2-3FT...LCLY
HIGHER WINDS AND SEAS IN OFFSHORE MOVG TS MAINLY NORTH OF CAPE
CANAVERAL AND THE LATE AFTERNOON ON THE INLAND LAKES
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...WIMMER
LONG TERM/IMPACT WX...LASCODY
AREA FORECAST DISCUSSION
NWS TOPEKA KS
625 AM CDT Wed May 20 2015
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 331 AM CDT WED MAY 20 2015
Mid/upper level trough currently lifting northeastward over SD and
NE, and will eventually merge with energy tracking over the upper
Midwest. An expansive area of light to moderate rain will move
across northeast KS early this morning, which is supported by upper
level forcing associated with the trough and low level
frontogenesis. Most of the forcing is forecast to continue eastward
and mainly exiting the area around 12Z. There are indications that
light rain showers and or drizzle could linger through the early
afternoon hours after the mid/upper levels dry out. Both RAP and NAM
soundings show steep low level lapse rates coinciding with
saturation along with weak lift. This could be enough to generate
these light showers and or drizzle. Although these models also
suggest isentropic downglide on the backside of the wave so very
little precip accumulations are expected after 12Z. Clouds will
stick around most of the day and northerly flow will keep
temperatures from warming up much, therefore highs will generally be
in the mid 50s. Surface high pressure will build into the region
tonight and clouds may begin to scatter out as the drier air filters
southward. As surface winds begin to lighten and temperatures cool
there is a chance fog could develop especially given the recent
rainfall. Temperatures are expected to drop into the low to mid 40s
with a few isolated locations in the upper 30s.
.LONG TERM...(Thursday through Tuesday)
Issued at 331 AM CDT WED MAY 20 2015
Thursday through Thursday night, A surface ridge of high pressure
over eastern KS will shift east into MO by Friday morning. An upper
level trough will move onshore across southern CA. Expect mostly
sunny skies on Thursday with highs reaching the mid 60s. Thursday
night will be a bit warmer as the center of the surface ridge moves
east into MO, allowing light winds to become southerly. Lows Friday
morning will only drop into the mid to upper 40s. High and mid level
clouds will increase late Thursday night.
Friday through Monday, The upper trough over southern CA will slowly
drift northeast into western CO and slowly fill. Southwest flow
aloft across the central Rockies will cause a surface lee trough to
deepen across the central and southern high plains. Deeper gulf
moisture will gradually be advected northward into the southern
plains Friday afternoon. The resulting isentropic lift ahead of the
deeper moisture return combined with any ascent from minor H5
troughs embedded within the southern stream of the H5 jet will
provide an increasing chance for showers and isolated thunderstorms
during the day Friday and into the Friday evening. The ECMWF shows a
brief amplification of the main H5 trough across AZ. This may
amplify a downstream H5 ridge across the southern plains which may
provide a break from the showers and thunderstorms across eastern KS
on Saturday. Due to cloud cover and increasing rain chances on
Friday, highs will only reach the mid 60s. If we see more insolation
on Saturday highs will reach the lower 70s.
Saturday night through Sunday night, the Upper trough will fill as
it lifts northeast into western CO. The southern stream H5 ridge
will shift east across the Gulf coast states. Embedded shortwave
trough combined with deeper moisture advection will cause periods of
showers and thunderstorms to develop. The mid level flow will weaken
below 40 KTS. The weaker vertical wind shear should prevent
organized storms updrafts. Also, the instability may be lower due to
the cloud cover. I don`t expect severe thunderstorms this weekend.
The primary hazard may be occasional heavy rainfall. Highs on Sunday
will reach the mid 70s
Monday (Memorial Day), The ECMWF and GEM forecast a slightly more
amplified H5 trough to move northeast from southwest TX into central
OK. The better ascent ahead of this trough will be across northern
TX and southern OK. Both models do not forecast much in the way of
QPF during the day. The showers and thunderstorms may increase
Monday night as the H5 trough lifts northeast into western MO. Highs
on Monday should reach the mid 70s
Tuesday, the H5 trough across western MO will lift northeast into
eastern IA and IL. We may see a break in the precip. The GFS is
slower moving the H5 trough northeast across MO and forecast higher
QPF across eastern KS on Tuesday. Looks a bit warmer on Tuesday as
16 to 18 degree C 850mb temps advect northeast across the CWA. Highs
should reach into the upper 70s to around 80.
&&
.AVIATION...(For the 12Z TAFs through 12Z Thursday Morning)
Issued at 619 AM CDT WED MAY 20 2015
MVFR/IFR conditions look to persist through a majority of the taf
period. Most of the rain has ended although an isolated shower can
not be ruled out through early afternoon. These showers should
not really affect the flight conditions. Model forecasts have
ceilings around 1 kft making it difficult to predict the category.
There are signs the clouds try to scatter out tonight and fog
could also be an issue late in the period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Sanders
LONG TERM...Gargan
AVIATION...Sanders
AREA FORECAST DISCUSSION
NWS PADUCAH KY
635 AM CDT WED MAY 20 2015
.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 316 AM CDT WED MAY 20 2015
TIGHTER ZONAL GRADIENT DEVELOPS TODAY IN THE WAKE OF THE DEPARTING
AND DAMPENING LOW/MIDDLE LEVEL RIDGE. COMBINED WITH SLIGHTLY
STRONGER VORTICITY IN MINOR LOW AMPLITUDE NORTH-SOUTH SHORTWAVE
SHOULD PROVIDE SUFFICIENT LIFT FOR SHOWER ACTIVITY. STILL BELIEVE
THE ANTECEDENT CLOUD COVER AND COOLER BOUNDARY LAYER TEMPERATURES
IN NORTHERLY/NORTHEASTERLY WOULD PROVIDE SUFFICIENT LIFT FOR
SHOWER GENERATION. OVERALL INSTABILITY ALOFT WILL BE ENOUGH TO
SUPPORTED LIMITED THUNDERSTORM CHANCES ALONG THE SOUTHERN 1/3 OF
THE WFO PAH FORECAST AREA.
THE EXTENT OF CLOUD COVER AND NORTH/NORTHEASTERLY COOL/DRY FLOW
FROM THE DEPARTING RIDGE WILL DETERMINE THE EASTWARD MOVEMENT OF
THE PRECIPITATION TODAY AND THIS EVENING ACROSS THE WFO PAH
FORECAST AREA. THE HRRR AND GFS GUIDANCE SUPPORT A MORE
PROGRESSIVE AND FASTER SCENARIO, BUT WITH LESSER RESIDENCE TIME
FOR INSTABILITY ACROSS THE AREA. BLENDED THIS GUIDANCE WITH
EXISTING FORECAST.
BEYOND TONIGHT...DRY CONDITIONS SHOULD RETURN TO THE FORECAST AREA
THROUGH NEARLY ALL OF FRIDAY NIGHT.
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 316 AM CDT WED MAY 20 2015
ABOVE AVERAGE FORECAST CONFIDENCE IN THE LONG TERM WITH MODELS
SHOWING MINOR DISAGREEMENTS.
AT THE BEGINNING OF THE LONG TERM PERIOD...AN H5 RIDGE IN PLACE OVER
THE REGION BEGINS TO FLATTEN AND SHIFT EASTWARD ALLOWING DEEPER
MOISTURE AND A SERIES OF UPPER LEVEL DISTURBANCES TO SPREAD
PRECIPITATION CHANCES EASTWARD ACROSS THE REGION. AS THE RIDGE AXIS
SHIFTS FARTHER EASTWARD...PRECIPITATION CHANCES WILL GENERALLY
INCREASE THROUGH THE LONG TERM PERIOD.
TEMPERATURES SHOULD REMAIN AT OR ABOVE NORMAL THROUGH THE PERIOD.
&&
.AVIATION...
ISSUED AT 635 AM CDT WED MAY 20 2015
ONLY A SLIGHT CHANGE FROM THE 06Z WEDNESDAY WFO PAH TAF ISSUANCE.
THE MAIN ADJUSTMENT WAS TO RAISE CEILINGS/CLOUD DECKS BY 1-2KFT AT
THE ONSET OF CLOUD COVER AND RAISE LATTER PERIOD CEILINGS FROM
UPPER IFR TO LOWER MVFR, ESPECIALLY DURING THE LAST 10-13 HOURS OF
THE FORECAST PERIOD.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...SMITH
LONG TERM...JP
AVIATION...SMITH
AREA FORECAST DISCUSSION...UPDATE
NWS JACKSON MS
1045 AM CDT WED MAY 20 2015
.UPDATE...LATEST SATELLITE AND UPPER AIR ANALYSIS SHOWED THE REGION
UNDER THE INFLUENCE OF MEAN RIDGING WITH BETTER JET ENERGY WELL
NORTH OF THE REGION. THE REMANTS OF AN MCS THAT CROSSED THE OZARKS
EARLIER WAS NOTED ACROSS NORTHWEST MISSISSIPPI. THERE WAS SOME GOOD
UPPER DIFFLUENCE OVER THE OZARKS EARLIER THIS MORNING WITH THE
MCS...PUSHING TOWARD THE REGION. HOWEVER MEAN RIDGING HAD SHUNTED
THE MCS IN AREAL COVERAGE AS OF LATE THIS MORNING. LATEST SURFACE
ANALYSIS SHOWED A WARM FRONTAL BOUNDARY EXTENDING ACROSS THE NORTH
WITH AN IMPRESSIVE BAROCLINIC ZONE NORTH OF THE COLD FRONT FROM
NW ARKANSAS THROUGH SOUTHEAST OK TO NORTH TEXAS. THIS WILL HELP
TO FOCUS THE PRECIP IN THE NORTH. LATEST SOUNDING ANALYSIS SHOWED SOME
DECENT MIDLEVEL FLOW OVER SHV AND LZK OF 30-35 KNOTS...WHICH ALONG WITH
THE UPPER DIVERGENCE WILL PUSH ACROSS THE REGION. ALSO SOME GOOD LOW LEVEL
INFLOW. LAPSE RATES AT SHV WAS AROUND 6C. OUR SNDG SHOWED WEAK LAPSE RATES
WITH PWATS AROUND 1.6...WHICH ACCOUNTS FOR THE SUNNY SKIES ACROSS THE CENTRAL
AND SOUTH EARLIER THIS MORNING. LATEST HIRES MODELS SHOWS THAT MOST OF THE
CONCENTRATION OF COVECTION SHOULD BE CONCENTRATED IN THE NORTHWEST FOR THIS
AFTERNOON. THE HRRR TRIED TO GET SOME GOING INTO THE EAST FOR THIS AFTERNOON...
BUT WAS DISCOUNTED DUE TO THE OTHER HIRES MODELS FOCUSING MORE IN THE NORTHWEST FOR
THIS AFTERNOON...WHICH SEEMS SENSIBLE. HRRR SHOWS SOME LAPSE RATES
AROUND 6C WITH MIDLEVEL FLOW AROUND 25-35 KNOTS. SO WITH THE MCS TO
THE NORTH OF THE REGION...IT COULD SEND A BOUNDARY FOR A POSSIBLE
STRONG OR SEVERE STORM FOR THIS AFTERNOON GENERALLY ALONG AND NORTH
OF THE HIGHWAY 82 CORRIDOR. DUE TO THE ISOLATED NATURE WILL KEEP THE
HWO CLEAR FOR NOW. SO WITH THIS IN MIND WILL KEEP CLOSE TO CURRENT
POPS AND CURRENT HIGHS IN THE 80S LOOKS TO BE ON TRACK./17/
&&
.AVIATION...THE EARLY MORNING FOG/STRATUS HAS DISSIPATED AND THE
APPROACHING THUNDERSTORM COMPLEX HAS WEAKENED PRIOR TO MOVING INTO
OUR AREA. VFR CONDITIONS WERE BEING REPORTED AREAWIDE AT 13Z AND WL
CONT THROUGH 17Z. A FEW STORMS WL COME IN VCTY OF GLH AROUND 17Z AND
HI-RES MODELS SUGGEST TSTM ACTIVITY WL MOSTLY AFFECT THE HIGHWAY 82
CORRIDOR THIS AFTN. VFR CONDS SHOULD CONTINUE TO PREVAIL CNTRL AND S
UNTIL THIS EVENING. A COLD FRONT WL DROP SOUTH ACROSS THE AREA LATER
TONIGHT INTO EARLY THURSDAY MORNING RESULTING IN A GREATER CHANCE
FOR IFR CIGS/VSBYS WITH CONVECTION. /22/
&&
./PREVIOUS DISCUSSION...501 AM CDT WED MAY 20 2015
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
AN IMPRESSIVE BAROCLINIC ZONE EXTENDING FROM THE SRN/CNTRL PLAINS
EWD TO THE MID MS VALLEY IS SUPPORTING A LARGE SLOW-MOVING MCS
MOVING INTO THE ARKLATEX REGION. CURRENT ANALYSES INDICATE A DEEP
MOISTURE AXIS (1.9 PRECIPITABLE WATER AND 335+ H850 THETA-E)
EXTENDING INTO NW PORTIONS OF THE ARKLAMISS ALONG A SURFACE FRONTAL
BOUNDARY...BUT SOUTHEASTWARD DEVELOPMENT OF THE MCS IS BEING
HINDERED BY THE SUBTROPICAL RIDGE THAT CONTINUES TO DEFLECT THE BULK
OF ENERGY ASSOC WITH THE WESTERLIES NORTH OF THE FORECAST AREA.
IN SPITE OF THE LACK OF LARGE SCALE SUPPORT...UPWIND PROPAGATION
VECTORS AND LOW LEVEL MOISTURE TRANSPORT SUGGEST THAT NW/NRN PORTION
OF THE ARKLAMISS WILL GET SOME SHOWER/TSTM ACTIVITY LATER THIS
MORNING...WITH EASTERN PORTIONS OF THE REGION HOLDING OFF UNTIL LATE
MORNING/EARLY AFTERNOON AFTER SUBSTANTIAL HEATING. STRONGER LOW-MID
LEVEL FLOW (20-30KT) ALONG AND NORTH OF THE HIGHWAY 82 CORRIDOR
COULD SUPPORT ORGANIZED STRONG STORMS LATER TODAY...BUT AIRMASS
RECOVERY AND INSTABILITY ARE MORE IN QUESTION THERE DEPENDING ON HOW
THINGS EVOLVE THIS MORNING. AS YOU GO FARTHER SOUTH TOWARD THE
INTERSTATE 20 CORRIDOR...MOISTURE/INSTABILITY INCREASE BUT THE FLOW
DECREASES. GIVEN THE UNCERTAINTIES AND DEPENDENCE ON MESOSCALE
INFLUENCES...WILL HOLD OFF ON MENTIONING ANY POTENTIAL FOR SEVERE
WEATHER IN THE HWO/GRAPHICS FOR TODAY.
GOING INTO TONIGHT AND THURSDAY...A COLD FRONT WILL PUSH SOUTH
THROUGH THE AREA FOLLOWED BY LESS HUMID CONDITIONS AND DECREASING
SHOWER/TSTM CHANCES - WITH POPS EVENTUALLY BECOME CONFINED TO AREAS
ALONG AND SOUTH OF THE HWY 84 CORRIDOR BY THURSDAY EVENING. LOW
TEMPERATURES IN THE MID/UPPER 50S COULD BE COMMON BY FRIDAY MORNING
OVER NORTHERN PORTIONS OF THE FORECAST AREA. /EC/
.LONG TERM...FRIDAY THROUGH WEDNESDAY...FAIRLY DRY AND WARM
CONDITIONS WILL OCCUR LATE THIS WEEK THROUGH THE WEEKEND. THIS
OCCURS AS HIGH PRESSURE AT THE SFC MOVES INTO THE NORTHERN PART OF
THE CWA AND UPPER RIDGING TAKES HOLD. SOME AFTERNOON STORMS WILL BE
POSSIBLE BUT THE UPPER RIDGE AND SUBSEQUENT CAPPING SHOULD KEEP THIS
CONVECTION AT BAY. THE UPPER RIDGE WILL CONTINUE TO HAVE AN
INFLUENCE OVER OUR WEATHER HEADING INTO THE WORK WEEK BUT THE CENTER
OF IT SHOULD BE MOVING EAST OF THE AREA. THIS WILL OPEN SOME
POTENTIAL FOR A LITTLE MORE IN THE WAY OF MAINLY AFTERNOON SHOWERS
AND STORMS. HIGHS WILL GENERALLY BE IN THE LOWER TO MID 80S THROUGH
THE PERIOD WITH LOWS STARTING IN THE MID TO UPPER 60S AND REACHING
BACK INTO THE 70S. /28/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 86 68 78 60 / 38 43 33 12
MERIDIAN 86 68 81 59 / 37 36 29 11
VICKSBURG 87 67 76 61 / 30 40 30 14
HATTIESBURG 89 70 86 64 / 34 25 43 24
NATCHEZ 86 69 79 61 / 30 26 41 19
GREENVILLE 85 62 72 58 / 51 50 21 8
GREENWOOD 84 62 73 57 / 49 47 16 7
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
17/22/EC/28
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
711 AM CDT Wed May 20 2015
.SHORT TERM: (Through Tonight)
Issued at 316 AM CDT Wed May 20 2015
A broad area of rain progresses across the forecast area today in
association with a wave of low pressure riding along a
quasistationary frontal boundary. The precipitation is forced and
maintained by a strong southerly H85 LLJ interacting with a
quasistationary boundary. Isolated embedded thunderstorms are
possible. The upper vort center behind the surface wave moves into
weakly confluent flow and merges with a separate vort center which
originates over Manitoba. The resulting trough forms over Iowa
tonight and moves to the east or slightly south of east. Surface
high pressure will have already spread into the forecast area by
this time and no additional precipitation is expected with the
trough overnight, although the slight increase in lift could
prolong any ongoing showers across the eastern forecast area
between 00-06z.
The forecast area remains on the cool side of a quasistationary
boundary today and extensive clouds/precip will limit insolation.
These unusually cool conditions might set or tie some climate
records. Please refer to the climate section below.
42
.LONG TERM: (Thursday through Tuesday)
Issued at 316 AM CDT Wed May 20 2015
High pressure remains in place on Thursday and Friday. An upper
ridge also builds over the central US on Friday then amplifies on
Saturday ahead of a deepening trough over the western half of the
US. Several disturbances lift through the trough between Saturday
and Monday. These disturbances should bring a period of unsettled
weather to the forecast area, especially between Sunday and
Tuesday. Similar to the last two weekends, day to day
precipitation chances will depend both on synoptic scale
shortwaves and on any MCVs which form upstream. Refinements are
likely. Temperatures begin to warm up again on Saturday when winds
become southerly around the retreating surface high. A more
noticeable jump in warmth is expected on Sunday after a warm
frontal passage.
42
&&
.AVIATION: (For the 12z TAFs through 12z Thursday Morning)
Issued at 705 AM CDT Wed May 20 2015
Have used extrapolation of current radar trends for onset of the
rain this morning, and the latest (10z) HRRR data to time the end
of the rain later this morning and early this afternoon. For
cig/vsby trends, it looks like a very atypical May day with MVFR
vsbys in rain/fog, and IFR to MVFR cigs developing in the steady
rainfall. I`ve gone with prevailing MVFR vsbys/IFR cigs in COU by midday
where low level saturation should be greatest due to the rain this
morning, but elsewhere I`ve kept cigs MVFR with the thinking that
rainfall will be somewhat less, and because NE winds will be
attempting to advect relatively drier low level air in from the
ridge to our north. This thinking dovetails fairly well with 06z
MAV guidance. Heading into tonight there is lots of
uncertainty...will the southward oozing of the surface ridge scour
out the residual low level moisture or will the moisture become
trapped beneath an inversion? Because of this, forecast specifics
trail off early this evening, and will let day shift take a crack
at this time period as we get a better feel for trends later this
afternoon.
Specifics for KSTL: Steady rain is expected to develop by mid
morning, with cigs/vsbys heading into MVFR category by midday.
Latest HRRR guidance suggests rain ending by mid afternoon, but
have maintained MVFR cigs into the evening due to saturation
produced by the rainfall. Some lingering MVFR vsbys in fog is also
anticipated for several hours after the rain ends.
Truett
&&
.CLIMATE:
Issued at 316 AM CDT Wed May 20 2015
Record cool high temperatures for May 20th are as follows.
St. Louis, MO....55/1924 (KSTL)
Columbia, MO.....57/1924 (KCOU)
Quincy, IL.......57/1967 (KUIN)
Farmington, MO...66/1954 (co-op station)
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
914 AM MDT WED MAY 20 2015
.UPDATE...
ISSUED AT 909 AM MDT WED MAY 20 2015
UPPER HIGH IS PUSHING DRIER AIR INTO THE NORTHERN PLAINS. SKIES
ARE BECOMING CLEAR FROM NORTH TO SOUTH...AND PRECIP IS
DIMINISHING. SURFACE HIGH PRESSURE IS DRAPED ACROSS THE CWA.
WINDS ARE LIGHT AND VARIABLE WITH TEMPS RISING INTO THE 40S AND
LOWER 50S. ADJUSTED SKY GRIDS AND POPS TO MATCH CURRENT
TRENDS...BUT REST OF FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 250 AM MDT WED MAY 20 2015
08Z SURFACE ANALYSIS HAD HIGH PRESSURE OVER THE DAKOTAS. WATER
VAPOR LOOP HAD UPPER LOW SPINNING OVER NORTH CENTRAL NE.
DEFORMATION ZONE -RASN ACROSS SOUTHERN SD STARTING TO WANE AS
MOISTURE PLUME IS CUTOFF AND MAIN FORCING SHIFTS NORTHEAST ON 90KT
JET STREAK ACROSS THE MIDDLE MO RIVER VALLEY. FEW INCHES OF SNOW
OVER THE HIGHER ELEVATIONS PER WEB CAMS/ROAD REPORTS SINCE TUESDAY
AFTERNOON. 00Z NAM/GFS AND LATEST RAP SHOW PRECIPITATION WANING
THROUGH THE MORNING HOURS WITH MOST SYNOPTIC SCALE ACTIVITY/LIFT
DONE BY 18Z. LOW LEVEL INSTABILITY SUGGESTS A FEW POPCORN SHOWERS
POSSIBLE THIS AFTERNOON ACROSS THE FAR SOUTH GIVEN RESIDUAL LOW
LEVEL MOISTURE...BUT DRIER AIR INFILTRATING BOUNDARY LAYER UNDER
SURFACE HIGH MAY LIMIT ACTIVITY TO SPRINKLES/VIRGA. TEMPERATURES
WILL COOL AND BE BELOW GUIDANCE ACROSS THE SOUTH BUT NEAR GUIDANCE
ACROSS THE NORTH WHERE CLEARING SKIES WILL MAKE FOR A PLEASANT
DAY...ALBEIT BELOW NORMAL.
TONIGHT/THURSDAY...WEAK UPPER RIDGE BUILDS INTO THE NORTHERN PLAINS
AS SURFACE HIGH SHIFTS INTO THE MIDDLE MS RIVER VALLEY. FROST MAY
OCCUR OVER PARTS OF THE SD PLAINS AND LATER SHIFTS WILL NEED TO
ASSESS FOR HEADLINES. WEAK RETURN FLOW EXPECTED THURSDAY WITH WARM
AIR ADVECTION PUSHING TEMPERATURES INTO THE 60S ON THE PLAINS AND
50S IN THE BLACK HILLS.
THURSDAY NIGHT...UPPER FLOW BECOMES SOUTHWEST IN RESPONSE TO UPPER
LOW/TROUGH OVER THE WEST COAST. SHORTWAVE MOVING THROUGH WY MAY
PRODUCE SMALL POPS OVER THE FAR SOUTHWEST LATE. TEMPERATURES WILL BE
NEAR GUIDANCE.
.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 250 AM MDT WED MAY 20 2015
THE NEXT LOW PRESSURE SYSTEM TO EJECT OUT OF THE WESTERN CONUS
TROF WILL BEGIN TO IMPACT THE AREA ON FRIDAY...WITH CHANCES FOR
SHOWERS AND THUNDERSTORMS INCREASING FROM SOUTHWEST TO NORTHEAST
ACROSS THE CWA INTO FRIDAY EVENING. MEDIUM RANGE MODELS SEEM TO BE
IN BETTER AGREEMENT ON THE TRACK OF THE SYSTEM...WITH SOME
DIFFERENCES ON TIMING AND WHERE HEAVIER RAINFALL MAY DEVELOP. THE
BEST CHANCES FOR MORE WIDESPREAD PCPN STILL LOOK TO BE FROM LATE
FRIDAY INTO SUNDAY MORNING...WITH THE THREAT FOR HEAVIEST RAINFALL
GENERALLY BEING SATURDAY AFTERNOON AND NIGHT. SATURDAY LOOKS TO BE
THE MOST FAVORABLE DAY FOR STRONGER THUNDERSTORMS AS WELL...
ESPECIALLY FROM THE BLACK HILLS AREA AND EASTWARD. AS THE SYSTEM
WEAKENS TO THE NORTH AND EAST OF THE AREA LATE IN THE
WEEKEND...SOUTHWEST FLOW ALOFT WILL REMAIN OVER THE REGION. THIS
WILL KEEP THE UNSETTLED PATTERN CONTINUING INTO EARLY NEXT WEEK.
TEMPERATURES WILL STAY BELOW AVERAGE THROUGH THE WEEKEND WITH
CLOUDS AND MOISTURE ACROSS THE AREA. WILL LIKELY SEE A WARMING
TREND TO NEAR AVERAGE TEMPERATURES EARLY NEXT WEEK.
&&
.AVIATION...FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING
ISSUED AT 535 AM MDT WED MAY 20 2015
LOW PRESSURE ALOFT WILL WEAKEN AND SHIFT EAST OF THE REGION
TODAY. AREAS OF LIGHT RAIN/SNOW WITH MVFR/IFR CONDITIONS OVER
SOUTHERN SD AND FAR NORTHEAST WY WILL CONTINUE EARLY THIS
MORNING...WITH PCPN TAPERING OFF AND CONDITIONS IMPROVING TO VFR
FROM NORTH TO SOUTH THROUGH THE REST OF THE MORNING AND MIDDAY
HOURS. VFR CONDITIONS WILL PERSIST ACROSS NORTHWEST SD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...POJORLIE
SHORT TERM...HELGESON
LONG TERM...26
AVIATION...26
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
536 AM MDT WED MAY 20 2015
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 250 AM MDT WED MAY 20 2015
08Z SURFACE ANALYSIS HAD HIGH PRESSURE OVER THE DAKOTAS. WATER
VAPOUR LOOP HAD UPPER LOW SPINNING OVER NORTH CENTRAL NE.
DEFORMATION ZONE -RASN ACROSS SOUTHERN SD STARTING TO WANE AS
MOISTURE PLUME IS CUTOFF AND MAIN FORCING SHIFTS NORTHEAST ON 90KT
JET STREAK ACROSS THE MIDDLE MO RIVER VALLEY. FEW INCHES OF SNOW
OVER THE HIGHER ELEVATIONS PER WEB CAMS/ROAD REPORTS SINCE TUESDAY
AFTERNOON. 00Z NAM/GFS AND LATEST RAP SHOW PRECIPITATION WANING
THROUGH THE MORNING HOURS WITH MOST SYNOPTIC SCALE ACTIVITY/LIFT
DONE BY 18Z. LOW LEVEL INSTABILITY SUGGESTS A FEW POPCORN SHOWERS
POSSIBLE THIS AFTERNOON ACROSS THE FAR SOUTH GIVEN RESIDUAL LOW
LEVEL MOISTURE...BUT DRIER AIR INFILTRATING BOUNDARY LAYER UNDER
SURFACE HIGH MAY LIMIT ACTIVITY TO SPRINKLES/VIRGA. TEMPERATURES
WILL COOL AND BE BELOW GUIDANCE ACROSS THE SOUTH BUT NEAR
GUIDANCE ACROSS THE NORTH WHERE CLEARING SKIES WILL MAKE FOR A
PLEASANT DAY...ALBEIT BELOW NORMAL.
TONIGHT/THURSDAY...WEAK UPPER RIDGE BUILDS INTO THE NORTHERN PLAINS
AS SURFACE HIGH SHIFTS INTO THE MIDDLE MS RIVER VALLEY. FROST MAY
OCCUR OVER PARTS OF THE SD PLAINS AND LATER SHIFTS WILL NEED TO
ASSESS FOR HEADLINES. WEAK RETURN FLOW EXPECTED THURSDAY WITH WARM
AIR ADVECTION PUSHING TEMPERATURES INTO THE 60S ON THE PLAINS AND
50S IN THE BLACK HILLS.
THURSDAY NIGHT...UPPER FLOW BECOMES SOUTHWEST IN RESPONSE TO UPPER
LOW/TROUGH OVER THE WEST COAST. SHORTWAVE MOVING THROUGH WY MAY
PRODUCE SMALL POPS OVER THE FAR SOUTHWEST LATE. TEMPERATURES WILL BE
NEAR GUIDANCE.
.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 250 AM MDT WED MAY 20 2015
THE NEXT LOW PRESSURE SYSTEM TO EJECT OUT OF THE WESTERN CONUS
TROF WILL BEGIN TO IMPACT THE AREA ON FRIDAY...WITH CHANCES FOR
SHOWERS AND THUNDERSTORMS INCREASING FROM SOUTHWEST TO NORTHEAST
ACROSS THE CWA INTO FRIDAY EVENING. MEDIUM RANGE MODELS SEEM TO BE
IN BETTER AGREEMENT ON THE TRACK OF THE SYSTEM...WITH SOME
DIFFERENCES ON TIMING AND WHERE HEAVIER RAINFALL MAY DEVELOP. THE
BEST CHANCES FOR MORE WIDESPREAD PCPN STILL LOOK TO BE FROM LATE
FRIDAY INTO SUNDAY MORNING...WITH THE THREAT FOR HEAVIEST RAINFALL
GENERALLY BEING SATURDAY AFTERNOON AND NIGHT. SATURDAY LOOKS TO BE
THE MOST FAVORABLE DAY FOR STRONGER THUNDERSTORMS AS WELL...
ESPECIALLY FROM THE BLACK HILLS AREA AND EASTWARD. AS THE SYSTEM
WEAKENS TO THE NORTH AND EAST OF THE AREA LATE IN THE
WEEKEND...SOUTHWEST FLOW ALOFT WILL REMAIN OVER THE REGION. THIS
WILL KEEP THE UNSETTLED PATTERN CONTINUING INTO EARLY NEXT WEEK.
TEMPERATURES WILL STAY BELOW AVERAGE THROUGH THE WEEKEND WITH
CLOUDS AND MOISTURE ACROSS THE AREA. WILL LIKELY SEE A WARMING
TREND TO NEAR AVERAGE TEMPERATURES EARLY NEXT WEEK.
&&
.AVIATION...FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING
ISSUED AT 535 AM MDT WED MAY 20 2015
LOW PRESSURE ALOFT WILL WEAKEN AND SHIFT EAST OF THE REGION
TODAY. AREAS OF LIGHT RAIN/SNOW WITH MVFR/IFR CONDITIONS OVER
SOUTHERN SD AND FAR NORTHEAST WY WILL CONTINUE EARLY THIS
MORNING...WITH PCPN TAPERING OFF AND CONDITIONS IMPROVING TO VFR
FROM NORTH TO SOUTH THROUGH THE REST OF THE MORNING AND MIDDAY
HOURS. VFR CONDITIONS WILL PERSIST ACROSS NORTHWEST SD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...HELGESON
LONG TERM...26
AVIATION...26
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
950 AM CDT Wed May 20 2015
.UPDATE...
A cold front is moving slowly south across the Big Country this
morning, currently extending from just near Big Spring, to just
north of Abilene, to Jacksboro. A few showers have developed along
and north of this boundary, but should remain relatively light and
unorganized. Temperatures have dropped into the upper 50s and
lower 60s in areas north of I-20, with dewpoints as low as the
50s. An outflow boundary from overnight convection has moved south
to near a Brownwood to San Angelo line and continues to sag slowly
toward I-10. Precipitation amounts should remain rather light
through early afternoon, but as the boundary layer destabilizes,
scattered convection is expected to develop.
The most likely area for convective initiation is roughly south of
a San Angelo to Brownwood line (where the cold front is forecast
to be near peak heating). If we get enough breaks in the cloud
cover, instability and vertical shear should be sufficient to
support strong to severe thunderstorms. This would present a
potential for localized heavy rainfall, but coverage is expected
to be limited, so not Flash Flood Watch will be issued.
Temperatures were lowered a few degrees across the Big Country
this afternoon, but otherwise minimal changes were made to the
inherited forecast.
Johnson
&&
.PREV DISCUSSION... /ISSUED 650 AM CDT Wed May 20 2015/
AVIATION...
/12Z TAFS/
Widespread stratus is expected across West Central Texas this
morning, with MVFR/IFR ceilings. The ceilings will lift to low end
VFR across much of the area this afternoon and continue this
evening, besides the KABI terminal remaining MVFR. Scattered
thunderstorms should develop this afternoon and evening across the
mainly the southern 2/3 of the area and have VCTS at most of the
terminals. A few storms may be severe.
PREV DISCUSSION... /ISSUED 450 AM CDT Wed May 20 2015/
SHORT TERM...
(Today and Tonight)
This morning, a cool front extended across central and southwest
Oklahoma and southwest to south of Lubbock. Also, a complex of
thunderstorms (latest IR indicating warming cloud tops) was
located across north Texas and southern Oklahoma or mainly along
the Red River valley. Scattered showers and storms extended back
west into Haskell and Throckmorton counties. For today, the cool
front will make some progress south across West Central Texas to
probably along a San Angelo to Brownwood line by 00Z. Looks like
the best potential for thunderstorms will be in the warm sector
across the southern half of the area, along and ahead of the
front. All the models indicate at least scattered thunderstorms
developing, with the high res HRRR the most aggressive. The
combination of moderate instability and 0-6km shear values of
30-35 knots will lead to a few storms becoming severe during
mainly this afternoon and evening. the main hazards will be large
hail and damaging winds. The Big Country will probably see more
stable conditions behind the front, so the severe weather concern
is mainly low for the next 24 hours. Highs today will range from
the upper 60s to lower 70s across the Northern Big Country to
lower 80s along the I-10 corridor.
For tonight, the scattered afternoon storms may form into an
organized complex during this evening. However, there is some
uncertainty on how and where the storms will organize. For now,
will keep the likely Pops going across the southeast half of the
area and chance Pops elsewhere. Locally heavy rainfall will be
possible mainly due to PW values of 1.25 to 1.5 inches. Again, A
few storms may be severe during the evening. The cool front
should move south of the area after midnight and convection should
begin to weaken some.
LONG TERM...
(Thursday through Tuesday)
.Unsettled weather will continue through the Memorial Day
Weekend...
Cloudy and cool conditions will start off the extended period on
Thursday, as the cold front remains stalled south of the area
during the day. Temperatures will be well below normal for this
time of year, with highs ranging from the upper 60s across the Big
Country, to the middle 70s along the I-10 corridor. Best rain
chances will be across the southern half of the forecast area
during the day, but will ramp up areawide by Thursday night as a
shortwave lifts northeast across the area.
Southerly flow returns on Friday as the stalled front lifts back
north as a warm front during the day. Temperatures will be warmer
but still below normal, with highs mainly in the upper 70s and
lower 80s. There will be a continued chance for showers and
thunderstorms on Friday, with highest POPs across northern
sections where aforementioned front is expected to lift north
during the afternoon hours.
Maintaining high POPs for next weekend as a short wave trough
moves east from the Four Corners region on Saturday and across
the southern Rockies by Sunday. This system will bring a threat
of strong to severe storms and heavy rainfall potential to the
area for the Memorial Day weekend. Precipitation chances will
start to wane by early next week as weak short wave ridging
develops in the wake of the departing upper trough.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 74 59 68 58 77 / 40 50 40 60 50
San Angelo 80 63 71 61 81 / 40 60 40 60 40
Junction 83 67 75 64 83 / 20 60 50 50 40
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
25
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
650 AM CDT Wed May 20 2015
.AVIATION...
/12Z TAFS/
Widespread stratus is expected across West Central Texas this
morning, with MVFR/IFR ceilings. The ceilings will lift to low end
VFR across much of the area this afternoon and continue this
evening, besides the KABI terminal remaining MVFR. Scattered
thunderstorms should develop this afternoon and evening across the
mainly the southern 2/3 of the area and have VCTS at most of the
terminals. A few storms may be severe.
&&
.PREV DISCUSSION... /ISSUED 450 AM CDT Wed May 20 2015/
SHORT TERM...
(Today and Tonight)
This morning, a cool front extended across central and southwest
Oklahoma and southwest to south of Lubbock. Also, a complex of
thunderstorms (latest IR indicating warming cloud tops) was
located across north Texas and southern Oklahoma or mainly along
the Red River valley. Scattered showers and storms extended back
west into Haskell and Throckmorton counties. For today, the cool
front will make some progress south across West Central Texas to
probably along a San Angelo to Brownwood line by 00Z. Looks like
the best potential for thunderstorms will be in the warm sector
across the southern half of the area, along and ahead of the
front. All the models indicate at least scattered thunderstorms
developing, with the high res HRRR the most aggressive. The
combination of moderate instability and 0-6km shear values of
30-35 knots will lead to a few storms becoming severe during
mainly this afternoon and evening. the main hazards will be large
hail and damaging winds. The Big Country will probably see more
stable conditions behind the front, so the severe weather concern
is mainly low for the next 24 hours. Highs today will range from
the upper 60s to lower 70s across the Northern Big Country to
lower 80s along the I-10 corridor.
For tonight, the scattered afternoon storms may form into an
organized complex during this evening. However, there is some
uncertainty on how and where the storms will organize. For now,
will keep the likely Pops going across the southeast half of the
area and chance Pops elsewhere. Locally heavy rainfall will be
possible mainly due to PW values of 1.25 to 1.5 inches. Again, A few
storms may be severe during the evening. The cool front should move
south of the area after midnight and convection should begin to
weaken some.
LONG TERM...
(Thursday through Tuesday)
..Unsettled weather will continue through the Memorial Day
Weekend...
Cloudy and cool conditions will start off the extended period on
Thursday, as the cold front remains stalled south of the area
during the day. Temperatures will be well below normal for this
time of year, with highs ranging from the upper 60s across the Big
Country, to the middle 70s along the I-10 corridor. Best rain
chances will be across the southern half of the forecast area
during the day, but will ramp up areawide by Thursday night as a
shortwave lifts northeast across the area.
Southerly flow returns on Friday as the stalled front lifts back
north as a warm front during the day. Temperatures will be warmer
but still below normal, with highs mainly in the upper 70s and
lower 80s. There will be a continued chance for showers and
thunderstorms on Friday, with highest POPs across northern
sections where aformentioned front is expected to lift north
during the afternoon hours.
Maintaining high POPs for next weekend as a short wave trough
moves east from the Four Corners region on Saturday and across
the southern Rockies by Sunday. This system will bring a threat
of strong to severe storms and heavy rainfall potential to the
area for the Memorial Day weekend. Precipitation chances will
start to wane by early next week as weak short wave ridging
develops in the wake of the departing upper trough.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 74 59 68 58 77 / 40 50 40 60 50
San Angelo 80 63 71 61 81 / 40 60 40 60 40
Junction 83 67 75 64 83 / 20 60 50 50 40
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
626 AM CDT WED MAY 20 2015
.DISCUSSION...12Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...MVFR STRATUS PREVAILS ACROSS MOST OF SOUTH-CENTRAL
TEXAS EARLY THIS MORNING...WITH SOME ISOLATED SPOTS IN IFR RANGE.
CEILINGS IMPROVING BACK TO VFR 18Z-21Z. ISOLATED SHRAS AND TSTMS
POSSIBLE DURING THE AFTERNOON ACROSS NORTHERN AND EASTERN
AREAS...INCLUDING VICINITY OF AUS. A COLD FRONT WILL APPROACH THE
HILL COUNTRY DURING THE LATE AFTERNOON...WITH SCATTERED SHRAS AND
TSTMS ALONG IT. TREND AMONG HI RESOLUTION MODELS HAS BEEN QUICKER
WITH THE SOUTHWARD PROGRESSION OF THE FRONT THROUGH THE DAY...
ALTHOUGH CONVECTIVE OUTFLOW BOUNDARIES WILL ULTIMATELY PLAY A KEY
ROLE IN EXACTLY HOW FAST THE FRONT MOVES SOUTH AND EXACT TIMING
INTO THE CWA. HAVE MOVED THE TIMING OF TSTMS UP IN THE 12Z AUS
AND DRT TAFS...WITH TSTMS MENTIONED AS EARLY AS 00Z NOW. THE
TIMING WILL LIKELY BE REFINED FURTHER IN THE 18Z TAFS AS TRENDS
BECOME BETTER ESTABLISHED. CONDITIONS WILL BE FAVORABLE FOR A FEW
STORMS TO BECOME STRONG TO SEVERE ALONG AND NORTH OF AN AUS TO UVA
LINE.
&&
.PREV DISCUSSION... /ISSUED 426 AM CDT WED MAY 20 2015/
SHORT TERM (TODAY THROUGH THURSDAY)...
AREA STREAMS AND RIVERS ARE HAVING A BRIEF PERIOD TO RECOVER
THROUGH EARLY TODAY BEFORE A COLD FRONT ARRIVES TO TRIGGER NEW
CONVECTION AND POSSIBLY RIVER RISES. MOST OF THE HIGHER RES MODELS
GENERATE WHAT LOOKS TO BE STRONG TO SEVERE STORMS OVER THE WESTERN
HALF OF THE FORECAST AREA WHERE THE COLD FRONT INTERACTS WITH HIGH
EVENING CAPE VALUES AND LIGHT TO MODERATE SHEAR. WITH SPC MESO-
ANALYSIS SHOWING HIGH PWAT VALUES OVER THE COMPLEX RIDING ALONG
THE COLD FRONT OVER THE RED RIVER VALLEY EARLY THIS MORNING...WILL
EXPECT A SIMILAR ENVIRONMENT SETTING UP FOR CENTRAL TX INTO THE
WESTERN HILL COUNTRY THIS EVENING. THE PAST COUPLE RUNS OF THE NAM
MODEL SEEM TO REFLECT A GOOD MIDDLE GROUND FROM THE HIGH RES CAMPS
THAT SHOW EXTRA EMPHASIS OVER WESTERN COUNTIES AND OTHERS...
INCLUDING RECENT HRRR RUNS...THAT KEEP THE CURRENT COMPLEX ALIVE
AND MOVE IT INTO MAINLY CENTRAL AND EASTERN COUNTIES IN THE LATE
AFTERNOON HOURS.
IN THE FIRST OPERATIONAL PERIOD FOR TODAY...WILL FOLLOW A PORTION
OF THE EASTERN SOLUTIONS OF HIGHER RES RUNS WITH THE EXPECTATION
THAT SOME GRAVITY WAVE INDUCED SHOWER ACTIVITY TAPS INTO LOCALLY
HIGHER PWAT VALUES. SLIGHTLY HIGHER POPS ARE SHOWN OVER CENTRAL
TX FOR THIS AFTERNOON. HOWEVER...EXPECT THE SURFACE FRONTAL
BOUNDARY TO MIX OUT...AND MID LEVEL STABILITY TO HOLD BACK MOST
DEEP CONVECTION. WILL NEED TO MONITOR THE CONVECTIVE DEVELOPMENT
CLOSELY OVER CENTRAL TX SHOULD THE CONVECTIVE OUTFLOW BE MORE
ROBUST OVER NORTH TX IN THE LATE MORNING HOURS.
BY THIS EVENING...THE NAM COMPROMISE SOLUTION SHOWS ITS HIGHEST
IMPACT OVER THE NORTHERN HILL COUNTRY AND COULD MEAN A THREAT FOR
BOTH SEVERE WEATHER AND FLASH FLOODING WITH SLOW SOUTHWARD
PROPAGATING CELLS MOVING DOWN HIGHWAY 281. WHILE THIS SIGNAL WAS
SIMILAR IN TWO STRAIGHT NAM RUNS...LOWER RES SOLUTIONS SHOW
HIGHEST RAIN POTENTIAL MUCH FARTHER TO THE WEST WITH FRONTAL
FORCING LIMITED OVER EASTERN COUNTIES. THUS WILL BALK AT ISSUING
AN FFA...AS FLOODING THREATS SHOULD BE SOMEWHAT ISOLATED SHOULD
THE WESTERN SOLUTIONS PREVAIL. TOWARD DAYBREAK...MUCH OF THE AREA
SHOULD SHOW SOME LOW LEVEL STABILITY FROM THE FRONT...WITH MOST OF
THE ELEVATED RAINS EXPECTED TO BE LIGHT TO MODERATE INTO THURSDAY.
THE FRONT IS EXPECTED TO BE WEAK AND SHALLOW...SO WILL SHOW CHANCE
CATEGORY POPS WHICH SIDE WITH THE LOWER RES MODELS OVER THE DRIER
SOLUTIONS OF MOST HIGHER RES RUNS.
LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)...
ASSUMING WE GET THROUGH TONIGHTS SITUATIONAL HEAVY RAIN THREAT
WITHOUT A MAJOR ORDEAL...THE HEAVY RAIN EMPHASIS WE ARE MOST
CONCERNED ABOUT IS OVER THE WEEKEND. A SHARPENING AND HIGH
AMPLITUDE UPPER TROUGH TO THE SOUTHWEST WILL INCREASE POPS
GRADUALLY FRIDAY INTO SATURDAY...AND THEN AGRESSIVELY SATURDAY
NIGHT THROUGH SUNDAY EVENING. A WIDESPREAD HEAVY RAIN OF 1 TO 3
INCHES IS EXPECTED FOR THIS ENHANCED PERIOD WITH ISOLATED HIGHER
AMOUNTS OF 4 TO 6 INCHES POSSIBLE. THE ECMWF AND CANADIAN EVEN
CARRY THE EVENT INTO MEMORIAL DAY...WHICH COULD SEND PROJECTIONS
EVEN HIGHER. FOR NOW...WILL ASSUME THAT A WIDESPREAD MCS OVER THE
WEEKEND SHOULD TEMPORARILY STABILIZE THE AIR FOR MONDAY WHICH
FAVORS THE MORE CONSERVATIVE GFS SOLUTION.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 86 69 79 66 83 / 30 50 30 40 40
AUSTIN BERGSTROM INTL AIRPORT 85 68 79 66 83 / 30 50 30 40 40
NEW BRAUNFELS MUNI AIRPORT 86 70 81 67 83 / 30 40 40 40 40
BURNET MUNI AIRPORT 83 66 75 63 80 / 30 60 30 40 40
DEL RIO INTL AIRPORT 86 71 82 69 85 / 20 60 50 60 40
GEORGETOWN MUNI AIRPORT 84 66 76 64 82 / 30 60 30 40 40
HONDO MUNI AIRPORT 86 71 82 68 84 / 20 50 40 50 40
SAN MARCOS MUNI AIRPORT 85 69 79 66 82 / 30 40 30 40 40
LA GRANGE - FAYETTE REGIONAL 86 70 81 69 83 / 30 20 40 30 40
SAN ANTONIO INTL AIRPORT 86 71 81 69 83 / 20 40 40 40 40
STINSON MUNI AIRPORT 87 72 82 69 84 / 20 30 40 40 40
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...76
SYNOPTIC/GRIDS...18
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
937 AM CDT WED MAY 20 2015
.UPDATE...
ISSUED AT 937 AM CDT WED MAY 20 2015
INCREASED/MOVED PRECIPITATION CHANCES A BIT MORE NORTHWARD ACROSS
NORTHEAST IA/SOUTHWEST WI THIS MORNING INTO THIS AFTERNOON WITH
INCOMING MID-LEVEL TROUGH/CIRCULATION. LATEST RAP SHOWS
INTENSIFICATION IN MID-LEVEL/700MB FRONTOGENESIS...SO EXPECTING
DESPITE DRYER LOW LEVELS...THE F-GEN WILL BE STRONG ENOUGH TO
GENERATE SOME SHOWERS.
UPDATE ISSUED AT 802 AM CDT WED MAY 20 2015
UPDATED TO REMOVE FROST ADVISORY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT WED MAY 20 2015
MAIN FCST CONCERNS THIS PERIOD...SMALL -SHRA CHANCES SOUTH TODAY...
TEMPERATURES.
DATA ANALYSIS AT 06Z HAD A BROAD AREA OF HIGH PRESSURE OVER THE
NORTHERN PLAINS AND UPPER MIDWEST. THE HIGH WAS BRINGING CLEAR
SKIES AND SUB-FREEZING TEMPS TO MUCH OF NORTHERN MN/WI INTO
CENTRAL WI EARLY THIS MORNING. WV IMAGERY SHOWED A RATHER VIGOROUS
LOOKING SHORTWAVE MOVING EAST ALONG THE NEB/SD BORDER. MID/HIGH
CLOUDS WITH THIS WAVE SPREADING ACROSS SOUTHERN MN/WI...HELPING
KEEP TEMPS ABOVE FREEZING. THE SHORTWAVE WAS BRINGING SOME LOWER
LEVEL MOISTURE TO IA...BUT EVEN THERE CLOUDS WERE MOSTLY ABOVE 5K-
6K FT. REGIONAL RADARS SHOWED REFLECTIVITY WITH THE SHORTWAVE FROM
SOUTH- CENTRAL SD TO NORTHERN MO BUT SFC OBS SHOW PRECIP REACHING
THE GROUND WAS MAINLY ALONG/SOUTH OF I-80 EARLY THIS MORNING.
20.00Z MODEL INITIALIZATIONS LOOK GOOD. MODELS OFFER A TIGHTER
CONSENSUS ON THE SD/NEB SHORTWAVE AS IT TRACKS EAST TODAY...AHEAD OF
BUT PARTLY PHASING WITH THE NORTHERN STREAM SHORTWAVE DROPPING INTO
EASTERN SD. TREND IS TO KEEP THE WAVES AS 2 SEPARATE PIECES OF
ENERGY QUICKLY FOLLOWING EACH OTHER THRU A MERGED TROUGH OVER THE
UPPER MIDWEST. TREND FAVORS STRONGER OF THE EARLIER MODELS AS THE
NORTHERN STREAM SHORTWAVE MOVES SOUTHEAST ACROSS THE REGION. WITH
THE TIGHT CONSENSUS OF SOLUTIONS...SHORT TERM FCST CONFIDENCE IS
GOOD THIS CYCLE.
IN THE SHORT TERM...SMALL -SHRA CHANCES ACROSS THE FAR SOUTH END OF
THE FCST AREA REMAIN A BATTLE OF 700-500MB FN/QG CONVERGENCE AND PV
ADVECTION WITH THE SHORTWAVE AND OVERCOMING DRIER NORTH TO NORTHEAST
FLOW/AIRMASS IN THE SFC-700MB PORTION OF THE COLUMN. PW VALUES IN
THE 0.5 TO 0.75 INCH RANGE ACROSS THE SOUTH END OF THE FCST AREA
TODAY BUT MAIN 850MB MOISTURE TRANSPORT STAYS WELL SOUTH IN MO AND
THE 700MB TRANSPORT MAINLY REACHES INTO THE SOUTHERN 2/3 OF IA.
MODELS...INCLUDING LOCAL/REGIONAL WRF MODELS ABOUT EVENLY SPLIT ON
-SHRA MAKING IT AS FAR NORTH AS THE KCCY/KOLZ AREAS. CONTINUED SOME
20-40 PERCENT -SHRA CHANCES ACROSS PARTS OF NORTHEAST IA INTO
EXTREME SOUTHWEST WI TODAY...PARTLY TO BLEND WITH NEIGHBORING GRIDS.
MAIN SHOT OF FORCING/LIFT MOVES ACROSS THE AREA THIS MORNING AND
CARRIED HIGHEST RAIN CHANCES AROUND 15Z...WITH RAIN CHANCES
DIMINISHING THRU THE AFTERNOON AS THE LEAD SHORTWAVE PASSES AND THE
COLUMN BEGINS TO DRY. MID/HIGH CLOUDS ACROSS THE AREA TODAY WILL
TEMPER HIGHS. 700-500MB TROUGH AXIS DROPS SOUTH OF THE AREA THIS
EVENING WITH AN INCREASE OF NORTHWEST TO NORTH FLOW AND DRIER AIR
SPREADING SOUTH ACROSS THE FCST AREA. CLOUDS LOOKING TO DECREASE
THIS EVENING WITH MOSTLY CLEAR TO CLEAR SKIES OVERNIGHT. ANOTHER
COOL NIGHT TONIGHT UNDER MOSTLY CLEAR SKIES...A DRY LOW LEVEL
AIRMASS AND WINDS EXPECTED TO BE LIGHT. MAY YET BE SOME PATCHY FROST
ACROSS THE NORTHEAST END OF THE FCST AREA LATE TONIGHT INTO EARLY
THU MORNING. WILL LEAVE IT TO DAY CREW TO FURTHER EVALUATE THIS
AFTER THE CURRENT ADVISORY HAS EXPIRED. FAVORED A BLEND OF THE
GUIDANCE HIGHS/LOWS FOR TODAY/TONIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 405 AM CDT WED MAY 20 2015
MAIN FCST CONCERNS FOR THU THRU FRI NIGHT...TEMPERATURES.
20.00Z MODELS IN GOOD AGREEMENT ON NORTHWEST FLOW ALOFT OVER THE
UPPER MIDWEST THU THRU FRI...AND REMAIN IN GOOD AGREEMENT FOR HGTS
TO RISE/RIDGING TO BUILD INTO THE REGION FRI NIGHT. MODELS ALSO WITH
RATHER GOOD RUN-TO-RUN CONSISTENCY THIS PERIOD. TREND BY FRI NIGHT
IS TOWARD STRONGER OF THE EARLIER RUNS WITH THE RIDGING OVER THE
REGION. FCST CONFIDENCE FOR THU THRU FRI NIGHT IS GOOD THIS CYCLE.
UNDER THE NORTHWEST FLOW ALOFT MODEL SOUNDINGS AND TIME-HGT X-
SECTIONS SHOWING A RATHER DRY AIRMASS/COLUMN OVER THE AREA FOR
THU THRU FRI. OTHER THAN PERHAPS SOME SCT AFTERNOON CUMULUS DURING
PEAK HEATING...THU THRU FRI SHAPING UP TO BE A CLEAR/SUNNY PERIOD.
DECENT CONSENSUS AMONG THE MODEL FOR A WEAK WAVE TO DROP ACROSS
THE WESTERN GREAT LAKES THU BUT ANY IMPACTS FROM THIS LOOKING TO
REMAIN WELL EAST OF THE FCST AREA. SFC PRESSURE GRADIENTS ON THE
WEAK SIDE FOR LIGHT WINDS...ESPECIALLY FRI WITH A SFC RIDGE AXIS
OVER THE REGION. MODEL SOUNDINGS INDICATING MIXING TO ABOUT 750MB
THU...WITH AROUND 25KTS OF WIND IN THE 850-750MB PORTION OF THE
MIXED LAYER. INCREASED WINDS/GUSTS A BIT THU AFTERNOON. COLUMN
MIXES TO AROUND 825MB FRI...WITH WINDS PROGGED TO BE LESS THAN
10KT THRU 800MB. 850MB TEMPS IN THE +7C TO +9C RANGE BOTH THU/FRI
AFTERNOONS... SUPPORTING HIGHS IN THE UPPER 60S TO NEAR 75. LIGHT
WINDS AND CLEAR SKIES FOR STRONGER RADIATIONAL COOLING THU
NIGHT...FOR A LARGER THAN NORMAL DIURNAL SWING OF TEMPERATURES. AS
PATTERN PROGRESSES FRI NIGHT...SFC-700MB TROUGHING STRENGTHENS IN
THE PLAINS. INCREASING SOUTH TO SOUTHWEST LOW LEVEL FLOW STARTS TO
SPREAD MOISTURE/WARMING NORTHEAST INTO THE UPPER MIDWEST...ALONG
WITH HIGHER LEVEL MOISTURE AHEAD OF THE WESTERN CONUS TROUGHING
SPILLING THRU THE RIDGING AND INTO THE REGION. TREND OF WARMER
LOWS AND SOME INCREASE OF CLOUDS FRI NIGHT LOOKS GOOD. TRENDED
TOWARD WARMER OF GUIDANCE HIGHS THU/FRI...THEN FAVORED A BLEND OF
THE GUIDANCE LOWS THU/FRI NIGHTS.
FOR SATURDAY THRU TUESDAY...DAYS 4 TO 7...
MEDIUM RANGE MODEL RUNS OF 20.00Z IN QUITE GOOD AGREEMENT SAT/SUN
SHOWING THE MID LEVEL RIDGE AXIS TO SLOWLY MOVE EAST OF THE REGION
AND DEEP SOUTHWEST FLOW ALOFT OVER MUCH OF THE UPPER MIDWEST BY LATE
SUN. DIFFERENCES BEGIN TO APPEAR BY SUN NIGHT/MON...ON THE TIMING/
STRENGTH DETAILS OF SHORTWAVE ENERGY EJECTING OUT OF THE WESTERN
CONUS TROUGH AND TOWARD/INTO THE UPPER MIDWEST. DETAIL DIFFERENCES
CONTINUE TUE...BUT GENERAL LONGWAVE CONSENSUS FOR BROAD TROUGHING
OVER MUCH OF THE CENTRAL/WESTERN CONUS. WITH THIS TRENDING TO BE A
MORE UNSETTLED WEATHER PERIOD AND SENSIBLE WEATHER ANY ONE DAY
STRONGLY IMPACTED BY THE SHORTWAVE/MESO-SCALE DETAILS...FCST
CONFIDENCE IN THE DAY 4-7 PERIOD IS AVERAGE THIS CYCLE.
MODEL CONSENSUS HAS SOUTHERLY FLOW AND MOISTURE CONTINUING TO
INCREASE INTO THE UPPER MIDWEST SATURDAY THRU SUN. PW VALUES PROGGED
IN THE 1.5 INCH RANGE OVER MUCH OF THE FCST AREA BY 12Z SUN. THIS
WITH A BROAD INCREASE OF LOWER LEVEL THERMO-DYNAMIC FORCING/LIFT AND
INSTABILITY. MODEL CONSENSUS OF INCREASING SHRA/TSRA CHANCES FROM
WEST TO EAST ACROSS THE AREA FROM SAT THRU SUN NIGHT LOOKING WELL
TRENDED...THOUGH THE SPECIFIC DETAILS OF PERIOD HAVE YET TO BE
SORTED OUT. WITH SLOW PROGRESSION OF THE LONGWAVE PATTERN...AND
ADDITIONAL SHORTWAVES TO COME THRU LONGWAVE TROUGHING THAT IS
PROGGED TO REMAIN OVER THE WEST HALF OF THE CONUS...THE MODEL/
ENSEMBLE CONSENSUS SHRA/ TSRA CHANCES CONTINUING THRU MON/TUE ARE
REASONABLE FOR NOW. GIVEN UNCERTAINTIES WITH SHRA/TSRA CHANCES/
TIMING/COVERAGE /AND CLOUD COVER/ ANY ONE DAY...DID NOT DEVIATE
FROM THE MODEL CONSENSUS HIGHS/LOWS FOR SAT THRU TUE. IF ANY ONE
OR MORE OF DAYS 4 TO 7 END UP DRY AND SUNNIER THAN CURRENTLY
EXPECTED... HIGHS THAT DAY COULD EASILY BE 5F TO 10F WARMER THAN
THOSE IN THE FCST GRIDS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 638 AM CDT WED MAY 20 2015
MID CLOUDS...ASSOCIATED WITH A LOW PRESSURE SYSTEM MOVING THROUGH
THE SOUTHERN MISSOURI...WILL REMAIN OVER BOTH TAF SITES THROUGH
THIS EVENING...AND THEN SKIES WILL CLEAR. LIGHT WINDS WILL
GRADUALLY VEER FROM THE NORTH THIS MORNING TO SOUTH AND SOUTHWEST
BY THIS AFTERNOON AND REMAIN THAT WAY THROUGH TONIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...DAS
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...BOYNE
AREA FORECAST DISCUSSION...UPDATED
NWS LITTLE ROCK AR
1253 PM CDT WED MAY 20 2015
.AVIATION...
DRIER AIR MOVING INTO SOUTHERN ARKANSAS...WITH CONDITIONS
IMPROVING THROUGH THE AFTERNOON. HOWEVER...WITH ABUNDANT
RAINFALL...CONDITIONS WILL DETERIORATE AND IFR CIGS WILL BE
POSSIBLE OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 1035 AM CDT WED MAY 20 2015/
DISCUSSION...
MID MORNING UPDATE LOWERED POPS IN THE WEST TO CENTRAL AR...WHILE
THE HIGHEST IN THE EAST. RADAR TRENDS ARE TAKING MUCH OF THE RAIN
OUT OF THE CWA BY NOON...THEN SHORT RANGE MODELS ONLY SHOW LOW
AMOUNTS OVER THE STATE THE REST OF TODAY. UNTIL THE SURFACE LOW
PULLS EAST AND THE COLD FRONT IS TOTALLY THROUGH AR...WILL HAVE TO
KEEP SOME CHANCES OF RAIN...ISOLATED THUNDER...IN THE FORECAST. AT
MID MORNING THE SURFACE LOW WAS OVER SW MO...WITH THE COLD FRONT
SOUTHWEST TO EASTERN OK. WILL SEE IT GRADUALLY MOVE THROUGH AR TODAY
TO THIS EVENING...WITH A WIND SHIFT TO THE W TO NW BEHIND THE FRONT.
LATER THIS EVENING...THE FRONT IS EXPECTED IN SOUTHERN AR...BUT
LOCATION WILL BE A BIT UNCERTAIN...ESPECIALLY HOW FAR SOUTH IT GOES.
AT SOME POINT OVER SOUTHERN AR THE STEERING FLOW WILL BECOME
PARALLEL AND BOUNDARY WILL STALL...MORE LIKELY NEAR THE AR AND LA
STATE LINE. LATE MORNING UPDATE WILL ADJUST POPS THIS
AFTERNOON...CLOUDS...TEMPS AND WINDS. (59)
PREV DISCUSSION... /ISSUED 417 AM CDT WED MAY 20 2015/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT
AN AREA OF SHOWERS AND THUNDERSTORMS HAS CONTINUED TO PUSH EASTWARD
AND INTO THE AREA DURING THE OVERNIGHT HOURS. SO FAR RAINFALL RATES
EXCEEDING ONE TO TWO INCHES PER HOUR HAVE BEEN SEEN ACROSS WESTERN
PORTIONS OF THE CWA. HRRR...ARW...NMM HAVE ALL HAD A GOOD HANDLE ON
THE SYSTEM TONIGHT AND DO AGREE THAT THE SYSTEM WILL WEAKEN BY
MIDMORNING. DO BELIEVE SOME DRIER AIR WILL FILTER INTO WESTERN
ARKANSAS...BUT AT THIS TIME ONLY THE HRRR COMPLETELY DRIES THINGS
OUT DURING THE AFTERNOON HOURS. DID CONTINUE WITH CHANCE POPS DURING
THE AFTERNOON HOURS FOR MUCH OF THE CWA...BUT THIS WILL NEED TO
CONTINUE TO BE MONITORED AND UPDATED AS NEEDED.
FRONT IS EXPECTED TO CLEAR THE STATE BY 00Z AND WILL CONTINUE TO
PUSH SOUTH AND REMAIN ACROSS LOUISIANA. FOR THE MOST PART...THURSDAY
WILL REMAIN DRY FOR MUCH OF THE STATE...WITH SOME PRECIP CHANCES
REMAINING ACROSS SOUTHERN ARKANSAS. HIGH PRESSURE WILL BUILD IN
BRIEFLY BEFORE PRECIPITATION CHANCES RETURN TO THE FORECAST ON
FRIDAY. MODELS HAVE COME IN BETTER AGREEMENT WITH THE PRECIP ON
FRIDAY...BUT IT LOOKS LIKE PRECIPITATION CHANCES WILL REMAIN
GENERALLY ACROSS WESTERN ARKANSAS. UNSETTLED WEATHER WILL CONTINUE
THROUGH THE WEEKEND WITH A LONGWAVE TROUGH ACROSS THE WESTERN CONUS.
LONG TERM...SUNDAY THROUGH TUESDAY
MODEL DATA THIS MRNG CONT TO INDC AN UNSETTLED WX PATTERN WL PERSIST
ACRS THE REGION TO CLOSE OUT THE HOLIDAY WEEKEND. AN UPR RDG WL SET
UP OVR THE SOUTHEASTERN STATES...RESULTING IN A SWLY FLOW ALOFT ACRS
AR. A SERIES OF IMPULSES WL TRACK NEWD AND BRING CONTD CHCS OF
SHRA/TSRA EACH DAY. KEPT POPS IN THE CHC CAT FOR NOW AS TIMING OF
EACH SHRTWV WL RMN DIFFICULT THIS FAR IN ADVANCE. HVY RAIN POTENTIAL
WL ALSO BE A CONCERN THRU THE PD...ALONG WITH THE CONTD THREAT OF
FLOODING.
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...58
AREA FORECAST DISCUSSION
NWS PUEBLO CO
328 PM MDT WED MAY 20 2015
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 328 PM MDT WED MAY 20 2015
CURRENT WATER VAPOR IMAGERY AND UPPER AIR ANALYSIS INDICATING A
UPPER RIDGING BUILDING ACROSS THE STATE WITH A BROAD UPPER TROUGH
DIGGING ACROSS THE WEST COAST. WATER VAPOR IMAGERY ALSO INDICATING
AN EMBEDDED SHORT WAVE LIFTING OUT ACROSS THE SOUTHERN GREAT BASIN
WITH ANOTHER ONE ROUNDING THE BASE OF THE TROUGH ACROSS THE SOUTHERN
CALIF COAST ATTM. WARMING ALOFT AND MOIST LOW LEVEL UPSLOPE KEEPING
LOW CLOUDS TRAPPED AND COOL TEMPERATURES IN THE 40S AND 50S ACROSS
THE EASTERN PLAINS AT THIS TIME. REGIONAL SATELLITE AND RADAR DATA
INDICATING INSOLATION ACROSS THE HIGHER TERRAIN TERRAIN WEST OF THE
FRONT RANGE IS HELPING TO DEVELOP ISOLATED SHOWERS AND A FEW
EMBEDDED THUNDERSTORMS THROUGH THE EARLY AFTERNOON...WITH THE BEST
COVERAGE ACROSS THE NORTHERN AND CENTRAL MTS.
TONIGHT...TRANSITORY UPPER RIDGE CONTINUES TO BUILD ACROSS THE STATE
WITH THE PASSING GREAT BASIN EMBEDDED WAVE HELPING TO DEVELOP
CONVECTION THROUGH THE LATE EVENING HOURS...MAINLY OVER THE HIGHER
TERRAIN. LATEST NAM...GFS AND EC ARE BULLISH WITH BRINGING SHOWERS
ACROSS THE STABLE I-25 CORRIDOR...AND HAVE STAYED CLOSER TO THE HRRR
AND RAP WHICH KEEPS BEST CHANCES OF GENERALLY LIGHT RAIN ACROSS EL
PASO COUNTY. MODEL SOUNDINGS INDICATING CLOUDS TO LOWER ACROSS THE
PLAINS AGAIN OVERNIGHT...WITH FOG AND PATCHY DRIZZLE POSSIBLE ALONG
AND WEST OF THE I-25 CORRIDOR.
THURSDAY...SOUTHERLY FLOW ALOFT INCREASES THROUGH THE DAY AS THE
WEST COAST SYSTEM SLOWLY MOVES EAST. LATEST MODELS ARE A TAD SLOWLY
WITH THE SOUTHERN CALIF SHORT WAVE LIFTING OUT ACROSS THE DESERT
SOUTHWEST AND INTO THE ROCKIES...WHICH MAY DELAY THE
ONSET...COVERAGE AND INTENSITY OF SHOWERS AND THUNDERSTORMS ACROSS
THE AREA. AT ANY RATE...WILL SEE SHOWERS AND STORMS DEVELOPING
ACROSS THE HIGHER TERRAIN THROUGH THE AFTERNOON WITH STORMS MOVING
ACROSS THE ADJACENT PLAINS THROUGH THE LATE AFTERNOON AND EARLY
EVENING. SLOWER MOVEMENT OF THE SYSTEM LOOKS TO HINDER MIXING ACROSS
THE EASTERN PLAINS...WITH LOW CLOUDS SLOWLY LIFTING THROUGH THE LATE
MORNING AND AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 328 PM MDT WED MAY 20 2015
THURSDAY NIGHT AND FRIDAY...AN UPPER LEVEL STORM SYSTEM ACROSS THE
SOUTHWEST US IS FORECAST TO EJECT A RATHER STRONG SHORTWAVE TROUGH
INTO COLORADO. SURFACE FLOW FROM THE SOUTHEAST WITH BRING IN A DEEP
LAYER OF MOISTURE...WHICH WILL BE LIFTED BY THE TERRAIN AND
SHORTWAVE DYNAMICS TO PRODUCE ANOTHER EPISODE OF WIDESPREAD
MODERATE...AND LOCALLY HEAVY RAINFALL TO THE EASTERN MOUNTAINS AND
PLAINS. THE SHOWERS AND STORMS ARE DEPICTED BY THE GFS AND NAM TO
MAINLY OCCUR DURING THE FIRST HALF OF THURSDAY NIGHT...AND QUICKLY
SPREAD NORTH AND EAST DURING THE OVERNIGHT. A FEW LIGHTNING STRIKES
ARE POSSIBLE ACROSS THE CWA WITH ELEVATED INSTABILITY...HOWEVER
SEVERE WEATHER IS UNLIKELY THROUGH THURSDAY NIGHT. GFS IS MORE HEAVY
HANDED WITH PRECIPITATION ACROSS THE I-25 AND EASTERN MOUNTAINS THAN
THE NAM ON THE LATEST RUNS. MORE THAN AN INCH OF RAIN IS POSSIBLE
OVER THE EASTERN HALF OF THE CWA...WITH LOCALLY HIGHER AMOUNTS. WITH
SATURATED GROUND...THE POTENTIAL FOR FLASH FLOODING AND FLOODING IS
THERE. RIVERS AND LARGE CREEKS MAY ALSO EXPERIENCE MORE EROSION
ISSUES. SNOW LEVELS WILL REMAIN HIGH...WITH SEVERAL INCHES OF SNOW
POSSIBLE THROUGH FRIDAY MORNING ABOVE 10 KFT.
IN THE WAKE OF THE SHORTWAVE...SINKING MOTION AND DRYING WILL OCCUR.
MODELS ARE HINTING AT A DRY LINE ACROSS THE FAR EASTERN
PLAINS...WHICH COULD SPARK STRONG TO SEVERE STORMS NEAR THE KANSAS
BORDER. CAPES OVER 1000 J/KG AND 0-6 KM BULK SHEARS ABOVE 50 KNOTS
COULD CAUSE SOME STORM ROTATION. ELSEWHERE ON FRIDAY...ISOLATED
SHOWERS AND STORMS WILL OCCUR ACROSS THE MOUNTAINS FRIDAY AFTERNOON
AND DISSIPATE FRIDAY EVENING.
SATURDAY...THE MAIN UPPER SYSTEM WILL MIGRATE THROUGH THE GREAT
BASIN...WITH SOUTH-SOUTHWEST FLOW ACROSS THE CWA. ISOLATED TO
SCATTERED SHOWERS AND STORMS MAY DEVELOP ACROSS THE MOUNTAINS AND
HIGH VALLEYS...AND THE DRY LINE IS FORECAST TO BE ACROSS THE EASTERN
COUNTIES AGAIN...WITH A RISK OF STRONG TO MARGINALLY SEVERE STORMS
DURING THE AFTERNOON AND EVENING.
SUNDAY AND MONDAY...THE NEXT SYSTEM WILL MOVE ACROSS THE ROCKIES
SUNDAY INTO MONDAY. A WEAK COLD FRONT WILL PUSH THROUGH THE PLAINS
SUNDAY MORNING BRINGING MOISTURE INTO THE REGION. AN UPPER
DISTURBANCE WILL BRING SOME SHOWERS AND STORM TO THE AREA...LASTING
INTO MONDAY AFTERNOON.
TUESDAY AND WEDNESDAY...A MODEST RIDGE MAY BUILD INTO THE
AREA...PROVIDING SOME SUNSHINE...AND ONLY THE POSSIBILITY OF
AFTERNOON AND EVENING ISOLATED SHOWERS AND STORMS. -TLM-
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 328 PM MDT WED MAY 20 2015
MVFR CONDITIONS EXPECTED TO PERSIST AT COS AND PUB WITH MOIST LOW
LEVEL UPSLOPE KEEPING CLOUDS IN PLACE. COULD SEE -SHRA AND ISOLD
-TRSA OVER THE HIGHER TERRAIN WEST OF THE TERMINALS...THOUGH DOES
NOT LOOK TO AFFECT THE TERMINALS ATTM. EXPECTING IFR AND LOCAL LIFR
CONDITIONS TO REDEVELOP OVERNIGHT...WITH BR/FG AND DZ
POSSIBLE...ESPECIALLY AT COS. MVFR CONDITIONS EXPECTED AFT 16Z WITH
POSSIBLE SHOWERS AND STORMS DEVELOPING ACROSS THE HIGHER TERRAIN AFT
20Z.
VFR CONDITIONS EXPECTED AT ALS OVER THE NEXT 24 HOURS WITH
INCREASING COVERAGE OF SHOWERS AND STORMS ACROSS THE AREA AFT 18Z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MW
LONG TERM...TM
AVIATION...MW
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
336 PM EDT WED MAY 20 2015
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
MAIN FORECAST CONCERN IS WITH PRECIP POTENTIAL THIS EVENING INTO THE
EARLY MORNING AS A SHORTWAVE AND SOME ENHANCED MOISTURE APPROACHES
THE CWA FROM THE WEST. CURRENTLY A BAND OF SHOWERS AND STORMS IS
PUSHING INTO WESTERN ALABAMA AHEAD OF THIS DISTURBANCE WITH A WEAK
TRANSLATED SFC LOW. WHILE SOME HI-RES SOLUTIONS DO NOT APPEAR TO
SUPPORT THIS HOLDING TOGETHER AND PUSHING INTO WEST GA...SOME
PREVIOUS RAP SOLUTIONS SUPPORTED IT AND WILL NEED TO BE CLOSELY
MONITORED ESPECIALLY IF SOME OUTFLOW BOUNDARIES OR OTHER MESOSCALE
FORCING COMES TO AID. THIS MAY RESULT IN UPPING POPS IN WESTERN
PORTIONS OF THE AREA BY THIS EVENING. STILL SOME MLCAPE NEAR 1000
J/KG AND DECENT DCAPE IN PLACE. IF ANY STORM DEVELOPMENT CAN
MUSTER...THERE COULD STILL BE STRONG DOWNDRAFT WINDS EVEN THOUGH IT
IS A SHEAR DEPRIVED ENVIRONMENT. KEEPING BEST CHANCE POPS MAINLY
NORTH OF I-20 CORRIDOR INTO THE EARLY MORNING WITH THE SHORTWAVE
INFLUENCE.
PROGGED THERMAL PROFILES INDICATE GOOD DRYING OF THE COLUMN FOR
THURSDAY AND NOW BETTER AGREEMENT WITH A NOTABLE CAPPING INVERSION
ABOVE 850 MB. HAVE TRIMMED BACK POPS NOW TO ONLY HAVE A SLIGHT
CHANCE IN THE FAR SOUTHERN TIER FOR THE AFTERNOON...OTHERWISE
LOOKING TO STAY TOO DRY AND STABLE. WINDS LOOK TO BE KICKING IN WITH
THE STRENGTHENING PRESSURE GRADIENT AND AFTERNOON MIXING. WHILE
CURRENTLY LOOKING TO STAY A BIT BELOW CRITERIA...WILL NEED TO KEEP
AN EYE ON TRENDS FOR ANY FIRE DANGER CONCERNS WITH ALREADY DRY FUELS
/THOUGH MAY BE ALTERED WITH AFOREMENTIONED PRECIP CHANCES/. TEMPS
THURSDAY LOOK TO HAVE A STRONG GRADIENT WITH BELOW NORMAL HIGHS IN
THE MID/UPPER 70S FOR THE NW TO THE LOW 90S SE.
BAKER
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
HAVE MADE A FEW MINOR ADJUSTMENTS TO POP AND WEATHER THROUGH THE
WEEKEND. LATEST LONG TERM MODELS HINT AT A MORE PROMINENT SURFACE
HIGH KEEPING MOISTURE TO THE WEST LARGELY AT BAY THROUGH
SUNDAY...WITH ONLY PORTIONS OF WESTERN AND NORTHERN GEORGIA AT
RISK FOR AN ISOLATED STORM. HAVE SCALED POPS BACK SOMEWHAT AS A
RESULT.
31
PREV DISCUSSION... /ISSUED 424 AM EDT WED MAY 20 2015/
LONG TERM PERIOD BEGINS A BIT DRIER AS THE FRONTAL SYSTEM WILL BE
SOUTH AND EAST OF THE AREA. HIGH PRESSURE BUILDING IN FROM THE
NORTHERN PLAINS AND MID WESTERN STATES BECOMES CENTERED OFF THE
MID ATLANTIC COAST AND STAYS THERE THROUGH THE WEEKEND. THIS RIDGE
CONTINUES TO ROTATE AND KEEPS THE DEEPER MOISTURE NORTH AND WEST
OF THE REGION THROUGH THE BEGINNING OF NEXT WEEK. THERE IS STILL
SOME MID AND UPPER LEVEL MOISTURE AROUND THE AREA SO WILL KEEP
SLIGHT CHANCE DIURNALLY DRIVEN POPS IN THE FORECAST DAYS 3-5. BY
TUESDAY THE RIDGE IS BEGINNING TO WEAKEN AND TRANSITION INTO MORE
OF A BERMUDA LIKE RIDGE. THIS WILL ALLOW DEEPER MOISTURE TO MOVE
IN FROM THE WEST ASSOCIATED WITH A WEAKENING FRONTAL BOUNDARY.
LOOKING AT INSTABILITIES INCREASING A BIT TUESDAY/WEDNESDAY ALONG
WITH PWS SO WILL INCREASE TO CHANCE POPS DAYS 6 AND 7.
01
&&
.AVIATION...
18Z UPDATE...
INITIAL VFR CONDITIONS WITH SCT-BKN CU FIELD IN 4-5 KFT AND SOME
VCSH IS POSSIBLE FOR MOST SITES FOR THE AFTERNOON. OTHERWISE
NEXT DISTURBANCE BRINGING SLIGHTLY BETTER CHANCE FOR -SHRA TONIGHT
IN 03-07Z PERIOD FOR KATL AND NEARBY NORTHERN SITES. ALSO CHANCE
FOR NORTHERN SITES TO GET MVFR CIGS IN 09-15Z THURSDAY MORNING.
WINDS MAINLY WNW 5-7 KTS INTO TONIGHT...THEN INCREASE TO 10-12 KTS
THURSDAY WITH GUSTS POSSIBLE 18-22 KTS.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM ON OVERNIGHT CIGS.
HIGH ON ALL ELSE.
BAKER
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 66 85 56 81 / 20 10 10 5
ATLANTA 67 80 58 80 / 30 10 5 5
BLAIRSVILLE 61 74 48 74 / 30 20 10 5
CARTERSVILLE 64 79 53 79 / 30 10 5 5
COLUMBUS 70 88 61 84 / 10 10 10 5
GAINESVILLE 65 80 55 78 / 30 10 10 5
MACON 67 89 59 85 / 20 10 10 5
ROME 65 77 52 79 / 40 10 10 5
PEACHTREE CITY 65 83 54 81 / 20 10 5 5
VIDALIA 71 92 65 86 / 30 20 10 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER
LONG TERM....31
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1232 PM CDT Wed May 20 2015
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 331 AM CDT WED MAY 20 2015
Mid/upper level trough currently lifting northeastward over SD and
NE, and will eventually merge with energy tracking over the upper
Midwest. An expansive area of light to moderate rain will move
across northeast KS early this morning, which is supported by upper
level forcing associated with the trough and low level
frontogenesis. Most of the forcing is forecast to continue eastward
and mainly exiting the area around 12Z. There are indications that
light rain showers and or drizzle could linger through the early
afternoon hours after the mid/upper levels dry out. Both RAP and NAM
soundings show steep low level lapse rates coinciding with
saturation along with weak lift. This could be enough to generate
these light showers and or drizzle. Although these models also
suggest isentropic downglide on the backside of the wave so very
little precip accumulations are expected after 12Z. Clouds will
stick around most of the day and northerly flow will keep
temperatures from warming up much, therefore highs will generally be
in the mid 50s. Surface high pressure will build into the region
tonight and clouds may begin to scatter out as the drier air filters
southward. As surface winds begin to lighten and temperatures cool
there is a chance fog could develop especially given the recent
rainfall. Temperatures are expected to drop into the low to mid 40s
with a few isolated locations in the upper 30s.
.LONG TERM...(Thursday through Tuesday)
Issued at 331 AM CDT WED MAY 20 2015
Thursday through Thursday night, A surface ridge of high pressure
over eastern KS will shift east into MO by Friday morning. An upper
level trough will move onshore across southern CA. Expect mostly
sunny skies on Thursday with highs reaching the mid 60s. Thursday
night will be a bit warmer as the center of the surface ridge moves
east into MO, allowing light winds to become southerly. Lows Friday
morning will only drop into the mid to upper 40s. High and mid level
clouds will increase late Thursday night.
Friday through Monday, The upper trough over southern CA will slowly
drift northeast into western CO and slowly fill. Southwest flow
aloft across the central Rockies will cause a surface lee trough to
deepen across the central and southern high plains. Deeper gulf
moisture will gradually be advected northward into the southern
plains Friday afternoon. The resulting isentropic lift ahead of the
deeper moisture return combined with any ascent from minor H5
troughs embedded within the southern stream of the H5 jet will
provide an increasing chance for showers and isolated thunderstorms
during the day Friday and into the Friday evening. The ECMWF shows a
brief amplification of the main H5 trough across AZ. This may
amplify a downstream H5 ridge across the southern plains which may
provide a break from the showers and thunderstorms across eastern KS
on Saturday. Due to cloud cover and increasing rain chances on
Friday, highs will only reach the mid 60s. If we see more insolation
on Saturday highs will reach the lower 70s.
Saturday night through Sunday night, the Upper trough will fill as
it lifts northeast into western CO. The southern stream H5 ridge
will shift east across the Gulf coast states. Embedded shortwave
trough combined with deeper moisture advection will cause periods of
showers and thunderstorms to develop. The mid level flow will weaken
below 40 KTS. The weaker vertical wind shear should prevent
organized storms updrafts. Also, the instability may be lower due to
the cloud cover. I don`t expect severe thunderstorms this weekend.
The primary hazard may be occasional heavy rainfall. Highs on Sunday
will reach the mid 70s
Monday (Memorial Day), The ECMWF and GEM forecast a slightly more
amplified H5 trough to move northeast from southwest TX into central
OK. The better ascent ahead of this trough will be across northern
TX and southern OK. Both models do not forecast much in the way of
QPF during the day. The showers and thunderstorms may increase
Monday night as the H5 trough lifts northeast into western MO. Highs
on Monday should reach the mid 70s
Tuesday, the H5 trough across western MO will lift northeast into
eastern IA and IL. We may see a break in the precip. The GFS is
slower moving the H5 trough northeast across MO and forecast higher
QPF across eastern KS on Tuesday. Looks a bit warmer on Tuesday as
16 to 18 degree C 850mb temps advect northeast across the CWA. Highs
should reach into the upper 70s to around 80.
&&
.AVIATION...(For the 18Z TAFs through 18Z Thursday Afternoon)
Issued at 1232 PM CDT WED MAY 20 2015
Expect slight improvements to rather frequent IFR cigs in next few
hours given typical diurnal trends and upstream obs, though
confidence is not high. Timing of stratus exit also difficult, but
guidance similar with a delayed exit from earlier expectations. Am
not too worried about FG development around 11Z at this point
with some boundary layer mixing occuring.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Sanders
LONG TERM...Gargan
AVIATION...65
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
604 PM EDT WED MAY 20 2015
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 329 PM EDT WED MAY 20 2015
COOLER THAN NORMAL WEATHER WILL CONTINUE THE REST OF THE WORK
WEEK...WITH FROST A GOOD BET EACH NIGHT ACROSS PORTIONS OF CENTRAL
LOWER MICHIGAN. SOME LIGHT RAIN SHOWERS OR SPRINKLES ARE POSSIBLE
ALONG INTERSTATE 94 THIS EVENING INTO TONIGHT. ANY RAINFALL AMOUNTS
WILL BE VERY LIGHT. AFTER A DRY AND PARTLY TO MOSTLY SUNNY DAY ON
THURSDAY SOME LIGHT RAIN SHOWERS WILL MOVE THROUGH THE AREA THURSDAY
NIGHT ALONG AND AHEAD OF A COLD FRONTAL PASSAGE. WARMER AIR WILL
MOVE IN FOR THE HOLIDAY WEEKEND WITH CHANCES FOR SHOWERS AND STORMS
RETURNING FOR SUNDAY INTO MEMORIAL DAY. HIGHS WILL REMAIN IN THE 60S
THE REST OF THE WORK WEEK RISING INTO THE 70S FOR SUNDAY AND
MEMORIAL DAY.
&&
.UPDATE...
ISSUED AT 604 PM EDT WED MAY 20 2015
ADDED CHANCE OF A MIX OF LIGHT RAIN AND SLEET TO THE FORECAST
THIS EVENING ACROSS THE SOUTHERN CWA PER NUMEROUS REPORTS OF A
RAIN/SLEET MIX IN THE CHICAGO AREA. AFTER THE PRECIP MOVED
IN...SOUTH HAVEN DROPPED TO 41 DEGREES REPORTING UP. THE FORECAST
IS DRY AFTER 06Z.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 329 PM EDT WED MAY 20 2015
SHORT TERM FOCUS WAS ON CHANCES FOR RAIN IN THE SOUTH THIS
EVENING...FROST POTENTIAL ACROSS CENTRAL LOWER MI TONIGHT AND THE
CHANCE FOR RAIN THURSDAY NIGHT WITH THE NEXT FRONT.
DECIDED TO ADD A MENTION OF LIGHT RAIN SHOWERS ALONG INTERSTATE 94
THIS EVENING AFTER ALL. HI-RES MODELS LIKE THE HRRR CONTINUE TO
INDICATE RAIN MAKING IT INTO OUR CWA...AND UPSTREAM RADAR TRENDS
WOULD AGREE. THAT SAID DRY AIR OVER LOWER MICHIGAN WILL TRY TO ERODE
IT AS IT MOVES IN. DEW POINT DEPRESSIONS AT THE SURFACE ACROSS THE
GRR CWA ARE IN EXCESS OF 20F IN MOST AREAS. PRECIP IS JUST TOO CLOSE
AT THIS POINT TO IGNORE. HAVE 20 PCT WORDING ALONG I-94 FOR NOW. WE
WILL BE WATCHING TO SEE IF IT MAKES IT INTO THE CWA AS WELL AS IF IT
TRENDS FURTHER NORTH TOWARDS I-96 WHICH THE HRRR CONTINUES TO SHOW
AS WELL.
OPTED TO ISSUE A FROST ADVISORY ACROSS THE FAR NORTHERN ROW OF
COUNTIES ALONG U.S. 10. CLOUDS WILL CLEAR OUT UP THERE OVERNIGHT
WITH VERY DRY AIR IN PLACE. VERY COLD READINGS OCCURRED LAST NIGHT
UP THERE AND THE AIR MASS HAS NOT CHANGED. FROST AND FREEZING
TEMPERATURES WILL BE POSSIBLE THE NEXT COUPLE NIGHTS UP THERE AS
WELL...THURSDAY NIGHT AND FRIDAY NIGHT.
A COLD FRONT WILL SWING THROUGH LOWER MICHIGAN THURSDAY NIGHT WITH
ALL OF THE SHORT TERM MODELS KICKING OUT SOME LIGHT PRECIPITATION.
THE COLD FRONT IS ASSOCIATED WITH AN UPPER LOW DRIFTING SOUTHEAST
ACROSS ONTARIO. MAY BE JUST ENOUGH MOISTURE AND LIFT FOR A FEW
SHOWERS. WILL CARRY 30 PCT CHANCES FOR RAIN THURSDAY NIGHT.
OTHERWISE QUIET WEATHER IS EXPECTED DURING THE DAY ON THURSDAY AND
AGAIN FRIDAY AND FRIDAY NIGHT.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 329 PM EDT WED MAY 20 2015
MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE LATE
SUNDAY THROUGH WEDNESDAY. THE WEATHER WILL TREND WARMER AND MORE
HUMID THIS WEEKEND INTO THE MIDDLE OF NEXT WEEK.
SATURDAY IS SHAPING UP TO BE A BEAUTIFUL DAY WITH SURFACE HIGH
PRESSURE SLIDING OFF TO THE SOUTHEAST AND AN UPPER RIDGE BUILDING
INTO THE GREAT LAKES REGION. SOUTHWESTERLY RETURN FLOW SETS UP ON
SATURDAY...AND LOWER MICHIGAN WILL FINALLY START TO WARM UP AFTER A
COOL WEEK. HIGHS SHOULD BE AROUND 70 ON SATURDAY.
TEMPS WILL BE WARMER STILL ON SUNDAY AS A WARM FRONT APPROACHES FROM
THE SOUTH. TIMING DIFFERENCES EXIST BETWEEN THE LATEST GFS AND EURO.
THE 12Z EURO KEEPS SW LOWER MI MOSTLY DRY ON SUNDAY...WITH PERHAPS
SOME LIGHT RAIN MOVING INTO THE EXTREME SW CWA SUNDAY EVENING. THE
GFS IS MUCH WETTER SUNDAY. I WOULD DEFINITELY FAVOR A DRY SUNDAY
MORNING WITH PRECIP CHANCES INCREASING SUNDAY EVENING AND ESPECIALLY
SUNDAY NIGHT. SHOWERS AND THUNDERSTORMS ARE EXPECTED SUNDAY NIGHT
THROUGH WEDNESDAY...WITH SOME BREAKS IN THERE OF COURSE. CONFIDENCE
IN SEVERE WEATHER IS LOW AT THIS TIME...BUT SOME INSTABILITY DOES
DEVELOP MONDAY AFTERNOON AND EVENING PRIMARILY SOUTH OF I-96 ALONG
WITH 30-40 KNOTS OF 0-6 KM BULK SHEAR. HIGHS MONDAY THROUGH
WEDNESDAY OF NEXT WEEK SHOULD BE IN THE MID TO UPPER 70S. 80
DEGREES SEEMS POSSIBLE ON WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 154 PM EDT WED MAY 20 2015
VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THURSDAY AFTERNOON.
HIGH CLOUDS WILL CONTINUE TO STREAM IN FROM THE WEST THIS
AFTERNOON AS AN UPPER WAVE OF LOW PRESSURE SWINGS INTO THE WESTERN
GREAT LAKES. CONSIDERABLE MID CLOUDS CAN BE EXPECTED AFTER 23Z
THIS EVENING...BASED BETWEEN 5 KFT AND 7KFT. SCATTERED CLOUDS
BELOW 5 KFT ARE POSSIBLE AFTER 00Z AT AZO/BTL/JXN.
IN ADDITION...A BAND OF LIGHT RAIN IS EXPECTED TO MOVE ACROSS
SOUTHERN LOWER MICHIGAN MAINLY BETWEEN 23Z AND 04Z THIS EVENING.
RAIN SHOWERS ARE EXPECTED TO ERODE SOMEWHAT AS THEY MOVE EAST INTO
LOWER MICHIGAN. FAIR AMOUNT OF UNCERTAINTY...SO INCLUDED VCSH AT
AZO/BTL. BOTTOM LINE...LIGHT RAIN SHOWERS ARE A POSSIBILITY AT
AZO/BTL/JXN AFTER 23Z...BUT CIGS AND VSBYS ARE EXPECTED TO REMAIN
VFR.
&&
.MARINE...
ISSUED AT 329 PM EDT WED MAY 20 2015
NOT EXPECTING SIGNIFICANT WINDS OR WAVES THE NEXT SEVERAL DAYS.
WINDS WILL COME UP A BIT THIS EVENING FROM HOLLAND SOUTH AND THEN
AGAIN THURSDAY AFTERNOON AND EVENING AHEAD OF A COLD FRONTAL
PASSAGE. IN BOTH CASES EXPECTING WINDS AND WAVES TO REMAIN BELOW
SMALL CRAFT ADVISORY THRESHOLDS. WAVES MAY RISE INTO THE 2-3 FOOT
RANGE DURING THE AFOREMENTIONED TIMES.
&&
.HYDROLOGY...
ISSUED AT 1139 AM EDT WED MAY 20 2015
NO REAL IMPACTS ARE EXPECTED IN THE NEAR FUTURE. RIVERS ARE STABLE
OR SLOWLY FALLING. ONLY SLIGHT CHANCES OF RAIN EXIST LATE THURSDAY
INTO EARLY FRIDAY. ANY MEANINGFUL PRECIPITATION IS EXPECTED TO
HOLD OFF UNTIL AT LEAST SUNDAY.
BY SUNDAY...CHANCES FOR PRECIPITATION WILL INCREASE AS A WARM
FRONT LIFTS NORTH AND BECOMES STATIONARY SOMEWHERE OVER THE GREAT
LAKES REGION. THE PLACEMENT OF THIS BOUNDARY...AND THE POSSIBILITY
OF IT MEANDERING A BIT...MAY PROVIDE MULTIPLE CHANCES FOR RAIN
THROUGH MUCH OF NEXT WEEK. THIS WILL BE SOMETHING TO MONITOR AND
UPDATES WILL BE PROVIDED AS WE GET CLOSER TO THE WEEKEND.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FROST ADVISORY FROM 2 AM TO 8 AM EDT THURSDAY FOR MIZ037>040.
LM...NONE.
&&
$$
UPDATE...EBW
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...EBW
AVIATION...EBW
HYDROLOGY...JAM
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
329 PM EDT WED MAY 20 2015
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/MARINE
.SYNOPSIS...
ISSUED AT 329 PM EDT WED MAY 20 2015
COOLER THAN NORMAL WEATHER WILL CONTINUE THE REST OF THE WORK
WEEK...WITH FROST A GOOD BET EACH NIGHT ACROSS PORTIONS OF CENTRAL
LOWER MICHIGAN. SOME LIGHT RAIN SHOWERS OR SPRINKLES ARE POSSIBLE
ALONG INTERSTATE 94 THIS EVENING INTO TONIGHT. ANY RAINFALL AMOUNTS
WILL BE VERY LIGHT. AFTER A DRY AND PARTLY TO MOSTLY SUNNY DAY ON
THURSDAY SOME LIGHT RAIN SHOWERS WILL MOVE THROUGH THE AREA THURSDAY
NIGHT ALONG AND AHEAD OF A COLD FRONTAL PASSAGE. WARMER AIR WILL
MOVE IN FOR THE HOLIDAY WEEKEND WITH CHANCES FOR SHOWERS AND STORMS
RETURNING FOR SUNDAY INTO MEMORIAL DAY. HIGHS WILL REMAIN IN THE 60S
THE REST OF THE WORK WEEK RISING INTO THE 70S FOR SUNDAY AND
MEMORIAL DAY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 329 PM EDT WED MAY 20 2015
SHORT TERM FOCUS WAS ON CHANCES FOR RAIN IN THE SOUTH THIS
EVENING...FROST POTENTIAL ACROSS CENTRAL LOWER MI TONIGHT AND THE
CHANCE FOR RAIN THURSDAY NIGHT WITH THE NEXT FRONT.
DECIDED TO ADD A MENTION OF LIGHT RAIN SHOWERS ALONG INTERSTATE 94
THIS EVENING AFTER ALL. HI-RES MODELS LIKE THE HRRR CONTINUE TO
INDICATE RAIN MAKING IT INTO OUR CWA...AND UPSTREAM RADAR TRENDS
WOULD AGREE. THAT SAID DRY AIR OVER LOWER MICHIGAN WILL TRY TO ERODE
IT AS IT MOVES IN. DEW POINT DEPRESSIONS AT THE SURFACE ACROSS THE
GRR CWA ARE IN EXCESS OF 20F IN MOST AREAS. PRECIP IS JUST TOO CLOSE
AT THIS POINT TO IGNORE. HAVE 20 PCT WORDING ALONG I-94 FOR NOW. WE
WILL BE WATCHING TO SEE IF IT MAKES IT INTO THE CWA AS WELL AS IF IT
TRENDS FURTHER NORTH TOWARDS I-96 WHICH THE HRRR CONTINUES TO SHOW
AS WELL.
OPTED TO ISSUE A FROST ADVISORY ACROSS THE FAR NORTHERN ROW OF
COUNTIES ALONG U.S. 10. CLOUDS WILL CLEAR OUT UP THERE OVERNIGHT
WITH VERY DRY AIR IN PLACE. VERY COLD READINGS OCCURRED LAST NIGHT
UP THERE AND THE AIR MASS HAS NOT CHANGED. FROST AND FREEZING
TEMPERATURES WILL BE POSSIBLE THE NEXT COUPLE NIGHTS UP THERE AS
WELL...THURSDAY NIGHT AND FRIDAY NIGHT.
A COLD FRONT WILL SWING THROUGH LOWER MICHIGAN THURSDAY NIGHT WITH
ALL OF THE SHORT TERM MODELS KICKING OUT SOME LIGHT PRECIPITATION.
THE COLD FRONT IS ASSOCIATED WITH AN UPPER LOW DRIFTING SOUTHEAST
ACROSS ONTARIO. MAY BE JUST ENOUGH MOISTURE AND LIFT FOR A FEW
SHOWERS. WILL CARRY 30 PCT CHANCES FOR RAIN THURSDAY NIGHT.
OTHERWISE QUIET WEATHER IS EXPECTED DURING THE DAY ON THURSDAY AND
AGAIN FRIDAY AND FRIDAY NIGHT.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 329 PM EDT WED MAY 20 2015
MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE LATE
SUNDAY THROUGH WEDNESDAY. THE WEATHER WILL TREND WARMER AND MORE
HUMID THIS WEEKEND INTO THE MIDDLE OF NEXT WEEK.
SATURDAY IS SHAPING UP TO BE A BEAUTIFUL DAY WITH SURFACE HIGH
PRESSURE SLIDING OFF TO THE SOUTHEAST AND AN UPPER RIDGE BUILDING
INTO THE GREAT LAKES REGION. SOUTHWESTERLY RETURN FLOW SETS UP ON
SATURDAY...AND LOWER MICHIGAN WILL FINALLY START TO WARM UP AFTER A
COOL WEEK. HIGHS SHOULD BE AROUND 70 ON SATURDAY.
TEMPS WILL BE WARMER STILL ON SUNDAY AS A WARM FRONT APPROACHES FROM
THE SOUTH. TIMING DIFFERENCES EXIST BETWEEN THE LATEST GFS AND EURO.
THE 12Z EURO KEEPS SW LOWER MI MOSTLY DRY ON SUNDAY...WITH PERHAPS
SOME LIGHT RAIN MOVING INTO THE EXTREME SW CWA SUNDAY EVENING. THE
GFS IS MUCH WETTER SUNDAY. I WOULD DEFINITELY FAVOR A DRY SUNDAY
MORNING WITH PRECIP CHANCES INCREASING SUNDAY EVENING AND ESPECIALLY
SUNDAY NIGHT. SHOWERS AND THUNDERSTORMS ARE EXPECTED SUNDAY NIGHT
THROUGH WEDNESDAY...WITH SOME BREAKS IN THERE OF COURSE. CONFIDENCE
IS SEVERE WEATHER IS LOW AT THIS TIME...BUT SOME INSTABILITY DOES
DEVELOP MONDAY AFTERNOON AND EVENING PRIMARILY SOUTH OF I-96 ALONG
WITH 30-40 KNOTS OF 0-6 KM BULK SHEAR. HIGHS MONDAY THROUGH
WEDNESDAY OF NEXT WEEK SHOULD BE IN THE MID TO UPPER 70S. 80 DEGREES
SEEMS POSSIBLE ON WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 154 PM EDT WED MAY 20 2015
VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THURSDAY AFTERNOON.
HIGH CLOUDS WILL CONTINUE TO STREAM IN FROM THE WEST THIS
AFTERNOON AS AN UPPER WAVE OF LOW PRESSURE SWINGS INTO THE WESTERN
GREAT LAKES. CONSIDERABLE MID CLOUDS CAN BE EXPECTED AFTER 23Z
THIS EVENING...BASED BETWEEN 5 KFT AND 7KFT. SCATTERED CLOUDS
BELOW 5 KFT ARE POSSIBLE AFTER 00Z AT AZO/BTL/JXN.
IN ADDITION...A BAND OF LIGHT RAIN IS EXPECTED TO MOVE ACROSS
SOUTHERN LOWER MICHIGAN MAINLY BETWEEN 23Z AND 04Z THIS EVENING.
RAIN SHOWERS ARE EXPECTED TO ERODE SOMEWHAT AS THEY MOVE EAST INTO
LOWER MICHIGAN. FAIR AMOUNT OF UNCERTAINTY...SO INCLUDED VCSH AT
AZO/BTL. BOTTOM LINE...LIGHT RAIN SHOWERS ARE A POSSIBILITY AT
AZO/BTL/JXN AFTER 23Z...BUT CIGS AND VSBYS ARE EXPECTED TO REMAIN
VFR.
&&
.MARINE...
ISSUED AT 329 PM EDT WED MAY 20 2015
NOT EXPECTING SIGNIFICANT WINDS OR WAVES THE NEXT SEVERAL DAYS.
WINDS WILL COME UP A BIT THIS EVENING FROM HOLLAND SOUTH AND THEN
AGAIN THURSDAY AFTERNOON AND EVENING AHEAD OF A COLD FRONTAL
PASSAGE. IN BOTH CASES EXPECTING WINDS AND WAVES TO REMAIN BELOW
SMALL CRAFT ADVISORY THRESHOLDS. WAVES MAY RISE INTO THE 2-3 FOOT
RANGE DURING THE AFOREMENTIONED TIMES.
&&
.HYDROLOGY...
ISSUED AT 1139 AM EDT WED MAY 20 2015
NO REAL IMPACTS ARE EXPECTED IN THE NEAR FUTURE. RIVERS ARE STABLE
OR SLOWLY FALLING. ONLY SLIGHT CHANCES OF RAIN EXIST LATE THURSDAY
INTO EARLY FRIDAY. ANY MEANINGFUL PRECIPITATION IS EXPECTED TO
HOLD OFF UNTIL AT LEAST SUNDAY.
BY SUNDAY...CHANCES FOR PRECIPITATION WILL INCREASE AS A WARM
FRONT LIFTS NORTH AND BECOMES STATIONARY SOMEWHERE OVER THE GREAT
LAKES REGION. THE PLACEMENT OF THIS BOUNDARY...AND THE POSSIBILITY
OF IT MEANDERING A BIT...MAY PROVIDE MULTIPLE CHANCES FOR RAIN
THROUGH MUCH OF NEXT WEEK. THIS WILL BE SOMETHING TO MONITOR AND
UPDATES WILL BE PROVIDED AS WE GET CLOSER TO THE WEEKEND.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FROST ADVISORY FROM 2 AM TO 8 AM EDT THURSDAY FOR MIZ037>040.
LM...NONE.
&&
$$
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...EBW
AVIATION...EBW
HYDROLOGY...JAM
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
154 PM EDT WED MAY 20 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 326 AM EDT WED MAY 20 2015
EXPECT BELOW NORMAL TEMPERATURES THROUGH AT LEAST SATURDAY AS A
SERIES OF CANADIAN COLD FRONTS COME THROUGH THE AREA. THE NEXT
COLD FRONT COMES THROUGH EARLY FRIDAY MORNING AND THAT WILL BE
PRECEDED BY A FEW LIGHT RAIN SHOWERS THURSDAY EVENING. A WARM UP
IS EXPECTED TOWARD MEMORIAL DAY. SHOWERS AND THUNDERSTORMS ARE
POSSIBLE SUNDAY INTO TUESDAY.
&&
.UPDATE...
ISSUED AT 1208 PM EDT WED MAY 20 2015
UPSTREAM SHORTWAVE SLIDING EAST FROM THE PLAINS WILL SPREAD CLOUDS
INTO SOUTHWEST LOWER MICHIGAN THIS AFTERNOON AND EVENING. SKIES IN
MOST AREAS WILL TURN MOSTLY CLOUDY WITH TIME. DILEMMA IS WHETHER
OR NOT WE WILL SEE PRECIPITATION INTO THE SOUTHERN PORTION OF THE
STATE. MORNING RUNS OF THE HRRR ARE TRYING TO BRING LIGHT RETURNS
INTO ABOUT THE SOUTHERN HALF OF THE GRR FORECAST AREA THIS EVENING.
AT THIS POINT HAVE DECIDED TO KEEP THE DRY FORECAST GOING AS WE
BELIEVE THE DRY AIR IS GOING TO WIN OUT. PRECIP UPSTREAM IS LIGHT
AND MAINLY FALLING OUT OF A MID DECK ON THE LEADING EDGE. IF THE
SYSTEM OVERPERFORMS IT WOULD BE IN THE FORM OF SPRINKLES ALONG
I-94 BETWEEN 800PM AND MIDNIGHT OR SO.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 326 AM EDT WED MAY 20 2015
LITTLE QUESTION THE PRECIPITATION EVENT ASSOCIATED WITH THE NEXT
SYSTEM WILL PASS SOUTH OF LOWER MICHIGAN THIS AFTERNOON AND
EVENING. THEN... ANOTHER DIGGING POLAR JET CORE FROM NORTHERN
CANADA WILL PUSH ANOTHER COLD FRONT THROUGH THE AREA LATER
THURSDAY NIGHT OR EARLY FRIDAY. THERE IS JUST MOIST LOW TO MID
LEVEL MOISTURE TO GET A FEW RAIN SHOWERS AHEAD OF THE COLD FRONT.
BEYOND THAT A CANADIAN HIGH MOVES IN BY MID MORNING FRIDAY
ASSURING MOSTLY CLEAR SKIES BUT COOLER TEMPERATURES. SOME FROST
WILL BE POSSIBLE SATURDAY MORNING.
EARLY THIS WEDNESDAY MORNING WE HAVE A SOUTHERN STREAM SYSTEM
CAUSING AN AREA OF RAIN AND THUNDERSTORMS NEAR THE MISSISSIPPI
RIVER. IT IS CURRENTLY HEADING EASTWARD AND WOULD NORMALLY
BRING RAIN TO OUR AREA TODAY. HOWEVER THIS TIME WE HAVE A
DIGGING NORTHERN STREAM SHORTWAVE AND ASSOCIATED POLAR JET CORE
HEADING FOR THE WESTERN GREAT LAKES. THAT WILL FORCE THE SOUTHERN
STREAM SYSTEM SOUTH OF MICHIGAN THIS AFTERNOON AND EVENING. WE
WILL SEE CONSIDERABLE HIGH AND MID CLOUDS TODAY WITH AREAS NEAR
I-94 SEEING THE THICKER CLOUDS WHILE AREA NORTH OF I-96 WILL HAVE
CONSIDERABLE MORE SUNSHINE. EVEN SO IT WILL NOT GET ALL THAT WARM
TODAY...HIGHS SHOULD MOSTLY BE IN THE 50S. SOME CLEARING IS
EXPECTED TONIGHT WITH LIGHTER WINDS SO NORTHERN AREA COULD SEE A
LITTLE PATCHY FROST.
MEANWHILE A CLOSED...COLD CORE UPPER LOW...CURRENTLY NEAR BAFFIN`SISLAND
DROPS SOUTHWARD...REACHING SOUTHERN HUDSON BAY THURSDAY MORNING.
THIS WILL BRING ANOTHER COLD FRONT THROUGH THE AREA LATE THURSDAY
NIGHT. THERE WILL BE JUST ENOUGH LOW TO MID LEVEL MOISTURE AND
LIFT AHEAD OF THE COLD FRONT TO CREATE A LIGHT RAIN SHOWERS.
CLEARING WILL QUICKLY FOLLOW BY MID MORNING FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 326 AM EDT WED MAY 20 2015
TWO MAIN CONCERNS IN THE EXTENDED...FIRST IS THE FROST THREAT ON
FRIDAY NIGHT AND THEN STORMY WEATHER FROM SUNDAY THROUGH TUESDAY.
SFC HIGH MOVES EAST BY 12Z SATURDAY...BUT RETURN FLOW MAY NOT BE
STRONG ENOUGH TO PREVENT FREEZING TEMPS UP NORTH AND SOME FROST
ESPECIALLY ACROSS EASTERN ZONES.
ONCE THE HIGH DEPARTS SATURDAY NIGHT...RETURN FLOW STRENGTHENS
WITH WARMER AND MORE HUMID AIR RETURNING BY MONDAY. ISENTROPIC
ASCENT NORTH OF THE SFC WARM FRONT SHOULD BRING SHOWERS BY SUNDAY
MORNING AND A SERIES OF WEAK WAVES MOVING ALONG STALLED FRONT
WILL CONTINUE INTO TUESDAY. CONFIDENCE IS HIGH ON THE OVERALL
PATTERN ALTHOUGH THERE ARE THE USUAL DIFFERENCES IN THE DETAILS.
OVERALL THERE IS A HIGH CONFIDENCE OF SHOWERS AND A FEW
THUNDERSTORMS THROUGH THE PERIOD FROM SUNDAY TO TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 154 PM EDT WED MAY 20 2015
VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THURSDAY AFTERNOON.
HIGH CLOUDS WILL CONTINUE TO STREAM IN FROM THE WEST THIS
AFTERNOON AS AN UPPER WAVE OF LOW PRESSURE SWINGS INTO THE WESTERN
GREAT LAKES. CONSIDERABLE MID CLOUDS CAN BE EXPECTED AFTER 23Z
THIS EVENING...BASED BETWEEN 5 KFT AND 7KFT. SCATTERED CLOUDS
BELOW 5 KFT ARE POSSIBLE AFTER 00Z AT AZO/BTL/JXN.
IN ADDITION...A BAND OF LIGHT RAIN IS EXPECTED TO MOVE ACROSS
SOUTHERN LOWER MICHIGAN MAINLY BETWEEN 23Z AND 04Z THIS EVENING.
RAIN SHOWERS ARE EXPECTED TO ERODE SOMEWHAT AS THEY MOVE EAST INTO
LOWER MICHIGAN. FAIR AMOUNT OF UNCERTAINTY...SO INCLUDED VCSH AT
AZO/BTL. BOTTOM LINE...LIGHT RAIN SHOWERS ARE A POSSIBILITY AT
AZO/BTL/JXN AFTER 23Z...BUT CIGS AND VSBYS ARE EXPECTED TO REMAIN
VFR.
&&
.MARINE...
ISSUED AT 1208 PM EDT WED MAY 20 2015
WE WILL BE KEEPING AN EYE ON A CORE OF WIND THAT THE HRRR IS
TRYING TO DEVELOP DOWN THE SHORELINE SOUTH OF HOLLAND LATE THIS
AFTERNOON AND EVENING. CHANNELING/FUNNELING DOWN THE SHORELINE
BLUFFS ARE LIKELY THE REASON FOR THE WIND THAT IS SHOWING UP IN
THE MODELS. NORTHWEST WINDS OF 15-20 KNOTS OR SO DEVELOP WHICH
WILL LIKELY KICK THE WAVE FIELD UP A BIT. THINKING WE WILL STAY
BELOW SCA CRITERIA...BUT WORTH WATCHING THE SOUTH HAVEN PIER AND
BUOY OBS BETWEEN 300PM AND 900PM OR SO.
&&
.HYDROLOGY...
ISSUED AT 1139 AM EDT WED MAY 20 2015
NO REAL IMPACTS ARE EXPECTED IN THE NEAR FUTURE. RIVERS ARE STABLE
OR SLOWLY FALLING. ONLY SLIGHT CHANCES OF RAIN EXIST LATE THURSDAY
INTO EARLY FRIDAY. ANY MEANINGFUL PRECIPITATION IS EXPECTED TO
HOLD OFF UNTIL AT LEAST SUNDAY.
BY SUNDAY...CHANCES FOR PRECIPITATION WILL INCREASE AS A WARM
FRONT LIFTS NORTH AND BECOMES STATIONARY SOMEWHERE OVER THE GREAT
LAKES REGION. THE PLACEMENT OF THIS BOUNDARY...AND THE POSSIBILITY
OF IT MEANDERING A BIT...MAY PROVIDE MULTIPLE CHANCES FOR RAIN
THROUGH MUCH OF NEXT WEEK. THIS WILL BE SOMETHING TO MONITOR AND
UPDATES WILL BE PROVIDED AS WE GET CLOSER TO THE WEEKEND.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...DUKE
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...OSTUNO
AVIATION...EBW
HYDROLOGY...JAM
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1208 PM EDT WED MAY 20 2015
LATEST UPDATE...
UPDATE/MARINE
.SYNOPSIS...
ISSUED AT 326 AM EDT WED MAY 20 2015
EXPECT BELOW NORMAL TEMPERATURES THROUGH AT LEAST SATURDAY AS A
SERIES OF CANADIAN COLD FRONTS COME THROUGH THE AREA. THE NEXT
COLD FRONT COMES THROUGH EARLY FRIDAY MORNING AND THAT WILL BE
PRECEDED BY A FEW LIGHT RAIN SHOWERS THURSDAY EVENING. A WARM UP
IS EXPECTED TOWARD MEMORIAL DAY. SHOWERS AND THUNDERSTORMS ARE
POSSIBLE SUNDAY INTO TUESDAY.
&&
.UPDATE...
ISSUED AT 1208 PM EDT WED MAY 20 2015
UPSTREAM SHORTWAVE SLIDING EAST FROM THE PLAINS WILL SPREAD CLOUDS
INTO SOUTHWEST LOWER MICHIGAN THIS AFTERNOON AND EVENING. SKIES IN
MOST AREAS WILL TURN MOSTLY CLOUDY WITH TIME. DILEMMA IS WHETHER
OR NOT WE WILL SEE PRECIPITATION INTO THE SOUTHERN PORTION OF THE
STATE. MORNING RUNS OF THE HRRR ARE TRYING TO BRING LIGHT RETURNS
INTO ABOUT THE SOUTHERN HALF OF THE GRR FORECAST AREA THIS EVENING.
AT THIS POINT HAVE DECIDED TO KEEP THE DRY FORECAST GOING AS WE
BELIEVE THE DRY AIR IS GOING TO WIN OUT. PRECIP UPSTREAM IS LIGHT
AND MAINLY FALLING OUT OF A MID DECK ON THE LEADING EDGE. IF THE
SYSTEM OVERPERFORMS IT WOULD BE IN THE FORM OF SPRINKLES ALONG
I-94 BETWEEN 800PM AND MIDNIGHT OR SO.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 326 AM EDT WED MAY 20 2015
LITTLE QUESTION THE PRECIPITATION EVENT ASSOCIATED WITH THE NEXT
SYSTEM WILL PASS SOUTH OF LOWER MICHIGAN THIS AFTERNOON AND
EVENING. THEN... ANOTHER DIGGING POLAR JET CORE FROM NORTHERN
CANADA WILL PUSH ANOTHER COLD FRONT THROUGH THE AREA LATER
THURSDAY NIGHT OR EARLY FRIDAY. THERE IS JUST MOIST LOW TO MID
LEVEL MOISTURE TO GET A FEW RAIN SHOWERS AHEAD OF THE COLD FRONT.
BEYOND THAT A CANADIAN HIGH MOVES IN BY MID MORNING FRIDAY
ASSURING MOSTLY CLEAR SKIES BUT COOLER TEMPERATURES. SOME FROST
WILL BE POSSIBLE SATURDAY MORNING.
EARLY THIS WEDNESDAY MORNING WE HAVE A SOUTHERN STREAM SYSTEM
CAUSING AN AREA OF RAIN AND THUNDERSTORMS NEAR THE MISSISSIPPI
RIVER. IT IS CURRENTLY HEADING EASTWARD AND WOULD NORMALLY
BRING RAIN TO OUR AREA TODAY. HOWEVER THIS TIME WE HAVE A
DIGGING NORTHERN STREAM SHORTWAVE AND ASSOCIATED POLAR JET CORE
HEADING FOR THE WESTERN GREAT LAKES. THAT WILL FORCE THE SOUTHERN
STREAM SYSTEM SOUTH OF MICHIGAN THIS AFTERNOON AND EVENING. WE
WILL SEE CONSIDERABLE HIGH AND MID CLOUDS TODAY WITH AREAS NEAR
I-94 SEEING THE THICKER CLOUDS WHILE AREA NORTH OF I-96 WILL HAVE
CONSIDERABLE MORE SUNSHINE. EVEN SO IT WILL NOT GET ALL THAT WARM
TODAY...HIGHS SHOULD MOSTLY BE IN THE 50S. SOME CLEARING IS
EXPECTED TONIGHT WITH LIGHTER WINDS SO NORTHERN AREA COULD SEE A
LITTLE PATCHY FROST.
MEANWHILE A CLOSED...COLD CORE UPPER LOW...CURRENTLY NEAR BAFFIN`SISLAND
DROPS SOUTHWARD...REACHING SOUTHERN HUDSON BAY THURSDAY MORNING.
THIS WILL BRING ANOTHER COLD FRONT THROUGH THE AREA LATE THURSDAY
NIGHT. THERE WILL BE JUST ENOUGH LOW TO MID LEVEL MOISTURE AND
LIFT AHEAD OF THE COLD FRONT TO CREATE A LIGHT RAIN SHOWERS.
CLEARING WILL QUICKLY FOLLOW BY MID MORNING FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 326 AM EDT WED MAY 20 2015
TWO MAIN CONCERNS IN THE EXTENDED...FIRST IS THE FROST THREAT ON
FRIDAY NIGHT AND THEN STORMY WEATHER FROM SUNDAY THROUGH TUESDAY.
SFC HIGH MOVES EAST BY 12Z SATURDAY...BUT RETURN FLOW MAY NOT BE
STRONG ENOUGH TO PREVENT FREEZING TEMPS UP NORTH AND SOME FROST
ESPECIALLY ACROSS EASTERN ZONES.
ONCE THE HIGH DEPARTS SATURDAY NIGHT...RETURN FLOW STRENGTHENS
WITH WARMER AND MORE HUMID AIR RETURNING BY MONDAY. ISENTROPIC
ASCENT NORTH OF THE SFC WARM FRONT SHOULD BRING SHOWERS BY SUNDAY
MORNING AND A SERIES OF WEAK WAVES MOVING ALONG STALLED FRONT
WILL CONTINUE INTO TUESDAY. CONFIDENCE IS HIGH ON THE OVERALL
PATTERN ALTHOUGH THERE ARE THE USUAL DIFFERENCES IN THE DETAILS.
OVERALL THERE IS A HIGH CONFIDENCE OF SHOWERS AND A FEW
THUNDERSTORMS THROUGH THE PERIOD FROM SUNDAY TO TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 725 AM EDT WED MAY 20 2015
SOME MVFR CONDITIONS NEAR JXN THIS MORNING WITH CEILINGS AROUND
2500 FEET AGL AT TIMES. ELSEWHERE...VFR CONDITIONS EXPECTED
THROUGH TONIGHT WITH WINDS BELOW 10 KNOTS.
&&
.MARINE...
ISSUED AT 1208 PM EDT WED MAY 20 2015
WE WILL BE KEEPING AN EYE ON A CORE OF WIND THAT THE HRRR IS
TRYING TO DEVELOP DOWN THE SHORELINE SOUTH OF HOLLAND LATE THIS
AFTERNOON AND EVENING. CHANNELING/FUNNELING DOWN THE SHORELINE
BLUFFS ARE LIKELY THE REASON FOR THE WIND THAT IS SHOWING UP IN
THE MODELS. NORTHWEST WINDS OF 15-20 KNOTS OR SO DEVELOP WHICH
WILL LIKELY KICK THE WAVE FIELD UP A BIT. THINKING WE WILL STAY
BELOW SCA CRITERIA...BUT WORTH WATCHING THE SOUTH HAVEN PIER AND
BUOY OBS BETWEEN 300PM AND 900PM OR SO.
&&
.HYDROLOGY...
ISSUED AT 1139 AM EDT WED MAY 20 2015
NO REAL IMPACTS ARE EXPECTED IN THE NEAR FUTURE. RIVERS ARE STABLE
OR SLOWLY FALLING. ONLY SLIGHT CHANCES OF RAIN EXIST LATE THURSDAY
INTO EARLY FRIDAY. ANY MEANINGFUL PRECIPITATION IS EXPECTED TO
HOLD OFF UNTIL AT LEAST SUNDAY.
BY SUNDAY...CHANCES FOR PRECIPITATION WILL INCREASE AS A WARM
FRONT LIFTS NORTH AND BECOMES STATIONARY SOMEWHERE OVER THE GREAT
LAKES REGION. THE PLACEMENT OF THIS BOUNDARY...AND THE POSSIBILITY
OF IT MEANDERING A BIT...MAY PROVIDE MULTIPLE CHANCES FOR RAIN
THROUGH MUCH OF NEXT WEEK. THIS WILL BE SOMETHING TO MONITOR AND
UPDATES WILL BE PROVIDED AS WE GET CLOSER TO THE WEEKEND.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...DUKE
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...OSTUNO
AVIATION...OSTUNO
HYDROLOGY...JAM
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS PORTLAND
951 AM PDT WED MAY 20 2015
.SYNOPSIS...A BROAD UPPER LEVEL LOW PRESSURE AND ONSHORE FLOW WILL
BRING A THREAT OF SHOWERS AND THUNDERSTORMS TO MAINLY THE CASCADES
TODAY AND THURSDAY. PLENTY OF LOW CLOUDS AND NEAR AVERAGE
TEMPERATURES WILL LINGER ALONG THE COAST AND IN THE WILLAMETTE
VALLEY. ANOTHER WEAK UPPER LEVEL LOW PRESSURE SLIDING DOWN FROM
BRITISH COLUMBIA MAY BRING A FEW AFTERNOON AND EVENING SHOWERS AND
POSSIBLY A THUNDERSTORM TO THE HIGHER TERRAIN FOR THE MEMORIAL DAY
WEEKEND.
&&
.SHORT TERM...WATER VAPOR SATELLITE IMAGERY THIS MORNING REVEALS A
BROAD UPPER LEVEL TROUGH LINGERING OVER THE EASTERN PACIFIC AND
WESTERN US. AN EMBEDDED SHORTWAVE TROUGH SITUATED OVER NORTHERN
CALIFORNIA CONTINUES TO PLACE THE PACIFIC NORTHWEST IN MID TO UPPER
LEVEL EASTERLY FLOW. SURFACE ANALYSIS SHOWS PRESSURE GRADIENTS
REMAINING ONSHORE...ALBEIT A BIT WEAKER THAN 24 HOURS AGO. AN
EXTENSIVE MARINE LAYER WITH PLENTY OF LOW CLOUDS EXISTS BELOW ABOUT
5000 FT ACROSS NORTHWEST OREGON AND SOUTHWEST WASHINGTON THIS
MORNING. AREAS OF DRIZZLE HAVE DEVELOPED ALONG THE COAST AND ALONG
THE LOWER COLUMBIA RIVER VALLEY. EXPECT MARINE CLOUDS TO BE A LITTLE
LESS STUBBORN TO BURN OFF THAN YESTERDAY...BUT NOT SURE ALL INTERIOR
VALLEYS WILL SEE SUNSHINE LATER THIS AFTERNOON EITHER. KEPT FORECAST
HIGH TEMPERATURES NEAR 70F FOR THE WILLAMETTE VALLEY...BUT IF MARINE
CLOUDS HOLD...THIS MAY BE A BIT HIGH BASED ON YESTERDAY.
MEANWHILE...THE MID TO UPPER LEVEL EASTERLY FLOW AND DAYTIME HEATING
WILL BRING A THREAT OF SHOWERS AND THUNDERSTORMS TO THE CASCADES
BEGINNING MIDDAY...AND PERSISTING INTO THIS EVENING. DEBRIS
CLOUDS FROM EARLIER CONVECTION ARE MOVING WESTWARD AND WILL MOVE OVER
THE NORTH OREGON CASCADES LATER THIS MORNING. THIS FEATURE SHOULD BE
ARRIVING EARLIER ENOUGH IN THE DAY THAT IT MAY END UP
INHIBITING...RATHER THAN ENHANCING...CONVECTION BETWEEN MOUNT
JEFFERSON AND MOUNT HOOD.
THE NAM AND GFS BOTH CONTINUE TO SUGGEST PLENTY OF CAPE WITH LITTLE
CONVECTIVE INHIBITION WILL DEVELOP OVER THE SOUTH WASHINGTON CASCADES
THIS AFTERNOON SO IT SEEMS SOME CONVECTION SHOULD DEVELOP IN THIS
REGION THIS AFTERNOON. HOWEVER...IT APPEARS THE MARINE LAYER WILL
REMAIN STRONG ENOUGH TO PREVENT VALLEY LOCATIONS FROM LIKELY GETTING
INTO THE ACTION WITH A NICE CAP INHIBITING CONVECTION.AS A
RESULT...THE MENTION OF THUNDER WAS REMOVED FROM TODAYS FORECAST.
NONETHELESS...SREF 12 HR THUNDER PROBABILITIES EXCEED 50 PERCENT FOR
THE WILLAMETTE VALLEY THIS EVENING. CANNOT IGNORE THIS SO RETAINED
THE SLIGHT CHANCE MENTION OF THUNDER FOR THIS EVENING IN THE NORTHERN
WILLAMETTE VALLEY AND LOWER COLUMBIA RIVER VALLEY.
STORM SCALE ENSEMBLE GUIDANCE AND THE LATEST HRRR RUNS DO SUGGEST
CONVECTION WILL BE MOST LIKELY TO DEVELOP OVER THE LANE AND LINN
COUNTY CASCADES THIS AFTERNOON AND EVENING...WHICH SEEMS PLAUSIBLE
GIVEN THIS REGIONS PROXIMITY TO THE MOISTURE AND INSTABILITY PRESENT
IN SOUTHERN OREGON. BOTH SETS OF GUIDANCE SUGGEST THERE IS A CHANCE
THESE SHOWERS AND THUNDERSTORMS COULD DRIFT WESTWARD OVER THE
SOUTHERN WILLAMETTE VALLEY THIS EVENING. HOWEVER...CONFIDENCE IN
THIS SCENARIO PANNING OUT IS STILL RELATIVELY LOW GIVEN THE MARINE
LAYER IN PLACE...AND NO STRONG UPPER LEVEL FORCING MECHANISMS HAVE
BEEN NOTED TO ALLOW FOR ELEVATED CONVECTION TO SUSTAIN ITSELF. IF THE
SOUTHERN VALLEY CLEARS EARLY THIS AFTERNOON...AND WARMS WELL INTO THE
70S THEN THESE SHORT TERM MODELS MAY BE ONTO SOMETHING...BUT AM
SKEPTICAL AT THIS POINT. WILL CONTINUE TO MONITOR TRENDS AND UPDATE
THE FORECAST ACCORDINGLY.
ADDITIONAL CONVECTION APPEARS POSSIBLE OVER THE CASCADES THURSDAY
AFTERNOON AND EVENING. ONSHORE PRESSURE GRADIENTS WILL INCREASE
THURSDAY NIGHT INTO FRIDAY...WHICH SHOULD RESULT IN ANOTHER EXTENSIVE
MARINE CLOUD LAYER DAY. AREAS OF MORNING DRIZZLE CERTAINLY APPEAR
POSSIBLE. ALTHOUGH...THE THREAT OF CONVECTION SHOULD SHIFT EAST OF
THE CASCADES ON FRIDAY...A LIGHT SHOWER OR TWO ACROSS THE WILLAMETTE
VALLEY OR IN THE CASCADES CANNOT BE RULED OUT AS THE MARINE LAYER
LIFTS WITH DAYTIME HEATING EACH DAY. /NEUMAN
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
FRIDAY NIGHT THROUGH TUESDAY...MODEL GUIDANCE CONTINUES TO REMAIN IN
GENERAL AGREEMENT FOR THE END OF THE WEEK WITH THE BLOCKING PATTERN
CONTINUING WITH HIGH PRESSURE OVER ALASKA AND WESTERN CANADA ABOVE
UPPER LOW PRESSURE SLOWLY SLIDING EAST ACROSS THE SOUTHWESTERN U.S.
AND GREAT BASIN. KEPT SOME SLIGHT CHANCE SHOWERS IN THE CASCADES FOR
THE WEEKEND WITH PERHAPS SHOWERS ATTEMPTING TO MAKE THEIR WAY INTO
THE FOOTHILLS OR EASTERN VALLEY...THOUGH CONFIDENCE IS LOW. HEIGHTS
MAY RISE A BIT FOR THE START OF THE WEEK THOUGH MODELS DIVERGE
CONSIDERABLY IN THE DETAILS SO CONFIDENCE REMAINS LOWER IN THE
SPECIFICS FOR THIS TIME. CULLEN
&&
.AVIATION...CONDITIONS ALONG THE COAST REMAIN MOSTLY IFR UNDER
ONSHORE FLOW WITH CIGS GENERALLY AOB 800 FT. EXPECT CONDITIONS TO
GRADUALLY IMPROVE TO MVFR WITH GUSTY WINDS POSSIBLE THIS
AFTERNOON/EVENING. HOWEVER...CIGS LOOK TO REMAIN AOB 2000 FT.
CONDITIONS INLAND REMAIN MOSTLY MVFR UNDER GENERALLY LIGHT AND
VARIABLE FLOW. CONDITIONS SHOULD IMPROVE TO VFR AFTER 18Z WITH
CIGS AROUND 4000 FT. THUNDERSTORMS WILL LIKELY REDEVELOP OVER THE
CASCADES THIS AFTERNOON AND COULD DRIFT OVER THE VALLEY...BUT
CONFIDENCE REMAINS TOO LOW TO INCLUDE IN THE 18Z TAF PACKAGE. MOST
LIKELY TIMES FOR THUNDERSTORMS IMPACTING INLAND TERMINALS WILL BE
BETWEEN 00Z-06Z THU.
KPDX AND APPROACHES...LOW-END MVFR CIGS EXPECTED THROUGH AROUND
20Z WITH CIGS GRADUALLY LIFTING OVER THE NEXT SEVERAL HOURS.
THERE IS A CHANCE THAT THUNDERSTORMS COULD DRIFT OVER THE
TERMINAL BETWEEN 00Z-06Z THU...BUT CONFIDENCE IS STILL TO LOW TO
INCLUDE IN THE 18Z TAF PACKAGE. /64
&&
.MARINE...SURFACE HIGH PRES OFFSHORE AND THERMAL LOW PRES OVER THE
INLAND NW SHOULD GIVE US RELATIVELY BENIGN WEATHER FOR THE NEXT
SEVERAL DAYS. WINDS SHOULD STAY BELOW 20 KT...BUT WOULD NOT BE
SURPRISED TO SEE ISOLATED GUSTS TO 25 KT IN THE AFTERNOON/EVENING
OVER THE OUTER WATERS. SEAS WILL HOVER BETWEEN 3 AND 6 FT OVER THE
FORECAST PERIOD. HOWEVER...STEEP AND CHOPPY SEAS CAN BE EXPECTED
AT TIMES DUE TO A FRESH NW SWELL. /64
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1131 AM MDT WED MAY 20 2015
.UPDATE...
ISSUED AT 909 AM MDT WED MAY 20 2015
UPPER HIGH IS PUSHING DRIER AIR INTO THE NORTHERN PLAINS. SKIES
ARE BECOMING CLEAR FROM NORTH TO SOUTH...AND PRECIP IS
DIMINISHING. SURFACE HIGH PRESSURE IS DRAPED ACROSS THE CWA.
WINDS ARE LIGHT AND VARIABLE WITH TEMPS RISING INTO THE 40S AND
LOWER 50S. ADJUSTED SKY GRIDS AND POPS TO MATCH CURRENT
TRENDS...BUT REST OF FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 250 AM MDT WED MAY 20 2015
08Z SURFACE ANALYSIS HAD HIGH PRESSURE OVER THE DAKOTAS. WATER
VAPOR LOOP HAD UPPER LOW SPINNING OVER NORTH CENTRAL NE.
DEFORMATION ZONE -RASN ACROSS SOUTHERN SD STARTING TO WANE AS
MOISTURE PLUME IS CUTOFF AND MAIN FORCING SHIFTS NORTHEAST ON 90KT
JET STREAK ACROSS THE MIDDLE MO RIVER VALLEY. FEW INCHES OF SNOW
OVER THE HIGHER ELEVATIONS PER WEB CAMS/ROAD REPORTS SINCE TUESDAY
AFTERNOON. 00Z NAM/GFS AND LATEST RAP SHOW PRECIPITATION WANING
THROUGH THE MORNING HOURS WITH MOST SYNOPTIC SCALE ACTIVITY/LIFT
DONE BY 18Z. LOW LEVEL INSTABILITY SUGGESTS A FEW POPCORN SHOWERS
POSSIBLE THIS AFTERNOON ACROSS THE FAR SOUTH GIVEN RESIDUAL LOW
LEVEL MOISTURE...BUT DRIER AIR INFILTRATING BOUNDARY LAYER UNDER
SURFACE HIGH MAY LIMIT ACTIVITY TO SPRINKLES/VIRGA. TEMPERATURES
WILL COOL AND BE BELOW GUIDANCE ACROSS THE SOUTH BUT NEAR GUIDANCE
ACROSS THE NORTH WHERE CLEARING SKIES WILL MAKE FOR A PLEASANT
DAY...ALBEIT BELOW NORMAL.
TONIGHT/THURSDAY...WEAK UPPER RIDGE BUILDS INTO THE NORTHERN PLAINS
AS SURFACE HIGH SHIFTS INTO THE MIDDLE MS RIVER VALLEY. FROST MAY
OCCUR OVER PARTS OF THE SD PLAINS AND LATER SHIFTS WILL NEED TO
ASSESS FOR HEADLINES. WEAK RETURN FLOW EXPECTED THURSDAY WITH WARM
AIR ADVECTION PUSHING TEMPERATURES INTO THE 60S ON THE PLAINS AND
50S IN THE BLACK HILLS.
THURSDAY NIGHT...UPPER FLOW BECOMES SOUTHWEST IN RESPONSE TO UPPER
LOW/TROUGH OVER THE WEST COAST. SHORTWAVE MOVING THROUGH WY MAY
PRODUCE SMALL POPS OVER THE FAR SOUTHWEST LATE. TEMPERATURES WILL BE
NEAR GUIDANCE.
.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 250 AM MDT WED MAY 20 2015
THE NEXT LOW PRESSURE SYSTEM TO EJECT OUT OF THE WESTERN CONUS
TROF WILL BEGIN TO IMPACT THE AREA ON FRIDAY...WITH CHANCES FOR
SHOWERS AND THUNDERSTORMS INCREASING FROM SOUTHWEST TO NORTHEAST
ACROSS THE CWA INTO FRIDAY EVENING. MEDIUM RANGE MODELS SEEM TO BE
IN BETTER AGREEMENT ON THE TRACK OF THE SYSTEM...WITH SOME
DIFFERENCES ON TIMING AND WHERE HEAVIER RAINFALL MAY DEVELOP. THE
BEST CHANCES FOR MORE WIDESPREAD PCPN STILL LOOK TO BE FROM LATE
FRIDAY INTO SUNDAY MORNING...WITH THE THREAT FOR HEAVIEST RAINFALL
GENERALLY BEING SATURDAY AFTERNOON AND NIGHT. SATURDAY LOOKS TO BE
THE MOST FAVORABLE DAY FOR STRONGER THUNDERSTORMS AS WELL...
ESPECIALLY FROM THE BLACK HILLS AREA AND EASTWARD. AS THE SYSTEM
WEAKENS TO THE NORTH AND EAST OF THE AREA LATE IN THE
WEEKEND...SOUTHWEST FLOW ALOFT WILL REMAIN OVER THE REGION. THIS
WILL KEEP THE UNSETTLED PATTERN CONTINUING INTO EARLY NEXT WEEK.
TEMPERATURES WILL STAY BELOW AVERAGE THROUGH THE WEEKEND WITH
CLOUDS AND MOISTURE ACROSS THE AREA. WILL LIKELY SEE A WARMING
TREND TO NEAR AVERAGE TEMPERATURES EARLY NEXT WEEK.
&&
.AVIATION...FOR THE 18Z TAFS THROUGH 18Z THURSDAY
ISSUED AT 1126 AM MDT WED MAY 20 2015
VFR CONDITIONS WILL PERSIST ACROSS NORTHWESTERN SOUTH DAKOTA. A
FEW LIGHT SHOWERS WILL CONTINUE THROUGH THE AFTERNOON AROUND THE
BLACK HILLS...CREATING ISOLD MVFR CIGS. OTHERWISE CONDITIONS WILL
IMPROVE TO VFR FROM NORTH TO SOUTH THROUGH THE REST OF THE
AFTERNOON.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...POJORLIE
SHORT TERM...HELGESON
LONG TERM...26
AVIATION...MLS
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
552 PM CDT Wed May 20 2015
.UPDATE...
Thunderstorms, some severe, will continue to develop along or near
the cold front this evening. The cold front now extends near a
line from Barnhart...to Eldorado...to Brady. After coordination
with the Storm Prediction Central...we have issued Severe
Thunderstorm Watch number 192, which is valid until midnight CDT
tonight, for counties along and south of a line from Mertzon to
Brady. The latest Zone package headlines this watch for the
appropriate counties.
&&
.PREV DISCUSSION... /ISSUED 350 PM CDT Wed May 20 2015/
SHORT TERM...
(Tonight and Thursday)
A rather strong cold front has moved south of a San Angelo to
Coleman line this afternoon, dropping temperatures into the upper
50s and lower 60s across the Big Country. Low clouds and cold
advection north of the front has greatly reduced instability,
limiting the potential for diurnal convection. Ahead of the front,
temperatures have warmed into the lower 80s with dewpoints hanging
in the mid/upper 60s. Modified RAP soundings indicate SBCAPE values
on the order of 2000-2500 J/kg in the warm sector with effective
shear values exceeding 35 kts. This will support organized
convection this afternoon and during the evening hours, with the
primary focus along and south of the front. The primary concern is
for large hail and damaging winds. However, a tornadic storm cannot
be ruled out in the vicinity of this boundary.
Right moving supercell vectors are from the west and northwest at 10
to 15 mph. This slow storm motion and the presence of the
aforementioned cold front will support the potential for locally
heavy rainfall along the I-10 corridor tonight. Additional storms
will be possible overnight as isentropic ascent develops over the
frontal zone. As the front moves south overnight and early Thursday,
rain chances are expected to diminish during the morning hours.
However, shortwave ridging aloft will be shifting to the east as a
strong shortwave trough moves across the southern Rockies.
Increasing large scale ascent will promote the development of
scattered showers and thunderstorms during the afternoon hours.
Fortunately, the severe weather potential is expected to remain low
on Thursday. Much cooler temperatures are anticipated tomorrow, with
highs in the 60s across most of the area.
Johnson
LONG TERM...
(Thursday night through next Wednesday)
The main focus is with the severe weather and heavy rainfall
possibility for the Memorial Day holiday weekend.
Increased chance and coverage of showers and thunderstorms
is expected across our area Thursday night, with the arrival
of a stronger shortwave in southwest flow aloft. With subsidence
and advection of some drier mid-level air in the wake of this
departing shortwave, will have reduced chances for showers and
thunderstorms on Friday.
An upper low will move northeast into southeastern Utah Friday
night, with an upper trough trailing from the low across the
Desert Southwest. The main chance for showers and thunderstorms
Friday night will be overnight, and across our northwestern
counties, with the possibility of a weak embedded disturbance
out ahead of the main trough lifting northeast into far west
or northwest Texas.
The aforementioned upper trough will move slowly east across
Arizona and New Mexico over the holiday weekend. Given the
forecast strength of this system, will have increased potential
for severe weather with stronger instability and increased
vertical shear. Carrying higher PoPs over the weekend with the
highest rain chance on Saturday night. Heavy rainfall will also
be possible with repeat convective activity and precipitable
water values at or above 1.5 inches across much of our area.
The upper trough is progged to eventually lift northeast across
Texas, but the 12Z GFS and ECMWF differ on the timing.
Following departure of this system, drier and warmer conditions
look to be in store for our area as heights build aloft. May
have another upper trough approach from the southwestern states
next Wednesday, but keeping PoPs below mention with the
uncertainty at this time.
19
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 57 66 58 78 67 / 50 40 60 50 40
San Angelo 60 68 61 81 67 / 60 40 60 30 30
Junction 65 72 65 82 68 / 70 50 50 30 30
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
350 PM CDT Wed May 20 2015
.SHORT TERM...
(Tonight and Thursday)
A rather strong cold front has moved south of a San Angelo to
Coleman line this afternoon, dropping temperatures into the upper
50s and lower 60s across the Big Country. Low clouds and cold
advection north of the front has greatly reduced instability,
limiting the potential for diurnal convection. Ahead of the front,
temperatures have warmed into the lower 80s with dewpoints hanging
in the mid/upper 60s. Modified RAP soundings indicate SBCAPE values
on the order of 2000-2500 J/kg in the warm sector with effective
shear values exceeding 35 kts. This will support organized
convection this afternoon and during the evening hours, with the
primary focus along and south of the front. The primary concern is
for large hail and damaging winds. However, a tornadic storm cannot
be ruled out in the vicinity of this boundary.
Right moving supercell vectors are from the west and northwest at 10
to 15 mph. This slow storm motion and the presence of the
aforementioned cold front will support the potential for locally
heavy rainfall along the I-10 corridor tonight. Additional storms
will be possible overnight as isentropic ascent develops over the
frontal zone. As the front moves south overnight and early Thursday,
rain chances are expected to diminish during the morning hours.
However, shortwave ridging aloft will be shifting to the east as a
strong shortwave trough moves across the southern Rockies.
Increasing large scale ascent will promote the development of
scattered showers and thunderstorms during the afternoon hours.
Fortunately, the severe weather potential is expected to remain low
on Thursday. Much cooler temperatures are anticipated tomorrow, with
highs in the 60s across most of the area.
Johnson
.LONG TERM...
(Thursday night through next Wednesday)
The main focus is with the severe weather and heavy rainfall
possibility for the Memorial Day holiday weekend.
Increased chance and coverage of showers and thunderstorms
is expected across our area Thursday night, with the arrival
of a stronger shortwave in southwest flow aloft. With subsidence
and advection of some drier mid-level air in the wake of this
departing shortwave, will have reduced chances for showers and
thunderstorms on Friday.
An upper low will move northeast into southeastern Utah Friday
night, with an upper trough trailing from the low across the
Desert Southwest. The main chance for showers and thunderstorms
Friday night will be overnight, and across our northwestern
counties, with the possibility of a weak embedded disturbance
out ahead of the main trough lifting northeast into far west
or northwest Texas.
The aforementioned upper trough will move slowly east across
Arizona and New Mexico over the holiday weekend. Given the
forecast strength of this system, will have increased potential
for severe weather with stronger instability and increased
vertical shear. Carrying higher PoPs over the weekend with the
highest rain chance on Saturday night. Heavy rainfall will also
be possible with repeat convective activity and precipitable
water values at or above 1.5 inches across much of our area.
The upper trough is progged to eventually lift northeast across
Texas, but the 12Z GFS and ECMWF differ on the timing.
Following departure of this system, drier and warmer conditions
look to be in store for our area as heights build aloft. May
have another upper trough approach from the southwestern states
next Wednesday, but keeping PoPs below mention with the
uncertainty at this time.
19
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 57 66 58 78 67 / 50 40 60 50 40
San Angelo 60 68 61 81 67 / 60 40 60 30 30
Junction 65 72 65 82 68 / 70 50 50 30 30
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1244 PM CDT Wed May 20 2015
.AVIATION...
/18Z TAFS/
IFR to LIFR conditions are prevalent behind the cold front moving
south across the area this afternoon. This will result ceilings
below 700 ft at both KABI and KSWW. This front should reach KSJT
by mid-afternoon, resulting in similar conditions after 20z.
Scattered, short-lived showers are developing across the area, but
are expected to become more organized this afternoon as
temperatures along the I-10 corridor approach 80 degrees.
Thunderstorms are expected south of a KSJT to KBBD line this
afternoon and evening, and could persist well into the overnight
hours as the boundary stalls across the southern portion of the
CWA. Expect southeast/east winds to shift to the north and
northeast behind this cold front.
Johnson
&&
.PREV DISCUSSION... /ISSUED 950 AM CDT Wed May 20 2015/
UPDATE...
A cold front is moving slowly south across the Big Country this
morning, currently extending from just near Big Spring, to just
north of Abilene, to Jacksboro. A few showers have developed along
and north of this boundary, but should remain relatively light and
unorganized. Temperatures have dropped into the upper 50s and
lower 60s in areas north of I-20, with dewpoints as low as the
50s. An outflow boundary from overnight convection has moved south
to near a Brownwood to San Angelo line and continues to sag slowly
toward I-10. Precipitation amounts should remain rather light
through early afternoon, but as the boundary layer destabilizes,
scattered convection is expected to develop.
The most likely area for convective initiation is roughly south of
a San Angelo to Brownwood line (where the cold front is forecast
to be near peak heating). If we get enough breaks in the cloud
cover, instability and vertical shear should be sufficient to
support strong to severe thunderstorms. This would present a
potential for localized heavy rainfall, but coverage is expected
to be limited, so not Flash Flood Watch will be issued.
Temperatures were lowered a few degrees across the Big Country
this afternoon, but otherwise minimal changes were made to the
inherited forecast.
PREV DISCUSSION... /ISSUED 650 AM CDT Wed May 20 2015/
AVIATION...
/12Z TAFS/
Widespread stratus is expected across West Central Texas this
morning, with MVFR/IFR ceilings. The ceilings will lift to low end
VFR across much of the area this afternoon and continue this
evening, besides the KABI terminal remaining MVFR. Scattered
thunderstorms should develop this afternoon and evening across the
mainly the southern 2/3 of the area and have VCTS at most of the
terminals. A few storms may be severe.
PREV DISCUSSION... /ISSUED 450 AM CDT Wed May 20 2015/
SHORT TERM...
(Today and Tonight)
This morning, a cool front extended across central and southwest
Oklahoma and southwest to south of Lubbock. Also, a complex of
thunderstorms (latest IR indicating warming cloud tops) was
located across north Texas and southern Oklahoma or mainly along
the Red River valley. Scattered showers and storms extended back
west into Haskell and Throckmorton counties. For today, the cool
front will make some progress south across West Central Texas to
probably along a San Angelo to Brownwood line by 00Z. Looks like
the best potential for thunderstorms will be in the warm sector
across the southern half of the area, along and ahead of the
front. All the models indicate at least scattered thunderstorms
developing, with the high res HRRR the most aggressive. The
combination of moderate instability and 0-6km shear values of
30-35 knots will lead to a few storms becoming severe during
mainly this afternoon and evening. the main hazards will be large
hail and damaging winds. The Big Country will probably see more
stable conditions behind the front, so the severe weather concern
is mainly low for the next 24 hours. Highs today will range from
the upper 60s to lower 70s across the Northern Big Country to
lower 80s along the I-10 corridor.
For tonight, the scattered afternoon storms may form into an
organized complex during this evening. However, there is some
uncertainty on how and where the storms will organize. For now,
will keep the likely Pops going across the southeast half of the
area and chance Pops elsewhere. Locally heavy rainfall will be
possible mainly due to PW values of 1.25 to 1.5 inches. Again, A
few storms may be severe during the evening. The cool front
should move south of the area after midnight and convection should
begin to weaken some.
LONG TERM...
(Thursday through Tuesday)
Unsettled weather will continue through the Memorial Day
Weekend...
Cloudy and cool conditions will start off the extended period on
Thursday, as the cold front remains stalled south of the area
during the day. Temperatures will be well below normal for this
time of year, with highs ranging from the upper 60s across the Big
Country, to the middle 70s along the I-10 corridor. Best rain
chances will be across the southern half of the forecast area
during the day, but will ramp up areawide by Thursday night as a
shortwave lifts northeast across the area.
Southerly flow returns on Friday as the stalled front lifts back
north as a warm front during the day. Temperatures will be warmer
but still below normal, with highs mainly in the upper 70s and
lower 80s. There will be a continued chance for showers and
thunderstorms on Friday, with highest POPs across northern
sections where aforementioned front is expected to lift north
during the afternoon hours.
Maintaining high POPs for next weekend as a short wave trough
moves east from the Four Corners region on Saturday and across
the southern Rockies by Sunday. This system will bring a threat
of strong to severe storms and heavy rainfall potential to the
area for the Memorial Day weekend. Precipitation chances will
start to wane by early next week as weak short wave ridging
develops in the wake of the departing upper trough.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 74 59 68 58 77 / 40 50 40 60 50
San Angelo 80 63 71 61 81 / 40 60 40 60 40
Junction 83 67 75 64 83 / 20 60 50 50 40
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
25
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1201 PM CDT WED MAY 20 2015
.UPDATE...
ISSUED AT 937 AM CDT WED MAY 20 2015
INCREASED/MOVED PRECIPITATION CHANCES A BIT MORE NORTHWARD ACROSS
NORTHEAST IA/SOUTHWEST WI THIS MORNING INTO THIS AFTERNOON WITH
INCOMING MID-LEVEL TROUGH/CIRCULATION. LATEST RAP SHOWS
INTENSIFICATION IN MID-LEVEL/700MB FRONTOGENESIS...SO EXPECTING
DESPITE DRYER LOW LEVELS...THE F-GEN WILL BE STRONG ENOUGH TO
GENERATE SOME SHOWERS.
UPDATE ISSUED AT 802 AM CDT WED MAY 20 2015
UPDATED TO REMOVE FROST ADVISORY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT WED MAY 20 2015
MAIN FCST CONCERNS THIS PERIOD...SMALL -SHRA CHANCES SOUTH TODAY...
TEMPERATURES.
DATA ANALYSIS AT 06Z HAD A BROAD AREA OF HIGH PRESSURE OVER THE
NORTHERN PLAINS AND UPPER MIDWEST. THE HIGH WAS BRINGING CLEAR
SKIES AND SUB-FREEZING TEMPS TO MUCH OF NORTHERN MN/WI INTO
CENTRAL WI EARLY THIS MORNING. WV IMAGERY SHOWED A RATHER VIGOROUS
LOOKING SHORTWAVE MOVING EAST ALONG THE NEB/SD BORDER. MID/HIGH
CLOUDS WITH THIS WAVE SPREADING ACROSS SOUTHERN MN/WI...HELPING
KEEP TEMPS ABOVE FREEZING. THE SHORTWAVE WAS BRINGING SOME LOWER
LEVEL MOISTURE TO IA...BUT EVEN THERE CLOUDS WERE MOSTLY ABOVE 5K-
6K FT. REGIONAL RADARS SHOWED REFLECTIVITY WITH THE SHORTWAVE FROM
SOUTH- CENTRAL SD TO NORTHERN MO BUT SFC OBS SHOW PRECIP REACHING
THE GROUND WAS MAINLY ALONG/SOUTH OF I-80 EARLY THIS MORNING.
20.00Z MODEL INITIALIZATIONS LOOK GOOD. MODELS OFFER A TIGHTER
CONSENSUS ON THE SD/NEB SHORTWAVE AS IT TRACKS EAST TODAY...AHEAD OF
BUT PARTLY PHASING WITH THE NORTHERN STREAM SHORTWAVE DROPPING INTO
EASTERN SD. TREND IS TO KEEP THE WAVES AS 2 SEPARATE PIECES OF
ENERGY QUICKLY FOLLOWING EACH OTHER THRU A MERGED TROUGH OVER THE
UPPER MIDWEST. TREND FAVORS STRONGER OF THE EARLIER MODELS AS THE
NORTHERN STREAM SHORTWAVE MOVES SOUTHEAST ACROSS THE REGION. WITH
THE TIGHT CONSENSUS OF SOLUTIONS...SHORT TERM FCST CONFIDENCE IS
GOOD THIS CYCLE.
IN THE SHORT TERM...SMALL -SHRA CHANCES ACROSS THE FAR SOUTH END OF
THE FCST AREA REMAIN A BATTLE OF 700-500MB FN/QG CONVERGENCE AND PV
ADVECTION WITH THE SHORTWAVE AND OVERCOMING DRIER NORTH TO NORTHEAST
FLOW/AIRMASS IN THE SFC-700MB PORTION OF THE COLUMN. PW VALUES IN
THE 0.5 TO 0.75 INCH RANGE ACROSS THE SOUTH END OF THE FCST AREA
TODAY BUT MAIN 850MB MOISTURE TRANSPORT STAYS WELL SOUTH IN MO AND
THE 700MB TRANSPORT MAINLY REACHES INTO THE SOUTHERN 2/3 OF IA.
MODELS...INCLUDING LOCAL/REGIONAL WRF MODELS ABOUT EVENLY SPLIT ON
-SHRA MAKING IT AS FAR NORTH AS THE KCCY/KOLZ AREAS. CONTINUED SOME
20-40 PERCENT -SHRA CHANCES ACROSS PARTS OF NORTHEAST IA INTO
EXTREME SOUTHWEST WI TODAY...PARTLY TO BLEND WITH NEIGHBORING GRIDS.
MAIN SHOT OF FORCING/LIFT MOVES ACROSS THE AREA THIS MORNING AND
CARRIED HIGHEST RAIN CHANCES AROUND 15Z...WITH RAIN CHANCES
DIMINISHING THRU THE AFTERNOON AS THE LEAD SHORTWAVE PASSES AND THE
COLUMN BEGINS TO DRY. MID/HIGH CLOUDS ACROSS THE AREA TODAY WILL
TEMPER HIGHS. 700-500MB TROUGH AXIS DROPS SOUTH OF THE AREA THIS
EVENING WITH AN INCREASE OF NORTHWEST TO NORTH FLOW AND DRIER AIR
SPREADING SOUTH ACROSS THE FCST AREA. CLOUDS LOOKING TO DECREASE
THIS EVENING WITH MOSTLY CLEAR TO CLEAR SKIES OVERNIGHT. ANOTHER
COOL NIGHT TONIGHT UNDER MOSTLY CLEAR SKIES...A DRY LOW LEVEL
AIRMASS AND WINDS EXPECTED TO BE LIGHT. MAY YET BE SOME PATCHY FROST
ACROSS THE NORTHEAST END OF THE FCST AREA LATE TONIGHT INTO EARLY
THU MORNING. WILL LEAVE IT TO DAY CREW TO FURTHER EVALUATE THIS
AFTER THE CURRENT ADVISORY HAS EXPIRED. FAVORED A BLEND OF THE
GUIDANCE HIGHS/LOWS FOR TODAY/TONIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 405 AM CDT WED MAY 20 2015
MAIN FCST CONCERNS FOR THU THRU FRI NIGHT...TEMPERATURES.
20.00Z MODELS IN GOOD AGREEMENT ON NORTHWEST FLOW ALOFT OVER THE
UPPER MIDWEST THU THRU FRI...AND REMAIN IN GOOD AGREEMENT FOR HGTS
TO RISE/RIDGING TO BUILD INTO THE REGION FRI NIGHT. MODELS ALSO WITH
RATHER GOOD RUN-TO-RUN CONSISTENCY THIS PERIOD. TREND BY FRI NIGHT
IS TOWARD STRONGER OF THE EARLIER RUNS WITH THE RIDGING OVER THE
REGION. FCST CONFIDENCE FOR THU THRU FRI NIGHT IS GOOD THIS CYCLE.
UNDER THE NORTHWEST FLOW ALOFT MODEL SOUNDINGS AND TIME-HGT X-
SECTIONS SHOWING A RATHER DRY AIRMASS/COLUMN OVER THE AREA FOR
THU THRU FRI. OTHER THAN PERHAPS SOME SCT AFTERNOON CUMULUS DURING
PEAK HEATING...THU THRU FRI SHAPING UP TO BE A CLEAR/SUNNY PERIOD.
DECENT CONSENSUS AMONG THE MODEL FOR A WEAK WAVE TO DROP ACROSS
THE WESTERN GREAT LAKES THU BUT ANY IMPACTS FROM THIS LOOKING TO
REMAIN WELL EAST OF THE FCST AREA. SFC PRESSURE GRADIENTS ON THE
WEAK SIDE FOR LIGHT WINDS...ESPECIALLY FRI WITH A SFC RIDGE AXIS
OVER THE REGION. MODEL SOUNDINGS INDICATING MIXING TO ABOUT 750MB
THU...WITH AROUND 25KTS OF WIND IN THE 850-750MB PORTION OF THE
MIXED LAYER. INCREASED WINDS/GUSTS A BIT THU AFTERNOON. COLUMN
MIXES TO AROUND 825MB FRI...WITH WINDS PROGGED TO BE LESS THAN
10KT THRU 800MB. 850MB TEMPS IN THE +7C TO +9C RANGE BOTH THU/FRI
AFTERNOONS... SUPPORTING HIGHS IN THE UPPER 60S TO NEAR 75. LIGHT
WINDS AND CLEAR SKIES FOR STRONGER RADIATIONAL COOLING THU
NIGHT...FOR A LARGER THAN NORMAL DIURNAL SWING OF TEMPERATURES. AS
PATTERN PROGRESSES FRI NIGHT...SFC-700MB TROUGHING STRENGTHENS IN
THE PLAINS. INCREASING SOUTH TO SOUTHWEST LOW LEVEL FLOW STARTS TO
SPREAD MOISTURE/WARMING NORTHEAST INTO THE UPPER MIDWEST...ALONG
WITH HIGHER LEVEL MOISTURE AHEAD OF THE WESTERN CONUS TROUGHING
SPILLING THRU THE RIDGING AND INTO THE REGION. TREND OF WARMER
LOWS AND SOME INCREASE OF CLOUDS FRI NIGHT LOOKS GOOD. TRENDED
TOWARD WARMER OF GUIDANCE HIGHS THU/FRI...THEN FAVORED A BLEND OF
THE GUIDANCE LOWS THU/FRI NIGHTS.
FOR SATURDAY THRU TUESDAY...DAYS 4 TO 7...
MEDIUM RANGE MODEL RUNS OF 20.00Z IN QUITE GOOD AGREEMENT SAT/SUN
SHOWING THE MID LEVEL RIDGE AXIS TO SLOWLY MOVE EAST OF THE REGION
AND DEEP SOUTHWEST FLOW ALOFT OVER MUCH OF THE UPPER MIDWEST BY LATE
SUN. DIFFERENCES BEGIN TO APPEAR BY SUN NIGHT/MON...ON THE TIMING/
STRENGTH DETAILS OF SHORTWAVE ENERGY EJECTING OUT OF THE WESTERN
CONUS TROUGH AND TOWARD/INTO THE UPPER MIDWEST. DETAIL DIFFERENCES
CONTINUE TUE...BUT GENERAL LONGWAVE CONSENSUS FOR BROAD TROUGHING
OVER MUCH OF THE CENTRAL/WESTERN CONUS. WITH THIS TRENDING TO BE A
MORE UNSETTLED WEATHER PERIOD AND SENSIBLE WEATHER ANY ONE DAY
STRONGLY IMPACTED BY THE SHORTWAVE/MESO-SCALE DETAILS...FCST
CONFIDENCE IN THE DAY 4-7 PERIOD IS AVERAGE THIS CYCLE.
MODEL CONSENSUS HAS SOUTHERLY FLOW AND MOISTURE CONTINUING TO
INCREASE INTO THE UPPER MIDWEST SATURDAY THRU SUN. PW VALUES PROGGED
IN THE 1.5 INCH RANGE OVER MUCH OF THE FCST AREA BY 12Z SUN. THIS
WITH A BROAD INCREASE OF LOWER LEVEL THERMO-DYNAMIC FORCING/LIFT AND
INSTABILITY. MODEL CONSENSUS OF INCREASING SHRA/TSRA CHANCES FROM
WEST TO EAST ACROSS THE AREA FROM SAT THRU SUN NIGHT LOOKING WELL
TRENDED...THOUGH THE SPECIFIC DETAILS OF PERIOD HAVE YET TO BE
SORTED OUT. WITH SLOW PROGRESSION OF THE LONGWAVE PATTERN...AND
ADDITIONAL SHORTWAVES TO COME THRU LONGWAVE TROUGHING THAT IS
PROGGED TO REMAIN OVER THE WEST HALF OF THE CONUS...THE MODEL/
ENSEMBLE CONSENSUS SHRA/ TSRA CHANCES CONTINUING THRU MON/TUE ARE
REASONABLE FOR NOW. GIVEN UNCERTAINTIES WITH SHRA/TSRA CHANCES/
TIMING/COVERAGE /AND CLOUD COVER/ ANY ONE DAY...DID NOT DEVIATE
FROM THE MODEL CONSENSUS HIGHS/LOWS FOR SAT THRU TUE. IF ANY ONE
OR MORE OF DAYS 4 TO 7 END UP DRY AND SUNNIER THAN CURRENTLY
EXPECTED... HIGHS THAT DAY COULD EASILY BE 5F TO 10F WARMER THAN
THOSE IN THE FCST GRIDS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1201 PM CDT WED MAY 20 2015
CURRENTLY TRACKING A MID-LEVEL TROUGH/CIRCULATION OVER NORTHWEST
IA. SO FAR...RAIN SHOWER ASSOCIATED WITH THIS WAVE ARE REMAINING
SOUTH OF THE KRST/KLSE TAF SITES WITH JUST BROKEN/OVERCAST VFR
MID-LEVEL CLOUD IN PLACE. THIS WAVE WILL CONTINUE TO PASS SOUTH OF
THE AREA THIS EVENING...KEEPING VFR CONDITIONS GOING AT KRST/KLSE
TAF SITES. WILL BE WATCHING ANOTHER TROUGH DROP SOUTH ACROSS THE
AREA OVERNIGHT INTO THURSDAY. WITH VFR CONDITIONS EXPECTED...MAIN
IMPACT WILL BE INCREASING WESTERLY WINDS THURSDAY IN THE 10-20KT
RANGE AS THE TROUGH DROPS THROUGH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...DAS
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
333 PM MDT WED MAY 20 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 243 PM MDT WED MAY 20 2015
SFC ANALYSIS SHOWS THE HIGH PRESSURE CENTER LOCATED NEAR THE PINE
RIDGE WITH EAST TO NORTHEAST UPSLOPE AND PERSISTENT LOW CLOUDS
ACROSS THE REGION. IT HAS BEEN ANOTHER COOL DAY WITH TEMPS A GOOD
20 DEGREES BELOW NORMAL. EXPIRED THE DENSE FOG ADVISORY FOR THE
SOUTH LARAMIE RANGE WITH WYDOT OBS SHOWING MOST VIS ABOVE 1 MILE.
THE HRRR DOES INDICATE VIS DROPPING BELOW ONE HALF MILE OVER THE
SOUTH LARAMIE RANGE BY 03Z. THIS MAKES SENSE WITH SFC WINDS
REMAINING SOUTHEAST TO SOUTH OVERNIGHT. HAVE AREAS OF FOG FROM
BUFORD TO THE SUMMIT BY EARLY TONIGHT AND CONTINUING THROUGH
THURSDAY MORING. WILL LET THE EVENING/NIGHT SHIFT MONITOR THE OBS
AND WEBCAMS OVER THE SUMMIT...AS DENSE FOG IS DEFINITELY POSSIBLE IN
THIS PATTERN. SHOWERS DEVELOPING THIS AFTN ALONG AND WEST OF THE
LARAMIE RANGE HAVE BEEN STRUGGLING TO STAY TOGETHER IN THE VERY
STABLE AIRMASS OVER THE PLAINS. KEPT ISOLATED TO SCATTERED SHOWERS
CONFINED TO MAINLY THE LARAMIE RANGE AND POINTS WEST THROUGH THE
EVENING.
PATTERN DOES NOT CHANGE A WHOLE LOT BY THURSDAY. LOW CLOUDS WILL BE
STUBBORN TO CLEAR YET AGAIN WITH MOIST SOUTHEAST LLVL FLOW.
SLIGHTLY BETTER INSTABILITY WILL EXIST ALONG THE LARAMIE RANGE (CAPE
VALUES OF 100-200 J/KG) BUT THIS IS LARGELY DEPENDENT ON SOME AFTN
CLEARING...WHICH IS QUESTIONABLE. INSTABILITY REALLY DROPS OFF TO
THE EAST OF CHEYENNE SO EXPECTING STORMS TO REMAIN CONFINED IN
VICINITY OF THE LARAMIE RANGE. A SHORTWAVE WILL EJECT NORTHWARD
FROM COLORADO BY LATE THURS NIGHT AND FRI MORNING. WITH GOOD UPPER
LEVEL DIFLUENCE...MODELS HAVE BEEN CONSISTENT AT SHOWING WIDESPREAD
RAIN DEVELOPING OVER THE PLAINS BY FRI MORNING AND CONTINUING
THROUGH MUCH OF THE DAY. THIS IS LOOKING LIKE ANOTHER 0.25-0.75
INCH MAINLY STRATIFORM RAIN EVENT FOR LOCATIONS TO THE EAST OF THE
LARAMIE RANGE. DID LOWER HIGHS A FEW DEGREES ON FRI WITH HIGHS
STRUGGLING TO GET ABOVE THE MID 50S.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 243 PM MDT WED MAY 20 2015
THE MAIN CONCERN WITH THIS PORTION OF THE FORECAST IS THE SEVERE
WEATHER POTENTIAL SATURDAY.
SATURDAY-SATURDAY NIGHT:
LATEST LOOK AT THE GEM/GEFS ENSEMBLES AND ECMWF ARE SHOWING
REALLY GOOD AGREEMENT IN THE TRACK OF THE UPPER LEVEL TROF THIS
WEEKEND. THE MODELS ARE ALSO IN AGREEMENT IN SHOWING THIS CLOSED
UPPER TROF OPENING UP IN NORTHWEST COLORADO AND SENDING ITS FIRST
PIECE OF ENERGY INTO OUR REGION SATURDAY. HOWEVER...THERE IS QUITE
A BIT OF STANDARD DEVIATION IN THE PLACEMENT OF THE SURFACE LOW
AROUND 00Z SUNDAY. THE MEAN ENSEMBLES ARE SHOWING THE SURFACE LOW
DEVELOPING IN EASTERN COLORADO. HOWEVER...THERE IS SOME HINTS THAT
THIS SURFACE LOW MAY ACTUALLY DEVELOP FURTHER NORTH IN NORTHEAST
COLORADO AND LIFT NORTHEAST THROUGH THE NEBRASKA PANHANDLE. IF
THIS SURFACE LOW DEVELOPS FURTHER NORTH...WE MAY SEE WARMER
TEMPERATURES AND HIGHER LOW LEVEL MOISTURE BEING DRAWN INTO AREAS
EAST OF THE LARAMIE WHICH WILL RESULT IN HIGHER INSTABILITY. THIS
COULD SET THE STAGE FOR SEVERE WEATHER IN AREAS EAST OF THE
LARAMIE RANGE SATURDAY AFTN/EVE...ESPECIALLY WITH 0-6KM SHEAR
VALUES APPROACHING 40 TO 50 KTS. ANOTHER CONCERN IS WHETHER OR NOT
WE WILL SEE LOW CLOUDS. AT THIS POINT...IT DOES NOT APPEAR THAT
THE LOW CLOUDS WILL BE PRESENT...BUT WE WILL HAVE TO SEE HOW THAT
EVOLVES. IF THE LOW CLOUDS ARE NOT PRESENT...TEMPERATURES SHOULD
BE ABLE TO CLIMB TO THE 60S.
SUNDAY-SUNDAY NIGHT:
THE MODELS ARE SHOWING THE MAIN UPPER LEVEL TROF MOVING INTO THE
AREA ON SUNDAY IN ITS WEAKENED STATE. THERE IS A LITTLE MORE
UNCERTAINTY ON HOW THIS TROF WILL IMPACT THE AREA ON SUNDAY
AFTERNOON INTO SUNDAY EVENING. AT THIS POINT...IT APPEARS LIKE THE
MAIN CONVECTION SHOW WILL BE ON SATURDAY AFTERNOON/EVENING.
HOWEVER...IF WE DO NOT SEE MANY STORMS DURING THAT TIME...THEN
SUNDAY MAY BE A DAY TO WATCH AS WELL. IF WE DO SEE WIDESPREAD
CONVECTION ON SATURDAY THEN SUNDAY CHANCES MAY BE MUCH SMALLER.
FOR NOW...WE WILL STAY WITH THE MODEL BLENDS FOR CONSISTENCY SAKE.
MONDAY-WEDNESDAY:
MODELS/ENSEMBLES ARE IN PRETTY GOOD AGREEMENT IN SHOWING THE UPPER
LEVEL RIDGE BUILDING OVER THE AREA AHEAD OF THE NEXT UPPER LEVEL
TROF MOVING INTO THE NORTHERN ROCKIES. THIS TROF WILL INDUCE UPPER
LEVEL DIFFLUENCE OVER THE AREA ON MONDAY AND TUESDAY WHICH COULD
SPARK SOME CONVECTION OVER THE MOUNTAINS WITH SOME OF THIS
CONVECTION POSSIBLY SPILLING OVER INTO THE PLAINS. OVERALL...IT
DOES NOT LOOK LIKE A REAL WET PATTERN...BUT WE CANNOT RULE OUT THE
AFTERNOON AND EVENING CONVECTION CHANCES OVER OUR AREA EITHER.
ALTHOUGH...TEMPERATURES WILL NOT BE TOO COOL WITH HIGHS CLIMBING
TO NEAR NORMAL READING WITH HIGHS MAINLY IN THE 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1059 AM MDT WED MAY 20 2015
THE MAIN CONCERN WITH THIS TAF ISSUANCE IS THE TIMING OF WHEN THE
IFR/MVFR CEILINGS WILL BEGIN TO CLEAR OUT.
LATEST SURFACE ANALYSIS WAS SHOWING COLD AIR DAMMING PERSISTING ALONG
THE LEE SIDE OF THE LARAMIE RANGE AROUND LUNCHTIME. THE MODELS ARE
CURRENTLY TOO FAST IN MOVING THIS CANADIAN SURFACE HIGH EAST THIS
AFTERNOON. AS A RESULT...WE ARE EXPECTING THE LOW CEILINGS TO
HANG ON TO MUCH OF THE AREA THIS AFTERNOON. THE LOWEST CEILINGS
ARE AROUND CYS (AROUND 800FT) AND POINTS WEST TO THE I-80 SUMMIT
WHERE THEY ARE STILL EXPERIENCING DENSE FOG. THIS SURFACE HIGH
SHOULD GRADUALLY SHIFT EAST LATE THIS AFTERNOON INTO THIS EVENING.
HOWEVER...WE ARE NOT CONFIDENT THAT CYS CEILINGS WILL CLIMB VERY
MUCH DUE TO THE EASTERLY FLOW KICKING IN. WE ARE LITTLE MORE
CONFIDENT THAT THE LOWER CEILINGS SHOULD BEGIN TO SCOUR OUT FROM
NORTH TO SOUTH ACROSS THE PANHANDLE SITES LATE THIS AFTERNOON
BASED ON THE LATEST SATELLITE TRENDS. HOWEVER...THERE IS A
POSSIBILITY THAT SOME PATCHY FOG COULD DEVELOP IN ITS WAKE.
OTHERWISE...WEAK ISENTROPIC ASCENT WILL BRING SOME VFR CEILINGS
INTO THE AREA AFTER MIDNIGHT.
&&
.FIRE WEATHER...
ISSUED AT 243 PM MDT WED MAY 20 2015
NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND. TEMPERATURES WILL
REMAIN BELOW NORMAL AND AFTERNOON HUMIDITY VALUES WILL BE ABOVE 50
PERCENT. THE BEST CHANCE OF WIDESPREAD WETTING RAIN WILL COME
THURSDAY NIGHT AND FRIDAY.
&&
.HYDROLOGY...
ISSUED AT 243 PM MDT WED MAY 20 2015
LARAMIE RIVER AT FORT LARAMIE AND LARAMIE WILL CONTINUE TO RUN AT
RELATIVELY HIGH LEVELS THROUGH THIS WEEK...BUT AT THIS TIME IS
EXPECTED TO REMAIN WITHIN ITS BANKS. ANOTHER ROUND OF MODERATE TO
HEAVY RAINFALL IS EXPECTED OVER THE HIGH PLAINS AND POSSIBLY THE
LARAMIE VALLEY ON FRIDAY...SO WILL NEED TO CONTINUE TO MONITOR
THE LARAMIE RIVER THROUGH LATE THIS WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...ZF
LONG TERM...REC
AVIATION...REC
FIRE WEATHER...ZF
HYDROLOGY...ZF
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1155 AM MDT WED MAY 20 2015
.UPDATE...
ISSUED AT 1059 AM MDT WED MAY 20 2015
LOWERED HIGHS FOR TODAY MAINLY FROM LARAMIE TO CHEYENNE AS LOW
CLOUDS WILL BE QUITE PERSISTENT INTO THE AFTERNOON. THE HRRR DOES
SHOW VIS IMPROVING OVER THE SOUTHERN LARAMIE RANGE AND THE
ARLINGTON AREA AFTER 18Z...AND WYDOT VIS IS SLOWLY STARTING TO
COME UP. DENSE FOG ADVISORY WILL PROBABLY BE EXPIRED AT NOON...BUT
WILL MONITOR OVER THE NEXT HOUR. WITH A STABLE AIRMASS OVER THE
PLAINS...SHOWERS AND AN ISOLATED TSTM WILL MAINLY BE CONFINED TO
THE SNOWY RANGE WESTWARD.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 346 AM MDT WED MAY 20 2015
THE PACIFIC STORM SYSTEM WHICH BROUGHT RAIN AND EVEN SOME SNOW TO
THE REGION YESTERDAY IS CURRENTLY WEAKENING AND MOVING EASTWARD
OVER THE NORTHERN PLAINS THIS MORNING. THERE IS STILL SOME LIGHT
SNOW BEING REPORTED ACROSS PORTIONS OF FAR EASTERN WYOMING AND
WESTERN NEBRASKA...BUT ACCUMULATIONS HAVE BEEN MINIMAL. OF MORE
SIGNIFICANCE IS THE FREEZING DRIZZLE NEAR THE RIDGE TOPS AND ALONG
THE LARAMIE RANGE...WITH CHEYENNE REPORTING FREEZING DRIZZLE
THROUGH MOST OF THE NIGHT. THERE HAVE BEEN A FEW REPORTS OF BLACK
ICE ON THE ROADWAYS...BUT SO FAR IT HAS BEEN RELATIVELY ISOLATED
WITH MAINLY JUST WET ROADWAYS. WILL CONTINUE TO KEEP AN EYE ON
THIS AS TEMPERATURES CONTINUE TO LOWER THROUGH THE UPPER 20S EARLY
THIS MORNING. HIGH TEMPERATURES TODAY WILL STRUGGLE TO REACH THE
MID TO UPPER 40S DUE TO A PERSISTENT LOW CLOUD DECK AND EVEN SOME
PATCHY FOG/DRIZZLE ALONG THE SOUTH FACING RIDGES.
EVENTUALLY...WINDS WILL SHIFT INTO THE EAST TO NORTHEAST TODAY
WITH CLOUD CEILINGS INCREASING A BIT BY THE AFTERNOON. NOT MUCH
SUN TODAY...WITH VALLEY LOCATIONS WEST OF THE LARAMIE RANGE HAVING
THE BEST CHANCE TO SEE SOME SUNSHINE. WITH SO MUCH MOISTURE AND
NEARLY SATURATED LOW TO MIDLEVELS...IT WILL NOT TAKE MUCH
INSTABILITY TO GENERATE SOME LIGHT SHOWERS. KEPT POP BETWEEN 20 TO
40 PERCENT FOR NOW...WITH SHOWERS LIKELY IN THE MOUNTAINS.
TONIGHT WILL BE MORE OF THE SAME...BUT WITH LESS CLOUD COVER OVER
THE NORTHERN AND WESTERN PORTION OF THE FORECAST AREA. MODELS SHOW
WINDS SHIFTING BACK INTO THE SOUTH OR SOUTHEAST...RESULTING IN
ANOTHER ROUND OF FOG AND/OR DRIZZLE FOR THE CHEYENNE AND PINE
RIDGE...ALONG WITH THE EASTERN FOOTHILLS OF THE LARAMIE RANGE. DO
NOT EXPECT THIS STRATUS DECK TO MAKE IT WEST OF THE LARAMIE
RANGE...SO LARAMIE AND RAWLINS MAY JUST BE PARTLY CLOUDY TONIGHT
BUT RELATIVELY COLD. MAY NEED A FROST OR FREEZE ADVISORY FOR
PORTIONS OF THE NORTHERN NEBRASKA PANHANDLE AS LOW TEMPERATURES
ARE PROGGED TO BE NEAR OR JUST BELOW FREEZING AT CHADRON AND
ALLIANCE...WHICH IS OVER ONE WEEK PAST THE AVERAGE LAST FREEZE.
IT IS UNCLEAR HOW MUCH CLOUDINESS WILL BE PRESENT IN THESE
AREAS...SO WILL HOLD OFF ON ANY HEADLINES FOR NOW.
WARMER TEMPERATURES ARE EXPECTED ON THURSDAY AS A SHORT WAVE
RIDGES MOVES ACROSS THE AREA. TEMPERATURES WILL STILL BE BELOW
NORMAL THOUGH AND GENERALLY IN THE MID 50S TO LOW 60S. THERE
SHOULD BE A BREAK IN THE PRECIPITATION ACROSS THE AREA DUE TO THE
MIDLEVEL SUBSIDENCE ASSOCIATED WITH THE RIDGE ALOFT. THE BREAK IN
THE PRECIPITATION WILL BE SHORT LIVED HOWEVER...AS ALL MODELS
INDICATE ANOTHER PACIFIC STORM SYSTEM MOVING TOWARDS THE AREA.
INITIALLY...EXPECT A ROUND OF SCATTERED SHOWERS AND ISOLATED TSTORMS
LATE ON THURSDAY AND INTO THURSDAY EVENING. WILL HAVE TO WATCH THE
NEXT SIGNIFICANT SHORTWAVE TROUGH LIFTING NORTHEAST OUT OF THE
SOUTHWEST LATE THURSDAY AND INTO FRIDAY. MODELS SHOW THIS
SHORTWAVE MOVING ACROSS COLORADO AND WYOMING EARLY ON FRIDAY
BRINGING ANOTHER ROUND OF RAINFALL AND MOUNTAIN SNOWS DUE TO A
LARGE AREA OF UPPER LEVEL DIFFLUENCE. SNOWLEVELS SHOULD BE
BETWEEN 7500 TO 8500 FEET THIS TIME AROUND...SO DO NOT EXPECT ANY
SNOW FLAKES OVER THE HIGH PLAINS AT THIS TIME. THIS SYSTEM HAS A
BETTER CHANCE TO CONTAIN HEAVIER RAIN SHOWERS COMPARED TO
YESTERDAYS SYSTEM...MAINLY BECAUSE OF THE CONDITIONAL INSTABILITY
ALOFT SHOWN BY MODEL SOUNDINGS. AFTER THE MAIN AREA OF
PRECIPITATION...EXPECT PARTIAL CLEARING SKIES FRIDAY AFTERNOON.
WITH THE COLD POOL ALOFT ASSOCIATED WITH THE UPPER LEVEL TROUGH
OVERHEAD...IT WILL NOT TAKE MUCH TO TRIGGER SCATTERED SHOWERS AND
TSTORMS LATE IN THE AFTERNOON EVEN AFTER THE TROUGH MOVES
NORTHWARD...WHICH IS TYPICAL THIS TIME OF THE YEAR. CONTINUED
INCREASING POP BETWEEN 60 TO 80 PERCENT...ESPECIALLY ALONG AND
EAST OF THE LARAMIE RANGE.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 340 AM MDT WED MAY 20 2015
ACTIVITY WEATHER PATTERN TO REMAIN IN PLACE THROUGH THE LONG TERM
FORECAST PERIOD. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL EXIST
EVERY DAY AS COOL UNSTABLE AIR ALOFT REMAINS IN PLACE ALONG WITH
SEVERAL DISTURBANCES WHICH WILL MOVE ACROSS THE FORECAST AREA
INTO EARLY NEXT WEEK. DIFFICULT TO PINPOINT THE BEST CHANCES FOR
PRECIPITATION GIVEN THE FACT IT IS TOUGH FOR THE MODELS TO RESOLVE
A NEARLY CONTINUOUS STREAM OF UPPER DISTURBANCES...BUT SAFE TO
SAY AFTERNOON SHOWERS AND THUNDERSTORMS WILL BE COMMON DUE TO
DIURNAL HEATING PRODUCING INSTABILITY MANY DAYS. NOT OVERLY
CONCERNED ABOUT SEVERE THUNDERSTORMS THROUGH THE PERIOD BUT IF
THERE IS A DAY TO WATCH IT IS SATURDAY. AT THIS TIME IT LOOKS AT
THROUGH THE BOUNDARY LAYER MAY STAY CAPPED WHILE A DISTURBANCE
MOVES ACROSS THE AREA EARLY IN THE DAY...BUT ELEVATED CONVECTION
MAY BE POSSIBLE TOO. SOMETHING TO KEEP AN EYE ON THE NEXT FEW
DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1059 AM MDT WED MAY 20 2015
THE MAIN CONCERN WITH THIS TAF ISSUANCE IS THE TIMING OF WHEN THE
IFR/MVFR CEILINGS WILL BEGIN TO CLEAR OUT.
LATEST SURFACE ANALYSIS WAS SHOWING COLD AIR DAMMING PERSISTING ALONG
THE LEE SIDE OF THE LARAMIE RANGE AROUND LUNCHTIME. THE MODELS ARE
CURRENTLY TOO FAST IN MOVING THIS CANADIAN SURFACE HIGH EAST THIS
AFTERNOON. AS A RESULT...WE ARE EXPECTING THE LOW CEILINGS TO
HANG ON TO MUCH OF THE AREA THIS AFTERNOON. THE LOWEST CEILINGS
ARE AROUND CYS (AROUND 800FT) AND POINTS WEST TO THE I-80 SUMMIT
WHERE THEY ARE STILL EXPERIENCING DENSE FOG. THIS SURFACE HIGH
SHOULD GRADUALLY SHIFT EAST LATE THIS AFTERNOON INTO THIS EVENING.
HOWEVER...WE ARE NOT CONFIDENT THAT CYS CEILINGS WILL CLIMB VERY
MUCH DUE TO THE EASTERLY FLOW KICKING IN. WE ARE LITTLE MORE
CONFIDENT THAT THE LOWER CEILINGS SHOULD BEGIN TO SCOUR OUT FROM
NORTH TO SOUTH ACROSS THE PANHANDLE SITES LATE THIS AFTERNOON
BASED ON THE LATEST SATELLITE TRENDS. HOWEVER...THERE IS A
POSSIBILITY THAT SOME PATCHY FOG COULD DEVELOP IN ITS WAKE.
OTHERWISE...WEAK ISENTROPIC ASCENT WILL BRING SOME VFR CEILINGS
INTO THE AREA AFTER MIDNIGHT.
&&
.FIRE WEATHER...
ISSUED AT 246 AM MDT WED MAY 20 2015
NO FIRE WEATHER CONCERNS THIS WEEK DUE TO UNSEASONABLY
COOL TEMPERATURES AND HIGH CHANCES OF PRECIPITATION. EVEN SOME SNOW
IS EXPECTED OVER THE MOUNTAINS EARLY TODAY AND ON FRIDAY. DAYTIME
RELATIVE HUMIDITIES ACROSS THE HIGH VALLEYS AND HIGH PLAINS WILL
LIKELY NOT LOWER BELOW 50 PERCENT UNTIL EARLY NEXT WEEK.
&&
.HYDROLOGY...
ISSUED AT 246 AM MDT WED MAY 20 2015
LARAMIE RIVER AT FORT LARAMIE WILL CONTINUE TO RUN AT RELATIVELY
HIGH LEVELS THROUGH THIS WEEK...BUT AT THIS TIME IS EXPECTED TO
REMAIN WITHIN ITS BANKS. THE PACIFIC STORM SYSTEM WHICH PUSHED
ACROSS THE REGION YESTERDAY DID NOT IMPACT RIVER LEVELS TOO MUCH
ACROSS THE AREA. HOWEVER...ANOTHER PACIFIC SYSTEM ON FRIDAY MAY
BRING MODERATE TO HEAVY RAINFALL AMOUNTS TO THE HIGH PLAINS AND
POSSIBLY THE LARAMIE VALLEY...SO WILL NEED TO CONTINUE TO MONITOR
THE LARAMIE RIVER THROUGH LATE THIS WEEK. THE LARAMIE RIVER AT
LARAMIE IS FORECAST TO FALL BELOW ACTION STAGE THIS WEEKEND OR
EARLY NEXT WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL NOON MDT TODAY FOR WYZ110-116.
NE...NONE.
&&
$$
UPDATE...ZF
SHORT TERM...TJT
LONG TERM...SML
AVIATION...REC
FIRE WEATHER...TJT
HYDROLOGY...TJT