Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/15/12
AREA FORECAST DISCUSSION
NWS EUREKA CA
340 AM PDT TUE MAY 15 2012
.SYNOPSIS...LOW CLOUDS AND FOG WILL PERSIST ALONG THE PACIFIC
COAST THROUGH WEDNESDAY MORNING. ISOLATED THUNDERSTORMS WILL BE
POSSIBLE WEDNESDAY AND THURSDAY AFTERNOONS OVER THE MOUNTAINS OF
EXTREME EASTERN TRINITY COUNTY.
&&
.DISCUSSION...UPPER LOW WHICH MOVED ACROSS THE S PORTION OF THE
AREA ON MON CONTINUES TO FILL AS IT MOVES SLOWLY E NEAR LAKE
TAHOE. BEHIND THE LOW...A WEAK UPPER RIDGE WILL BUILD OVER THE
LOCAL AREA TODAY. ALTHO THERE WILL BE SOME LINGERING MOISTURE OVER
THE TRINITY MOUNTAINS ALONG WITH MODEST INSTABILITY...FEEL THAT
RIDGE...MINIMAL DYNAMICS...AND CONVECTIVE INHIBITION SHOULD LIMIT
SHOWER ACTIVITY. AS A RESULT...HAVE REMOVED MENTIONABLE POPS FROM
THE FORECAST FOR TODAY.
LOW CLOUDS AND FOG WILL PERSIST ALONG THE PAC COAST TODAY...
EXPANDING INLAND LATER THIS EVENING AND OVERNIGHT. FOG IS EXPECTED
TO DECREASE IN COVERAGE ON WEDNESDAY...BUT WILL LIKELY HOLD FIRM
ALONG THE IMMEDIATE COASTAL AREAS OF N HUMBOLDT INTO EARLY THU AS
WELL AS COASTAL MENDOCINO COUNTY.
ISOLATED CONVECTION MAY RETURN TO THE TRINITY MOUNTAINS ON WED
AFTERNOON...BUT NEXT BEST SHOT OF PRECIP WILL LIKELY BE ASSOCIATED
WITH A DIGGING UPPER TROF THAT WILL SWING INTO THE AREA ON
THU. MOISTURE WILL AGAIN BE SOMEWHAT LIMITED WITH THIS SYSTEM.
HOWEVER...MODELS ARE INDICATING ENUF MOISTURE AND INSTABILITY TO
PRODUCE BETTER CHANCES OF PRECIP E OF THE COUNTY WARNING AREA.
HAVE INCLUDED LOW END CHANCE POPS OVER THE TRINITY HORN.
A COLD FRONT WILL APPROACH THE N PORTION OF THE AREA SUN NIGHT AND
EARLY MON...AND HAVE GONE ABOVE CLIMO POPS DURING THIS PERIOD
MAINLY OVER DEL NORTE COUNTY. /SEC
&&
.AVIATION...CURRENT 11-3.9U SAT AND SURFACE OBS SHOW A BROAD AREA OF
STRATUS ALONG THE COAST AND OFFSHORE. THIS STRATUS MAINLY APPEARS TO
BE LIFR WITH SOME IFR. THERE IS A HOLE IN THIS STRATUS FROM NORTH OF
HUMBOLDT BAY TO NORTH OF THE OR BORDER ALTHOUGH THIS HAS BEGUN TO
FILL IN. SATELLITE ALSO SHOWS A DECENT FINGER OF STRATUS UP THE EEL
RIVER VALLEY UP TO NEARLY WEOTT. THE NAM HAS A DECENT HANDLE ON THIS
AREA OF STRATUS AND SHOWS IT STAYING ALONG THE COAST THROUGH
TONIGHT. THE LOCAL WRF AND 3K HRRR MODELS SHOW THE SAME IDEA
ALTHOUGH THEY SHOW THE STRATUS PUSHING BACK TO NEARLY THE COAST IN
THE AFTERNOON. THE EXACT IMPACT ON THE COASTAL TAF SITES IS
DIFFICULT TO DETERMINE BUT EXPECT A FEW HOURS IN THE AFTERNOON OF
SCATTERED CLOUDS. TONIGHT AS THE NORTHERLIES PICK BACK UP MODELS
SHOW AREAS IMMEDIATELY SOUTH OF CAPE MENDOCINO CLEARING IN THE
AFTERNOON AND REMAINING CLEARING TONIGHT. INLAND AREAS LOOK TO
REMAIN MAINLY CLEAR. MKK
&&
.MARINE...LIGHT TO MODERATE WINDS ARE EXPECTED TO CONTINUE ACROSS
THE WATERS THROUGH TONIGHT IN RESPONSE TO WEAK HIGH PRESSURE.
WEDNESDAY HIGH PRESSURE LOOKS TO BUILD INTO THE NORTHEAST PACIFIC
AND IN CONJUNCTION WITH A THERMAL TROUGH ALONG THE COAST WILL CAUSE
NORTHERLY WINDS TO INCREASE. WINDS LOOK AT PEAK AROUND 20 TO 30 KT.
MODELS ARE IN GOOD AGREEMENT ON THESE NORTHERLIES THROUGH SATURDAY
AND CONFIDENCE IS FAIRLY HIGH. SUNDAY THE GFS BRINGS ANOTHER SYSTEM
THROUGH WHICH WOULD SHIFT THE WINDS TO THE SOUTH. THE ECMWF IS
SLOWER WITH THIS SYSTEM AND DOESNT BRING SOUTHERLIES TO OUR WATERS
UNTIL MONDAY. PREFERENCE WOULD BE TO LEAN TOWARD THE SLOWER ECMWF
BUT LEFT THE GOING FORECAST WHICH IS A COMPROMISE BETWEEN THE TWO
MODELS BRINGING SOME SOUTHERLIES IN SUNDAY NIGHT. SOUTHERLIES LOOK
TO PEAK AROUND 10 TO 20 KT.
WAVES ARE EXPECTED TO BE MAINLY LOCALLY GENERATED THROUGH THE PERIOD
AS THE GLOBAL MODELS ARENT DEVELOPING ANY SIGNIFICANT DISTANT
SYSTEMS TO GENERATE WAVES. WIND WAVES LOOK TO PEAK AROUND 11 FEET ON
THURSDAY IN RESPONSE TO THE NORTHERLIES. MKK
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS NEW YORK NY
1135 PM EDT SUN MAY 13 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH OVERNIGHT AND BECOME NEARLY STATIONARY
JUST TO THE WEST. A BROAD...WEAK AREA OF LOW PRESSURE WILL SLOWLY
MOVES NORTHEAST FROM THE SOUTHEASTERN STATES ON MONDAY...MOVING
OVER THE REGION BY WEDNESDAY MORNING. A COLD FRONT WILL THEN MOVE
INTO AREAS NORTH AND WEST OF NEW YORK CITY BY LATE WEDNESDAY...
AND THEN CROSSES THE REMAINDER OF THE AREA WEDNESDAY NIGHT.
HIGH PRESSURE WILL BUILD FROM THE GREAT LAKES FROM THURSDAY INTO
FRIDAY...AND THEN SLIDE INTO THE CANADIAN MARITIMES...WHERE IT
WILL DOMINATE OUR WEATHER INTO SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
TRICKY BUSINESS WITH POP ASSOCIATED WITH APPROACHING COLD FRONT
OVERNIGHT INTO MON MORNING. THE 00Z NAM AND 00Z RAP BOTH EXPAND
AREA OF LIGHT RAIN OVER SE PA EWD TOWARD NYC METRO TOWARD DAYBREAK
AS A MID LEVEL VORT MAX APPROACHES FROM THE SW AND AS UPPER JET RR
QUAD FORCING JUST TO THE NORTH ALSO GETS INVOLVED...BUT ITS AREAL
COVERAGE AND QPF LOOK OVERDONE BASED ON CURRENT OBS/TREND. HRRR
LOOKS MORE REALISTIC...KEEPING CURRENT ACTIVITY MAINLY TO THE
WEST...BUT ALSO ALSO DEVELOPS SCT SHOWERS MAINLY OVER LI/SOUTHERN
CT LATE WITH THE SHORTWAVE/UPPER JET STREAK COMBO. ANY 300K
ISENTROPIC LIFT THAT WOULD SUPPORT A STEADY LIGHT RAIN IS
CURRENTLY OVER SE VA...AND DOES NOT LOOK TO ARRIVE UNTIL AFTER 12Z
MON. POP GRIDS HAVE BEEN ADJUSTED ACCORDINGLY FOR THE OVERNIGHT
INTO EARLY MON MORNING...WITH LIKELY WELL NW OF NYC...LOW CHANCE
FOR THE LOWER HUDSON VALLEY/SOUTHERN CT/LONG ISLAND...AND ONLY
SLIGHT CHANCE IN NYC PROPER.
THE MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THE OVERNIGHT LOWS
REMAINING WELL ABOVE NORMAL...WITH 925MB TEMPS NEARING 15 DEGREES
CELSIUS. SHOULD SEE LOWS MAINLY IN THE MID TO UPPER 50S...WITH
LOWER 60S IN NYC. THIS IS CONSISTENT WITH A BLEND OF 2/3 MAV/MET
GUIDANCE AND 1/3 NAM 2-METER TEMPERATURE.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
PRECIP TIMING AND INTENSITY REMAINS THE QUESTION FOR THIS PERIOD AS
THE FRONT REMAINS NEARLY STATIONARY OVER CENTRAL NY AND STRONG HIGH
PRESSURE REMAINS SETTLED OVER THE NORTH ATLANTIC. WITH THE BROAD
UPPER LEVEL TROUGH PERSISTING...A VORT MAX LOOKS TO TRAVERSE THE
REGION SOMETIME BETWEEN 12Z AND 18Z MON...BRINGING ENOUGH FORCING
THAT WILL ASSIST IN TRIGGERING SCT SHOWERS. WITH LITTLE TO NO
INSTABILITY EXPECTED...ANY PRECIP SHOULD REMAIN JUST SHOWERS. THE
MODELS DEVELOP A BROAD SURFACE LOW MONDAY AND BRING IT NORTH ALONG
THE FRONT. AS THIS LOW APPROACHES...IT SHOULD GENERATE A STRONG
SOUTH TO SOUTH SOUTHEAST FLOW...INCREASING THE ISENTROPIC
LIFT...RESULTING IN MORE RAIN SHOWERS. HAVE THEREFORE KEPT CHANCE TO
LIKELY POPS OVER THE WESTERN HALF OF THE CWA WITH THE BETTER
FORCING...AND SLIGHT CHANCE TO CHANCE IN THE MORE STABLE EASTERN HALF.
THE SOUTHERLY FLOW WILL FINALLY MOISTEN UP THE LOWER LEVELS...SO
EXPECTING BKN TO OVC SKIES WITH SOME LOWER CLOUDS MOVING IN. THE OVC
SKIES...ALONG WITH ANY PRECIP...AND 925MB TEMPS REMAINING NEAR 12
DEGREES...EXPECTING MUCH COOLER TEMPS MON AND MON NIGHT...ESP ALONG
THE COAST WHERE AN ONSHORE FLOW WILL GENERATE HIGHS ONLY IN THE 60S.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
THERE IS QUITE A BIT OF MODEL SPREAD AS TO WHO MUCH IF ANY
PRECIPITATION THE REGION RECEIVES ON TUESDAY...WITH THE NAM BEING
BASICALLY DRY AND THE ECMWF BEING THE WETTEST AND FARTHEST EAST.
GIVEN THE BLOCKING PATTERN SET UP OVER THE NORTHERN STREAM AND THE
STRENGTH OF THE HIGH TO THE EAST...DO NOT WANT TO COMPLETELY
DISCOUNT THE NAM SOLUTION. SO WENT WITH LIKELY POPS OVER FAR NW
ZONES TO SLIGHT CHANCE POPS OVER FAR SE ZONES. THIS IS ALSO
CONSISTENT WITH ALL MODELS HAVING THE BEST DYNAMICS WITH A 700-500
HPA SHORTWAVE TROUGH THAT LIFTS NE THROUGH THE REGION PASS MAINLY TO
THE NW OF THE CWA. WITH MINIMAL CAPE...THE THETA-E RIDGE FORECAST TO
STAY TO OUR WEST...AND WEAK INSTABILITY ALOFT...HAVE KEPT THUNDER
OUT OF THE FORECAST FOR TUESDAY.
FOR HIGHS TUESDAY USED A BLEND OF 4/5 MAV/MET/MIX FROM 950 NEAR THE
COAST/MIX FROM 900 ACROSS THE INTERIOR AND 1/5 NAM 2-METER
TEMPERATURES. THIS YIELDS VALUES NEAR NORMAL.
TUESDAY NIGHT BRINGS THE BEST CHANCE FOR HEAVY PRECIPITATION TO THE
REGION WITH STRONG ISENTROPIC LIFT FROM THE I-295 TO I-305
SURFACES...A PASSING 700-500 HPA SHORTWAVE AND THE REGION BEING IN
THE RIGHT REAR QUADRANT OF A 80+ KT 300 HPA JET. SO HAVE LIKELY
POPS...WITH A SLIGHT CHANCE OF THUNDER...WITH SHOWALTER INDICES
PROGGED AROUND ZERO. FOR LOWS TUESDAY NIGHT USED A BLEND OF 2/3
MET/MAV AND 1/3 NAM 2-METER TEMPERATURES. THIS YIELDED VALUES AROUND
5 DEGREES ABOVE NORMAL.
HAVE LIKELY POPS E WEDNESDAY MORNING AS THE SURFACE WAVE SLOWLY MOVES
OUT...THIS WILL TAKE THE CORE OF THE LOW LEVEL MOISTURE WITH
IT...LEAVING NOT MUCH BEHIND FOR THE APPROACHING COLD FRONT AND
FAIRLY STRONG 700-500 HPA SHORTWAVE PASSING ACROSS THE REGION TO ACT
ON. SO HAVE POPS IN THE AFTERNOON RANGING FROM SLIGHT CHANCE FAR NW
TO CHANCE ELSEWHERE. DO HAVE A SLIGHT CHANCE OF THUNDER...WITH CAPES
GENERALLY FROM 250-750 J/KG...SHOWALTER INDICES AS LOW AS -2...THE
LOW LEVEL THETA-E RIDGE OVER THE REGION...AND CONTINUATION OF
BEING IN THE RIGHT REAR QUADRANT OF AN 80+ KT 300 HPA JET. FOR
HIGHS WEDNESDAY BLENDED MEX/MEX MEAN GUIDANCE AND NAM 2-METER
TEMPERATURES...WITH A MIX DOWN FROM 925 HPA ACROSS THE INTERIOR
AND 975 HPA AT THE COAST. THIS YIELDS VALUES 3-5 DEGREES ABOVE
NORMAL.
OTHER THAN A CHANCE TO SLIGHT CHANCE OF SHOWERS EARLY...WEDNESDAY
NIGHT SHOULD BE DRY AS THE 700-500 HPA TROUGH AXIS SLIDES TO OUR
EAST.
MODEL DIFFERENCE IN THE EXTENDED WITH THE ECMWF FEATURING WNW-NW
FLOW ALOFT AND THE GFS MORE ZONAL FLOW. THE ECMWF IS ALSO MORE
ROBUST WITH ITS HANDLING OF A COASTAL LOW FORECAST TO DEVELOP OFF
THE SE COAST BY FRIDAY MORNING. THE GFS TAKES THIS SYSTEM OFF WELL
TO OUR EAST THEN NE...WHILE THE ECMWF HAS IT MEANDER OFF THE
CAROLINA COAST. THIS SYSTEM COULD ULTIMATELY END UP PLAYING A ROLE
IN OUR WEATHER...SO WILL HAVE TO CONTINUE TO MONITOR.
FOR NOW...WITH HIGH PRESSURE THE MAIN PLAYER AT THE SURFACE...OTHER
THAN POSSIBLY A BACKDOOR COLD FRONT OR TWO...WENT WITH A DRY
FORECAST THURSDAY-SUNDAY. FOR TEMPERATURES USED A BLEND OF MEX/MEX
ENSEMBLE MEAN GUIDANCE WITH HPC GUIDANCE. THIS YIELDED ABOVE NORMAL
HIGHS AND LOWS NEAR TO SLIGHTLY ABOVE NORMAL.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
TERMINALS REMAIN NESTLED BETWEEN HIGH PRESSURE OFFSHORE AND A
SLOW MOVING COLD FRONT ACROSS NORTHERN/WESTERN NY STATE...WHILE A
WEAK TROF RESIDES CLOSE TO THE AREA. THIS GENERAL SCENARIO SHOULD
NOT CHANGE MUCH OVER THE NEXT 24 HR...WHILE UPPER LEVEL
DISTURBANCES MOVE ACROSS AND CREATE OPPORTUNITIES FOR LOWER CIGS
AND SHOWERS LATE TONIGHT INTO MON MORNING...AND AGAIN MON
AFTERNOON. CONFIDENCE IN SHOWERS ACTUALLY OCCURRING IS HIGH
ENOUGH TO AT LEAST MENTION...BUT EXACT TIMING IS STILL SOMEWHAT IN
QUESTION. CONDITIONS SHOULD BE MOSTLY VFR...BUT AFTERNOON SHOWERS
AT KSWF LOOK MORE LIKELY TO BRING MVFR CONDITIONS.
SOUTHERLY SEA BREEZES WILL DIMINISH EARLY...AND WINDS ACROSS THE
BOARD MAY VEER A LITTLE MORE SW THIS EVENING. WEAKER SEA BREEZE
DEVELOPMENT THAN THAT OF TODAY EXPECTED MON AFTERNOON.
OUTLOOK FOR 00Z TUE THROUGH FRI...
.MON NIGHT-WED...MVFR OR LOWER CONDITIONS POSSIBLE IN SHOWERS.
ISOLD THUNDER POSSIBLE TUE NIGHT-WED.
.WED NIGHT-FRI...VFR.
&&
.MARINE...
MINOR CHANGES IN THE NEAR TERM TO REFLECT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. THE MAIN CHANGE WAS TO REMOVE ALL
MENTION OF PRECIPITATION UNTIL LATE TONIGHT.
WINDS WILL INCREASE OVERNIGHT AS A COLD FRONT APPROACHES...
PRODUCING A SOUTHERLY FLOW WITH GUSTS UP TO AROUND 20 KT.
HOWEVER...WITH THE PERSISTENT SOUTHERLY FLOW...UP TO 5 FT SEAS ARE
EXPECTED OVER THE OCEAN E OF FIRE ISLAND INLET...SO HAVE CONTINUED
THE SCA FOR HAZARDOUS SEAS INTO MONDAY. DEPENDING ON WHETHER THE
CONDITIONS ARE MET...MAY NEED TO CONTINUE INTO MONDAY NIGHT AS
WELL. ALL OTHER WATERS SHOULD REMAIN BELOW SCA CRITERIA THROUGH
MONDAY NIGHT.
WINDS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY TUESDAY-FRIDAY...AS
THE PRESSURE GRADIENT AND WINDS IN THE LOW LEVELS SUPPORT ONLY WINDS
OF AT MOST 10-15KT WITH GUSTS OF AT MOST 20 KT. HOWEVER...A
PERSISTENT ONSHORE FLOW FROM TUESDAY INTO WEDNESDAY NIGHT WILL KEEP
SEAS AT HAZARDOUS LEVELS ON ALL THE COASTAL OCEAN ZONES...AND
POSSIBLY INTO THURSDAY ON THE WATERS EAST OF MORICHES INLET.
&&
.HYDROLOGY...
THERE WILL BE THE POTENTIAL BETWEEN 1 AND 3 INCHES WITH THE PRECIP
EXPECTED TONIGHT THROUGH INTO WEDNESDAY EVENING. TONIGHT/S AMOUNTS
SHOULD REMAIN LESS THAN A TENTH...WITH THE AMOUNTS PICKING UP
MONDAY DURING THE DAY WITH BETWEEN A QUARTER AND THREE QUARTERS INCH
POSSIBLE THROUGH MONDAY NIGHT. THE HEAVIEST PRECIP IS EXPECTED
FROM LATE TUESDAY INTO WEDNESDAY MORNING...WITH BETWEEN 1 AND 2
INCHES POSSIBLE OVER THE LOWER HUDSON RIVER VALLEY AND
NORTHEASTERN NJ...AND HALF AN INCH TO AN INCH OVER CT...LONG
ISLAND...AND THE NYC METRO AREA.
DUE TO ANTECEDENT DRY CONDITIONS...THERE IS INITIALLY A HIGHER
PROBABILITY OF MINOR URBAN FLOODING THAN MINOR SMALL STREAM
FLOODING...BUT WILL HAVE TO MONITOR FOR TRAINING SHOWER/TSTM
ACTIVITY ACROSS NE NJ AND THE LOWER HUDSON VALLEY MONDAY NIGHT INTO
WEDNESDAY.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EDT MONDAY
FOR ANZ350.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL NOON EDT MONDAY
FOR ANZ353.
&&
$$
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1101 AM EDT Tue May 15 2012
.UPDATE...
Previous forecast seems generally on track and very few changes
were made. Most of the focus was on the evolution of convection
through this afternoon, the associated distribution of PoPs, and
severe weather potential. PoPs were split out into 3-hourly grids
to get a bit more detail on timing of the best rain chances. So
far, the evolution of cumulus fields and light showers appear to
be close to a sea-breeze `regime 5` from our local climatology
(stronger W-SW flow in the 1000-700mb layer). This should be
augmented slightly by a NW-SE low-level moisture gradient with
higher 0-1km mixing ratios situated over the SE half of our area.
Additionally, a weakly defined and stalled front is lingering over
our forecast area which should place the best focus for storms in
the eastern half. PoP grids were a combination of convection-
allowing model (CAM) guidance, ongoing trends, and sea-breeze
`regime 5` climatology. This places likely PoPs along and SE of a
Tallahassee to Tifton line.
The latest SPC Day 1 Convective Outlook places the eastern half of
our area in a region of 5% probabilities for severe wind and hail
(within 25 miles of a point). This seems reasonable as there will
be an abundance of instability. Additionally, wind shear will be
slightly stronger today as compared to yesterday - when storms
failed to show much organization. 14z objective RAP analysis shows
effective bulk shear has now climbed to around 30 knots over much
of our area, near the lower bound for supercell parameter space.
The greatest threat would seem to be for isolated occurences of
damaging winds, particularly in the area of likely PoPs (SE of a
TMA-TLH line) - or SC GA and FL Big Bend. Storm scale ensembles
of high-res model guidance show max gusts in that area around 20
m/s (close to 40 knots) with lower values to the north and west.
Forecast soundings also reveal favorable downburst parameters in
that area with an abundance of dry air in the mid-levels: max
delta thetae around 25C and higher WMSI values. As such, a mention
of damaging winds and heavy rain was added to the forecast in the
aforementioned areas.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 85 65 87 63 88 / 60 30 30 20 30
Panama City 81 67 84 66 84 / 30 10 20 20 20
Dothan 84 64 86 63 88 / 30 30 20 10 20
Albany 86 64 86 63 90 / 20 30 20 10 30
Valdosta 86 64 87 63 89 / 70 20 30 20 40
Cross City 85 65 86 63 88 / 40 20 40 20 40
Apalachicola 82 67 82 65 83 / 30 10 30 20 20
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.
&&
$$
Lamers
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
915 PM EDT MON MAY 14 2012
.UPDATE (TONIGHT AND TUESDAY)...
00Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS AN UPPER LEVEL PATTERN
WHICH CONSISTS OF A LARGE LONGWAVE TROUGH COVERING MUCH OF THE
CENTRAL/EASTERN HALF OF THE CONUS. PLENTY OF DEEP TROPICAL MOISTURE
CONTINUES TO STREAM NORTHWARD AHEAD OF THIS TROUGH AXIS OVER THE FL
PENINSULA THIS EVENING. LINGERING CONVECTION IS STILL FIRING IN A
SCT VARIETY ALONG THE SEA-BREEZE AND OTHER RESIDUAL CONVECTIVE
BOUNDARIES OVER THE SOUTHERN HALF OF THE FORECAST AREA...MAINLY
SOUTH OF I-4. THESE WILL LIKELY CONTINUE FOR ANOTHER HOUR OR 2
BEFORE ENDING WITH THE COMPLETE LOSS OF DIURNAL HEATING. ADDITIONAL
SHOWER/STORM ACTIVITY IS ONGOING OVER THE EASTERN GULF ASSOCIATED
WITH SHORTWAVE ENERGY AND A FAVORABLE POSITION WITHIN THE LEFT EXIT
REGION OF AN APPROACHING UPPER LEVEL JET. ALTHOUGH NOT EXPECTING ANY
SIGNIFICANT RAINFALL CLOSER TO THE COAST...THE APPROACH OF THIS
ENERGY ARGUES TO KEEP AT LEAST A SMALL RAIN CHANCE IN THE FORECAST.
CURRENT TRENDS WOULD SUGGEST THE BEST CHANCE FOR THE OFFSHORE
SHOWERS TO REACH SHORE WOULD BE FROM MANATEE COUNTY
SOUTHWARD...ESPECIALLY THROUGH THE PRE-DAWN HOURS.
TUESDAY...DEEP COLUMN MOISTURE COMBINED WITH UPPER DIVERGENCE
ASSOCIATED WITH THE JET SUGGESTS ANOTHER ACTIVE DAY IN TERMS OF
CONVECTION (AT LEAST FOR MID-MAY). FORECAST WILL BE RATHER
SUMMER-LIKE WITH WARM AND HUMID CONDITIONS. WDLY SCT SHOWERS IN
THE MORNING CLOSER TO THE COAST WILL MIGRATE INLAND AND BECOME MORE
NUMEROUS OVER THE INTERIOR ZONES DURING THE AFTERNOON. THE 1000-700
MB FLOW IS NOT ALL THAT STRONG AND SOMEWHAT NORMAL TO THE SEA-BREEZE
WHICH SHOULD KEEP ITS INLAND PROPAGATION ON THE SLOW SIDE. THIS
SLOWER MIGRATION WILL ALLOW BETTER CHANCES FOR SHOWERS AND STORMS
DURING THE EARLY AFTERNOON ALONG THE I-75 CORRIDOR.
&&
.AVIATION...
A FEW LIGHT SHOWERS WITH VFR CIGS AND VSBYS THROUGH THE EVENING NEAR
ALL TERMINALS...BUT PREDOMINATELY DRY. HIGH OVERCAST CLOUDINESS
WILL PERSIST THROUGH THE NIGHT WITH SCT CU DEVELOPING TUESDAY
MORNING 030-040. SCT SHWRS AND TSTMS WILL DEVELOP DURING THE
AFTERNOON WITH LCL MVFR CIGS/VSBYS...AND ISOLD IFR CIGS/VSBYS IN
AREAS OF HEAVIER RAIN.
&&
.MARINE...
A WEAK PRESSURE PATTERN UNDER WEAK SURFACE HIGH PRESSURE WILL
SUPPORT LIGHT WINDS AND SLIGHT SEAS OVER THE GULF WATERS TONIGHT
THROUGH THE REMAINDER OF THE WORK WEEK WITH AN ENHANCED ONSHORE
SEA BREEZE COMPONENT DEVELOPING ALONG THE COAST EACH AFTERNOON.
WIND AND SEAS WILL BE ON THE INCREASE BY THE UPCOMING WEEKEND AS
THE GRADIENT TIGHTENS IN RESPONSE TO A LARGE SURFACE HIGH BUILDING
DOWN THE EASTERN SEABOARD WITH EXERCISE CAUTION OR LOW END SMALL
CRAFT CONDITIONS A POSSIBILITY BY LATE SATURDAY INTO SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 72 85 71 87 / 20 30 20 20
FMY 71 86 71 90 / 20 40 20 30
GIF 70 86 69 88 / 30 50 30 40
SRQ 70 85 70 86 / 20 30 20 20
BKV 66 85 62 88 / 20 40 20 20
SPG 73 83 73 86 / 20 30 20 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
MROCZKA/OGLESBY
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
939 AM EDT Mon May 14 2012
.MESOSCALE UPDATE...
Surface cold front now just to the west of the Tallahassee
forecast area this morning. Low level moisture ahead of this front
is clearly evident in the surface analysis. The main moisture
access extends from near Apalachicola northward to Tifton. This
is also where showers and a few isolated thunderstorms are firing
up early this morning. These showers will continue to develop
along this axis and slowly drift east over the morning hours. The
real question is the activity this afternoon. This morning`s upper
air sounding from TLH is indicating that at fair amount of
instability can be release. Modified sounding CAPE values of
1700-2500 J/kg this afternoon. Convection-allowing model (CAM)
guidance indicating similar numbers which gives increased
confidence in this afteroons activity. Latest SPC mesoanalysis
based off the new RAP model also showing a huge jump in
instability this past hour. While shower and thunderstorms are
expected to increase this afternoon, wind shear will keep the
threat of severe storms low. Latest effective shear values are in
the 20-25 kt range which would seem to limit the severe potential.
One possible wild card is the short wave currently digging through
central Mississippi. This wave is now clearly evident on Satellite
water vapor imagery. This may act to enhance instability and shear
more than current guidance would indicate.
In summary, the severe threat is low for this afternoon. However,
the digging short wave may be a game changer this afternoon and
bears watching. We will provide more updates as needed.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 85 66 85 65 87 / 50 20 30 10 20
Panama City 82 68 82 66 82 / 30 20 20 10 10
Dothan 85 65 85 65 86 / 40 20 20 10 20
Albany 85 66 85 65 87 / 50 30 30 20 30
Valdosta 85 65 84 65 87 / 50 30 30 20 30
Cross City 85 66 84 64 87 / 50 20 30 10 20
Apalachicola 82 68 81 66 82 / 40 20 20 10 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.
&&
$$
Lericos/Lamers
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
400 PM EDT SUN MAY 13 2012
.DISCUSSION...
TONIGHT...
EXTENSIVE CI DECK OVER CENTRAL FL COUPLED WITH A DRY SLOT THRU THE
H85-H50 LYR OVERHEAD HAS HAD A DRASTIC EFFECT ON PRECIP DVLPMNT THIS
AFTN. WX RADARS SHOWING ONLY VIRGA OVER THE NRN CWA...IR SAT IMAGERY
SHOWS NO DEEP CONVECTION OVER LAND. AFTN TEMPS HOLDING IN THE
U70S/L80S UNDER STEADY ONSHORE FLOW...LITTLE PROSPECT OF ANY
ADDITIONAL HEATING THIS AFTN. RAP ANALYSIS SHOWS A WEAK H85-H50
SHORT WAVE OVER THE NE GOMEX WITH ITS PRECEDING MID LVL SUPPRESSION
DIRECTLY OVER THE FL PENINSULA.
PRECIP CHANCES APPEAR SLIM IN THE FACE OF THESE WX FEATURES.
HOWEVER...SHOULD THE SHORT WAVE PUSH FAR ENOUGH EAST THERE IS THE
POTENTIAL OF SOME CONVECTIVE DVLPMNT BEFORE MIDNIGHT. WILL KEEP
30PCT IN FOR THE CENTRAL/NRN COUNTIES...20PCT AROUND THE LAKE. ISOLD
COASTAL SHRAS S OF THE CAPE AFT MIDNIGHT...THOUGH EVEN THIS CHANCE
WILL DIMINISH OVERNIGHT AS WINDS THRU THE H100-H70 LYR VEER TO THE
S/SW AS A DVLPG STORMS SYSTEM OVER THE DEEP SOUTH PUSHES EWD.
EXTENSIVE CLOUD COVER AND LIGHT SRLY FLOW WILL KEEP MIN TEMPS IN THE
U60S/L70S AREAWIDE.
MONDAY...
STORM SYSTEM WILL DVLP SLOWLY AS IT DRIFTS EWD UNDER THE INFLUENCE
OF A 70-80KT H30-H20 JET OVER THE NRN GOMEX. INTERACTION WITH THE
HI PRES RIDGE OFF THE MID ATLC COAST WILL GENERATE A DEEP W/SWRLY
FLOW THOUGH THE TIGHTEST PGRAD WILL REMAIN N OF CENTRAL FL. SFC
HEATING WILL BE IMPEDED BY EXTENSIVE MID/UPR LVL CLOUD DECK...
WHICH MAY PREVENT THE EAST COAST SEA BREEZE FROM FORMING. EVEN IF IT
DOES...THE WRLY FLOW WOULD KEEP IT PINNED OVER THE COASTAL COUNTIES.
GFS SHOWS SOME DECENT UPR LVL DIVERGENCE PASSING OVERHEAD DURING
PEAK HEATING HRS...BUT PASSES AN H50 VORT MAX JUST S OF LAKE
OKEECHOBEE. THIS WOULD GENERATE MID LVL SUPPRESSION OVER MUCH OF THE
CWA. MEANWHILE...A SLUG OF DRY AIR IN THE H100-H70 LYR WILL WRAP
AROUND THE BASE OF THE RIDGE AXIS...KEEPING DEW POINT DEPRESSION IN
THE 5-7C RANGE THRU THE LOW LVLS. INDEED...GFS/ECMWF MOS POPS ARE UP
TO 70PCT FROM ORLANDO/CAPE CANAVERAL NWD...DIMINISHING TO BLO 50PCT
AROUND THE LAKE. WILL UNDERCUT POPS BY 10PCT CENTRAL/NRN
COUNTIES...SRN COUNTIES LOOK OKAY.
S/SWRLY FLOW WILL BE COUNTERACTED BY INCREASING CLOUD COVER...
KEEPING MAX TEMPS IN THE L/M/U80S.
TUE-WED...
POSITIVE TILTED TROUGH ALOFT EXTENDING ACROSS THE SOUTHEAST STATES
WILL MOVE SLOWLY EASTWARD AND A WEAK FRONTAL TROUGH STRETCHING FROM
THE SOUTHEAST STATES INTO THE CENTRAL GULF WILL PUSH ONLY VERY
SLOWLY EAST. THIS WILL MAINTAIN A SOUTHWEST LOW LEVEL FLOW...BUT NOT
STRONG ENOUGH TO INHIBIT AN EAST COAST SEA BREEZE. THE TIMING OF
IMPULSES MOVING THROUGH THE INCREASING WEST/SOUTHWEST FLOW ALOFT
WILL CONTINUE TO BE A DIFFICULT THING TO NAIL DOWN. DEEP LAYER
MOISTURE IS GREATEST ON TUESDAY WITH WITH AN IMPULSES MOVING THROUGH
THE TROUGH AND MODEL POPS ARE HIGHEST FOR TUESDAY AFTERNOON AT
AROUND 50 PCT WITH 30ISH PCT FOR WEDNESDAY AND HAVE GENERALLY
ACCEPTED THAT SCENARIO. DAILY HIGHS AND LOWS WILL BE NEAR NORMAL.
THU-SUN...(PREVIOUS DISCUSSION)
AXIS OF SLOW MOVING TROUGH ALOFT IS FORECAST TO PASS EAST OF THE
AREA BY FRI...WITH A CUT OFF LOW FORMING OFFSHORE THE CAROLINAS
SAT-SUN. LIGHT LOW LEVEL WESTERLY FLOW WILL PERSIST ON THU AND THE
PRESENCE OF THE TROUGH AXIS/COLD POOL ALOFT SHOULD CONTINUE TO BE
FAVORABLE FOR AFTERNOON CONVECTION. THE AMOUNT OF DEEP MOISTURE
SHOULD LIMIT COVERAGE...BUT MOS POPS HAVE INCREASED TO 30 PERCENT...
AND WILL FOLLOW.
LARGE SCALE ASCENT SHOULD DIMINISH FRI AS TROUGH ALOFT PASSES AND
THE AREA WILL LIE TO THE SOUTHWEST OF CUT OFF LOW NEXT WEEKEND.
WITH SLIGHTLY DRIER LOW LEVEL THETA E AIR BEHIND WEAK SURFACE
TROUGH...POPS WILL DECREASE. WILL LEAVE SLIGHT CHANCE POPS FOR
FRI WITH SURFACE TROUGH POSSIBLY STILL NEAR THE AREA. LESS
FAVORABLE SYNOPTIC FLOW REGIME...NORTHEAST...IS FORECAST NEXT
WEEKEND...SO WILL GO WITH A DRY FORECAST FOR NOW.
&&
.AVIATION...
THRU 14/03Z...PREVAILING VFR ALL SITES...OCNL E/SE SFC WND G20KTS...
SCT MVFR SHRAS/ISOLD IFR TSRAS NW OF KVRB-KOBE...ISOLD SHRAS/TSRAS S
OF KVRB-KOBE. BTWN 14/03Z-14/15Z...PREVAILING VFR WITH PREVAILING
CIGS BTWN FL100-120...LCL CIGS BTWN FL040-060...ISOLD MVFR COASTAL
SHRAS S OF KMLB. AFT 14/15Z...PREVAILING CIGS BTWN FL080-100...NMRS
MVFR SHRAS/SCT IFR TSRAS N OF KISM-KTIX...SCT MVFR SHRAS/ISOLD IFR
TSRAS S OF KISM-KTIX.
&&
.MARINE...
TONIGHT-MONDAY...MODERATE SE BREEZE WILL DIMINISH OVERNIGHT AS A
HIGH PRES RIDGE EXTENDING FROM BERMUDA TO THE SE GOMEX IS ERODED BY
A WEAK STORM SYSTEM OVER THE DEEP SOUTH. INTERACTION BETWEEN THE
RIDGE AND THE SYSTEM WILL GENERATE A LIGHT TO GENTLE S/SE BREEZE
THRU MONDAY. SEAS 3-4FT NEARSHORE AND 4-6FT OFFSHORE. DOMINANT WAVE
PDS WILL INCREASE FROM 5-6SEC TO 7-8SEC AS WINDS DIMINISH...THOUGH A
ERLY SWELL WILL ADVECT INTO THE LCL ATLC AND KEEP SEAS ELEVATED.
SCT/NMRS SHRAS AND SCT TSTMS MOVING OFFSHORE MON AFTN.
TUE-FRI...HIGH PRESSURE MOVES EAST OF FLORIDA WITH BROAD TROUGH OF
LOW PRESSURE LINGERING OVER NORTHEAST GULF AND SOUTHEAST FOR MUCH OF
THE PERIOD. THE GENERALLY SOUTHWEST FLOW AND A WEAK PRESSURE
GRADIENT WILL RESULT IN WINDS OF 10 KNOTS OR LESS WITH SEAS 2 TO 3
FEET NEARSHORE AND 3 TO 4 FEET OFFSHORE. THE MAIN HAZARD FOR
MARINERS WILL BE OFFSHORE MOVING THUNDERSTORMS DURING THE
AFTERNOON/EVENING. THE HIGHEST COVERAGE SHOULD BE ON TUESDAY WITH
MORE SCATTERED STORMS AFTER THAT.
&&
.FIRE WEATHER...
TONIGHT-MONDAY...NO WIND/RH CONCERNS. A HIGH PRESSURE RIDGE OVER
PENINSULA WILL INTERACTS WITH A BROAD AND SLOW MOVING STORM SYSTEM
OVER THE DEEP SOUTH TO PRODUCE A DEEP SRLY SFC AND TRANSPORT FLOW
THAT WILL PULL MOISTURE UP FROM THE SE GOMEX/NW CARIB TO KEEP AFTN
RH VALUES ABV CRITICAL LVLS. PGRAD WILL NOT BE TIGHT ENOUGH TO
SUPPORT WINDS MUCH GREATER THAN 10-12MPH...RESULT IN POOR TO FAIR
DISPERSION AND MODERATE TO HIGH LVORI READINGS. CHC AFTN/EVNG TSTMS
THRU MIDNIGHT. SHRAS/TSTMS BCMG LIKELY AFT MIDDAY MONDAY N OF CAPE
CANAVERAL/KISSIMMEE...CHC AFTN/EVNG TSTMS SWD.
TUE-THU...LOW RHS SHOULD BE IN 40 TO 50 PCT RANGE WITH WINDS
GENERALLY 10 MPH OR LESS. ISOLATED TO SCATTERED LIGHTNING STORMS ARE
FORECAST DURING THE AFTERNOON AND EVENING FOR MOST OF THE PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 69 82 66 86 / 40 60 30 50
MCO 69 85 67 90 / 40 60 20 50
MLB 71 81 68 87 / 30 50 30 50
VRB 71 81 67 87 / 30 50 30 50
LEE 69 85 68 89 / 40 60 30 50
SFB 69 85 68 90 / 40 60 30 50
ORL 70 85 69 90 / 40 60 30 50
FPR 69 81 65 87 / 30 50 30 50
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...HAGEMEYER
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1228 PM EDT TUE MAY 15 2012
.SYNOPSIS...
A WEAK FRONTAL BOUNDARY ACROSS THE REGION WILL PROVIDE A FOCUS FOR
SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND THIS EVENING.
THE FRONT WILL SLOWLY PUSH EASTWARD TONIGHT BUT AGAIN PROVIDE
INCREASED CHANCES OF RAIN ACROSS THE EASTERN MIDLANDS ON WEDNESDAY
BEFORE SHIFTING TO THE COAST. SURFACE HIGH PRESSURE WILL BUILD
INTO THE REGION THURSDAY AND PROVIDE DRY WEATHER THROUGH THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A WEAK FRONTAL BOUNDARY AND LEFT OVER OUTFLOW BOUNDARIES WILL
PROVIDE A FOCUS FOR SHOWER AND THUNDERSTORM DEVELOPMENT. SPC HAS
REGION IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS THIS AFTERNOON
AND THIS EVENING. THE LATEST RAP SOUNDING FOR LATE THIS AFTERNOON
CONFIRMS THAT THE ATMOSPHERE SHOULD BE UNSTABLE ENOUGH TO PRODUCE
STRONG TO POTENTIALLY SEVERE STORMS. RAP LIS -5...CAPES OVER 2000
J/KG...TOTALS OVER 50. NAM SOUNDING GIVES CONVECTIVE TEMPERATURES
82-84 DEGREE THIS AFTERNOON. TEMPERATURES NOW RISING ABOVE 80...
SO CONVECTIVE ACTIVITY SHOULD BE ON THE INCREASE OVER THE NEXT
2-3 HOURS. WILL START WITH A SLIGHT CHANCE THIS AFTERNOON...THEN
INCREASE TO 40-50 PERCENT THIS EVENING. LOCAL WRF SHOWS SAME TREND
...LESS COVERAGE IN THE AFTERNOON WITH MOST OF THE COVERAGE BEING
IN THE EVENING HOURS. UPDATED HIGH TEMPERATURES THIS AFTERNOON
WITH MOSTLY LOWER 80S BUT DID INCLUDE SOME MIDDLE 80S IN THE SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
EXPECT LINGERING CONVECTION THIS EVENING ACROSS THE FORECAST AREA
SUPPORTED BY UPPER IMPULSES MOVING THROUGH THE SOUTHWESTERLY FLOW
ALOFT. WILL MAINTAIN HIGH CHANCE POPS EARLY WITH DIMINISHING
CHANCES THROUGH THE OVERNIGHT HOURS AS THE ATMOSPHERE BECOMES MORE
STABLE. EXPECT PLENTY OF CONVECTIVE DEBRIS CLOUDS AND THIS SHOULD
LIMIT THE AMOUNT OF RADIATIONAL COOLING OVERNIGHT. MIN
TEMPERATURES SHOULD REMAIN ABOVE NORMAL IN THE LOWER TO MID 60S.
THE SURFACE BOUNDARY SHIFTS VERY SLOWLY EASTWARD ACROSS THE
FORECAST AREA ON WEDNESDAY AND WILL AGAIN PROVIDE A FOCUS FOR
CONVECTIVE DEVELOPMENT. A WEST TO EAST GRADIENT IN DEEPER MOISTURE
WILL EXIST ACROSS THE REGION ON WEDNESDAY WITH THE BEST MOISTURE
BEING FOCUS CLOSER TO THE COASTAL PLAIN AND EASTERN MIDLANDS. THE
ATMOSPHERE WILL DESTABILIZE WITH DAYTIME HEATING AIDED BY COOLING
500 MB TEMPERATURES (-13C). WILL CONTINUE WITH THE CHANCE FOR
SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS...WITH
THE HIGHEST POPS ACROSS THE EASTERN MIDLANDS WHERE BETTER MOISTURE
IS FORECAST AND IN THE VICINITY OF THE SLOW MOVING SURFACE
BOUNDARY. ISOLATED SEVERE THUNDERSTORMS WILL BE POSSIBLE BUT THE
COVERAGE IS NOT EXPECTED TO BE AS GREAT. TEMPERATURES ON WEDNESDAY
WILL GENERALLY BE IN THE LOWER TO MID 80S.
THE UPPER TROUGH AXIS FINALLY SHIFTS EAST ACROSS THE FORECAST AREA
WEDNESDAY NIGHT AND THURSDAY AND DRIER AIR WILL BUILD IN FROM THE
NORTHWEST AS SURFACE HIGH PRESSURE BUILDS IN BEHIND THE DEPARTED
SURFACE FRONT. DESPITE THE COOLER AND DRIER AIR BUILDING INTO THE
REGION...PLENTY OF SUNSHINE IS EXPECTED THURSDAY WHICH WILL OFFSET
ANY WEAK COLD ADVECTION AND TEMPERATURES SHOULD REMAIN SEASONABLE
IN THE LOWER 80S WITH LITTLE CHANCE OF RAIN.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
MEDIUM RANGE MODELS ARE IN REASONABLE AGREEMENT INDICATING
TROUGHING ALONG THE WEST COAST DURING THE EXTENDED PERIOD WHICH
WILL RESULT IN DOWNSTREAM RIDGING AND RISING UPPER HEIGHTS OVER
THE FORECAST AREA. DRY WEATHER IS EXPECTED THROUGH THIS PERIOD AS
HIGH PRESSURE AT THE SURFACE AND ALOFT PROVIDE A RELATIVELY STABLE
AND DRY ATMOSPHERE. TEMPERATURES DURING THE PERIOD WILL BE NEAR
NORMAL WITH HIGHS IN THE 80S AND LOWS IN THE 50S TO LOWER 60S.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
MORNING SUN HAS HELPED TO BREAK UP THE FOG AND STRATUS. CONDITIONS
WILL BECOME VFR BY LATE MORNING. CONVERGENCE ASSOCIATED WITH THE
SURFACE TROUGH AND ANOTHER MID-LEVEL SHORTWAVE TROUGH PLUS
HEATING SUPPORTS THUNDERSTORMS...ESPECIALLY DURING THE AFTERNOON.
DID NOT INCLUDE THUNDERSTORMS IN THE TERMINAL FORECAST BECAUSE OF
TIMING UNCERTAINTY. STRONG HEATING WITH COLD AIR ALOFT ASSOCIATED
WITH THE UPPER TROUGH WILL RESULT IN MODERATE TO STRONG
INSTABILITY. ANY THUNDERSTORMS MAY CONTAIN STRONG WIND AND HAIL.
EXTENDED AVIATION OUTLOOK...WIDESPREAD MVFR TO IFR CONDITIONS
ASSOCIATED WITH THE SLOW MOVING FRONT MAY OCCUR THROUGH WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
SYNOPSIS...07
NEAR TERM...07
SHORT TERM...
LONG TERM...
AVIATION...07
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
949 AM EDT TUE MAY 15 2012
.SYNOPSIS...
A NEARLY STATIONARY FRONTAL BOUNDARY WILL PROVIDE A FOCUS FOR
SHOWER AND THUNDERSTORM DEVELOPMENT THIS AFTERNOON. THE FRONT WILL
SLOWLY PUSH EASTWARD TONIGHT BUT AGAIN PROVIDE INCREASED CHANCES
OF RAIN ACROSS THE EASTERN MIDLANDS ON WEDNESDAY BEFORE SHIFTING
TO THE COAST. SURFACE HIGH PRESSURE WILL BUILD INTO THE REGION
THURSDAY AND PROVIDE DRY WEATHER THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CONVERGENCE ASSOCIATED WITH THE SURFACE TROUGH AND ANOTHER MID-
LEVEL SHORTWAVE TROUGH PLUS HEATING SUPPORTS SHOWERS AND
THUNDERSTORMS...ESPECIALLY DURING THE AFTERNOON. USED THE HIGHER
GUIDANCE POPS BECAUSE OF THIS SUPPORT. LOW-LEVEL MOISTURE
ASSOCIATED WITH CONVERGENCE INTO THE SURFACE TROUGH WILL REMAIN
HIGH TODAY. UPPER-LEVEL MOISTURE WILL BE A LITTLE LESS COMPARED TO
THE PAST FEW DAYS. EXPECT THE DIMINISHED MOISTURE WILL LEAD TO
MORE HEATING AND INSTABILITY. LATEST RAP SOUNDING SHOWS ATMOSPHERE
BECOMING UNSTABLE LATE THIS AFTERNOON WITH LIS -5...CAPES OVER
2000 J/KG...AND TOTALS OVER 50. OTHER MODELS ALSO SHOW MODERATE
TO STRONG INSTABILITY THIS AFTERNOON. SPC HAS ARE OUTLOOKED IN A
SLIGHT RISK...SO THERE COULD BE POSSIBLY DAMAGING WIND AND HAIL
WITH A FEW OF THE THUNDERSTORMS. USED THE GUIDANCE CONSENSUS FOR
THE TEMPERATURE FORECAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
EXPECT LINGERING CONVECTION THIS EVENING ACROSS THE FORECAST AREA
SUPPORTED BY UPPER IMPULSES MOVING THROUGH THE SOUTHWESTERLY FLOW
ALOFT. WILL MAINTAIN HIGH CHANCE POPS EARLY WITH DIMINISHING
CHANCES THROUGH THE OVERNIGHT HOURS AS THE ATMOSPHERE BECOMES MORE
STABLE. EXPECT PLENTY OF CONVECTIVE DEBRIS CLOUDS AND THIS SHOULD
LIMIT THE AMOUNT OF RADIATIONAL COOLING OVERNIGHT. MIN
TEMPERATURES SHOULD REMAIN ABOVE NORMAL IN THE LOWER TO MID 60S.
THE SURFACE BOUNDARY SHIFTS VERY SLOWLY EASTWARD ACROSS THE
FORECAST AREA ON WEDNESDAY AND WILL AGAIN PROVIDE A FOCUS FOR
CONVECTIVE DEVELOPMENT. A WEST TO EAST GRADIENT IN DEEPER MOISTURE
WILL EXIST ACROSS THE REGION ON WEDNESDAY WITH THE BEST MOISTURE
BEING FOCUS CLOSER TO THE COASTAL PLAIN AND EASTERN MIDLANDS. THE
ATMOSPHERE WILL DESTABILIZE WITH DAYTIME HEATING AIDED BY COOLING
500 MB TEMPERATURES (-13C). WILL CONTINUE WITH THE CHANCE FOR
SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS...WITH
THE HIGHEST POPS ACROSS THE EASTERN MIDLANDS WHERE BETTER MOISTURE
IS FORECAST AND IN THE VICINITY OF THE SLOW MOVING SURFACE
BOUNDARY. ISOLATED SEVERE THUNDERSTORMS WILL BE POSSIBLE BUT THE
COVERAGE IS NOT EXPECTED TO BE AS GREAT. TEMPERATURES ON WEDNESDAY
WILL GENERALLY BE IN THE LOWER TO MID 80S.
THE UPPER TROUGH AXIS FINALLY SHIFTS EAST ACROSS THE FORECAST AREA
WEDNESDAY NIGHT AND THURSDAY AND DRIER AIR WILL BUILD IN FROM THE
NORTHWEST AS SURFACE HIGH PRESSURE BUILDS IN BEHIND THE DEPARTED
SURFACE FRONT. DESPITE THE COOLER AND DRIER AIR BUILDING INTO THE
REGION...PLENTY OF SUNSHINE IS EXPECTED THURSDAY WHICH WILL OFFSET
ANY WEAK COLD ADVECTION AND TEMPERATURES SHOULD REMAIN SEASONABLE
IN THE LOWER 80S WITH LITTLE CHANCE OF RAIN.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
MEDIUM RANGE MODELS ARE IN REASONABLE AGREEMENT INDICATING
TROUGHING ALONG THE WEST COAST DURING THE EXTENDED PERIOD WHICH
WILL RESULT IN DOWNSTREAM RIDGING AND RISING UPPER HEIGHTS OVER
THE FORECAST AREA. DRY WEATHER IS EXPECTED THROUGH THIS PERIOD AS
HIGH PRESSURE AT THE SURFACE AND ALOFT PROVIDE A RELATIVELY STABLE
AND DRY ATMOSPHERE. TEMPERATURES DURING THE PERIOD WILL BE NEAR
NORMAL WITH HIGHS IN THE 80S AND LOWS IN THE 50S TO LOWER 60S.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
MORNING SUN HAS HELPED TO BREAK UP THE FOG AND STRATUS. CONDITIONS
WILL BECOME VFR BY LATE MORNING. CONVERGENCE ASSOCIATED WITH THE
SURFACE TROUGH AND ANOTHER MID-LEVEL SHORTWAVE TROUGH PLUS
HEATING SUPPORTS THUNDERSTORMS...ESPECIALLY DURING THE AFTERNOON.
DID NOT INCLUDE THUNDERSTORMS IN THE TERMINAL FORECAST BECAUSE OF
TIMING UNCERTAINTY. STRONG HEATING WITH COLD AIR ALOFT ASSOCIATED
WITH THE UPPER TROUGH WILL RESULT IN MODERATE TO STRONG
INSTABILITY. ANY THUNDERSTORMS MAY CONTAIN STRONG WIND AND HAIL.
EXTENDED AVIATION OUTLOOK...WIDESPREAD MVFR TO IFR CONDITIONS
ASSOCIATED WITH THE SLOW MOVING FRONT MAY OCCUR THROUGH WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...07
SHORT TERM...
LONG TERM...
AVIATION...07
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
632 AM CDT TUE MAY 15 2012
.AVIATION...
VFR CONDITIONS EXPECTED NEXT 24 HRS. COLD FRONT TO PASS THROUGH
THE TERMINALS BETWEEN 21Z AND 03Z BRINGING SHIFT IN WINDS FROM
W/SW TO N/NW. THERE IS A SMALL CHANCE OF A SHOWER OR THUNDERSTORM
AHEAD OF FRONT... BUT CONSIDERABLE UNCERTAINTY WITH DEVELOPMENT
AS MODELS VERIFYING TOO MOIST WITH SFC DEWPTS. THUS...FAVORING
A DRY FRONTAL PASSAGE AS DEPICTED BY RECENT RAP AND HRRR MODEL
RUNS GIVEN DEEP MIXING AND GUSTY SOUTHWEST WINDS 10-20+ KTS PRE-
FRONTAL DRYING OUT THE LOW LEVELS.
&&
.PREV DISCUSSION... /ISSUED 353 AM CDT TUE MAY 15 2012/
SYNOPSIS...
RATHER VIGOROUS COMPACT SHORTWAVE DIVING E/SE INTO WRN ONTARIO
PROVINCE AND NRN MN EARLY THIS AM. ATTENDANT WEAK SFC LOW WAS
LOCATED OVER THE ARROWHEAD OF MN WITH COLD FRONT TRAILING SWWD
THROUGH SD. LIMITED MOISTURE WITH FRONT WITH SFC DEWPTS IN THE
30S AND 40S... AND PRECIPITABLE WATER VALUES AROUND 0.5 INCH
OR LESS OVER THE UPPER MIDWEST.
SHORT TERM...TODAY AND TONIGHT...
MAIN FCST CONCERN IS PCPN CHCS AND SEVERE POTENTIAL WITH FRONT
THIS AFTN/EVE.
SHORTWAVE OVER NRN MN AND WESTERN ONTARIO AND ATTENDANT 100 KT
H3 JET WILL SLIDE S/E THROUGH GREAT LAKES TDY... WITH
CWA GENERALLY S/W OF MAIN FORCING IN FORM OF LEFT EXIT REGION
OF JET AND POSITIVE VORTICITY ADVECTION. COLD FRONT IS
EXPECTED TO MOVE INTO NORTHERN CWA BY MID AFTN AND CONTINUE
SLIDING S/E EXITING THE SOUTHERN CWA BY LATE EVE. MODELS INSIST
ON INCREASING SFC DEWPTS INTO THE MID/UPPER 50S AHEAD OF THE
FRONT WITH LAYER PRECIPITABLE WATER VALUES CLIMBING TO AROUND
1 INCH. BELIEVE THIS IS AGGRESSIVE GIVEN RECENT DRY STRETCH
COUPLED WITH GUSTY SW WINDS AND DEEP MIXING... AND VEERING H85
WINDS TO WESTERLY. ADJUSTING SFC DEWPTS INTO THE 40S TO
POSSIBLY LOWER 50S YIELDS MLCAPE GENERALLY ON THE ORDER OF 750-
1100 J/KG OR SO. WEAK SFC CONVERGENCE AND CONVECTIVE TEMPS
(83-86F) BREACHED SHOULD BE SUFFICIENT TO GENERATE AT LEAST
WIDELY SCT CONVECTION BY MID AFTN AHEAD OF THE FRONT SLIDING E/SE
INTO EVE. 0-6 KM BULK SHEAR OF 30-35 KTS AND STEEP MID LEVEL
LAPSE RATES COUPLED WITH DRY AIR WILL SUPPORT HAIL RISK WITH
LOCAL CALCULATIONS FOR KCID AT 21Z BASED ON T/TD OF 85/46F
SUGGESTS HAIL POTENTIAL AROUND 1.25 INCH IN DIAMETER. LARGE DEWPT
DEPRESSIONS SFC TO CLOUD BASE WITH INVERTED V TYPE SOUNDINGS
WOULD ALSO SUPPORT STRONG GUSTY WINDS. SO... BOTTOM LINE ANTICIPATE
ISOLD-SCT BKN LINE OF CONVECTION FIRING AHEAD OF FRONT AND
SLIDING S/E BETWEEN ROUGHLY 20Z-03Z... WITH ISOLD SEVERE THREAT IN
FORM OF OF LARGE HAIL AND DAMAGING WINDS. SEVERE RISK SUBJECT TO
CHANGE DEPENDING ON LOW LEVEL MOISTURE WITH SIGNFICANT IMPACT ON
THERMODYNAMICS. DEEP MIXING AOA 700 MB WITH GUSTY PRE-FRONTAL
COMPRESSIONAL HEATING SHOULD RESULT IN WIDESPREAD HIGHS IN MID 80S
WITH SOME UPPER 80S ESPECIALLY IN CORRIDOR FROM NEAR KDBQ AND KCID
TO KBRL WITHIN LOW LEVEL THERMAL RIDGE. FRONT TO BE SOUTH OF THE
CWA BY 03Z-06Z WITH CLEARING AND NORTH WINDS USHERING IN COOLER AND
DRIER AIR... WITH COOLEST LOWS NORTH (46-49F) AND WARMEST FAR SOUTH
(52-55F). ..05..
LONG TERM...WEDNESDAY THROUGH NEXT MONDAY...
WEDNESDAY...LATEST 00Z MODEL RUNS CONTINUE TO ADVERTISE THE IDEA OF
A BACKDOOR TYPE HIGH PRESSURE SYSTEM BUILDING DOWN THE WESTERN GRT
LKS EFFECTIVELY SHUNTING SFC BOUNDARY DOWN THROUGH THE MID/LOWER MS
RVR VALLEY...AS UPPER RIDGING AMPLIFIES ACRS THE NORTHERN PLAINS. THE
LATEST RUNS NOT AS ROBUST WITH STRENGTH AND DEPTH OF INCOMING POST-
FRONTAL NORTHEASTERN FETCH BUT STILL ENOUGH COOL AIR ADVECTION TO
HOLD DOWN TEMPS WELL IN THE 70S FOR WED HIGHS. SOME UPPER 60S EVEN
POSSIBLE IN NORTHWESTERN IL. WED NIGHT...LATEST INDICATIONS STILL
SUGGEST NOCTURNAL MCS GENERATION PARAMETERS INCLUDING A SOUTHERLY 50+
KT LLJ COME TOGETHER ACRS THE NORTHERN PLAINS AND THEN FEED ANY
RESULTANT CONVECTIVE SYSTEM EASTWARD ACRS THE EASTERN DAKOTAS...MN
AND WI INTO THU MORNING. THUS IT APPEARS LOW CHANCE OF ANY CONVECTION
MAKING IT INTO THE NORTHERN CWA BY THU MORNING AND WILL REMOVE
MENTIONABLE POPS. WED NIGHT RELATIVELY COOL IN THE LOWER 50S TO MID
40S BEFORE RETURN FLOW INCREASES TOWARD THU MORNING.
THURSDAY AND FRIDAY...00Z RUN MEDIUM RANGE SOLUTIONS INCLUDING THE
NEW GFS AND ECMWF GENERALLY AGREE THAT WARM FRONTAL RETREAT PROCESS
WILL COMBINE WITH RIDGE-RIDING VORT MAX/S FOR MCS GENERATION OR
REGENERATION THIS PERIOD MAINLY UP ACRS THE NORTHWESTERN HIGH
PLAINS...EASTWARD ACRS MN...WI AND INTO THE GRT LKS. THE DVN CWA
STILL LOOKS TO BE MAINLY SOUTH OF THESE CONVECTIVELY ACTION ZONES AND
INCREASINGLY IN THE WARM SECTOR WITH FRI HIGHS WELL UP IN THE 80S.
WILL IGNORE THE 00Z GFS SPURIOUS CONVECTIVE DEVELOPMENT RIGHT ACRS
THE DVN CWA FRI AFTERNOON AS CAPPING INVERSION WILL BE ON THE
INCREASE.
SATURDAY THROUGH MONDAY...LONGER RANGE TRENDS CONTINUING TO SUGGEST
EASTERN PACIFIC UPPER JET ENERGY AND INLAND PROPAGATING UPPER WAVES
WILL COMBINE TO PUMMEL OUT A L/W COMPLEX ACRS THE WESTERN ROCKIES BY
THE WEEKEND. IF THIS PROCESS UNFOLDS AS CURRENTLY INDICATED BY THE
FAVORED ECMWF AND UKMET SOLUTIONS...RESULTANT AMPLIFIED LEE SIDE
UPPER RIDGE WOULD MEAN A VERY WARM AND DRY SAT AND SAT NIGHT FOR THE
LOCAL FCST AREA WITH SAT HIGHS IN THE UPPER 80S. LOOKING AT UPPER
JET PROJECTILE PATHS...A LARGE PIECE OF THE WESTERN UPPER TROF WILL
HAVE TO EVENTUALLY PUSH ACRS THE UPPER MIDWEST AND PREFER THE SLOWER
ECMWF SOLUTION OF SHUNTING AN ASSOCIATED SFC FRONT TOWARD THE AREA
SOMETIME LATE SUNDAY NIGHT OR MONDAY MORNING. WITH ANY KIND OF
MOISTURE RETURN OFF THE WESTERN GULF/ALTHOUGH LATEST SOLUTIONS ARE
NOW MARGINAL WITH THIS PROCESS/...THERE WILL BE AN INCREASING
CHANCE OF SHOWERS AND STORMS FROM THE WEST WITH THE HIGHER POP WINDOW
APPEARING TO BE LATE SUNDAY...SUNDAY NIGHT AND LINGERING INTO MONDAY
MORNING IN POST-FRONTAL FORM BY THEN. TIMING AN HANDLING OF THIS
FEATURE AS WELL AS PHASING WITH THE BROAD SCALE FORCING STILL
SOMEWHAT UNCERTAIN AND DIFFICULT TO BETTER TO DEFINE AT THIS POINT.
ANY SLOW DOWN OF THESE PROCESSES WOULD MEAN A ANOTHER UNSEASONABLY
WARM AND MAINLY DRY DAY ON SUNDAY AND A STORMY MONDAY. THIS IS WHAT
THE 00Z ECMWF IS ADVERTISING WHILE THE MORE PROGRESSIVE GFS TARGETS
THE MAIN CONVECTIVE EVENT ON SUNDAY. LATEST AO/NAO PROGS SUGGEST A
DECENT COOL DOWN ACRS THE UPPER MIDWEST/WESTERN GRT LKS EARLY NEXT
WEEK BEHIND THE PASSING UPPER TROF. ..12..
AVIATION... /ISSUED 1158 PM CDT MON MAY 14 2012/
HIGH PRESSURE SOUTHEAST OF THE REGION WILL CONTINUE THE VFR
CONDITIONS WITH CLEAR SKIES AND LIGHT WEST WINDS THROUGH TUESDAY
AFTERNOON. TUESDAY MORNING WINDS WILL INCREASE OUT OF THE
SOUTHWEST AT 10 TO 20KTS WITH GUSTS. THERE IS A CHANCE OF
THUNDERSTORMS AFTER 21Z AS A COLD FRONT SLOWLY DROPS INTO THE
REGION. COVERAGE AND PROBABILITY IS STILL SOMEWHAT LOW...AS THERE
MAY BE MORE DRY AIR WHICH WOULD ACT TO SUPPRESS STORMS. FOR
NOW...HAVE PUT IN SOME VCSH TO KCID...KDBQ AND KMLI AS THESE WILL
BE CLOSEST TO THE FRONT AT THE TIMES WHEN IT IS MOST LIKELY TO
PRODUCE ANYTHING CONVECTIVE. THE REDUCED LOW LEVEL MOISTURE MAY DO
NO MORE THAN REDUCE STORM COVERAGE AND KEEP STORMS THAT DO FORM
RELATIVELY WEAK...SO HAVE GONE WITH JUST THE SHOWERS FOR NOW.
LATER FORECASTS WILL HAVE TO REFINE FURTHER. FOR NOW HAVE JUST VFR
CONDITIONS THOUGH ANY STORMS MAY HAVE MVFR CIGS AND VSBYS. LE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
320 PM EDT SUN MAY 13 2012
.SYNOPSIS...
LOW PRESSURE APPROACHING FROM THE SOUTHWEST WILL BRING RAIN TO
MOST OF THE AREA THROUGH TONIGHT. THE LOW WILL CONTINUE TO BRING
SHOWERS TO THE UPPER OHIO VALLEY THROUGH TUESDAY AS IT PASSES JUST
EAST OF THE AREA.
&&
.NEAR TERM /THROUGH MONDAY/...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A BROAD TROUGH ACROSS
THE OHIO VALLEY. 850-750MB LAYER VORT ENERGY IS MOVING ACROSS
OHIO AND HELPING TO PROVIDE FORCING FOR RAIN WITH AN INVERTED
SURFACE TROUGH APPROACHING THE AREA FROM THE TENNESSEE VALLEY. THUS,
A BROAD AREA OF RAIN ACROSS EASTERN OHIO IS BEGINNING TO PUSH INTO
NORTHERN WV AND SOUTHWESTERN PA.
THERE IS MODEL AGREEMENT THAT FAIRLY WIDESPREAD SHOWERS WILL
CONTINUE ACROSS THE AREA TONIGHT AS THE INVERTED TROUGH MOVES INTO
THE AREA AHEAD OF A LOW COMING FROM THE SOUTHWEST AND A MID-LEVEL
TROUGH APPROACHES FROM THE WEST. OVERNIGHT LOWS ARE CLOSE TO MET
GUIDANCE, IN THE LOWER 50S ACROSS MUCH OF THE AREA.
ADDITIONAL RAINFALL TONIGHT WILL RANGE FROM A QUARTER OF AN INCH
TO A HALF OF AN INCH SOUTHEAST OF PITTSBURGH TO A TENTH TO A
QUARTER OF AN INCH TO THE NORTHWEST.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
GFS/ECMWF ARE IN AGREEMENT THAT THE MID-LEVEL TROUGH WILL MOVE
SLOWLY ACROSS THE OHIO VALLEY MONDAY INTO TUESDAY. THE MORE
AMPLIFIED NAM IS CONSIDERED TO BE AN OUTLIER AT THIS TIME. WITH THE
BROAD SURFACE LOW MOVING UP THE SPINE OF THE APPALACHIANS, ITS
ASSOCIATED INVERTED TROUGH WILL CONTINUE TO BE THE FOCUS OF
SHOWERS IN THE UPPER OHIO VALLEY ON MONDAY. LIKELY POPS ARE
FORECAST ACROSS THE RIDGES AS A VORT ENERGY IS PROGGED TO MOVE ACROSS
THESE AREAS ON MONDAY. ELSEWHERE, CHANCE POPS ARE FORECAST ON
MONDAY AHEAD OF THE TROUGH. SYNOPTIC FORCING WITH THE MID-LEVEL
TROUGH AXIS CROSSING THE AREA AND THE SURFACE LOW PASSING JUST EAST
WILL MAINTAIN THE CHANCE OF SHOWERS ACROSS THE AREA ON TUESDAY.
WITH WEAK INSTABILITY ON TUESDAY, A SCHC OF THUNDER IS MENTIONED.
WEAK HIGH PRESSURE WILL BUILD IN FROM THE SOUTHWEST ON WEDNESDAY AS
THE MID-LEVEL TROUGH MOVES EAST OF THE AREA. A FRONTAL BOUNDARY WILL
SLIDE SOUTHEASTWARD INTO THE AREA LATE IN THE DAY. MOISTURE WITH THE
FRONTAL BOUNDARY APPEARS TO BE LIMITED, SO JUST SCHC POPS ARE
FORECAST FOR PORTIONS OF THE AREA.
TEMPERATURES WILL MODERATE EACH DAY AS CLOUD COVERAGE DECREASES EACH
DAY AND 850 TEMPS WARM SLIGHTLY. HIGHS WILL BE NEAR NORMALS SEASONAL
VALUES MONDAY, WARMING TO AROUND 5 DEGREES ABOVE NORMAL BY
WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
A WEAK FRONT WILL PUSH SOUTH OF THE REGION WEDNESDAY NIGHT AS HIGH
PRESSURE MOVES INTO THE UPPER OHIO VALLEY. MAINTAINED DRY AND MILD
FORECAST THROUGH THE EXTENDED BUT A COUPLE OF DIFFERENT FACTORS MAY
LEAD TO CHANGES IN LATER PACKAGES. FIRST IS A BACK DOOR COLD FRONT
SINKING ACROSS GREAT LAKES AND NEW ENGLAND FRIDAY AND SATURDAY.
MODELS FOR THE MOST PART KEEP SYSTEM NORTH OF UPPER OHIO VALLEY BUT
ANY FURTHER SOUTHWARD TREND IN MODELS WOULD BRING SHOWER CHANCES TO
THE NORTHERN TIER. ALSO LATE IN PERIOD EVOLUTION OF TROUGH IN THE
EAST AND PLACEMENT OF COASTAL SYSTEM OFF THE CAROLINAS HEADING NORTH
FOR THE WEEKEND WILL NEED TO BE MONITORED. FOR NOW CLOSELY FOLLOWED
HPC SOLUTION.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
AS LOW PRESSURE MOVES NORTHEAST FROM THE MISSISSIPPI VALLEY LIGHT
RAIN WILL CONTINUE TO SPREAD ACROSS REGION GENERALLY SOUTH OF I-80
WITH VFR CIGS AND VSBY GRADUALLY DECLINING TO MVFR LATE AFTERNOON
AND IFR CIGS EXCEPT FOR KFKL AND KDUJ WHICH SHOULD FALL TO IFR
TOWARD DAYBREAK. GENERAL IFR CIGS AND MVFR VSBY INTO EARLY AFTERNOON
MONDAY SHOULD IMPROVE TO MFVR IN THE AFTERNOON AS THE SURFACE LOW
EXITS EAST. WINDS WILL REMAIN LIGHT AND VARIABLE.
.OUTLOOK...MONDAY NIGHT THROUGH FRIDAY...
GENERAL VFR MONDAY NIGHT THROUGH FRIDAY. A WEAK FRONT MAY BRING
SCATTERED SHOWERS WITH POSSIBLE MVFR WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
148 PM EDT TUE MAY 15 2012
.SYNOPSIS...
ISSUED AT 301 AM EDT TUE MAY 15 2012
LOW PRESSURE WILL PASS NORTH OF LAKE SUPERIOR AND LAKE HURON TODAY
AND TONIGHT. THIS SYSTEM WILL PUSH A COLD FRONT ACROSS THE REGION
TONIGHT. OUR FIRE DANGER WILL REMAIN QUITE ELEVATED UNTIL THE FRONT
PASSES. IN ADDITION...SHOWERS AND A FEW THUNDERSTORMS ARE
POSSIBLE...ESPECIALLY AS THE FRONT GOES THROUGH. AFTER A WARM DAY
TODAY...MUCH COOLER WEATHER IS EXPECTED WEDNESDAY AND
THURSDAY...INCLUDING POTENTIAL FROST ON WEDNESDAY NIGHT. MUCH WARMER
WEATHER WILL ARRIVE FOR THE WEEKEND.
&&
.UPDATE...
ISSUED AT 148 PM EDT TUE MAY 15 2012
AFTERNOON DEW POINT/INSTABILITY UPDATE: DEW POINTS STILL STRUGGLE
TO CLIMB OUT OF THE 30S ACROSS MUCH OF NORTH CENTRAL/NORTHEAST
LOWER...WITH LOWER-MID 40S ACROSS SOUTHWEST QUARTER OF THE
FORECAST AREA. OBJECTIVE ANALYSES SUGGESTS 300-500J/KG MLCAPE WEST
OF I-75 IN NORTHERN LOWER WITH >50J/KG MLCINH...CORRIDOR OF
500-750J/KG MLCAPE ACROSS CENTRAL/WESTERN UPPER AND EASTERN
WISCONSIN AHEAD OF APPROACHING COLD FRONT...GETTING SOME SCATTERED
CONVECTION TO POP OVER CENTRAL UPPER ALONG THE FRONT AND CLOSER TO
UPPER VORTICITY CENTER. NOT SURE IF THIS WILL MAKE IT INTO EASTERN
UPPER WHERE INSTABILITY IS MINIMAL AS OF NOW. WILL CONTINUE TO
MONITOR...BUT LIKELY STILL SEVERAL HOURS OFF BEFORE ANYTHING
EXCITING HAPPENS OVER NORTHERN MICHIGAN.
UPDATE ISSUED AT 1054 AM EDT TUE MAY 15 2012
12Z SURFACE ANALYSIS SHOWS 1004MB LOW OVER WESTERN LAKE SUPERIOR
WITH A TRAILING COLD FRONT INTO NORTHWEST WISCONSIN/FAR SOUTHEAST
MINNESOTA. ASSOCIATED MID LEVEL SHORT WAVE TROUGH DIGGING SOUTHEAST
OUT OF NORTHWEST ONTARIO...FORCING AHEAD OF THIS WAVE PRODUCING SOME
AC/ACCAS AND SCATTERED LIGHT SHOWERS ACROSS EASTERN UPPER/FAR
NORTHERN LOWER. 12Z APX SOUNDING HAD A RESIDUAL MIXED LAYER FROM
JUST OFF THE DECK TO 700MB...MEAN MIXING RATIO WITHIN THIS LAYER
AROUND 4G/KG WITH DEW POINT DEPRESSIONS OF 14C 850MB/17C 925MB.
SHOULD BE A VERY INTERESTING AFTERNOON AS DIFFERENCES IN GUIDANCE
DEW POINT FORECASTS AND RESULTANT INSTABILITY FORECASTS HAVE SPARKED
A NICE INTRA-OFFICE DISCUSSION/DEBATE. FIRST OFF...THE OLD "BRAIN
MODEL" ADJUSTED APX SOUNDING BASED ON MIXING TO 700MB AND INCREASING
MEAN 925-850MB MIXING RATIOS INTO THE 5-6 G/KG RANGE BASED ON
UPSTREAM SOUNDINGS YIELDS A PARCEL OF 76/45 AND AN MLCAPE VALUE IN
THE VICINITY OF 500J/KG. SO IT WON`T TAKE MUCH ADDITIONAL MOISTURE
(LOWER-MID 40S DEW POINTS) TO GENERATE ENOUGH HIGH BASED CAPE TO GIN
UP SOME CONVECTION AHEAD OF COLD FRONT WHICH IS NOT EXPECTED TO
ARRIVE UNTIL THE 19-21Z TIME FRAME. LATEST RAP FORECASTS HOLDING
DEW POINTS DOWN IN THE 30S THROUGH THE AFTERNOON...PROBABLY A BIT
TOO LOW. NAM-WRF HOWEVER PUSHES DEW POINTS INTO THE LOWER-MID
50S...AND RESULTS IN FORECAST MLCAPE VALUES OVER 1500J/KG...A BIG
DIFFERENCE FROM 500J/KG WITH REGARD TO CONVECTIVE EVOLUTION/SEVERE
WEATHER POTENTIAL. GIVEN THE RATHER UNIFORM LOW LEVEL MOISTURE
PROFILES ON UPSTREAM SOUNDINGS...THINK SUSTAINED DEW POINTS IN THE
50S WILL BE HARD TO COME BY. BUT THAT WILL BE THE THING TO WATCH
FOR THE AFTERNOON...IF DEW POINTS CAN CLIMB INTO THE 50S AND STAY
THERE (SUGGEST A CERTAIN AMOUNT OF "DEPTH" TO THE LOW LEVEL MOIST
LAYER) THEN WE WILL HAVE SOME ISSUES. AS IT STANDS...GIVEN STEEP
LOW LEVEL LAPSE RATES AND DRY SUB-CLOUD LAYER DAMAGING WIND GUSTS
WOULD BE THE PRIMARY THREAT WITH ANY CONVECTION THAT DEVELOPS
(ORGANIZED OR NOT)...MORE INSTABILITY WOULD INCREASE THE THREAT FOR
HAIL AS WELL AS STRONGER WIND GUSTS. SHOULD HAVE A PRETTY GOOD
IDEA BY 18-19Z WHERE WE STAND WITH THIS...WILL ELABORATE MORE IN
EARLY AFTERNOON UPDATE.
UPDATE ISSUED AT 630 AM EDT TUE MAY 15 2012
HAVE UPDATED GRIDS TO ADJUST MORNING POPS. AREA RADARS ARE STILL
RUNNING HOT THANKS TO DRY AIR DOWN LOW...BUT GIVEN TRENDS HAVE
PUSHED POPS A BIT HIGHER...AND HAVE EXTENDED AT LEAST A SLIGHT
CHANCE FOR A SPRINKLE/SHRA INTO PART OF FAR NORTHERN LOWER MI.
AM ALSO TRYING TO FINE-TUNE PRECIP EXPECTATIONS FOR THIS
AFTERNOON/EVENING. ALL THE HIGH RESOLUTION OUTPUT I CAN FIND
(INCLUDING VARIOUS NMM/ARW OUTPUT) SUPPORT CONVECTION KICKING OFF
IN CENTRAL AND ESPECIALLY SOUTHERN SECTIONS...MAINLY BETWEEN 21Z
AND 03Z (A FEW GO SOMEWHAT EARLIER). THIS OCCURS AS THE 500MB TROF
DIGS/DEEPENS ACROSS SUPERIOR AND UPPER MI...WITH 500MB TEMPS
LOWERING TO -20C OVER NORTHERN LOWER...AND 700-500MB LAPSE RATES
INCREASING TO NEAR 8.5C/KM. CAN WE SUSTAIN SURFACE DEW POINTS TO
INITIATE DEEP CONVECTION? WE/LL BE ADVECTING IN LOW/MID 40S FROM
SOUTHERN WI/EASTERN IOWA...BUT WE/VE SEEN OUR TREMENDOUS ABILITY
TO MIX THAT OUT ON MULTIPLE OCCASIONS OVER THE LAST WEEK.
STILL...THEY ARE NOT MANY SIGNALS THAT SAY THAT NOTHING IS GOING
TO HAPPEN.
AM GOING TO KICK POPS UP TO LOW-END LIKELY IN SOUTHERN SECTIONS
LATE AFTERNOON/EARLY EVENING. (THIS LINES UP BETTER WITH OUR
SOUTHERN NEIGHBORS.) WILL ALSO UPDATE HWO TO MENTION AN ISOLATED
SVR WIND GUST POSSIBLE. NEITHER MLCAPE (500-700J/KG) NOR 0-6KM
BULK SHEAR (20-25KT) ARE IMPRESSIVE. BUT SIMPLY THE AMOUNT OF DRY
AIR SUPPORTS CONSIDERABLE EVAP COOLING POTENTIAL WITHIN
DOWNDRAFTS. STORMS WILL NOT BE WELL ORGANIZED...DOWNDRAFT AIR/COLD
POOLS ARE GOING TO OVERWHELM INSTABILITY ON THE STORM SCALE VERY
QUICKLY. NOTE THAT THIS THINKING LINES UP WITH THE SPC DAY 1
OUTLOOK...WHICH HAS A SLIGHT RISK ESSENTIALLY ON OUR SOUTHERN
DOORSTEP.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 301 AM EDT TUE MAY 15 2012
TODAY...THERE ARE A HOST OF ISSUES TO TACKLE TODAY AND THEY ARE
SOMEWHAT INTERRELATED. FIRST OFF, THE RAIN SHOWERS THAT ARE MAKING
THEIR WAY THROUGH UPPER MICHIGAN ARE FAIRLY LIGHT AND ALIGNED
ALONG THE WARM FRONT THAT IS OUT AHEAD OF THE SFC LOW HEADING INTO
WESTERN LAKE SUPERIOR. HOWEVER, THE 00Z SOUNDINGS AT INL AND MPX,
LOOK A LOT LIKE OUR 00Z SOUNDING, THAT IS VERY DRY AND WARM. SO
AGREE WITH THE MODEL SOUNDINGS THAT THE LOWER LEVELS OF THE
SOUNDINGS WILL SHOW SIGNIFICANT DRY AIR. AS THE FRONT MOVES
THROUGH THE REGION AND THE SFC LOW WITH IT, THERE WILL BE SOME
RAIN SHOWERS AND THUNDER. HOWEVER, WITH SOME MUCH DRY AIR, IT
DOESN`T LOOK LIKE MUCH WILL HIT THE GROUND A THE WARMER AIR MOVES
INTO THE REGION. THE MODELS SHOW THAT THE LARGEST AREA OF
CONVECTION WILL PROBABLY BE ON THE EAST SIDE OF THE STATE IN THE
AFTERNOON AS THE 500 MB SHORTWAVE AND THE COLD FRONT BEGIN TO
MARCH ACROSS THE REGION. WINDS PICK UP AHEAD OF THE FRONT WITH THE
SUSTAINED WINDS AROUND 15 MPH. IF THE SOUNDINGS FROM THE UPSTREAM
AREAS ARE ANYTHING TO TAKE INTO ACCOUNT, THEN WE ARE EXPECTING
THAT THE RH IN THE AFTERNOON WILL BE AROUND 20% PRIOR TO THE
FROPA. WHILE THUNDER IS POSSIBLE, AND WITH THE DRY AIR IN THE
LOWER LEVELS EXPECTED, THIS COULD BE A RARE SET UP FOR SOME DRY
LIGHTNING ACTIVITY. TEMPERATURES ARE GOING TO MAKE A RUN AT 80F IN
NE LOWER AS WELL WITH THE 850 MB TEMPERATURES SPIKING TO AROUND
13C ON BOTH THE ECMWF AND THE GFS. SO WITH THE WARM TEMPS, DRY RH,
AND WINDS, THERE WILL BE A RED FLAG WARNING ISSUED WITH THE FIRE
WEATHER PACKAGE COMING UP.
TONIGHT...ANY RAIN THAT GETS STARTED IN THE AFTERNOON WILL BE ON
THE WAY OUT AS BOTH MODELS START TO PUSH THIS SYSTEM RAPIDLY TO
THE EAST. ONCE THE FRONT GOES THROUGH THE RED FLAG WARNING WILL
EXPIRE (AROUND 01Z) WITH TEMPERATURES COOLING, BU THE WINDS WILL
SWITCH TO THE NORTHWEST AND RAMP BACK UP, INITIALLY, IT WILL TAKE
SOME TIME TO RECOVER THE RH, BUT BY 03 OR 04Z, THE TEMPERATURES
SHOULD HAVE COOLED ENOUGH FOR THE RH TO RECOVER OVERNIGHT. ALL THE
RAIN SHOULD BE OUT OF THE REGION BY 06Z. THE REST OF THE OVERNIGHT
SHOULD BE DRY.
WEDNESDAY...MODELS REMAINED CONSISTENT FOR THE DAY WITH THE SFC
HIGH BUILT INTO THE REGION. IT LOOKS LIKE THERE COULD BE SOME
RAIN SHOWERS NORTHEAST OF ANJ AS THE ECMWF DIGS ANOTHER 500 MB
SHORTWAVE INTO THE AREA NE OF ANJ, HOWEVER, FOR THE FORECAST AREA,
THE DAY SHOULD BE DRY, WITH THE HIGH BUILDING INTO THE AREA. WILL
HAVE TO WATCH FOR SOME ELEVATED FIRE ISSUES, WITH THE LOW SFC RH,
AND THE WINDS, NEAR LAKE HURON, OUT OF THE NW AT 10-15 MPH.
FARTHER WEST NOT AS FAST.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 301 AM EDT TUE MAY 15 2012
SUMMER WILL ASSERT ITSELF THIS WEEKEND...BUT ONLY TEMPORARILY. THE
UPPER TROF THAT STARTS IN THE EASTERN LAKES WED EVENING...WILL EJECT
TO EASTERN CANADA BY FRIDAY. THAT WILL ALLOW RIDGING TO PROGRESS
INTO THE MS VALLEY AND CENTRAL CANADA...AND OUR TEMPS WILL WARM IN
RESPONSE. HOWEVER...WE MAY HAVE SOME ACTIVE WX TO PASS THRU IN ORDER
TO GET THE WARM AIR HERE.
WED NIGHT/THURSDAY...HIGH PRESSURE WILL BE OVERHEAD WED NIGHT.
THOUGH SOME WARM ADVECTION MID/HIGH CLOUDS COULD ARRIVE FROM THE
WEST LATE AT NIGHT...SKIES WILL BE CLEAR ENOUGH LONG ENOUGH TO
READILY DECOUPLE. TEMPS WILL PLUNGE AS A RESULT...AND A FROSTY NIGHT
APPEARS INEVITABLE IN SPOTS. GUIDANCE TEMPS ARE MAINLY IN THE
30S...WITH SOME UPPER 20S IN THE USUAL COLD SPOTS. TEMPS COULD WELL
GO A FEW DEGREES COLDER THAN THIS. WILL CONTINUE TO ADVERTISE FROST
POTENTIAL IN BOTH PENINSULAS IN THE HWO (NOTE THAT WE BEGAN THE
FROST/FREEZE SEASON IN EASTERN UPPER MI YESTERDAY).
THURSDAY IS LOOKING INCREASINGLY LIKE IT WILL BE DRY. THERE/S A NICE
SURGE OF WARM ADVECTION OFF THE DECK...AS SURFACE HIGH PRESSURE
MOVES TO THE EASTERN LAKES. A SLOW-MOVING WARM FRONT WILL GRADUALLY
EXTEND EASTWARD ACROSS UPPER MI. BUT WARM ADVECTION PROGGED TO
GENERALLY BE STRONGER WITH HEIGHT...THUS THE AIRMASS IS TENDING TO
BECOME MORE STABLE WITH TIME. MID AND UPPER LEVEL MOISTURE BECOMES
PLENTIFUL DURING THE DAY (ABOVE 700MB)...BUT THE LOW LEVELS ARE
RELATIVELY DRY (BELOW 800MB). WILL HANG INTO POPS IN EASTERN
UPPER...WHERE ASCENT IS SOMEWHAT STRONGER AND WHERE THE WARM FRONT
TRIES TO POKE IN DURING THE DAY...BUT EVEN THERE GUIDANCE POPS ARE
IN THE SINGLE DIGITS TO LOWER TEENS. WE/LL SEE. THEY ARE EVEN LESS
IN NORTHERN LOWER...AND POPS WILL BE REMOVED THERE. CLOUDS WILL KEEP
MAX TEMPS IN THE 60S TO LOWER 70S.
REST OF THE FORECAST...NAM/GFS ARE IN REASONABLE AGREEMENT THAT
WE/LL SEE A BETTER (THOUGH NOT GREAT) CHANCE OF RAIN THU NIGHT...AS
THE LOW LEVEL JET DEVELOPS AND WARM/MOIST INFLOW INCREASES. BOTH
MODELS SUGGEST CENTRAL/NORTHERN PORTIONS OF THE FORECAST AREA HAVE
THE BEST CHANCE FOR RAIN. POSSIBILITY EXISTS FOR ONE MORE ROUND
DURING THE DAY ON FRIDAY (AGAIN ESPECIALLY NORTHERN SECTIONS)...
BEFORE THE WARM FRONT MORE EMPHATICALLY LIFTS TO OUR NORTH AND WE
BECOME MORE ENTRENCHED IN THE WARM SECTOR. THAT LEAVES SATURDAY DRY
AND TOASTY. STILL TOASTY SUNDAY...BUT HEIGHT FALLS BEGIN AND A COLD
FRONT IS INBOUND SUNDAY NIGHT. SO PRECIP CHANCES SUNDAY-MONDAY...
WITH MUCH COOLER TEMPS MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 141 PM EDT TUE MAY 15 2012
VFR CONDITIONS AND GUSTY NORTHWEST WINDS EXPECTED THIS AFTERNOON...
WILL WATCH POTENTIAL CONVECTIVE THREAT THROUGH THE AFTERNOON.
WINDS SHIFT TO NORTHWEST BEHIND COLD FRONT THIS EVENING...POSSIBLE
PERIOD OF MVFR CEILINGS AT PLN/APN OVERNIGHT.
&&
.MARINE...
ISSUED AT 301 AM EDT TUE MAY 15 2012
THROUGH THE FORECAST PERIOD, DESPITE THE RAMP UP OF THE WIND TODAY
PRE AND POST FRONTAL WINDS AND WAVES TODAY, TONIGHT, AND WEDNESDAY
WILL REMAIN BELOW SMALL CRAFT CRITERIA, ALTHOUGH CAN`T COUNT OUT A
HIGHER GUST ALONG NEAR THE LAND/WATER INTERFACE. ONCE THE HIGH
BUILDS BACK INTO THE REGION ON WEDNESDAY AFTERNOON, WINDS WILL
SLACKEN AND WAVES WILL SUBSIDE FOR WEDNESDAY NIGHT.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...RED FLAG WARNING UNTIL 9 PM EDT THIS EVENING FOR MIZ016>036-041-
042.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JPB
SYNOPSIS...JZ
SHORT TERM...JL
LONG TERM...JZ
MARINE...JL
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1055 AM EDT TUE MAY 15 2012
.SYNOPSIS...
ISSUED AT 301 AM EDT TUE MAY 15 2012
LOW PRESSURE WILL PASS NORTH OF LAKE SUPERIOR AND LAKE HURON TODAY
AND TONIGHT. THIS SYSTEM WILL PUSH A COLD FRONT ACROSS THE REGION
TONIGHT. OUR FIRE DANGER WILL REMAIN QUITE ELEVATED UNTIL THE FRONT
PASSES. IN ADDITION...SHOWERS AND A FEW THUNDERSTORMS ARE
POSSIBLE...ESPECIALLY AS THE FRONT GOES THROUGH. AFTER A WARM DAY
TODAY...MUCH COOLER WEATHER IS EXPECTED WEDNESDAY AND
THURSDAY...INCLUDING POTENTIAL FROST ON WEDNESDAY NIGHT. MUCH WARMER
WEATHER WILL ARRIVE FOR THE WEEKEND.
&&
.UPDATE...
ISSUED AT 1054 AM EDT TUE MAY 15 2012
12Z SURFACE ANALYSIS SHOWS 1004MB LOW OVER WESTERN LAKE SUPERIOR
WITH A TRAILING COLD FRONT INTO NORTHWEST WISCONSIN/FAR SOUTHEAST
MINNESOTA. ASSOCIATED MID LEVEL SHORT WAVE TROUGH DIGGING SOUTHEAST
OUT OF NORTHWEST ONTARIO...FORCING AHEAD OF THIS WAVE PRODUCING SOME
AC/ACCAS AND SCATTERED LIGHT SHOWERS ACROSS EASTERN UPPER/FAR
NORTHERN LOWER. 12Z APX SOUNDING HAD A RESIDUAL MIXED LAYER FROM
JUST OFF THE DECK TO 700MB...MEAN MIXING RATIO WITHIN THIS LAYER
AROUND 4G/KG WITH DEW POINT DEPRESSIONS OF 14C 850MB/17C 925MB.
SHOULD BE A VERY INTERESTING AFTERNOON AS DIFFERENCES IN GUIDANCE
DEW POINT FORECASTS AND RESULTANT INSTABILITY FORECASTS HAVE SPARKED
A NICE INTRA-OFFICE DISCUSSION/DEBATE. FIRST OFF...THE OLD "BRAIN
MODEL" ADJUSTED APX SOUNDING BASED ON MIXING TO 700MB AND INCREASING
MEAN 925-850MB MIXING RATIOS INTO THE 5-6 G/KG RANGE BASED ON
UPSTREAM SOUNDINGS YIELDS A PARCEL OF 76/45 AND AN MLCAPE VALUE IN
THE VICINITY OF 500J/KG. SO IT WON`T TAKE MUCH ADDITIONAL MOISTURE
(LOWER-MID 40S DEW POINTS) TO GENERATE ENOUGH HIGH BASED CAPE TO GIN
UP SOME CONVECTION AHEAD OF COLD FRONT WHICH IS NOT EXPECTED TO
ARRIVE UNTIL THE 19-21Z TIME FRAME. LATEST RAP FORECASTS HOLDING
DEW POINTS DOWN IN THE 30S THROUGH THE AFTERNOON...PROBABLY A BIT
TOO LOW. NAM-WRF HOWEVER PUSHES DEW POINTS INTO THE LOWER-MID
50S...AND RESULTS IN FORECAST MLCAPE VALUES OVER 1500J/KG...A BIG
DIFFERENCE FROM 500J/KG WITH REGARD TO CONVECTIVE EVOLUTION/SEVERE
WEATHER POTENTIAL. GIVEN THE RATHER UNIFORM LOW LEVEL MOISTURE
PROFILES ON UPSTREAM SOUNDINGS...THINK SUSTAINED DEW POINTS IN THE
50S WILL BE HARD TO COME BY. BUT THAT WILL BE THE THING TO WATCH
FOR THE AFTERNOON...IF DEW POINTS CAN CLIMB INTO THE 50S AND STAY
THERE (SUGGEST A CERTAIN AMOUNT OF "DEPTH" TO THE LOW LEVEL MOIST
LAYER) THEN WE WILL HAVE SOME ISSUES. AS IT STANDS...GIVEN STEEP
LOW LEVEL LAPSE RATES AND DRY SUB-CLOUD LAYER DAMAGING WIND GUSTS
WOULD BE THE PRIMARY THREAT WITH ANY CONVECTION THAT DEVELOPS
(ORGANIZED OR NOT)...MORE INSTABILITY WOULD INCREASE THE THREAT FOR
HAIL AS WELL AS STRONGER WIND GUSTS. SHOULD HAVE A PRETTY GOOD
IDEA BY 18-19Z WHERE WE STAND WITH THIS...WILL ELABORATE MORE IN
EARLY AFTERNOON UPDATE.
UPDATE ISSUED AT 630 AM EDT TUE MAY 15 2012
HAVE UPDATED GRIDS TO ADJUST MORNING POPS. AREA RADARS ARE STILL
RUNNING HOT THANKS TO DRY AIR DOWN LOW...BUT GIVEN TRENDS HAVE
PUSHED POPS A BIT HIGHER...AND HAVE EXTENDED AT LEAST A SLIGHT
CHANCE FOR A SPRINKLE/SHRA INTO PART OF FAR NORTHERN LOWER MI.
AM ALSO TRYING TO FINE-TUNE PRECIP EXPECTATIONS FOR THIS
AFTERNOON/EVENING. ALL THE HIGH RESOLUTION OUTPUT I CAN FIND
(INCLUDING VARIOUS NMM/ARW OUTPUT) SUPPORT CONVECTION KICKING OFF
IN CENTRAL AND ESPECIALLY SOUTHERN SECTIONS...MAINLY BETWEEN 21Z
AND 03Z (A FEW GO SOMEWHAT EARLIER). THIS OCCURS AS THE 500MB TROF
DIGS/DEEPENS ACROSS SUPERIOR AND UPPER MI...WITH 500MB TEMPS
LOWERING TO -20C OVER NORTHERN LOWER...AND 700-500MB LAPSE RATES
INCREASING TO NEAR 8.5C/KM. CAN WE SUSTAIN SURFACE DEW POINTS TO
INITIATE DEEP CONVECTION? WE/LL BE ADVECTING IN LOW/MID 40S FROM
SOUTHERN WI/EASTERN IOWA...BUT WE/VE SEEN OUR TREMENDOUS ABILITY
TO MIX THAT OUT ON MULTIPLE OCCASIONS OVER THE LAST WEEK.
STILL...THEY ARE NOT MANY SIGNALS THAT SAY THAT NOTHING IS GOING
TO HAPPEN.
AM GOING TO KICK POPS UP TO LOW-END LIKELY IN SOUTHERN SECTIONS
LATE AFTERNOON/EARLY EVENING. (THIS LINES UP BETTER WITH OUR
SOUTHERN NEIGHBORS.) WILL ALSO UPDATE HWO TO MENTION AN ISOLATED
SVR WIND GUST POSSIBLE. NEITHER MLCAPE (500-700J/KG) NOR 0-6KM
BULK SHEAR (20-25KT) ARE IMPRESSIVE. BUT SIMPLY THE AMOUNT OF DRY
AIR SUPPORTS CONSIDERABLE EVAP COOLING POTENTIAL WITHIN
DOWNDRAFTS. STORMS WILL NOT BE WELL ORGANIZED...DOWNDRAFT AIR/COLD
POOLS ARE GOING TO OVERWHELM INSTABILITY ON THE STORM SCALE VERY
QUICKLY. NOTE THAT THIS THINKING LINES UP WITH THE SPC DAY 1
OUTLOOK...WHICH HAS A SLIGHT RISK ESSENTIALLY ON OUR SOUTHERN
DOORSTEP.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 301 AM EDT TUE MAY 15 2012
TODAY...THERE ARE A HOST OF ISSUES TO TACKLE TODAY AND THEY ARE
SOMEWHAT INTERRELATED. FIRST OFF, THE RAIN SHOWERS THAT ARE MAKING
THEIR WAY THROUGH UPPER MICHIGAN ARE FAIRLY LIGHT AND ALIGNED
ALONG THE WARM FRONT THAT IS OUT AHEAD OF THE SFC LOW HEADING INTO
WESTERN LAKE SUPERIOR. HOWEVER, THE 00Z SOUNDINGS AT INL AND MPX,
LOOK A LOT LIKE OUR 00Z SOUNDING, THAT IS VERY DRY AND WARM. SO
AGREE WITH THE MODEL SOUNDINGS THAT THE LOWER LEVELS OF THE
SOUNDINGS WILL SHOW SIGNIFICANT DRY AIR. AS THE FRONT MOVES
THROUGH THE REGION AND THE SFC LOW WITH IT, THERE WILL BE SOME
RAIN SHOWERS AND THUNDER. HOWEVER, WITH SOME MUCH DRY AIR, IT
DOESN`T LOOK LIKE MUCH WILL HIT THE GROUND A THE WARMER AIR MOVES
INTO THE REGION. THE MODELS SHOW THAT THE LARGEST AREA OF
CONVECTION WILL PROBABLY BE ON THE EAST SIDE OF THE STATE IN THE
AFTERNOON AS THE 500 MB SHORTWAVE AND THE COLD FRONT BEGIN TO
MARCH ACROSS THE REGION. WINDS PICK UP AHEAD OF THE FRONT WITH THE
SUSTAINED WINDS AROUND 15 MPH. IF THE SOUNDINGS FROM THE UPSTREAM
AREAS ARE ANYTHING TO TAKE INTO ACCOUNT, THEN WE ARE EXPECTING
THAT THE RH IN THE AFTERNOON WILL BE AROUND 20% PRIOR TO THE
FROPA. WHILE THUNDER IS POSSIBLE, AND WITH THE DRY AIR IN THE
LOWER LEVELS EXPECTED, THIS COULD BE A RARE SET UP FOR SOME DRY
LIGHTNING ACTIVITY. TEMPERATURES ARE GOING TO MAKE A RUN AT 80F IN
NE LOWER AS WELL WITH THE 850 MB TEMPERATURES SPIKING TO AROUND
13C ON BOTH THE ECMWF AND THE GFS. SO WITH THE WARM TEMPS, DRY RH,
AND WINDS, THERE WILL BE A RED FLAG WARNING ISSUED WITH THE FIRE
WEATHER PACKAGE COMING UP.
TONIGHT...ANY RAIN THAT GETS STARTED IN THE AFTERNOON WILL BE ON
THE WAY OUT AS BOTH MODELS START TO PUSH THIS SYSTEM RAPIDLY TO
THE EAST. ONCE THE FRONT GOES THROUGH THE RED FLAG WARNING WILL
EXPIRE (AROUND 01Z) WITH TEMPERATURES COOLING, BU THE WINDS WILL
SWITCH TO THE NORTHWEST AND RAMP BACK UP, INITIALLY, IT WILL TAKE
SOME TIME TO RECOVER THE RH, BUT BY 03 OR 04Z, THE TEMPERATURES
SHOULD HAVE COOLED ENOUGH FOR THE RH TO RECOVER OVERNIGHT. ALL THE
RAIN SHOULD BE OUT OF THE REGION BY 06Z. THE REST OF THE OVERNIGHT
SHOULD BE DRY.
WEDNESDAY...MODELS REMAINED CONSISTENT FOR THE DAY WITH THE SFC
HIGH BUILT INTO THE REGION. IT LOOKS LIKE THERE COULD BE SOME
RAIN SHOWERS NORTHEAST OF ANJ AS THE ECMWF DIGS ANOTHER 500 MB
SHORTWAVE INTO THE AREA NE OF ANJ, HOWEVER, FOR THE FORECAST AREA,
THE DAY SHOULD BE DRY, WITH THE HIGH BUILDING INTO THE AREA. WILL
HAVE TO WATCH FOR SOME ELEVATED FIRE ISSUES, WITH THE LOW SFC RH,
AND THE WINDS, NEAR LAKE HURON, OUT OF THE NW AT 10-15 MPH.
FARTHER WEST NOT AS FAST.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 301 AM EDT TUE MAY 15 2012
SUMMER WILL ASSERT ITSELF THIS WEEKEND...BUT ONLY TEMPORARILY. THE
UPPER TROF THAT STARTS IN THE EASTERN LAKES WED EVENING...WILL EJECT
TO EASTERN CANADA BY FRIDAY. THAT WILL ALLOW RIDGING TO PROGRESS
INTO THE MS VALLEY AND CENTRAL CANADA...AND OUR TEMPS WILL WARM IN
RESPONSE. HOWEVER...WE MAY HAVE SOME ACTIVE WX TO PASS THRU IN ORDER
TO GET THE WARM AIR HERE.
WED NIGHT/THURSDAY...HIGH PRESSURE WILL BE OVERHEAD WED NIGHT.
THOUGH SOME WARM ADVECTION MID/HIGH CLOUDS COULD ARRIVE FROM THE
WEST LATE AT NIGHT...SKIES WILL BE CLEAR ENOUGH LONG ENOUGH TO
READILY DECOUPLE. TEMPS WILL PLUNGE AS A RESULT...AND A FROSTY NIGHT
APPEARS INEVITABLE IN SPOTS. GUIDANCE TEMPS ARE MAINLY IN THE
30S...WITH SOME UPPER 20S IN THE USUAL COLD SPOTS. TEMPS COULD WELL
GO A FEW DEGREES COLDER THAN THIS. WILL CONTINUE TO ADVERTISE FROST
POTENTIAL IN BOTH PENINSULAS IN THE HWO (NOTE THAT WE BEGAN THE
FROST/FREEZE SEASON IN EASTERN UPPER MI YESTERDAY).
THURSDAY IS LOOKING INCREASINGLY LIKE IT WILL BE DRY. THERE/S A NICE
SURGE OF WARM ADVECTION OFF THE DECK...AS SURFACE HIGH PRESSURE
MOVES TO THE EASTERN LAKES. A SLOW-MOVING WARM FRONT WILL GRADUALLY
EXTEND EASTWARD ACROSS UPPER MI. BUT WARM ADVECTION PROGGED TO
GENERALLY BE STRONGER WITH HEIGHT...THUS THE AIRMASS IS TENDING TO
BECOME MORE STABLE WITH TIME. MID AND UPPER LEVEL MOISTURE BECOMES
PLENTIFUL DURING THE DAY (ABOVE 700MB)...BUT THE LOW LEVELS ARE
RELATIVELY DRY (BELOW 800MB). WILL HANG INTO POPS IN EASTERN
UPPER...WHERE ASCENT IS SOMEWHAT STRONGER AND WHERE THE WARM FRONT
TRIES TO POKE IN DURING THE DAY...BUT EVEN THERE GUIDANCE POPS ARE
IN THE SINGLE DIGITS TO LOWER TEENS. WE/LL SEE. THEY ARE EVEN LESS
IN NORTHERN LOWER...AND POPS WILL BE REMOVED THERE. CLOUDS WILL KEEP
MAX TEMPS IN THE 60S TO LOWER 70S.
REST OF THE FORECAST...NAM/GFS ARE IN REASONABLE AGREEMENT THAT
WE/LL SEE A BETTER (THOUGH NOT GREAT) CHANCE OF RAIN THU NIGHT...AS
THE LOW LEVEL JET DEVELOPS AND WARM/MOIST INFLOW INCREASES. BOTH
MODELS SUGGEST CENTRAL/NORTHERN PORTIONS OF THE FORECAST AREA HAVE
THE BEST CHANCE FOR RAIN. POSSIBILITY EXISTS FOR ONE MORE ROUND
DURING THE DAY ON FRIDAY (AGAIN ESPECIALLY NORTHERN SECTIONS)...
BEFORE THE WARM FRONT MORE EMPHATICALLY LIFTS TO OUR NORTH AND WE
BECOME MORE ENTRENCHED IN THE WARM SECTOR. THAT LEAVES SATURDAY DRY
AND TOASTY. STILL TOASTY SUNDAY...BUT HEIGHT FALLS BEGIN AND A COLD
FRONT IS INBOUND SUNDAY NIGHT. SO PRECIP CHANCES SUNDAY-MONDAY...
WITH MUCH COOLER TEMPS MONDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 726 AM EDT TUE MAY 15 2012
MAINLY VFR...THOUGH SOME RISK FOR MVFR CIGS AT PLN/APN TONIGHT.
SMALL CHANCE FOR TSRA LATE AFTERNOON NEAR MBL/TVC.
LOW PRESSURE NEAR THUNDER BAY ONTARIO THIS MORNING...WILL GRAZE
THE NORTH COAST OF SUPERIOR AND PASS NORTH OF LAKE HURON TODAY. AN
ASSOCIATED COLD FRONT WILL CROSS NORTHERN MI LATE THIS AFTERNOON
AND EARLY THIS EVENING. SOMEWHAT GUSTY SW WINDS WILL DEVELOP THIS
MORNING...AND CONTINUE UNTIL THE FRONT MOVES THRU. HIGH BASED SHRA
AND PERHAPS A FEW TSRA WILL DEVELOP AS THE FRONT GOES THRU...
CHANCES OF TAF SITES BEING IMPACTED INCREASE AS YOU HEAD SOUTH.
(PLN SHOULD NOT BE IMPACTED AT ALL...BUT WILL SEE SOME WEAK SHRA
IN THE AREA THIS MORNING). BEHIND THE FRONT...A RELATIVELY SMALL
AREA OF LOW CLOUDS (MVFR CIGS) WILL SKIRT BY APN/PLN ON ITS WAY TO
THE SOUTH AND EAST.
&&
.MARINE...
ISSUED AT 301 AM EDT TUE MAY 15 2012
THROUGH THE FORECAST PERIOD, DESPITE THE RAMP UP OF THE WIND TODAY
PRE AND POST FRONTAL WINDS AND WAVES TODAY, TONIGHT, AND WEDNESDAY
WILL REMAIN BELOW SMALL CRAFT CRITERIA, ALTHOUGH CAN`T COUNT OUT A
HIGHER GUST ALONG NEAR THE LAND/WATER INTERFACE. ONCE THE HIGH
BUILDS BACK INTO THE REGION ON WEDNESDAY AFTERNOON, WINDS WILL
SLACKEN AND WAVES WILL SUBSIDE FOR WEDNESDAY NIGHT.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...RED FLAG WARNING UNTIL 9 PM EDT THIS EVENING FOR MIZ016>036-041-
042.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JPB
SYNOPSIS...JZ
SHORT TERM...JL
LONG TERM...JZ
AVIATION...JL
MARINE...JL
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1157 PM CDT SUN MAY 13 2012
.AVIATION...VFR CONDITIONS WILL PREVAIL THROUGHOUT THE TAF PERIOD
AS A SURFACE HIGH RESIDES OVER THE REGION. THE PREVAILING
SOUTHWEST WINDS WILL BECOME SOUTH TOWARDS THE END OF THE TAF
PERIOD AROUND 02Z. SINCE THE WIND WILL BE LIGHT...THESE
CONDITIONS DO NOT REQUIRE A FROM GROUP FOR THE FORECAST.
&&
.PREV DISCUSSION... /ISSUED 944 PM CDT SUN MAY 13 2012/
UPDATE...EVENING SURFACE ANALYSIS INDICATES AN AREA OF HIGH
PRESSURE EXTENDING ACROSS MUCH OF THE CENTRAL PLAINS...WITH LIGHT
AND VARIABLE WINDS PERSISTING ACROSS OUR AREA AS OF 02Z. THE
AFTERNOON CU FIELD HAS SINCE DISSIPATED WITH THE LOSS OF DIABATIC
HEATING AND CLEAR SKIES ARE NOW BEING OBSERVED ACROSS MOST ALL OF THE
CWA. UPPER AIR ANALYSIS PER RAP INITIALIZATION DATA SUGGEST
FLOW THROUGH THE ENTIRE TROPOSPHERIC COLUMN OVER OUR AREA REMAINS
VERY WEAK WITH MID AND UPPER LEVEL JET ENERGY REMAINING RELEGATED
TO SOUTHERN CANADA AND THE SOUTHERN CONUS. EVENING WATER VAPOR
IMAGERY SHOWS A MID LEVEL SHORT WAVE OVER THE FOUR-CORNERS REGION
AND MOVING SOUTH/SOUTHEAST. SCATTERED CONVECTION CONTINUES OVER
THE CENTRAL HIGH PLAINS AT THIS HOUR...BUT THE CURRENT TRAJECTORY
OF THIS SHORT WAVE SUGGESTS PRECIPITATION SHOULD STAY WELL
SOUTHWEST OF OUR CWA TONIGHT.
OVERALL THE GOING FORECAST IS IN GOOD SHAPE. THE COMBINATION OF
CLEAR SKIES AND LIGHT WINDS SHOULD ALLOW THE LOW LEVEL AIRMASS TO
RADIATE OUT QUITE EFFICIENTLY TONIGHT...WITH OVERNIGHT TEMPERATURE
DROP-OFFS GENERALLY IN THE 25-30 DEGREE RANGE EXPECTED ACROSS THE CWA.
WITH SUNDAY HIGH TEMPERATURES IN THE 70S...OVERNIGHT LOWS RANGING
FROM THE MID-40S TO NEAR 50 WILL LIKELY BE OBSERVED BY SUNRISE
MONDAY. SURFACE DEW POINTS ACROSS THE AREA ARE CURRENTLY IN THE
UPPER 30S TO LOW 40S...SO DESPITE THE SIGNIFICANT DROP IN
TEMPERATURES AND LIGHT WINDS...FOG DOES NOT APPEAR TO BE A MAJOR
CONCERN AT THIS TIME. WENT AHEAD AND TWEAKED OVERNIGHT LOWS BY A
DEGREE OR TWO FOR A FEW LOCATIONS...ALONG WITH HOURLY DEW POINTS
AND SKY COVER TO BETTER REFLECT CURRENT OBSERVATIONS. REMAINDER OF
THE FORECAST REMAINS UNCHANGED.
PREV DISCUSSION... /ISSUED 246 PM CDT SUN MAY 13 2012/
SHORT TERM...TONIGHT AND MONDAY. MAIN FORECAST CONCERN WILL BE
TEMPERATURES.
SURFACE ANALYSIS SHOWS A SURFACE HIGH PRESSURE SYSTEM IN WESTERN
NEBRASKA THIS AFTERNOON. SATELLITE AND OBSERVATIONS HAVE CUMULUS
AROUND THE AREA. CLOUDS SHOULD DIMINISH THIS EVENING AS THE SUN GOES
DOWN. THE SURFACE HIGH MOVES THROUGH THE AREA TONIGHT AND IS TO THE
SOUTHEAST OF THE AREA ON MONDAY. THE WINDS WILL TURN TOWARD THE
SOUTHWEST TO WEST BUT SHOULD STILL REMAIN MAINLY LIGHT. LATE TONIGHT
AND INTO MONDAY THERE IS A LITTLE BIT OF WARM ADVECTION ACROSS THE
AREA AND THE TEMPERATURES ALOFT WARM SOME. EXPECT TEMPERATURES TO BE
A LITTLE WARMER ON MONDAY THAN TODAY...BUT IT DEPENDS SOMEWHAT ON IF
THERE IS ANY MIXING TO GET THE WARMER TEMPERATURES TO THE SURFACE.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY. WARMER WEATHER WILL
SPREAD ONTO THE CENTRAL PLAINS THIS WEEK WITH PSEUDO RIDGING
EXPANDING FROM THE NORTHERN AND CENTRAL ROCKIES ONTO THE PLAINS.
H85 TEMPS CLIMB TO THE UPPER TEENS TO LOWER 20S ON TUESDAY AND
THE WARM AIRMASS SETTLES IN FOR THE WORKWEEK. FORECAST SOUNDINGS BOTH
TUESDAY AND WEDNESDAY INDICATE MIXING ABOVE THIS LEVEL...NEARING
H7...OR PERHAPS EVEN HIGHER AT TIMES. FORTUNATELY WINDS ARE NOT
LOOKING TOO STRONG ON TUESDAY BUT WITH DOWNSLOPE WIND COMPONENT
WARM TEMPS IN THE UPPER 80S TO AROUND 90F ARE EXPECTED...WELL
ABOVE OUR SEASONAL NORMAL HIGHS IN THE LOWER 70S. HIGHS IN THE 80S
ARE FORECAST THROUGH THE REMAINDER OF THE WEEK AS WELL.
SURFACE LOW PRESSURE DEEPENS ALONG THE NORTHERN HIGH PLAINS ON
WEDNESDAY AND WINDS WILL BE ON THE INCREASE FROM THE SOUTH AND SOME
BETTER MOISTURE WILL BEGIN TO BE DRAWN NORTHWARD. MODELS DIFFER ON
THE STRENGTH AND TIMING OF A SHORTWAVE TROUGH TO CROSS THE CENTRAL
PLAINS WITH THE GFS FASTER/STRONGER THAN OTHER MODELS WITH THIS ON
WEDNESDAY NIGHT. HAVE LOW CONFIDENCE IN THE GFS SOLUTION ATTM...AND
WILL KEEP WEDNESDAY NIGHT DRY WITH SOME SMALL CHCS FOR PCPN
RETURNING ON THURSDAY WITH A SLOWER TIMING OF WAVE PROGRESSION AS
INDICATED BY ECMWF/GEM.
FRIDAY IS STILL LOOKING DRY AT THIS TIME IN BETWEEN THE DEPARTING
WAVE WHILE THE NEXT TROUGH MOVES INTO THE ROCKIES. AGAIN MODELS ARE
NOT IN COMPLETE AGREEMENT WITH THE STRENGTH OF THIS NEXT WAVE/TROUGH WITH
THE GEM/ECMWF IN BETTER AGREEMENT WITH EACH OTHER THAN THE LATEST
GFS RUN. THAT BEING SAID...THE WEEKEND PERIOD COULD POTENTIALLY BE
MORE ACTIVE AS TROUGH OVER THE ROCKIES MOVES ONTO THE CENTRAL PLAINS
AND SURFACE FRONT ORIENTS ACROSS OUR REGION...ESPECIALLY FOR DAY 7.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...GUERRERO
AREA FORECAST DISCUSSION
NWS HASTINGS NE
944 PM CDT SUN MAY 13 2012
.UPDATE...EVENING SURFACE ANALYSIS INDICATES AN AREA OF HIGH
PRESSURE EXTENDING ACROSS MUCH OF THE CENTRAL PLAINS...WITH LIGHT
AND VARIABLE WINDS PERSISTING ACROSS OUR AREA AS OF 02Z. THE
AFTERNOON CU FIELD HAS SINCE DISSIPATED WITH THE LOSS OF DIABATIC
HEATING AND CLEAR SKIES ARE NOW BEING OBSERVED ACROSS MOST ALL OF THE
CWA. UPPER AIR ANALYSIS PER RAP INITIALIZATION DATA SUGGEST
FLOW THROUGH THE ENTIRE TROPOSPHERIC COLUMN OVER OUR AREA REMAINS
VERY WEAK WITH MID AND UPPER LEVEL JET ENERGY REMAINING RELEGATED
TO SOUTHERN CANADA AND THE SOUTHERN CONUS. EVENING WATER VAPOR
IMAGERY SHOWS A MID LEVEL SHORT WAVE OVER THE FOUR-CORNERS REGION
AND MOVING SOUTH/SOUTHEAST. SCATTERED CONVECTION CONTINUES OVER
THE CENTRAL HIGH PLAINS AT THIS HOUR...BUT THE CURRENT TRAJECTORY
OF THIS SHORT WAVE SUGGESTS PRECIPITATION SHOULD STAY WELL
SOUTHWEST OF OUR CWA TONIGHT.
OVERALL THE GOING FORECAST IS IN GOOD SHAPE. THE COMBINATION OF
CLEAR SKIES AND LIGHT WINDS SHOULD ALLOW THE LOW LEVEL AIRMASS TO
RADIATE OUT QUITE EFFICIENTLY TONIGHT...WITH OVERNIGHT TEMPERATURE
DROP-OFFS GENERALLY IN THE 25-30 DEGREE RANGE EXPECTED ACROSS THE CWA.
WITH SUNDAY HIGH TEMPERATURES IN THE 70S...OVERNIGHT LOWS RANGING
FROM THE MID-40S TO NEAR 50 WILL LIKELY BE OBSERVED BY SUNRISE
MONDAY. SURFACE DEW POINTS ACROSS THE AREA ARE CURRENTLY IN THE
UPPER 30S TO LOW 40S...SO DESPITE THE SIGNIFICANT DROP IN
TEMPERATURES AND LIGHT WINDS...FOG DOES NOT APPEAR TO BE A MAJOR
CONCERN AT THIS TIME. WENT AHEAD AND TWEAKED OVERNIGHT LOWS BY A
DEGREE OR TWO FOR A FEW LOCATIONS...ALONG WITH HOURLY DEW POINTS
AND SKY COVER TO BETTER REFLECT CURRENT OBSERVATIONS. REMAINDER OF
THE FORECAST REMAINS UNCHANGED.
&&
.PREV DISCUSSION... /ISSUED 546 PM CDT SUN MAY 13 2012/
AVIATION...00Z KGRI TAF. VFR CONDITIONS TO CONTINUE THROUGH THE
NEXT 24 HOURS. SCATTERED CU FIELD NEAR 7000FT AGL WILL DISSIPATE
SHORTLY AFTER SUNSET...WITH CLEAR SKIES THEN EXPECTED UNTIL MID-
LEVEL CU DEVELOPS AROUND 9000FT AGL BY LATE MORNING OR EARLY
AFTERNOON MONDAY. SURFACE WINDS SHOULD NOT EXCEED 07KTS THROUGH
THE NEXT 24 HOURS...GENERALLY REMAINING FROM THE WEST/SOUTHWEST.
VISIBILITY RESTRICTIONS ARE NOT EXPECTED THROUGH THE NEXT 24
HOURS.
PREV DISCUSSION... /ISSUED 246 PM CDT SUN MAY 13 2012/
SHORT TERM...TONIGHT AND MONDAY. MAIN FORECAST CONCERN WILL BE
TEMPERATURES.
SURFACE ANALYSIS SHOWS A SURFACE HIGH PRESSURE SYSTEM IN WESTERN
NEBRASKA THIS AFTERNOON. SATELLITE AND OBSERVATIONS HAVE CUMULUS
AROUND THE AREA. CLOUDS SHOULD DIMINISH THIS EVENING AS THE SUN GOES
DOWN. THE SURFACE HIGH MOVES THROUGH THE AREA TONIGHT AND IS TO THE
SOUTHEAST OF THE AREA ON MONDAY. THE WINDS WILL TURN TOWARD THE
SOUTHWEST TO WEST BUT SHOULD STILL REMAIN MAINLY LIGHT. LATE TONIGHT
AND INTO MONDAY THERE IS A LITTLE BIT OF WARM ADVECTION ACROSS THE
AREA AND THE TEMPERATURES ALOFT WARM SOME. EXPECT TEMPERATURES TO BE
A LITTLE WARMER ON MONDAY THAN TODAY...BUT IT DEPENDS SOMEWHAT ON IF
THERE IS ANY MIXING TO GET THE WARMER TEMPERATURES TO THE SURFACE.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY. WARMER WEATHER WILL
SPREAD ONTO THE CENTRAL PLAINS THIS WEEK WITH PSEUDO RIDGING
EXPANDING FROM THE NORTHERN AND CENTRAL ROCKIES ONTO THE PLAINS.
H85 TEMPS CLIMB TO THE UPPER TEENS TO LOWER 20S ON TUESDAY AND
THE WARM AIRMASS SETTLES IN FOR THE WORKWEEK. FORECAST SOUNDINGS BOTH
TUESDAY AND WEDNESDAY INDICATE MIXING ABOVE THIS LEVEL...NEARING
H7...OR PERHAPS EVEN HIGHER AT TIMES. FORTUNATELY WINDS ARE NOT
LOOKING TOO STRONG ON TUESDAY BUT WITH DOWNSLOPE WIND COMPONENT
WARM TEMPS IN THE UPPER 80S TO AROUND 90F ARE EXPECTED...WELL
ABOVE OUR SEASONAL NORMAL HIGHS IN THE LOWER 70S. HIGHS IN THE 80S
ARE FORECAST THROUGH THE REMAINDER OF THE WEEK AS WELL.
SURFACE LOW PRESSURE DEEPENS ALONG THE NORTHERN HIGH PLAINS ON
WEDNESDAY AND WINDS WILL BE ON THE INCREASE FROM THE SOUTH AND SOME
BETTER MOISTURE WILL BEGIN TO BE DRAWN NORTHWARD. MODELS DIFFER ON
THE STRENGTH AND TIMING OF A SHORTWAVE TROUGH TO CROSS THE CENTRAL
PLAINS WITH THE GFS FASTER/STRONGER THAN OTHER MODELS WITH THIS ON
WEDNESDAY NIGHT. HAVE LOW CONFIDENCE IN THE GFS SOLUTION ATTM...AND
WILL KEEP WEDNESDAY NIGHT DRY WITH SOME SMALL CHCS FOR PCPN
RETURNING ON THURSDAY WITH A SLOWER TIMING OF WAVE PROGRESSION AS
INDICATED BY ECMWF/GEM.
FRIDAY IS STILL LOOKING DRY AT THIS TIME IN BETWEEN THE DEPARTING
WAVE WHILE THE NEXT TROUGH MOVES INTO THE ROCKIES. AGAIN MODELS ARE
NOT IN COMPLETE AGREEMENT WITH THE STRENGTH OF THIS NEXT WAVE/TROUGH WITH
THE GEM/ECMWF IN BETTER AGREEMENT WITH EACH OTHER THAN THE LATEST
GFS RUN. THAT BEING SAID...THE WEEKEND PERIOD COULD POTENTIALLY BE
MORE ACTIVE AS TROUGH OVER THE ROCKIES MOVES ONTO THE CENTRAL PLAINS
AND SURFACE FRONT ORIENTS ACROSS OUR REGION...ESPECIALLY FOR DAY 7.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE/AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1257 PM EDT TUE MAY 15 2012
.SYNOPSIS...
LOW PRESSURE WILL CONTINUE TO SPREAD RAIN ACROSS THE AREA THROUGH
TODAY...MAINLY EAST OF ROUTE 81...BEFORE ENDING TONIGHT. SKIES
WILL CLEAR EARLY WEDNESDAY AHEAD OF A COLD FRONT. THIS FRONT WILL
MOVE THROUGH LATE WEDNESDAY WITH SHOWERS AND A FEW THUNDERSTORMS.
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT AND BRING DRY WEATHER
FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
930 AM UPDATE...
BATCH OF MDT TO HVY RAIN MOVG THRU NE PA AND THE SUSQ RGN/CATSILLS
OF NY. THUS FAR NO PRBLMS BUT RR RATES OF UP TO .4 IN/HR ARE NOTED
ACRS PORTIONS OF NE PA. FORTUNATELY...BACKEDGE OF HEAVIER RAIN IS
NOW ENTERING SW LUZERNE...AND HEAVIER RAINS THIS AFTN SHUD BE
FOCUSED E OF THIS AREA WHERE ANTECEDENT RAINFALL HAS BEEN LOWER. NO
PRBLMS SO FAR FROM LACK/LUZ EMO`S. AS THIS S/WV EXITS...OTHER WEAK
IMPUSLES IN THE WSW FLOW ALOFT ARE NOTED UPSTREAM. REMNANTS OF SFC
TROF...ALSO EVIDENT IN THE 925/850 MB FCSTS FOR THIS AFTN...WILL
RESULT IN WEAK LOW LVL MSTR CONVERGENCE ACRS THE CNTRL SRN TIER
AND FINGER LAKES. RUC/GFS INDICATE POTNL CAPES UP TO NEARLY
1000 J/KG...BUT THE LOW LVL TD`S SEEM ON THE HIGH SIDE. FROM OUR
PERSPECTIVE...THE NAM LOOKED MORE RSNBL WITH CAPES IN THE 300-500
RNG. TCNTRL SRN TIER AND FINGER LAKES ARE MOST LIKELY TO SEE SOME
SUNSHINE THIS AFTN....SO ISOLD TO WDLY SCT TSRA PSBL THIS AFTN
ACRS CNTRL NY...MAINLY W OF I-81. MINOR TWEEKS TO CRNT FCST...OTRW
NO SIG CHGS.
LOW PRESSURE WILL CONTINUE TO BRING RAIN TO THE CWA THROUGH THE
DAY TODAY. MODELS SHOW A WEAK AREA OF LOW PRESSURE STALLING OVER
THE AREA TODAY, BEFORE BEING PUSHED OUT TONIGHT BY AN UPPER LEVEL
TROUGH. THE BEST LIFT WILL BE FROM THE EASTERN ZONE EASTWARD.
LOOKING AT RAINFALL ACCUMULATIONS FROM THE PRECIPITATION THAT HAS
OCCURRED, MODELS HAVE OVERDONE AMOUNTS. GOING WITH THIS SAME TREND
FOR TODAY WILL ALLOW FOR LOWER STORM TOTALS AND REINFORCE THE
FORECAST FOR NO FLOODING IN THE RIVERS. SO FAR, STORM TOTAL
FORECASTS ARE ABOUT ONE HALF TO THREE QUARTERS OF AN INCH LOWER
THAN PREVIOUSLY THOUGHT.
AS THE DAY PROGRESSES, THERE WILL ALSO BE SOME INSTABILITY IN THE
AREA. CAPES OF BETWEEN 500 AND 1000 JOULES WILL BE ACROSS THE
AREA. HOWEVER, FORCING IS WEAK AND DAYTIME HEATING WILL BE
LIMITED. SO, HAVE RAIN SHOWERS IN THE FORECAST WITH ISOLD THUNDER
FOR THE AFTERNOON, EXCEPT IN THE SE ZONES WHERE SCATTERED
THUNDERSTORMS ARE FORECAST. THIS COULD CHANGE IF CLOUDS BREAK UP
OVER THE WESTERN ZONES AND TEMPS ARE HIGHER THAN FORECAST. WILL
LOOK AT THE NEW MODEL RUNS AND POSSIBLY CHANGE THUNDERSTORM
COVERAGE WITH NEXT FORECAST ISSUANCE AT 19Z.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
LOW PRESSURE BEGINS TO SLIDE OF TO THE EAST THIS EVENING, TAKING
THE PRECIPITATION ALONG WITH IT. THIS WILL ALLOW FOR A BREAK
THROUGH A GOOD PORTION OF THE NIGHT.
WEDNESDAY WILL SEE A COLD FRONT APPROACH THE CWA FROM THE WEST. IT
LOOKS TO PROVIDE ENOUGH LIFT BY TOMORROW AFTERNOON THAT SOME
ADDITIONAL THUNDERSTORMS MAY DEVELOP, ESPECIALLY ALONG THE FRONT.
MODELS ARE INDICATING THAT THE STRONGEST LIFT WILL BE OVER THE NY
ZONES. THE FURTHER SOUTH, THE DRIER THE FRONTAL PASSAGE, ALTHOUGH
SOME SHOWERS AND STORMS COULD STILL DEVELOP OVER NEPA. CURRENT SPC
OUTLOOK HAS THE CWA IN GENERAL THUNDERSTORMS. MODELS ARE SHOWING
THAT THE BEST CAPE TOMORROW WILL BE IN THE FAR EASTERN ZONES
DURING THE AFTERNOON HOURS. THE NAM HAS ABOUT 1200 JOULES TOMORROW
AFTERNOON IN THESE AREAS.
THIS FRONT WILL MOVE QUICKLY THROUGH THE CWA AND SHOULD BE EXITING
BY TOMORROW EVENING. BEHIND IT, HIGH PRESSURE WILL BUILD IN FOR
THE REMAINDER OF THE SHORT TERM FORECAST PERIOD. THERE WILL BE A
SOMEWHAT COOLER AIR MASS IN PLACE THROUGH THURSDAY NIGHT. HIGH
TEMPS THURSDAY WILL BE IN THE LOW TO MID 60S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
RDG BLDG OVER THE GREAT LAKES AND NE US DOMINATES THE LONG TERM
PD. SUBTLE DFRNCS IN THE PSN OF THE RDG BY THE MODELS ALLOW FOR
SOME MINOR DAY TO DAY FCST DFRNCS FOR THE PD. IN GNRL...THE ECMWF
KEEPS THE UPR RIDGE ORIENTED DIRECTLY OVER THE FCST AREA KEEPING
THE WEAK TROF OVER THE WRN LAKES FROM AFFECTING THE AREA...WHILE
THE GFS POSITIONS THE RDG LINE FURTHER SOUTH ALLOWING FOR SOME
SHRT WV ENERGY TO TRIGGER SCT SHWRS AND TRWS...ESP LATE IN THE PD.
ALSO...GFS ALLOWS SOMEWHAT WRMR AIR INTO THE FCST AREA ON A SLY
FLOW...THEREBY KEEPING TEMPS A BIT HIER. FOR THE PD...GNRLY USED
HPC GUID ALTHOUGH DID SOME ADJUSTMENTS TWRDS THE GFS SOLN BY
BUMPING UP TEMPS AND ADDING SOME VERY LOW CHANCE AND SLGT CHANCE
POS AT THE ENDS OF THE PD. IN GNRL THOUGH...PD WILL BE DRY AND
WARM AND A MARKED CONTRAST FROM THE FIRST PART OF THE WEEK.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
UPR WV SLOWLY PULLING NE AND RAIN COMING TO AN END. DRIER IS WRKG IN
BEHIND THE RAIN AND SHD SLOWLY RAISE CIGS AND VSBY TO VFR LVLS THIS
AFTN. SFC HIPRES LATE TNGT WILL BRING CLRG SKIES...BUT WITH LGT
WIND SHALLOW FOG IS XPCTD LATE. DFCLT FCST ON CONDS AS FOG SHD BE
VERY PTCHY...BUT MOST TERMINALS SHD XPCT SOME BRIEF IFR CONDS
LATE...ENDING QUICKLY AS DRY AIR AND BRIGHT SUN ABV MIX OUT THE
FOG.
STRONGER COLD FNT APRCHS LATE IN THE TAF PD AND COULD BRING SOME
SHWRS AND TRWS IN THE NORTH AND WEST BEFORE THE END OF THE PD.
.OUTLOOK...
WED AFTN...MAINLY VFR...WDLY SCT AFTN -TSRA...WITH MVFR PSBL.
THU/FRI/SAT/SUN...VFR...XCPT LATE NGT VLY FOG AFFECTING KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...SLI
NEAR TERM...
SHORT TERM...SLI
LONG TERM...DGM
AVIATION...DGM/HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1134 AM EDT TUE MAY 15 2012
.SYNOPSIS...
LOW PRESSURE WILL CONTINUE TO SPREAD RAIN ACROSS THE AREA THROUGH
TODAY...MAINLY EAST OF ROUTE 81...BEFORE ENDING TONIGHT. SKIES
WILL CLEAR EARLY WEDNESDAY AHEAD OF A COLD FRONT. THIS FRONT WILL
MOVE THROUGH LATE WEDNESDAY WITH SHOWERS AND A FEW THUNDERSTORMS.
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT AND BRING DRY WEATHER
FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
930 AM UPDATE...
BATCH OF MDT TO HVY RAIN MOVG THRU NE PA AND THE SUSQ RGN/CATSILLS
OF NY. THUS FAR NO PRBLMS BUT RR RATES OF UP TO .4 IN/HR ARE NOTED
ACRS PORTIONS OF NE PA. FORTUNATELY...BACKEDGE OF HEAVIER RAIN IS
NOW ENTERING SW LUZERNE...AND HEAVIER RAINS THIS AFTN SHUD BE
FOCUSED E OF THIS AREA WHERE ANTECEDENT RAINFALL HAS BEEN LOWER. NO
PRBLMS SO FAR FROM LACK/LUZ EMO`S. AS THIS S/WV EXITS...OTHER WEAK
IMPUSLES IN THE WSW FLOW ALOFT ARE NOTED UPSTREAM. REMNANTS OF SFC
TROF...ALSO EVIDENT IN THE 925/850 MB FCSTS FOR THIS AFTN...WILL
RESULT IN WEAK LOW LVL MSTR CONVERGENCE ACRS THE CNTRL SRN TIER
AND FINGER LAKES. RUC/GFS INDICATE POTNL CAPES UP TO NEARLY
1000 J/KG...BUT THE LOW LVL TD`S SEEM ON THE HIGH SIDE. FROM OUR
PERSPECTIVE...THE NAM LOOKED MORE RSNBL WITH CAPES IN THE 300-500
RNG. TCNTRL SRN TIER AND FINGER LAKES ARE MOST LIKELY TO SEE SOME
SUNSHINE THIS AFTN....SO ISOLD TO WDLY SCT TSRA PSBL THIS AFTN
ACRS CNTRL NY...MAINLY W OF I-81. MINOR TWEEKS TO CRNT FCST...OTRW
NO SIG CHGS.
LOW PRESSURE WILL CONTINUE TO BRING RAIN TO THE CWA THROUGH THE
DAY TODAY. MODELS SHOW A WEAK AREA OF LOW PRESSURE STALLING OVER
THE AREA TODAY, BEFORE BEING PUSHED OUT TONIGHT BY AN UPPER LEVEL
TROUGH. THE BEST LIFT WILL BE FROM THE EASTERN ZONE EASTWARD.
LOOKING AT RAINFALL ACCUMULATIONS FROM THE PRECIPITATION THAT HAS
OCCURRED, MODELS HAVE OVERDONE AMOUNTS. GOING WITH THIS SAME TREND
FOR TODAY WILL ALLOW FOR LOWER STORM TOTALS AND REINFORCE THE
FORECAST FOR NO FLOODING IN THE RIVERS. SO FAR, STORM TOTAL
FORECASTS ARE ABOUT ONE HALF TO THREE QUARTERS OF AN INCH LOWER
THAN PREVIOUSLY THOUGHT.
AS THE DAY PROGRESSES, THERE WILL ALSO BE SOME INSTABILITY IN THE
AREA. CAPES OF BETWEEN 500 AND 1000 JOULES WILL BE ACROSS THE
AREA. HOWEVER, FORCING IS WEAK AND DAYTIME HEATING WILL BE
LIMITED. SO, HAVE RAIN SHOWERS IN THE FORECAST WITH ISOLD THUNDER
FOR THE AFTERNOON, EXCEPT IN THE SE ZONES WHERE SCATTERED
THUNDERSTORMS ARE FORECAST. THIS COULD CHANGE IF CLOUDS BREAK UP
OVER THE WESTERN ZONES AND TEMPS ARE HIGHER THAN FORECAST. WILL
LOOK AT THE NEW MODEL RUNS AND POSSIBLY CHANGE THUNDERSTORM
COVERAGE WITH NEXT FORECAST ISSUANCE AT 19Z.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
LOW PRESSURE BEGINS TO SLIDE OF TO THE EAST THIS EVENING, TAKING
THE PRECIPITATION ALONG WITH IT. THIS WILL ALLOW FOR A BREAK
THROUGH A GOOD PORTION OF THE NIGHT.
WEDNESDAY WILL SEE A COLD FRONT APPROACH THE CWA FROM THE WEST. IT
LOOKS TO PROVIDE ENOUGH LIFT BY TOMORROW AFTERNOON THAT SOME
ADDITIONAL THUNDERSTORMS MAY DEVELOP, ESPECIALLY ALONG THE FRONT.
MODELS ARE INDICATING THAT THE STRONGEST LIFT WILL BE OVER THE NY
ZONES. THE FURTHER SOUTH, THE DRIER THE FRONTAL PASSAGE, ALTHOUGH
SOME SHOWERS AND STORMS COULD STILL DEVELOP OVER NEPA. CURRENT SPC
OUTLOOK HAS THE CWA IN GENERAL THUNDERSTORMS. MODELS ARE SHOWING
THAT THE BEST CAPE TOMORROW WILL BE IN THE FAR EASTERN ZONES
DURING THE AFTERNOON HOURS. THE NAM HAS ABOUT 1200 JOULES TOMORROW
AFTERNOON IN THESE AREAS.
THIS FRONT WILL MOVE QUICKLY THROUGH THE CWA AND SHOULD BE EXITING
BY TOMORROW EVENING. BEHIND IT, HIGH PRESSURE WILL BUILD IN FOR
THE REMAINDER OF THE SHORT TERM FORECAST PERIOD. THERE WILL BE A
SOMEWHAT COOLER AIR MASS IN PLACE THROUGH THURSDAY NIGHT. HIGH
TEMPS THURSDAY WILL BE IN THE LOW TO MID 60S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
RDG BLDG OVER THE GREAT LAKES AND NE US DOMINATES THE LONG TERM
PD. SUBTLE DFRNCS IN THE PSN OF THE RDG BY THE MODELS ALLOW FOR
SOME MINOR DAY TO DAY FCST DFRNCS FOR THE PD. IN GNRL...THE ECMWF
KEEPS THE UPR RIDGE ORIENTED DIRECTLY OVER THE FCST AREA KEEPING
THE WEAK TROF OVER THE WRN LAKES FROM AFFECTING THE AREA...WHILE
THE GFS POSITIONS THE RDG LINE FURTHER SOUTH ALLOWING FOR SOME
SHRT WV ENERGY TO TRIGGER SCT SHWRS AND TRWS...ESP LATE IN THE PD.
ALSO...GFS ALLOWS SOMEWHAT WRMR AIR INTO THE FCST AREA ON A SLY
FLOW...THEREBY KEEPING TEMPS A BIT HIER. FOR THE PD...GNRLY USED
HPC GUID ALTHOUGH DID SOME ADJUSTMENTS TWRDS THE GFS SOLN BY
BUMPING UP TEMPS AND ADDING SOME VERY LOW CHANCE AND SLGT CHANCE
POS AT THE ENDS OF THE PD. IN GNRL THOUGH...PD WILL BE DRY AND
WARM AND A MARKED CONTRAST FROM THE FIRST PART OF THE WEEK.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
12Z UPDATE...MVFR TO IFR CONDITIONS EXPECTED THROUGH THE NEXT FEW
HOURS WITH A SLOW IMPROVEMENT TO VFR FROM MID MORNING INTO THE
AFTERNOON. HIGHLY VARIABLE FORECAST ACROSS THE TERMINALS SO HERE
ARE THE SPECIFICS.
KBGM...WORST CONDITIONS EXPECTED HERE WITH IFR CIGS AND VSBYS
THROUGH 13Z...WITH PERIODS OF LIFR CIGS AND VSBYS POSSIBLE.
SLOW IMPROVEMENT TO MVFR WILL NOT OCCUR UNTIL MID-MORNING WITH VFR
NOT UNTIL AFTERNOON.
KITH/KRME...MVFR CONDITIONS NOW MAY BRIEFLY LOWER TO IFR THROUGH
13ZBASED ON OBS TO THE SOUTH AND EAST. MVFR TO VFR BY LATE MORNING.
KSYR...A BRIEF PERIOD OF IFR/MVFR CIGS POSSIBLE THROUGH
13Z...OTHERWISE VFR WITH LIGHT SHOWERS THROUGH EARLY AFTERNOON.
KELM...IFR CIGS AND VSBYS IMPROVE TO MVFR THROUGH MID-MORNING
THEN VFR.
KAVP...MVFR LOWRING TO IFR IN THE NEXT HOUR OR SO. IFR THROUGH
MID-MORNING THEN MVFR THROUGH AFTERNOON.
MAINLY SOUTHEAST TO EAST WINDS THIS MORNING...WILL BECOME W TO NW AT
KELM/KITH/KSYR/KRME...AND W TO SW AT KBGM/KAVP THIS AFTERNOON...AT
5-10 KT.
.OUTLOOK...
TUE NGT...VFR EARLY...WITH POTNL FOR VLY FOG LATE AFFECTING KELM.
WED...MAINLY VFR...WDLY SCT AFTN -TSRA...WITH MVFR PSBL.
THU/FRI/SAT...VFR...XCPT LATE NGT VLY FOG AFFECTING KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...SLI
NEAR TERM...
SHORT TERM...SLI
LONG TERM...DGM
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
938 AM EDT TUE MAY 15 2012
.SYNOPSIS...
LOW PRESSURE WILL CONTINUE TO SPREAD RAIN ACROSS THE AREA THROUGH
TODAY...MAINLY EAST OF ROUTE 81...BEFORE ENDING TONIGHT. SKIES
WILL CLEAR EARLY WEDNESDAY AHEAD OF A COLD FRONT. THIS FRONT WILL
MOVE THROUGH LATE WEDNESDAY WITH SHOWERS AND A FEW THUNDERSTORMS.
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT AND BRING DRY WEATHER
FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
930 AM UPDATE...
BATCH OF MDT TO HVY RAIN MOVG THRU NE PA AND THE SUSQ RGN/CATSILLS
OF NY. THUS FAR NO PRBLMS BUT RR RATES OF UP TO .4 IN/HR ARE NOTED
ACRS PORTIONS OF NE PA. FORTUNATELY...BACKEDGE OF HEAVIER RAIN IS
NOW ENTERING SW LUZERNE...AND HEAVIER RAINS THIS AFTN SHUD BE
FOCUSED E OF THIS AREA WHERE ANTECEDENT RAINFALL HAS BEEN LOWER. NO
PRBLMS SO FAR FROM LACK/LUZ EMO`S. AS THIS S/WV EXITS...OTHER WEAK
IMPUSLES IN THE WSW FLOW ALOFT ARE NOTED UPSTREAM. REMNANTS OF SFC
TROF...ALSO EVIDENT IN THE 925/850 MB FCSTS FOR THIS AFTN...WILL
RESULT IN WEAK LOW LVL MSTR CONVERGENCE ACRS THE CNTRL SRN TIER
AND FINGER LAKES. RUC/GFS INDICATE POTNL CAPES UP TO NEARLY
1000 J/KG...BUT THE LOW LVL TD`S SEEM ON THE HIGH SIDE. FROM OUR
PERSPECTIVE...THE NAM LOOKED MORE RSNBL WITH CAPES IN THE 300-500
RNG. TCNTRL SRN TIER AND FINGER LAKES ARE MOST LIKELY TO SEE SOME
SUNSHINE THIS AFTN....SO ISOLD TO WDLY SCT TSRA PSBL THIS AFTN
ACRS CNTRL NY...MAINLY W OF I-81. MINOR TWEEKS TO CRNT FCST...OTRW
NO SIG CHGS.
LOW PRESSURE WILL CONTINUE TO BRING RAIN TO THE CWA THROUGH THE
DAY TODAY. MODELS SHOW A WEAK AREA OF LOW PRESSURE STALLING OVER
THE AREA TODAY, BEFORE BEING PUSHED OUT TONIGHT BY AN UPPER LEVEL
TROUGH. THE BEST LIFT WILL BE FROM THE EASTERN ZONE EASTWARD.
LOOKING AT RAINFALL ACCUMULATIONS FROM THE PRECIPITATION THAT HAS
OCCURRED, MODELS HAVE OVERDONE AMOUNTS. GOING WITH THIS SAME TREND
FOR TODAY WILL ALLOW FOR LOWER STORM TOTALS AND REINFORCE THE
FORECAST FOR NO FLOODING IN THE RIVERS. SO FAR, STORM TOTAL
FORECASTS ARE ABOUT ONE HALF TO THREE QUARTERS OF AN INCH LOWER
THAN PREVIOUSLY THOUGHT.
AS THE DAY PROGRESSES, THERE WILL ALSO BE SOME INSTABILITY IN THE
AREA. CAPES OF BETWEEN 500 AND 1000 JOULES WILL BE ACROSS THE
AREA. HOWEVER, FORCING IS WEAK AND DAYTIME HEATING WILL BE
LIMITED. SO, HAVE RAIN SHOWERS IN THE FORECAST WITH ISOLD THUNDER
FOR THE AFTERNOON, EXCEPT IN THE SE ZONES WHERE SCATTERED
THUNDERSTORMS ARE FORECAST. THIS COULD CHANGE IF CLOUDS BREAK UP
OVER THE WESTERN ZONES AND TEMPS ARE HIGHER THAN FORECAST. WILL
LOOK AT THE NEW MODEL RUNS AND POSSIBLY CHANGE THUNDERSTORM
COVERAGE WITH NEXT FORECAST ISSUANCE AT 19Z.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
LOW PRESSURE BEGINS TO SLIDE OF TO THE EAST THIS EVENING, TAKING
THE PRECIPITATION ALONG WITH IT. THIS WILL ALLOW FOR A BREAK
THROUGH A GOOD PORTION OF THE NIGHT.
WEDNESDAY WILL SEE A COLD FRONT APPROACH THE CWA FROM THE WEST. IT
LOOKS TO PROVIDE ENOUGH LIFT BY TOMORROW AFTERNOON THAT SOME
ADDITIONAL THUNDERSTORMS MAY DEVELOP, ESPECIALLY ALONG THE FRONT.
MODELS ARE INDICATING THAT THE STRONGEST LIFT WILL BE OVER THE NY
ZONES. THE FURTHER SOUTH, THE DRIER THE FRONTAL PASSAGE, ALTHOUGH
SOME SHOWERS AND STORMS COULD STILL DEVELOP OVER NEPA. CURRENT SPC
OUTLOOK HAS THE CWA IN GENERAL THUNDERSTORMS. MODELS ARE SHOWING
THAT THE BEST CAPE TOMORROW WILL BE IN THE FAR EASTERN ZONES
DURING THE AFTERNOON HOURS. THE NAM HAS ABOUT 1200 JOULES TOMORROW
AFTERNOON IN THESE AREAS.
THIS FRONT WILL MOVE QUICKLY THROUGH THE CWA AND SHOULD BE EXITING
BY TOMORROW EVENING. BEHIND IT, HIGH PRESSURE WILL BUILD IN FOR
THE REMAINDER OF THE SHORT TERM FORECAST PERIOD. THERE WILL BE A
SOMEWHAT COOLER AIR MASS IN PLACE THROUGH THURSDAY NIGHT. HIGH
TEMPS THURSDAY WILL BE IN THE LOW TO MID 60S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
IMPRVMNT WITH A WARMING TREND FOR THE MEDIUM RNG AS THE NE U.S.
TROF BEGINS TO PULL OUT AND UPR LVL/SFC RIDGING COMMENCES. BY
LATER IN THE WEEKEND THE PTRN DOES BCM MORE FVRBL FOR THE DVLPMNT
OF SOME ISOLD/WDLY SCT -TSRA MAINLY DUE TO DIURNAL EFFECTS...AND
THE PREV 00Z EURO SUGGESTED SOME POTNL FOR MCS ACTIVITY WITH
SYSTEMS DROPPING OUT OF CANADA OVER THE WEEKEND. GFS NOT SHOWING
THIS...AND INDEED HPC POPS INDICATE A DRY FCST UNTIL MONDAY OF NXT
WEEK. WE SEE NO REASON TO TO DISAGREE. WE DID GO MORE OPTIMISTIC
WITH THE SKY COVER THAN THE HPC FCST...WITH GNRLY PARTLY
SUNNY/PARTLY CLOUDY SKIES THRU THE PD.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
12Z UPDATE...MVFR TO IFR CONDITIONS EXPECTED THROUGH THE NEXT FEW
HOURS WITH A SLOW IMPROVEMENT TO VFR FROM MID MORNING INTO THE
AFTERNOON. HIGHLY VARIABLE FORECAST ACROSS THE TERMINALS SO HERE
ARE THE SPECIFICS.
KBGM...WORST CONDITIONS EXPECTED HERE WITH IFR CIGS AND VSBYS
THROUGH 13Z...WITH PERIODS OF LIFR CIGS AND VSBYS POSSIBLE.
SLOW IMPROVEMENT TO MVFR WILL NOT OCCUR UNTIL MID-MORNING WITH VFR
NOT UNTIL AFTERNOON.
KITH/KRME...MVFR CONDITIONS NOW MAY BRIEFLY LOWER TO IFR THROUGH
13ZBASED ON OBS TO THE SOUTH AND EAST. MVFR TO VFR BY LATE MORNING.
KSYR...A BRIEF PERIOD OF IFR/MVFR CIGS POSSIBLE THROUGH
13Z...OTHERWISE VFR WITH LIGHT SHOWERS THROUGH EARLY AFTERNOON.
KELM...IFR CIGS AND VSBYS IMPROVE TO MVFR THROUGH MID-MORNING
THEN VFR.
KAVP...MVFR LOWRING TO IFR IN THE NEXT HOUR OR SO. IFR THROUGH
MID-MORNING THEN MVFR THROUGH AFTERNOON.
MAINLY SOUTHEAST TO EAST WINDS THIS MORNING...WILL BECOME W TO NW AT
KELM/KITH/KSYR/KRME...AND W TO SW AT KBGM/KAVP THIS AFTERNOON...AT
5-10 KT.
.OUTLOOK...
TUE NGT...VFR EARLY...WITH POTNL FOR VLY FOG LATE AFFECTING KELM.
WED...MAINLY VFR...WDLY SCT AFTN -TSRA...WITH MVFR PSBL.
THU/FRI/SAT...VFR...XCPT LATE NGT VLY FOG AFFECTING KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...SLI
SHORT TERM...SLI
LONG TERM...HEDEN
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
202 AM EDT TUE MAY 15 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE UP THE EAST COAST TONIGHT, AND SPREAD RAIN
INTO THE AREA THROUGH TUESDAY, BEFORE ENDING LATE TUESDAY AND
TUESDAY NIGHT. SKIES WILL CLEAR BRIEFLY LATE TUESDAY AND EARLY
WEDNESDAY AHEAD OF A COLD FRONT. THIS FRONT WILL MOVE THROUGH LATE
WEDNESDAY WITH SHOWERS. HIGH PRESSURE WILL BUILD IN BEHIND THE
FRONT AND BRING DRY WEATHER FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
9PM UPDATE...
WITH PRECIP ADVANCING TO THE MOHAWK VALLEY AND ELMIRA UPPED POPS.
RAINFALL AMOUNTS LAST 6 HOURS UNDER HALF AN INCH. HEAVIER RAIN
STILL EXPECTED DURING THE OVERNIGHT BUT AT THIS RATE MAY BE HARD
TO GET 2 INCHES IN THE SE. MINOR OTHER CHANGES.
625 PM UPDATE...
MINOR ADJUSTMENTS...MOSTLY FOR THE SPEED AND COVERAGE OF THE RAIN.
IN GENERAL FORECAST ON TRACK. RAINFALL AMOUNTS SO FAR UNDER AN
INCH.
PREVIOUS DISCUSSION...
MODELS STILL RESOLVING THE UPCOMING RAIN EVENT. OPERATIONAL NAM
HAS GONE BACK TO IT/S EARLIER SOLN AND BRINGS RAIN BACK TO THE
WEST WITHOUT GENERATING THE QPF BULLSEYE OVER THE ERN ZONES. SREF
MEAN SOLN IS MORE IN LINE WITH THE OPERATIONAL GFS WHICH HAS A
PCPN MAX OVER THE UPSLOPE AREAS IN THE CATSKILLS AND POCONOS.
HWVR...GFS MAX ACCUMULATED QPF OF OVER 4.5 INCHES SEEMS TOO
HIGH...AND MODEL MAY BE SUFFERING FROM CONV FEEDBACK WITH STRONG
STORMS FIRING OVER THE SE. SYSTEM HAS GOOD JET STRUCTURE WITH UPR
DIVERGENCE IN THE RR QUAD AND GOOD LL SLY INFLOW. PWATS APRCHS 2"
OVER THE EAST CST...A BIT LESS OVER THE FCST AREA.
CONSENSUS AVGD QPF PUTS 30 HR AMTS OVER THE WRN CATS APRCHG 2
INCHES...WELL BLO FFG AND HEADWATERS GUID. AREA HAS ACTUALLY BEEN A
BIT DRY AND HAS SOME OF THE HIGHEST GUID IN THEN FCST AREA.
SO...AFTER XTNSV COORD WITH SURROUNDING OFFICES HAVE DECIDED TO
HOLD OFF ON A WATCH ATTM. WILL KEEP HWO GOING WITH A MENTION OF
PTNL PRBLMS IF AMTS ARE HIGHER.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
OLD FNT IS SLOW TO MVE AS YET ANOTHER WV RIDES UP ON TUE...SLOWING
THE EWRD ADVANCE. LOOKS LIKE SOME HEAVIER RAIN COULD LINGER IN THE
EAST THRU ABT 18Z TUE AS THE WV PASSES. STILL...BNDRY REMAINS
NEARLY STATIONARY INTO EARLY WED BEFORE A STRONGER SHRT WV AND
SFC FNT APRCHS FROM THE WEST AND PUSHES IT ALONG.
WED/S FNT DOES NOT HAVE THE MOISTURE CONNECTION THAT TUE/S
DOES...SO DESPITE GOOD LL CONVERGENCE AND SUPPORT ALOFT...FNT MAY
NOT GENERATE ALL THAT MUCH PCPN. SOME MRGNL INSTABILITY DOES BRING
THE CHANCE OF CONV WITH THE FNT...ESP OVER THE NORTH NEAR THE
BETTER DYNAMICS AND SOME POOLED LL MOISTURE.
MUCH COOLER AND DRIER AIR FOLLOWS THE FNT ON THU AS A SFC HIPRES
BLDS INTO THE OH VLY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
IMPRVMNT WITH A WARMING TREND FOR THE MEDIUM RNG AS THE NE U.S.
TROF BEGINS TO PULL OUT AND UPR LVL/SFC RIDGING COMMENCES. BY
LATER IN THE WEEKEND THE PTRN DOES BCM MORE FVRBL FOR THE DVLPMNT
OF SOME ISOLD/WDLY SCT -TSRA MAINLY DUE TO DIURNAL EFFECTS...AND
THE PREV 00Z EURO SUGGESTED SOME POTNL FOR MCS ACTIVITY WITH
SYSTEMS DROPPING OUT OF CANADA OVER THE WEEKEND. GFS NOT SHOWING
THIS...AND INDEED HPC POPS INDICATE A DRY FCST UNTIL MONDAY OF NXT
WEEK. WE SEE NO REASON TO TO DISAGREE. WE DID GO MORE OPTIMISTIC
WITH THE SKY COVER THAN THE HPC FCST...WITH GNRLY PARTLY
SUNNY/PARTLY CLOUDY SKIES THRU THE PD.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
06Z UPDATE...MVFR TO IFR CONDITIONS EXPECTED THROUGH
DAYBREAK...WITH A SLOW IMPROVEMENT TO VFR FROM MID MORNING INTO
THE AFTERNOON. HIGHLY VARIABLE FORECAST ACROSS THE TERMINALS SO
HERE ARE THE SPECIFICS.
KBGM...WORST CONDITIONS EXPECTED HERE WITH IFR CIGS AND VSBYS
THROUGH DAYBREAK...WITH PERIODS OF LIFR CIGS AND VSBYS POSSIBLE.
SLOW IMPROVEMENT TO MVFR WILL NOT OCCUR UNTIL MID-MORNING WITH VFR
NOT UNTIL AFTERNOON.
KITH/KRME...CONDITIONS SHOULD GRADUALLY LOWER TO MVFR THROUGH THE
NEXT FEW HOURS. BASED ON OBS TO THE SOUTH AND EAST...IFR CIGS
APPEAR TO BE MOST LIKELY BETWEEN 09Z AND 13Z. IMPROVEMENT TO MVFR
BY MID-MORNING WITH VFR BY AFTERNOON.
KSYR...GENERALLY VFR WEATHER IS EXPECTED. AS STEADIER RAIN
APPROACHES THE TERMINAL FROM THE SOUTHEAST...LOWER CIGS (MVFR) ARE
POSSIBLE JUST PRIOR TO DAYBREAK.
KELM...SOME IFR CIGS POSSIBLE THE NEXT HOUR OR SO BUT GENERALLY
MVFR THROUGH MID-MORNING THEN VFR.
KAVP...GRADUALLY LOWERING TO MVFR BY 09Z. MOST MODEL GUIDANCE
CONTINUES TO SUGGEST IFR CIGS FOR A SIGNIFICANT PERIOD BEYOND 09Z.
CONTINUED THE COURSE BASED ON OBS TO THE SOUTHWEST...WITH IFR
THROUGH MID-MORNING THEN MVFR THROUGH AFTERNOON.
MAINLY SOUTHEAST TO EAST WINDS THIS MORNING...WILL BECOME W TO NW AT
KELM/KITH/KSYR/KRME...AND W TO SW AT KBGM/KAVP THIS AFTERNOON...AT
5-10 KT.
.OUTLOOK...
TUE NGT...VFR EARLY...WITH POTNL FOR VLY FOG LATE AFFECTING KELM.
WED...MAINLY VFR...WDLY SCT AFTN -TSRA...WITH MVFR PSBL.
THU/FRI/SAT...VFR...XCPT LATE NGT VLY FOG AFFECTING KELM.
&&
.HYDROLOGY...
IN GENERAL FLASH FLOOD AND HEADWATER GUID BLO FCSTD QPF FROM
NEARLY ALL SOURCES. OUTLIER IS THE GFS WHICH DROPS A 30 HR TTL OF
ARND 4.5 INCHES OVER THE UPR DELAWARE BASIN. THAT AMT WLD CAUSE
FLOODING ISSUES BUT CONSENSUS IS THAT THE MODEL IS SUFFERING SOME
CONV FEEDBACK ISSUES. HWVR...PLACEMENT FROM THE GFS SEEMS CORRECT
SO BEST LOCATION FOR THE HIGHEST QPF APPEARS TO BE OVER ERN
DELAWARE AND NRN SULLIVAN...IN THE DELAWARE BASIN. HERE THE TOTAL QPF
IS 2 TO 2.5 INCHES WHICH COULD CAUSE MINOR FLOODING OF THE
FLASHIER CREEKS AND STREAMS SUCH AS THE WEST BRANCH AT WALTON. TO
THE WEST OVER THE UPR AND NORTH BRANCH SUSQ BASINS...AVERAGED
AMTS WILL BE LESS SO RVRS SHD STAY WELL BLO FLOOD STAGE. FOR THE
FINGER LAKES AND CHEMUNG BASINS AMOUNTS AN INCH OR LESS SO NO
PROBLEMS EXPECTED.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/TAC
SHORT TERM...DGM
LONG TERM...
AVIATION...HEDEN
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
935 PM EDT MON MAY 14 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE UP THE EAST COAST TONIGHT, AND SPREAD RAIN
INTO THE AREA THROUGH TUESDAY, BEFORE ENDING LATE TUESDAY AND
TUESDAY NIGHT. SKIES WILL CLEAR BRIEFLY LATE TUESDAY AND EARLY
WEDNESDAY AHEAD OF A COLD FRONT. THIS FRONT WILL MOVE THROUGH LATE
WEDNESDAY WITH SHOWERS. HIGH PRESSURE WILL BUILD IN BEHIND THE
FRONT AND BRING DRY WEATHER FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
9PM UPDATE...
WITH PRECIP ADVANCING TO THE MOHAWK VALLEY AND ELMIRA UPPED POPS.
RAINFALL AMOUNTS LAST 6 HOURS UNDER HALF AN INCH. HEAVIER RAIN
STILL EXPECTED DURING THE OVERNIGHT BUT AT THIS RATE MAY BE HARD
TO GET 2 INCHES IN THE SE. MINOR OTHER CHANGES.
625 PM UPDATE...
MINOR ADJUSTMENTS...MOSTLY FOR THE SPEED AND COVERAGE OF THE RAIN.
IN GENERAL FORECAST ON TRACK. RAINFALL AMOUNTS SO FAR UNDER AN
INCH.
PREVIOUS DISCUSSION...
MODELS STILL RESOLVING THE UPCOMING RAIN EVENT. OPERATIONAL NAM
HAS GONE BACK TO IT/S EARLIER SOLN AND BRINGS RAIN BACK TO THE
WEST WITHOUT GENERATING THE QPF BULLSEYE OVER THE ERN ZONES. SREF
MEAN SOLN IS MORE IN LINE WITH THE OPERATIONAL GFS WHICH HAS A
PCPN MAX OVER THE UPSLOPE AREAS IN THE CATSKILLS AND POCONOS.
HWVR...GFS MAX ACCUMULATED QPF OF OVER 4.5 INCHES SEEMS TOO
HIGH...AND MODEL MAY BE SUFFERING FROM CONV FEEDBACK WITH STRONG
STORMS FIRING OVER THE SE. SYSTEM HAS GOOD JET STRUCTURE WITH UPR
DIVERGENCE IN THE RR QUAD AND GOOD LL SLY INFLOW. PWATS APRCHS 2"
OVER THE EAST CST...A BIT LESS OVER THE FCST AREA.
CONSENSUS AVGD QPF PUTS 30 HR AMTS OVER THE WRN CATS APRCHG 2
INCHES...WELL BLO FFG AND HEADWATERS GUID. AREA HAS ACTUALLY BEEN A
BIT DRY AND HAS SOME OF THE HIGHEST GUID IN THEN FCST AREA.
SO...AFTER XTNSV COORD WITH SURROUNDING OFFICES HAVE DECIDED TO
HOLD OFF ON A WATCH ATTM. WILL KEEP HWO GOING WITH A MENTION OF
PTNL PRBLMS IF AMTS ARE HIGHER.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
OLD FNT IS SLOW TO MVE AS YET ANOTHER WV RIDES UP ON TUE...SLOWING
THE EWRD ADVANCE. LOOKS LIKE SOME HEAVIER RAIN COULD LINGER IN THE
EAST THRU ABT 18Z TUE AS THE WV PASSES. STILL...BNDRY REMAINS
NEARLY STATIONARY INTO EARLY WED BEFORE A STRONGER SHRT WV AND
SFC FNT APRCHS FROM THE WEST AND PUSHES IT ALONG.
WED/S FNT DOES NOT HAVE THE MOISTURE CONNECTION THAT TUE/S
DOES...SO DESPITE GOOD LL CONVERGENCE AND SUPPORT ALOFT...FNT MAY
NOT GENERATE ALL THAT MUCH PCPN. SOME MRGNL INSTABILITY DOES BRING
THE CHANCE OF CONV WITH THE FNT...ESP OVER THE NORTH NEAR THE
BETTER DYNAMICS AND SOME POOLED LL MOISTURE.
MUCH COOLER AND DRIER AIR FOLLOWS THE FNT ON THU AS A SFC HIPRES
BLDS INTO THE OH VLY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
IMPRVMNT WITH A WARMING TREND FOR THE MEDIUM RNG AS THE NE U.S.
TROF BEGINS TO PULL OUT AND UPR LVL/SFC RIDGING COMMENCES. BY
LATER IN THE WEEKEND THE PTRN DOES BCM MORE FVRBL FOR THE DVLPMNT
OF SOME ISOLD/WDLY SCT -TSRA MAINLY DUE TO DIURNAL EFFECTS...AND
THE PREV 00Z EURO SUGGESTED SOME POTNL FOR MCS ACTIVITY WITH
SYSTEMS DROPPING OUT OF CANADA OVER THE WEEKEND. GFS NOT SHOWING
THIS...AND INDEED HPC POPS INDICATE A DRY FCST UNTIL MONDAY OF NXT
WEEK. WE SEE NO REASON TO TO DISAGREE. WE DID GO MORE OPTIMISTIC
WITH THE SKY COVER THAN THE HPC FCST...WITH GNRLY PARTLY
SUNNY/PARTLY CLOUDY SKIES THRU THE PD.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
00Z TUE UPDATE... OTHER THAN VFR EARLY THIS EVE AT
KSYR/KRME...RESTRICTIVE CONDS SHOULD DOMINATE FOR MUCH OF THE
VALID TAF PD. STEADY RAIN WILL CONTINUE INTO TUE AM AT
KAVP/KBGM...AND WILL GRADUALLY BECOME MORE PREVALENT ELSEWHERE.
FOR THE MOST PART...WE`RE LOOKING FOR MVFR CIGS/VSBYS.
HOWEVER...AT KAVP...IFR IS A DISTINCT PSBLTY EARLY TUE (BETWEEN
ABT 09Z AND 15Z). IFR COULD OCCUR JUST ABT ANYTIME OVERNIGHT INTO TUE
AM AT KBGM.
TUE AFTN...AS THE STEADIER RAIN BEGINS TO MOVE OFF TO THE E...WE
SHOULD BE LEFT WITH LINGERING CLDNS/SCTD SHRA. THERE COULD BE
ENOUGH IMPROVEMENT TO BRING A RETURN TO VFR AT KELM AND KSYR.
ELSEWHERE HOWEVER...WE SHOULD HANG ON TO MVFR RESTRICTIONS.
LGT AND VRBL WINDS OVERNIGHT AND TUE AM...WILL BECOME W TO NW AT
KELM/KITH/KSYR/KRME...AND W TO SW AT KBGM/KAVP TUE AFTN...AT 5-10
KT.
.OUTLOOK...
TUE NGT...LINGERING MVFR AT KAVP...VFR ELSEWHERE...WITH POTNL FOR
VLY FOG LATE AFFECTING KELM.
WED...MAINLY VFR...WDLY SCT AFTN -TSRA...WITH MVFR PSBL.
THU/FRI/SAT...VFR...XCPT LATE NGT VLY FOG AFFECTING KELM.
&&
.HYDROLOGY...
IN GENERAL FLASH FLOOD AND HEADWATER GUID BLO FCSTD QPF FROM
NEARLY ALL SOURCES. OUTLIER IS THE GFS WHICH DROPS A 30 HR TTL OF
ARND 4.5 INCHES OVER THE UPR DELAWARE BASIN. THAT AMT WLD CAUSE
FLOODING ISSUES BUT CONSENSUS IS THAT THE MODEL IS SUFFERING SOME
CONV FEEDBACK ISSUES. HWVR...PLACEMENT FROM THE GFS SEEMS CORRECT
SO BEST LOCATION FOR THE HIGHEST QPF APPEARS TO BE OVER ERN
DELAWARE AND NRN SULLIVAN...IN THE DELAWARE BASIN. HERE THE TOTAL QPF
IS 2 TO 2.5 INCHES WHICH COULD CAUSE MINOR FLOODING OF THE
FLASHIER CREEKS AND STREAMS SUCH AS THE WEST BRANCH AT WALTON. TO
THE WEST OVER THE UPR AND NORTH BRANCH SUSQ BASINS...AVERAGED
AMTS WILL BE LESS SO RVRS SHD STAY WELL BLO FLOOD STAGE. FOR THE
FINGER LAKES AND CHEMUNG BASINS AMOUNTS AN INCH OR LESS SO NO
PROBLEMS EXPECTED.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/TAC
SHORT TERM...DGM
LONG TERM...
AVIATION...MLJ
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
806 PM EDT MON MAY 14 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE UP THE EAST COAST TONIGHT, AND SPREAD RAIN
INTO THE AREA THROUGH TUESDAY, BEFORE ENDING LATE TUESDAY AND
TUESDAY NIGHT. SKIES WILL CLEAR BRIEFLY LATE TUESDAY AND EARLY
WEDNESDAY AHEAD OF A COLD FRONT. THIS FRONT WILL MOVE THROUGH LATE
WEDNESDAY WITH SHOWERS. HIGH PRESSURE WILL BUILD IN BEHIND THE
FRONT AND BRING DRY WEATHER FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
625 PM UPDATE...
MINOR ADJUSTMENTS...MOSTLY FOR THE SPEED AND COVERAGE OF THE RAIN.
IN GENERAL FORECAST ON TRACK. RAINFALL AMOUNTS SO FAR UNDER AN
INCH.
PREVIOUS DISCUSSION...
MODELS STILL RESOLVING THE UPCOMING RAIN EVENT. OPERATIONAL NAM
HAS GONE BACK TO IT/S EARLIER SOLN AND BRINGS RAIN BACK TO THE
WEST WITHOUT GENERATING THE QPF BULLSEYE OVER THE ERN ZONES. SREF
MEAN SOLN IS MORE IN LINE WITH THE OPERATIONAL GFS WHICH HAS A
PCPN MAX OVER THE UPSLOPE AREAS IN THE CATSKILLS AND POCONOS.
HWVR...GFS MAX ACCUMULATED QPF OF OVER 4.5 INCHES SEEMS TOO
HIGH...AND MODEL MAY BE SUFFERING FROM CONV FEEDBACK WITH STRONG
STORMS FIRING OVER THE SE. SYSTEM HAS GOOD JET STRUCTURE WITH UPR
DIVERGENCE IN THE RR QUAD AND GOOD LL SLY INFLOW. PWATS APRCHS 2"
OVER THE EAST CST...A BIT LESS OVER THE FCST AREA.
CONSENSUS AVGD QPF PUTS 30 HR AMTS OVER THE WRN CATS APRCHG 2
INCHES...WELL BLO FFG AND HEADWATERS GUID. AREA HAS ACTUALLY BEEN A
BIT DRY AND HAS SOME OF THE HIGHEST GUID IN THEN FCST AREA.
SO...AFTER XTNSV COORD WITH SURROUNDING OFFICES HAVE DECIDED TO
HOLD OFF ON A WATCH ATTM. WILL KEEP HWO GOING WITH A MENTION OF
PTNL PRBLMS IF AMTS ARE HIGHER.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
OLD FNT IS SLOW TO MVE AS YET ANOTHER WV RIDES UP ON TUE...SLOWING
THE EWRD ADVANCE. LOOKS LIKE SOME HEAVIER RAIN COULD LINGER IN THE
EAST THRU ABT 18Z TUE AS THE WV PASSES. STILL...BNDRY REMAINS
NEARLY STATIONARY INTO EARLY WED BEFORE A STRONGER SHRT WV AND
SFC FNT APRCHS FROM THE WEST AND PUSHES IT ALONG.
WED/S FNT DOES NOT HAVE THE MOISTURE CONNECTION THAT TUE/S
DOES...SO DESPITE GOOD LL CONVERGENCE AND SUPPORT ALOFT...FNT MAY
NOT GENERATE ALL THAT MUCH PCPN. SOME MRGNL INSTABILITY DOES BRING
THE CHANCE OF CONV WITH THE FNT...ESP OVER THE NORTH NEAR THE
BETTER DYNAMICS AND SOME POOLED LL MOISTURE.
MUCH COOLER AND DRIER AIR FOLLOWS THE FNT ON THU AS A SFC HIPRES
BLDS INTO THE OH VLY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
IMPRVMNT WITH A WARMING TREND FOR THE MEDIUM RNG AS THE NE U.S.
TROF BEGINS TO PULL OUT AND UPR LVL/SFC RIDGING COMMENCES. BY
LATER IN THE WEEKEND THE PTRN DOES BCM MORE FVRBL FOR THE DVLPMNT
OF SOME ISOLD/WDLY SCT -TSRA MAINLY DUE TO DIURNAL EFFECTS...AND
THE PREV 00Z EURO SUGGESTED SOME POTNL FOR MCS ACTIVITY WITH
SYSTEMS DROPPING OUT OF CANADA OVER THE WEEKEND. GFS NOT SHOWING
THIS...AND INDEED HPC POPS INDICATE A DRY FCST UNTIL MONDAY OF NXT
WEEK. WE SEE NO REASON TO TO DISAGREE. WE DID GO MORE OPTIMISTIC
WITH THE SKY COVER THAN THE HPC FCST...WITH GNRLY PARTLY
SUNNY/PARTLY CLOUDY SKIES THRU THE PD.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
00Z TUE UPDATE... OTHER THAN VFR EARLY THIS EVE AT
KSYR/KRME...RESTRICTIVE CONDS SHOULD DOMINATE FOR MUCH OF THE
VALID TAF PD. STEADY RAIN WILL CONTINUE INTO TUE AM AT
KAVP/KBGM...AND WILL GRADUALLY BECOME MORE PREVALENT ELSEWHERE.
FOR THE MOST PART...WE`RE LOOKING FOR MVFR CIGS/VSBYS.
HOWEVER...AT KAVP...IFR IS A DISTINCT PSBLTY EARLY TUE (BETWEEN
ABT 09Z AND 15Z). IFR COULD OCCUR JUST ABT ANYTIME OVERNIGHT INTO TUE
AM AT KBGM.
TUE AFTN...AS THE STEADIER RAIN BEGINS TO MOVE OFF TO THE E...WE
SHOULD BE LEFT WITH LINGERING CLDNS/SCTD SHRA. THERE COULD BE
ENOUGH IMPROVEMENT TO BRING A RETURN TO VFR AT KELM AND KSYR.
ELSEWHERE HOWEVER...WE SHOULD HANG ON TO MVFR RESTRICTIONS.
LGT AND VRBL WINDS OVERNIGHT AND TUE AM...WILL BECOME W TO NW AT
KELM/KITH/KSYR/KRME...AND W TO SW AT KBGM/KAVP TUE AFTN...AT 5-10
KT.
.OUTLOOK...
TUE NGT...LINGERING MVFR AT KAVP...VFR ELSEWHERE...WITH POTNL FOR
VLY FOG LATE AFFECTING KELM.
WED...MAINLY VFR...WDLY SCT AFTN -TSRA...WITH MVFR PSBL.
THU/FRI/SAT...VFR...XCPT LATE NGT VLY FOG AFFECTING KELM.
&&
.HYDROLOGY...
IN GENERAL FLASH FLOOD AND HEADWATER GUID BLO FCSTD QPF FROM
NEARLY ALL SOURCES. OUTLIER IS THE GFS WHICH DROPS A 30 HR TTL OF
ARND 4.5 INCHES OVER THE UPR DELAWARE BASIN. THAT AMT WLD CAUSE
FLOODING ISSUES BUT CONSENSUS IS THAT THE MODEL IS SUFFERING SOME
CONV FEEDBACK ISSUES. HWVR...PLACEMENT FROM THE GFS SEEMS CORRECT
SO BEST LOCATION FOR THE HIGHEST QPF APPEARS TO BE OVER ERN
DELAWARE AND NRN SULLIVAN...IN THE DELAWARE BASIN. HERE THE TOTAL QPF
IS 2 TO 2.5 INCHES WHICH COULD CAUSE MINOR FLOODING OF THE
FLASHIER CREEKS AND STREAMS SUCH AS THE WEST BRANCH AT WALTON. TO
THE WEST OVER THE UPR AND NORTH BRANCH SUSQ BASINS...AVERAGED
AMTS WILL BE LESS SO RVRS SHD STAY WELL BLO FLOOD STAGE. FOR THE
FINGER LAKES AND CHEMUNG BASINS AMOUNTS AN INCH OR LESS SO NO
PROBLEMS EXPECTED.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/TAC
SHORT TERM...DGM
LONG TERM...
AVIATION...MLJ
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
142 PM EDT TUE MAY 15 2012
.SYNOPSIS...
A VERY SLOW MOVING COLD FRONT WILL BE A FOCUS FOR SHOWERS AND
THUNDERSTORMS TODAY...WITH A FEW THUNDERSTORMS PRODUCING HEAVY
RAIN AND GUSTY WINDS. SHOWERS AND THUNDERSTORMS WILL DEVELOP AGAIN
WEDNESDAY BEFORE COLD FRONT MOVES OFFSHORE WEDNESDAY NIGHT. HIGH
PRESSURE WILL BUILD INTO THE REGION THURSDAY...BRINGING DRIER AND
SEASONABLE WEATHER INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2:00 PM TUESDAY...STATIONARY FRONT REMAINS TO THE WEST AS A
BROAD SOUTHWESTERLY FLOW CONTINUES ALOFT. SEA BREEZE CONVECTION
HAS FIRED AND SPC MESO-ANALYSIS PAGE SHOWS MIXED LAYER CAPE VALUES
NEAR 2000 J/KG INLAND. SHOULD SEE CONVECTION FIRE SHORTLY IN THESE
AREAS AS HEATING CONTINUES. GFS HAS BACKED OFF THE POPS INLAND FOR
OVERNIGHT BUT THE NAM AND HRRR CONTINUE TO BE QUITE AGGRESSIVE.
BACKED OFF POPS SLIGHTLY BUT WILL CONTINUE TO ADVERTISE LIKELY
VALUES MAXIMIZED AROUND 0000 UTC ACROSS WESTERN COUNTIES WITH
CHANCE ELSEWHERE. LATEST SPC DAY ONE OUTLOOK HAS NOT CHANGED FROM
EARLIER VERSIONS. FOR OVERNIGHT LOWS...WITH THE TROPICAL AIRMASS
IN PLACE CONTINUED TO GO WARMER THAN GUIDANCE.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 2:00 PM TUESDAY...COLD FRONT WILL REMAIN A FOCUS FOR
CONVECTION ON WEDNESDAY AS IT MOVES SLOWLY SOUTHEAST ACROSS THE
FORECAST AREA. AIR MASS WILL REMAIN JUICY AND WARM AND AT LEAST
MARGINALLY UNSTABLE...WITH DEW POINTS WELL IN THE 60S AND P/W
VALUES OF AROUND AN INCH AND A HALF. FRONT SHOULD MOVE OFFSHORE
AROUND DAYBREAK ON THURSDAY.
LATEST GUIDANCE HINTS AT FRONT LINGERING JUST OFFSHORE INTO THE
DAYLIGHT HOURS ON THURSDAY AS AN UPPER WEAKNESS LINGERS OVER THE
EASTERN CAROLINAS. THIS WILL KEEP IN THE POSSIBILITY OF
CONVECTION ON THURSDAY...ESPECIALLY FOR THE COASTAL COUNTIES.
MODEL SOUNDINGS ALSO KEEP IN DEEP MOISTURE FOR MUCH OF THAT DAY.
HAVE RAMPED UP POPS FOR THURSDAY AS A RESULT...ALTHOUGH CONFIDENCE
NOT HIGH AT THIS POINT.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM TUESDAY...THERE ARE TWO GUIDANCE CAMPS FOR THE
EXTENDED. THE GFS/CMC DEVELOP ELONGATED RIDGING ACROSS THE OH VLY
WITH A BAGGY TROUGH PERSISTING FROM THE WESTERN ATLANTIC INTO
FLORIDA...WHILE THE ECMWF STILL DEVELOPS A CLOSED UPPER LOW OVER THE
WESTERN ATLANTIC ABOVE A HYBRID SURFACE CYCLONE. ALTHOUGH THE ECMWF
HAS BEEN SHOWING THIS FOR SEVERAL RUNS...WEAKER BLOCKING UPSTREAM
COMBINED WITH THE VERY SIMILAR GFS/CMC AND OVERALL DRIER FORECAST
PROFILES SUGGEST MUCH LESS CHANCE OF HYBRID CYCLONE DEVELOPMENT.
STILL...SOME LOWERED HEIGHTS TROUGHING BACK TOWARDS THE SOUTHEAST
SUGGEST THAT THE GFS IS NOT GIVING UP ON THIS SOLUTION
ENTIRELY...AND EVEN SO...WOULD NOT JUMP EXCLUSIVELY ON THE CMC/GFS
BANDWAGON SINCE THIS MARKS A LARGE DEPARTURE FROM PREVIOUS
SOLUTIONS. HOWEVER...WILL GO WITH A DRY FORECAST THROUGH THE PERIOD
THANKS TO SURFACE RIDGING PERSISTING FROM THE NORTH...AND THE NOW
EXPECTED DRY/STABLE LAYERS ABOVE THE SURFACE.
WITH NE FLOW THROUGH THE PERIOD...TEMPS WILL REMAIN RIGHT AROUND
CLIMO FOR BOTH HIGHS AND LOWS...EVEN AS THICKNESSES BEGIN TO RETURN
TO MORE SUBTROPICAL LEVELS. SOME PRECIP MAY AGAIN APPROACH THE
REGION MONDAY...BUT FOR NOW WILL KEEP POP OUT OF THE FORECAST 7 DAYS
OUT.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AS OF 18Z...THERE MAY BE ENOUGH OF A DRY PUNCH ALOFT TO KEEP STORMS
FROM BEING NUMEROUS THIS AFTERNOON. THERE WILL BE TWO MAIN
AREAS...ALONG THE SEA BREEZE BOUNDARY EARLY...MAINLY OVER NORTH
CAROLINA...AND ALONG A TROUGH OVER THE WESTERN CWA TOWARDS EVENING.
THE AREA WEST WILL PROBABLY HAVE THE STRONGEST STORMS.
OVERNIGHT...CONVECTION WILL STILL BE ONGOING AND WILL LIKELY NOT DIE
OUT UNTIL AFTER MIDNIGHT...AND EVEN THEN WE MAY GET ISOLATED
ACTIVITY REACHING THE COAST. STRATUS/FOG WILL COME INTO THE PICTURE
AGAIN WITH ALL THE LOW LEVEL MOISTURE AVAILABLE. WEDNESDAY...SLOW
IMPROVEMENT IN THE CEILINGS...BUT ANOTHER ROUND OF CONVECTION LIKELY
WITH DAYTIME HEATING. CONTINUED SOUTHWEST FLOW.
EXTENDED OUTLOOK...UNSETTLED WEATHER THROUGH THURSDAY WITH A GOOD
CHANCE FOR SHOWERS/ISOLATED THUNDERSTORMS/TEMPO MVFR. VFR FRIDAY
THROUGH SUNDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 2:00 PM TUESDAY...SUMMERTIME PATTERN CONTINUES ACROSS THE
COASTAL WATERS WITH THE SOUTH TO SOUTHWESTERLY FLOW BETWEEN A WEAK
STATIONARY FRONT TO THE WEST AND BERMUDA HIGH PRESSURE TO THE
EAST. WILL PROBABLY SEE A SIMILAR PATTERN OF WINDS BACKING OFF A
COUPLE OF KNOTS LATE TONIGHT TO NEAR TEN KNOTS AS THE GRADIENT
DECREASES SLIGHTLY. SEAS REMAIN CONSISTENT AS WELL WITH 2-4 FEET.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 2:00 PM TUESDAY...A COLD FRONT WILL DROP SLOWLY SOUTHEAST
ACROSS THE CAROLINAS ON WEDNESDAY...MOVING ACROSS THE WATERS ON
THURSDAY MORNING. SLACK GRADIENT WILL KEEP WINDS LIGHT AND
SOUTHERLY UNTIL THEN...MAINLY IN THE 10 TO 15 KT RANGE...WITH SEAS
IN THE 3 TO 4 FT RANGE. WINDS WILL SHIFT NE ON
THURSDAY...INCREASING TO AROUND 15 KTS LATE OVERNIGHT. SEAS WILL
BE IN THE 2 TO 4 FT RANGE FOR MUCH OF THURSDAY.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3:00 AM TUESDAY...HIGH PRESSURE RIDGING DOWN THE EAST COAST
WILL KEEP MODERATE-TO-STRONG NE WINDS THROUGH THE PERIOD. WINDS OF
15-20 KTS...WITH ONLY MINOR DIURNAL VARIATIONS...WILL OCCUR THROUGH
SATURDAY. ALTHOUGH A WEAK SE SWELL WILL PERSIST...THE SIGNIFICANT
WAVES WILL BE A NE WIND CHOP OF 5FT/5SEC WHICH BUILDS SEAS TO 4-5 FT
FRIDAY...WITH 6 FT SEAS DEVELOPING ON SATURDAY. CAUTIONARY HEADLINES
ARE LIKELY FRIDAY...WITH SCA CONDITIONS POSSIBLE FOR THE WEEKEND.
ONCE AGAIN...THERE WILL BE A SIGNIFICANT SHADOW REGION SW OF FRYING
PAN SHOALS...WHERE SEAS WILL PERSIST AT ONLY 1-3 FT IN THE INNER 10
NM OF AMZ252 AND AMZ254.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...SHK
SHORT TERM...REK
LONG TERM...JDW
AVIATION...DL
MARINE...REK/JDW/SHK
AREA FORECAST DISCUSSION
NWS RALEIGH NC
630 AM EDT MON MAY 14 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH AND ASSOCIATED SURFACE LOW PRESSURE SYSTEM
WILL SLOWLY PROGRESS EAST TOWARD THE SOUTHEAST COAST THROUGH MID
WEEK...RESULTING IN AN EXTENDED PERIOD OF UNSETTLED WEATHER.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 210 AM MONDAY...
OVERVIEW:
WEAK TROUGHING ALOFT WILL PERSIST WEST OF THE SOUTHERN APPALACHIANS
THIS AFTERNOON THROUGH TONIGHT...WITH SOUTHWEST FLOW ALOFT
PREVAILING OVER THE CAROLINAS. IN THE LOWER LEVELS...WEAK AND BROAD
LOW PRESSURE WILL SLOWLY PROGRESS INTO THE SOUTHERN APPALACHIANS
THIS AFTERNOON...AND INTO THE CENTRAL CAROLINAS BY 12Z TUE.
TODAY:
THE EXACT TIMING/LOCATION/COVERAGE OF PRECIPITATION REMAINS
DIFFICULT TO ASCERTAIN GIVEN THAT IT WILL LARGELY DEPEND ON SMALL
AMPLITUDE DISTURBANCES THAT MAY PROGRESS INTO THE AREA VIA SW FLOW
ALOFT AND SHORTWAVE ACTIVITY ROUNDING THE BASE OF THE UPSTREAM
TROUGH INTO THE SOUTHERN APPALACHIANS. BASED ON THE LATEST SATELLITE
IMAGERY AND RAP MODEL DATA...THE MORE SUBSTANTIAL SHORTWAVE ACTIVITY
IS MOST LIKELY TO AFFECT WESTERN PORTIONS OF THE STATE...PRIMARILY
WEST OF I-77...THOUGH THE WEST/NW PIEDMONT MAY SEE SOME ENHANCED
PRECIP IN CONNECTION WITH THESE FEATURES. THE FIRST SHORTWAVE WAS
LOCATED IN CENTRAL TN AT 06Z...AND IS PROGGED TO CLIP FAR WESTERN
PORTIONS OF THE STATE AS IT PROGRESSES NORTHEAST INTO SOUTHWEST VA
BY 12-15Z. THE SECOND SHORTWAVE...PROGRESSING INTO ARKANSAS AT 06Z
THIS MORNING...IS EXPECTED TO DO ROUGHLY THE SAME LATER THIS AFT/
EVE. COMPLICATING MATTERS...SMALL AMPLITUDE DISTURBANCES WILL REMAIN
POSSIBLE ACROSS THE ENTIRE AREA TODAY. GIVEN THE AFOREMENTIONED
SHORTWAVES...THE POTENTIAL FOR SMALL AMPLITUDE DISTURBANCES IN
SOUTHWEST FLOW ALOFT...AND PLENTIFUL MOISTURE COURTESY OF A
CONTINUED SOUTHERLY LOW-LEVEL (SFC-925 MB) FLOW OFF THE ATLANTIC...
EXPECT PERIODS OF SHOWERS THROUGHOUT THE DAY (THUNDERSTORMS ALSO
POSSIBLE DURING PEAK HEATING)...PRIMARILY WEST OF HWY 1. WILL LOWER
PRECIP CHANCES TO 40-50% IN THE COASTAL PLAIN THROUGH EARLY
AFTERNOON WHERE UPPER LEVEL SUPPORT IS MORE IN DOUBT...BUT WILL
INCREASE CHANCES BACK TO 60% BY MID AFTERNOON IN ASSOC/W DIURNAL
DESTABILIZATION AND PLENTIFUL MOISTURE. HIGHS TODAY ARE SOMEWHAT
CHALLENGING SINCE THEY WILL IN LARGE PART DEPEND ON THE EVOLUTION OF
PRECIPITATION. WITH THE ABOVE IN MIND...WILL INDICATE HIGHS RANGING
FROM THE LOWER 70S NW PIEDMONT TO THE UPPER 70S IN THE COASTAL
PLAIN. RAINFALL AMOUNTS UP TO (POSSIBLY EXCEEDING) AN INCH WILL BE
POSSIBLE IN THE NW PIEDMONT...WITH LESSER AMOUNTS TO THE
SOUTH/EAST...THOUGH CONFIDENCE IN PRECIP AMOUNTS REMAINS RELATIVELY
LOW. A MINOR FLOODING THREAT (PRIMARILY URBAN AREAS) WILL BE PRESENT
WHERE RAINFALL RATES ARE LOCALLY HIGH...MOST LIKELY IN THE W/NW
PIEDMONT.
SEVERE THREAT:
DESPITE EXTENSIVE CLOUD COVER...THE GFS/NAM CONTINUE TO INDICATE
SLIGHTLY STEEPER MID-LEVEL LAPSE RATES ADVECTING INTO THE AREA FROM
THE WEST TODAY...IN THE PRESENCE OF A MOIST AIRMASS (SFC DEWPOINTS
LOWER/MID 60S). AS A RESULT...BOTH MODELS INDICATE ROUGHLY 500-1000
J/KG OF MLCAPE DURING PEAK HEATING. DEEP LAYER (0-6 KM) SHEAR IS
PROGGED TO BE NO HIGHER THAN 20-25 KT TODAY. GIVEN HIGH PWAT VALUES
(~1.50")...DEEP LAYER SHEAR REASONABLY SUPPORTIVE OF MULTICELL
ORGANIZATION...AND 20-25 KT SOUTHERLY LOW-LEVEL FLOW PROGGED THIS
AFTERNOON IN THE PRESENCE OF 500-1000 J/KG MLCAPE...EXPECT A LOW-END
PROBABILITY FOR ISOLD SEVERE STORMS BETWEEN 18Z THIS AFTERNOON AND
03Z THIS EVENING...WITH A PRIMARY THREAT OF DAMAGING WINDS.
TONIGHT:
LITTLE CHANGE IN THE OVERALL PATTERN IS EXPECTED OVERNIGHT...WITH
CONTINUED SW FLOW ALOFT JUST DOWNSTREAM OF AN UPPER LEVEL TROUGH
WEST OF THE MOUNTAINS. EXPECT THE BROAD SURFACE LOW ATTENDANT THE
UPPER TROUGH TO MAKE SLOW PROGRESS EASTWARD INTO THE NC FOOTHILLS BY
12Z TUE. GIVEN A VERY MOIST ATMOSPHERE...STRENGTHENING LOW-LEVEL
SOUTHERLY FLOW/WARM ADVECTION IN ADVANCE OF THE APPROACHING SFC
LOW...AND THE CONTINUED POTENTIAL FOR SHORTWAVES OR SMALL AMPLITUDE
DISTURBANCES IN SW FLOW ALOFT...ONE WOULD EXPECT RELATIVELY HIGH
PRECIPITATION CHANCES. THE LATEST WRF-NMM SHOWS VERY LITTLE COVERAGE
OVERNIGHT (ESPECIALLY AFTER 06Z). IT IS POSSIBLE THAT MEASURABLE
PRECIP MAY BE TOUGH TO COME BY IN THE ABSENCE OF UPPER SUPPORT...AND
CONFIDENCE IN PRECIP CHANCES/COVERAGE REMAINS LOW. WITH THE ABOVE IN
MIND...WILL MAINTAIN 70-80% PRECIP CHANCES THROUGH MIDNIGHT...WITH
CHANCES DECREASING TO THE 50-60% RANGE THEREAFTER. WITH A MOIST
ATMOSPHERE IN PLACE AND CONTINUED SOUTHERLY FLOW...EXPECT LOWS
GENERALLY IN THE LOWER 60S...COOLEST NW PIEDMONT. -VINCENT
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 245 AM MONDAY...
OVERVIEW:
THE SYNOPTIC PATTERN WILL REMAIN RELATIVELY UNCHANGED ON TUE/TUE
NIGHT...WITH WEAK TROUGHING WEST OF THE SOUTHERN APPALACHIANS THIS
AND SOUTHWEST FLOW ALOFT OVER THE CAROLINAS. IN THE LOWER
LEVELS...WEAK AND BROAD LOW PRESSURE ATTENDANT THE UPPER TROUGH WILL
REMAIN STALLED IN VICINITY OF THE CENTRAL CAROLINAS.
TUESDAY:
THE FORECAST REASONING ON TUESDAY IS MORE-OR-LESS THE SAME AS TODAY.
WITH A WEAK UPPER LEVEL TROUGH PERSISTING JUST UPSTREAM OF THE
AREA...A LOW-LEVEL REFLECTION STALLED OUT IN VICINITY OF THE
FOOTHILLS OR WESTERN PIEDMONT...A MOIST/DIURNALLY UNSTABLE
AIRMASS... AND A CONTINUED POTENTIAL FOR SMALL AMPLITUDE
DISTURBANCES IN SW FLOW ALOFT...FEEL THAT ABOVE NORMAL PRECIPITATION
CHANCES ARE WARRANTED. HOWEVER...GIVEN SIGNIFICANT UNCERTAINTY IN
THE EVOLUTION OF ANY SMALL AMPLITUDE DISTURBANCES (WHICH COULD
SIGNIFICANTLY AFFECT THE EVOLUTION OF CONVECTION)...FEEL THAT THERE
IS INSUFFICIENT EVIDENCE TO MAKE MUCH OF A CHANGE THE PREVIOUS
FORECAST...WHICH INDICATES A 50% CHANCE FOR SHOWERS AND
STORMS...WITH THE BEST CHANCE DURING PEAK HEATING. THE MID/UPPER
LEVELS ARE PROGGED TO DRY OUT TO SOME DEGREE TUE AFTERNOON...AND
HIGH TEMPS ON TUE WILL BE COMPLICATED BY BOTH CLOUD COVER AND
PRECIPITATION. AT THIS TIME...WILL INDICATE HIGHS A BIT WARMER THAN
TODAY...IN THE MID/UPPER 70S TO LOWER 80S.
SEVERE THREAT:
SLIGHTLY BETTER DIURNAL DESTABILIZATION IS EXPECTED TUESDAY VERSUS
TODAY GIVEN AN INCREASED POTENTIAL FOR MID/UPPER LEVEL DRYING AND
SUNSHINE DURING PEAK HEATING...IN ADDITION TO SLIGHTLY STEEPER
MID-LEVEL LAPSE RATES (6-6.5 C/KM) ADVECTING INTO THE AREA FROM THE
WEST. EXPECT MLCAPE VALUES GENERALLY IN THE 750-1500 J/KG RANGE. 0-6
KM BULK SHEAR VALUES ARE ALSO EXPECTED TO BE SLIGHTLY STRONGER
(25-30 KT) AS THE UPPER LEVEL TROUGH AXIS JUST UPSTREAM OF THE
MOUNTAINS CONTINUES TO SLOWLY ADVANCE TOWARD THE CAROLINAS. WITH THE
ABOVE IN MIND...A POTENTIAL FOR ISOLD SEVERE STORMS CAPABLE OF
PRODUCING DAMAGING WINDS WILL EXIST DURING PEAK HEATING ON TUE.
SMALL HAIL (PEA TO DIME SIZE) CANNOT BE RULED OUT GIVEN SLIGHTLY
BETTER SHEAR/INSTABILITY AND THE AFOREMENTIONED MID/UPPER LEVEL
DRYING. THE STORM PREDICTION IS INDICATING A 5% PROBABILITY OF
SEVERE WEATHER OVER CENTRAL NC ON TUE.
TUESDAY NIGHT:
ASIDE FROM A SLIGHT EASTWARD SHIFT OF THE AFOREMENTIONED UPPER LEVEL
TROUGH AND ATTENDANT SURFACE LOW...THE SYNOPTIC PATTERN OVER CENTRAL
NC WILL REMAIN MUCH THE SAME...WITH ABOVE NORMAL CHANCES FOR
PRECIPITATION...THOUGH ONCE AGAIN COVERAGE WILL HEAVILY DEPEND ON
THE EVOLUTION OF SMALL AMPLITUDE DISTURBANCES ALOFT. AT THIS TIME
WILL CONTINUE 50% CHANCES FOR PRECIP THROUGH MIDNIGHT...DECREASING
TO 30-40% AFTER MIDNIGHT...LOWEST IN THE WESTERN PIEDMONT. THUNDER
CANNOT BE RULED OUT...THOUGH PRIMARILY IN ASSOC/W ANY UPPER LEVEL
DISTURBANCES THAT MAY BE PRESENT. EXPECT LOWS SIMILAR TO PREVIOUS
NIGHTS...RANGING FROM THE UPPER 50S IN THE FAR NW PIEDMONT TO THE
LOWER 60S ELSEWHERE. -VINCENT
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 210 AM MONDAY...
A BAGGY UPPER TROUGH IS FORECAST TO BE DROPPING OFF THE MOUNTAINS
INTO THE FOOTHILLS AT SUNRISE WEDNESDAY. PROGRESS IS SLOW WITH THE
TROUGH AXIS NO FURTHER EAST THAN HIGHWAY ONE AT SUNSET. THE GFS
CONTINUES TO BE SHARPEST AND MOST PROGRESSIVE WITH UPPER LEVEL
RIDGING IN THE MIDWEST...SLOWING THE EASTWARD PROGRESS OF THE EAST
COAST TROUGH. THE MAJORITY OF MODELS ARE FLATTER AND FURTHER WEST
WITH MIDWEST RIDGING... WITH THE 850 MILLIBAR TROUGH WELL EAST OF
CENTRAL NORTH CAROLINA BY SUNSET. WILL FAVOR THE CONSENSUS WITH
SLIGHT CHANCES FOR SHOWERS WEDNESDAY MORNING... AND SMALL AFTERNOON
CHANCES FOR THUNDERSTORMS IN THE EAST EXITING DURING THE EVENING.
WEAK HIGH PRESSURE ADVANCES TOWARD THE MID ATLANTIC STATES WEDNESDAY
NIGHT AND THURSDAY. MID LEVEL FLOW OVER THE CAROLINAS IS WEAK AND
GENERALLY FROM THE WEST TO NORTHWEST. MEASURABLE RAIN CHANCES APPEAR
MINIMAL IN THIS PATTERN AND WILL PLACE CHANCES AT LESS THAN SLIGHT.
1000 TO 850 MILLIBAR THICKNESSES FORECAST TO BE NEAR CLIMATOLOGY.
EXPECT ENOUGH SUNSHINE BOTH DAYS FOR AFTERNOON HIGH TEMPERATURES
SETTLE NEAR CLIMATOLOGY AS WELL... WITH HIGHS IN THE UPPER 70S TO
LOWER 80S. LOW TEMPERATURES WEDNESDAY AND THURSDAY NIGHTS IN THE MID
TO UPPER 50S.
MID LEVEL HIGH PRESSURE OVER TENNESSEE FRIDAY WILL EXPAND TOWARD NEW
ENGLAND DURING THE WEEKEND. A BROAD AREA OF LOW PRESSURE IS EXPECTED
TO BE CENTERED FAR ENOUGH OFF THE CAROLINA COAST TO LEAVE CENTRAL
NORTH CAROLINA DRY FRIDAY INTO SUNDAY. WITH THE WEATHER PATTERN OVER
THE SOUTHEAST SOMEWHAT STATIC AND LOW LEVEL THICKNESSES NEAR
CLIMATOLOGY... TEMPERATURES WILL FOLLOW SUIT. AFTERNOON HIGH
TEMPERATURES IN THE UPPER 80S TO LOWER 80S AND LOWS IN THE UPPER
50S TO LOWER 60S.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 630 AM MONDAY...
24-HR TAF PERIOD:
MODERATE TO OCCASIONALLY HEAVY RAIN LARGELY REMAINED JUST WEST OF
THE AREA THIS MORNING...AND AS A RESULT...ONLY THE INT/GSO TERMINALS
WERE REPORTING IFR CONDITIONS. FURTHER EAST AT RDU/FAY/RWI...VFR
CONDITIONS WERE PRESENT AS OF 10Z. GIVEN THAT PRECIPITATION FELL
FURTHER WEST THAN ANTICIPATED...VFR CONDITIONS ARE LIKELY TO PREVAIL
THROUGH LATE MORNING TO EARLY AFTERNOON AT RDU/FAY/RWI...WHILE THE
INT/GSO TERMINALS MAY SEE LITTLE IMPROVEMENT THROUGH THAT TIME DUE
TO INCREASING CHANCES FOR RAIN BETWEEN 12-18Z. AFTER 18Z...CHANCES
FOR SCATTERED SHOWERS AND THUNDERSTORMS WILL INCREASE AT THE EASTERN
TAF SITES...FIRST AT RDU/FAY FOLLOWED BY RWI. CEILINGS AND VISBYS MAY
DETERIORATE INTO THE IFR RANGE EVERYWHERE LATE TONIGHT (03-12Z TUE)
IN ASSOC/W AN INCREASINGLY MOIST LOW-LEVEL AIRMASS AND CONTINUED
CHANCES FOR RAIN.
LOOKING AHEAD:
LINGERING LOW-LEVEL MOISTURE COMBINED WITH ANOTHER UPPER LEVEL
TROUGH APPROACHING THE AREA FROM THE NORTHWEST WILL ALLOW ADVERSE
AVIATION CONDITIONS TO PERSIST TUE/TUE NIGHT...WITH SCATTERED
SHOWERS AND THUNDERSTORMS POSSIBLE AT ALL TERMINALS. IMPROVING
CONDITIONS ARE EXPECTED WED/WED NIGHT AS THE UPPER LEVEL TROUGH AND
ASSOCIATED SURFACE LOW PROGRESS CLOSER TOWARD THE SOUTHEAST COAST...
THOUGH MVFR CONDITIONS APPEAR LIKELY IN MANY LOCATIONS. UNCERTAINTY
INCREASES TOWARD THE LATTER PORTION OF THE WEEK. AT THIS TIME...
VFR/MVFR CEILINGS (2500-4500 FT AGL) ARE EXPECTED THU/FRI. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...VINCENT
LONG TERM...99
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
253 AM EDT MON MAY 14 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH AND ASSOCIATED SURFACE LOW PRESSURE SYSTEM
WILL SLOWLY PROGRESS EAST TOWARD THE SOUTHEAST COAST THROUGH MID
WEEK...RESULTING IN AN EXTENDED PERIOD OF UNSETTLED WEATHER.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 210 AM MONDAY...
OVERVIEW:
WEAK TROUGHING ALOFT WILL PERSIST WEST OF THE SOUTHERN APPALACHIANS
THIS AFTERNOON THROUGH TONIGHT...WITH SOUTHWEST FLOW ALOFT
PREVAILING OVER THE CAROLINAS. IN THE LOWER LEVELS...WEAK AND BROAD
LOW PRESSURE WILL SLOWLY PROGRESS INTO THE SOUTHERN APPALACHIANS
THIS AFTERNOON...AND INTO THE CENTRAL CAROLINAS BY 12Z TUE.
TODAY:
THE EXACT TIMING/LOCATION/COVERAGE OF PRECIPITATION REMAINS
DIFFICULT TO ASCERTAIN GIVEN THAT IT WILL LARGELY DEPEND ON SMALL
AMPLITUDE DISTURBANCES THAT MAY PROGRESS INTO THE AREA VIA SW FLOW
ALOFT AND SHORTWAVE ACTIVITY ROUNDING THE BASE OF THE UPSTREAM
TROUGH INTO THE SOUTHERN APPALACHIANS. BASED ON THE LATEST SATELLITE
IMAGERY AND RAP MODEL DATA...THE MORE SUBSTANTIAL SHORTWAVE ACTIVITY
IS MOST LIKELY TO AFFECT WESTERN PORTIONS OF THE STATE...PRIMARILY
WEST OF I-77...THOUGH THE WEST/NW PIEDMONT MAY SEE SOME ENHANCED
PRECIP IN CONNECTION WITH THESE FEATURES. THE FIRST SHORTWAVE WAS
LOCATED IN CENTRAL TN AT 06Z...AND IS PROGGED TO CLIP FAR WESTERN
PORTIONS OF THE STATE AS IT PROGRESSES NORTHEAST INTO SOUTHWEST VA
BY 12-15Z. THE SECOND SHORTWAVE...PROGRESSING INTO ARKANSAS AT 06Z
THIS MORNING...IS EXPECTED TO DO ROUGHLY THE SAME LATER THIS AFT/
EVE. COMPLICATING MATTERS...SMALL AMPLITUDE DISTURBANCES WILL REMAIN
POSSIBLE ACROSS THE ENTIRE AREA TODAY. GIVEN THE AFOREMENTIONED
SHORTWAVES...THE POTENTIAL FOR SMALL AMPLITUDE DISTURBANCES IN
SOUTHWEST FLOW ALOFT...AND PLENTIFUL MOISTURE COURTESY OF A
CONTINUED SOUTHERLY LOW-LEVEL (SFC-925 MB) FLOW OFF THE ATLANTIC...
EXPECT PERIODS OF SHOWERS THROUGHOUT THE DAY (THUNDERSTORMS ALSO
POSSIBLE DURING PEAK HEATING)...PRIMARILY WEST OF HWY 1. WILL LOWER
PRECIP CHANCES TO 40-50% IN THE COASTAL PLAIN THROUGH EARLY
AFTERNOON WHERE UPPER LEVEL SUPPORT IS MORE IN DOUBT...BUT WILL
INCREASE CHANCES BACK TO 60% BY MID AFTERNOON IN ASSOC/W DIURNAL
DESTABILIZATION AND PLENTIFUL MOISTURE. HIGHS TODAY ARE SOMEWHAT
CHALLENGING SINCE THEY WILL IN LARGE PART DEPEND ON THE EVOLUTION OF
PRECIPITATION. WITH THE ABOVE IN MIND...WILL INDICATE HIGHS RANGING
FROM THE LOWER 70S NW PIEDMONT TO THE UPPER 70S IN THE COASTAL
PLAIN. RAINFALL AMOUNTS UP TO (POSSIBLY EXCEEDING) AN INCH WILL BE
POSSIBLE IN THE NW PIEDMONT...WITH LESSER AMOUNTS TO THE
SOUTH/EAST...THOUGH CONFIDENCE IN PRECIP AMOUNTS REMAINS RELATIVELY
LOW. A MINOR FLOODING THREAT (PRIMARILY URBAN AREAS) WILL BE PRESENT
WHERE RAINFALL RATES ARE LOCALLY HIGH...MOST LIKELY IN THE W/NW
PIEDMONT.
SEVERE THREAT:
DESPITE EXTENSIVE CLOUD COVER...THE GFS/NAM CONTINUE TO INDICATE
SLIGHTLY STEEPER MID-LEVEL LAPSE RATES ADVECTING INTO THE AREA FROM
THE WEST TODAY...IN THE PRESENCE OF A MOIST AIRMASS (SFC DEWPOINTS
LOWER/MID 60S). AS A RESULT...BOTH MODELS INDICATE ROUGHLY 500-1000
J/KG OF MLCAPE DURING PEAK HEATING. DEEP LAYER (0-6 KM) SHEAR IS
PROGGED TO BE NO HIGHER THAN 20-25 KT TODAY. GIVEN HIGH PWAT VALUES
(~1.50")...DEEP LAYER SHEAR REASONABLY SUPPORTIVE OF MULTICELL
ORGANIZATION...AND 20-25 KT SOUTHERLY LOW-LEVEL FLOW PROGGED THIS
AFTERNOON IN THE PRESENCE OF 500-1000 J/KG MLCAPE...EXPECT A LOW-END
PROBABILITY FOR ISOLD SEVERE STORMS BETWEEN 18Z THIS AFTERNOON AND
03Z THIS EVENING...WITH A PRIMARY THREAT OF DAMAGING WINDS.
TONIGHT:
LITTLE CHANGE IN THE OVERALL PATTERN IS EXPECTED OVERNIGHT...WITH
CONTINUED SW FLOW ALOFT JUST DOWNSTREAM OF AN UPPER LEVEL TROUGH
WEST OF THE MOUNTAINS. EXPECT THE BROAD SURFACE LOW ATTENDANT THE
UPPER TROUGH TO MAKE SLOW PROGRESS EASTWARD INTO THE NC FOOTHILLS BY
12Z TUE. GIVEN A VERY MOIST ATMOSPHERE...STRENGTHENING LOW-LEVEL
SOUTHERLY FLOW/WARM ADVECTION IN ADVANCE OF THE APPROACHING SFC
LOW...AND THE CONTINUED POTENTIAL FOR SHORTWAVES OR SMALL AMPLITUDE
DISTURBANCES IN SW FLOW ALOFT...ONE WOULD EXPECT RELATIVELY HIGH
PRECIPITATION CHANCES. THE LATEST WRF-NMM SHOWS VERY LITTLE COVERAGE
OVERNIGHT (ESPECIALLY AFTER 06Z). IT IS POSSIBLE THAT MEASURABLE
PRECIP MAY BE TOUGH TO COME BY IN THE ABSENCE OF UPPER SUPPORT...AND
CONFIDENCE IN PRECIP CHANCES/COVERAGE REMAINS LOW. WITH THE ABOVE IN
MIND...WILL MAINTAIN 70-80% PRECIP CHANCES THROUGH MIDNIGHT...WITH
CHANCES DECREASING TO THE 50-60% RANGE THEREAFTER. WITH A MOIST
ATMOSPHERE IN PLACE AND CONTINUED SOUTHERLY FLOW...EXPECT LOWS
GENERALLY IN THE LOWER 60S...COOLEST NW PIEDMONT. -VINCENT
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 245 AM MONDAY...
OVERVIEW:
THE SYNOPTIC PATTERN WILL REMAIN RELATIVELY UNCHANGED ON TUE/TUE
NIGHT...WITH WEAK TROUGHING WEST OF THE SOUTHERN APPALACHIANS THIS
AND SOUTHWEST FLOW ALOFT OVER THE CAROLINAS. IN THE LOWER
LEVELS...WEAK AND BROAD LOW PRESSURE ATTENDANT THE UPPER TROUGH WILL
REMAIN STALLED IN VICINITY OF THE CENTRAL CAROLINAS.
TUESDAY:
THE FORECAST REASONING ON TUESDAY IS MORE-OR-LESS THE SAME AS TODAY.
WITH A WEAK UPPER LEVEL TROUGH PERSISTING JUST UPSTREAM OF THE
AREA...A LOW-LEVEL REFLECTION STALLED OUT IN VICINITY OF THE
FOOTHILLS OR WESTERN PIEDMONT...A MOIST/DIURNALLY UNSTABLE
AIRMASS... AND A CONTINUED POTENTIAL FOR SMALL AMPLITUDE
DISTURBANCES IN SW FLOW ALOFT...FEEL THAT ABOVE NORMAL PRECIPITATION
CHANCES ARE WARRANTED. HOWEVER...GIVEN SIGNIFICANT UNCERTAINTY IN
THE EVOLUTION OF ANY SMALL AMPLITUDE DISTURBANCES (WHICH COULD
SIGNIFICANTLY AFFECT THE EVOLUTION OF CONVECTION)...FEEL THAT THERE
IS INSUFFICIENT EVIDENCE TO MAKE MUCH OF A CHANGE THE PREVIOUS
FORECAST...WHICH INDICATES A 50% CHANCE FOR SHOWERS AND
STORMS...WITH THE BEST CHANCE DURING PEAK HEATING. THE MID/UPPER
LEVELS ARE PROGGED TO DRY OUT TO SOME DEGREE TUE AFTERNOON...AND
HIGH TEMPS ON TUE WILL BE COMPLICATED BY BOTH CLOUD COVER AND
PRECIPITATION. AT THIS TIME...WILL INDICATE HIGHS A BIT WARMER THAN
TODAY...IN THE MID/UPPER 70S TO LOWER 80S.
SEVERE THREAT:
SLIGHTLY BETTER DIURNAL DESTABILIZATION IS EXPECTED TUESDAY VERSUS
TODAY GIVEN AN INCREASED POTENTIAL FOR MID/UPPER LEVEL DRYING AND
SUNSHINE DURING PEAK HEATING...IN ADDITION TO SLIGHTLY STEEPER
MID-LEVEL LAPSE RATES (6-6.5 C/KM) ADVECTING INTO THE AREA FROM THE
WEST. EXPECT MLCAPE VALUES GENERALLY IN THE 750-1500 J/KG RANGE. 0-6
KM BULK SHEAR VALUES ARE ALSO EXPECTED TO BE SLIGHTLY STRONGER
(25-30 KT) AS THE UPPER LEVEL TROUGH AXIS JUST UPSTREAM OF THE
MOUNTAINS CONTINUES TO SLOWLY ADVANCE TOWARD THE CAROLINAS. WITH THE
ABOVE IN MIND...A POTENTIAL FOR ISOLD SEVERE STORMS CAPABLE OF
PRODUCING DAMAGING WINDS WILL EXIST DURING PEAK HEATING ON TUE.
SMALL HAIL (PEA TO DIME SIZE) CANNOT BE RULED OUT GIVEN SLIGHTLY
BETTER SHEAR/INSTABILITY AND THE AFOREMENTIONED MID/UPPER LEVEL
DRYING. THE STORM PREDICTION IS INDICATING A 5% PROBABILITY OF
SEVERE WEATHER OVER CENTRAL NC ON TUE.
TUESDAY NIGHT:
ASIDE FROM A SLIGHT EASTWARD SHIFT OF THE AFOREMENTIONED UPPER LEVEL
TROUGH AND ATTENDANT SURFACE LOW...THE SYNOPTIC PATTERN OVER CENTRAL
NC WILL REMAIN MUCH THE SAME...WITH ABOVE NORMAL CHANCES FOR
PRECIPITATION...THOUGH ONCE AGAIN COVERAGE WILL HEAVILY DEPEND ON
THE EVOLUTION OF SMALL AMPLITUDE DISTURBANCES ALOFT. AT THIS TIME
WILL CONTINUE 50% CHANCES FOR PRECIP THROUGH MIDNIGHT...DECREASING
TO 30-40% AFTER MIDNIGHT...LOWEST IN THE WESTERN PIEDMONT. THUNDER
CANNOT BE RULED OUT...THOUGH PRIMARILY IN ASSOC/W ANY UPPER LEVEL
DISTURBANCES THAT MAY BE PRESENT. EXPECT LOWS SIMILAR TO PREVIOUS
NIGHTS...RANGING FROM THE UPPER 50S IN THE FAR NW PIEDMONT TO THE
LOWER 60S ELSEWHERE. -VINCENT
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 210 AM MONDAY...
A BAGGY UPPER TROUGH IS FORECAST TO BE DROPPING OFF THE MOUNTAINS
INTO THE FOOTHILLS AT SUNRISE WEDNESDAY. PROGRESS IS SLOW WITH THE
TROUGH AXIS NO FURTHER EAST THAN HIGHWAY ONE AT SUNSET. THE GFS
CONTINUES TO BE SHARPEST AND MOST PROGRESSIVE WITH UPPER LEVEL
RIDGING IN THE MIDWEST...SLOWING THE EASTWARD PROGRESS OF THE EAST
COAST TROUGH. THE MAJORITY OF MODELS ARE FLATTER AND FURTHER WEST
WITH MIDWEST RIDGING... WITH THE 850 MILLIBAR TROUGH WELL EAST OF
CENTRAL NORTH CAROLINA BY SUNSET. WILL FAVOR THE CONSENSUS WITH
SLIGHT CHANCES FOR SHOWERS WEDNESDAY MORNING... AND SMALL AFTERNOON
CHANCES FOR THUNDERSTORMS IN THE EAST EXITING DURING THE EVENING.
WEAK HIGH PRESSURE ADVANCES TOWARD THE MID ATLANTIC STATES WEDNESDAY
NIGHT AND THURSDAY. MID LEVEL FLOW OVER THE CAROLINAS IS WEAK AND
GENERALLY FROM THE WEST TO NORTHWEST. MEASURABLE RAIN CHANCES APPEAR
MINIMAL IN THIS PATTERN AND WILL PLACE CHANCES AT LESS THAN SLIGHT.
1000 TO 850 MILLIBAR THICKNESSES FORECAST TO BE NEAR CLIMATOLOGY.
EXPECT ENOUGH SUNSHINE BOTH DAYS FOR AFTERNOON HIGH TEMPERATURES
SETTLE NEAR CLIMATOLOGY AS WELL... WITH HIGHS IN THE UPPER 70S TO
LOWER 80S. LOW TEMPERATURES WEDNESDAY AND THURSDAY NIGHTS IN THE MID
TO UPPER 50S.
MID LEVEL HIGH PRESSURE OVER TENNESSEE FRIDAY WILL EXPAND TOWARD NEW
ENGLAND DURING THE WEEKEND. A BROAD AREA OF LOW PRESSURE IS EXPECTED
TO BE CENTERED FAR ENOUGH OFF THE CAROLINA COAST TO LEAVE CENTRAL
NORTH CAROLINA DRY FRIDAY INTO SUNDAY. WITH THE WEATHER PATTERN OVER
THE SOUTHEAST SOMEWHAT STATIC AND LOW LEVEL THICKNESSES NEAR
CLIMATOLOGY... TEMPERATURES WILL FOLLOW SUIT. AFTERNOON HIGH
TEMPERATURES IN THE UPPER 80S TO LOWER 80S AND LOWS IN THE UPPER
50S TO LOWER 60S.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 1205 AM MONDAY...
24-HR TAF PERIOD:
DETERIORATING CONDITIONS ARE EXPECTED THIS MORNING...WITH LITTLE (IF
ANY) IMPROVEMENT THROUGH THE REMAINDER OF THE TAF PERIOD. AN UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE LOW PRESSURE SYSTEM WILL
CONTINUE TO SLOWLY APPROACH THE CAROLINAS FROM THE WEST TODAY AND
TONIGHT. PERIODS OF SHOWERS ARE EXPECTED THIS MORNING...WITH
CEILINGS LOWERING TO IFR/LIFR AT THE INT/GSO TERMINALS AND MVFR/IFR
AT THE RDU/FAY/RWI TERMINALS. PERIODS OF SHOWERS AND THUNDERSTORMS
ARE EXPECTED THIS AFTERNOON...WITH ONLY A MARGINAL IMPROVEMENT IN
CEILINGS DURING PEAK HEATING. EXPECT CEILINGS AND VISBYS TO DECREASE
INTO THE IFR/LIFR RANGE EVERYWHERE BETWEEN SUNSET THIS EVENING AND
SUNRISE TUE MORNING. SE/SSE WINDS AT ~5 KT WILL PERSIST THROUGH
SUNRISE...WITH SE/SSE WINDS INCREASING TO ~10 KT BY THIS AFTERNOON.
LOOKING AHEAD:
LINGERING LOW-LEVEL MOISTURE COMBINED WITH ANOTHER UPPER LEVEL
TROUGH APPROACHING THE AREA FROM THE NORTHWEST WILL ALLOW ADVERSE
AVIATION CONDITIONS TO PERSIST TUE/TUE NIGHT...WITH SCATTERED
SHOWERS AND THUNDERSTORMS POSSIBLE AT ALL TERMINALS. IMPROVING
CONDITIONS ARE EXPECTED WED/WED NIGHT AS THE UPPER LEVEL TROUGH AND
ASSOCIATED SURFACE LOW PROGRESS CLOSER TOWARD THE SOUTHEAST COAST...
THOUGH MVFR CONDITIONS APPEAR LIKELY IN MANY LOCATIONS. UNCERTAINTY
INCREASES TOWARD THE LATTER PORTION OF THE WEEK. AT THIS TIME...
VFR/MVFR CEILINGS (2500-4500 FT AGL) ARE EXPECTED THU/FRI. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...VINCENT
LONG TERM...99
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
211 AM EDT MON MAY 14 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH AND ASSOCIATED SURFACE LOW PRESSURE SYSTEM
WILL SLOWLY PROGRESS EAST TOWARD THE SOUTHEAST COAST THROUGH MID
WEEK...RESULTING IN AN EXTENDED PERIOD OF UNSETTLED WEATHER.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 210 AM MONDAY...
OVERVIEW:
WEAK TROUGHING ALOFT WILL PERSIST WEST OF THE SOUTHERN APPALACHIANS
THIS AFTERNOON THROUGH TONIGHT...WITH SOUTHWEST FLOW ALOFT
PREVAILING OVER THE CAROLINAS. IN THE LOWER LEVELS...WEAK AND BROAD
LOW PRESSURE WILL SLOWLY PROGRESS INTO THE SOUTHERN APPALACHIANS
THIS AFTERNOON...AND INTO THE CENTRAL CAROLINAS BY 12Z TUE.
TODAY:
THE EXACT TIMING/LOCATION/COVERAGE OF PRECIPITATION REMAINS
DIFFICULT TO ASCERTAIN GIVEN THAT IT WILL LARGELY DEPEND ON SMALL
AMPLITUDE DISTURBANCES THAT MAY PROGRESS INTO THE AREA VIA SW FLOW
ALOFT AND SHORTWAVE ACTIVITY ROUNDING THE BASE OF THE UPSTREAM
TROUGH INTO THE SOUTHERN APPALACHIANS. BASED ON THE LATEST SATELLITE
IMAGERY AND RAP MODEL DATA...THE MORE SUBSTANTIAL SHORTWAVE ACTIVITY
IS MOST LIKELY TO AFFECT WESTERN PORTIONS OF THE STATE...PRIMARILY
WEST OF I-77...THOUGH THE WEST/NW PIEDMONT MAY SEE SOME ENHANCED
PRECIP IN CONNECTION WITH THESE FEATURES. THE FIRST SHORTWAVE WAS
LOCATED IN CENTRAL TN AT 06Z...AND IS PROGGED TO CLIP FAR WESTERN
PORTIONS OF THE STATE AS IT PROGRESSES NORTHEAST INTO SOUTHWEST VA
BY 12-15Z. THE SECOND SHORTWAVE...PROGRESSING INTO ARKANSAS AT 06Z
THIS MORNING...IS EXPECTED TO DO ROUGHLY THE SAME LATER THIS AFT/
EVE. COMPLICATING MATTERS...SMALL AMPLITUDE DISTURBANCES WILL REMAIN
POSSIBLE ACROSS THE ENTIRE AREA TODAY. GIVEN THE AFOREMENTIONED
SHORTWAVES...THE POTENTIAL FOR SMALL AMPLITUDE DISTURBANCES IN
SOUTHWEST FLOW ALOFT...AND PLENTIFUL MOISTURE COURTESY OF A
CONTINUED SOUTHERLY LOW-LEVEL (SFC-925 MB) FLOW OFF THE ATLANTIC...
EXPECT PERIODS OF SHOWERS THROUGHOUT THE DAY (THUNDERSTORMS ALSO
POSSIBLE DURING PEAK HEATING)...PRIMARILY WEST OF HWY 1. WILL LOWER
PRECIP CHANCES TO 40-50% IN THE COASTAL PLAIN THROUGH EARLY
AFTERNOON WHERE UPPER LEVEL SUPPORT IS MORE IN DOUBT...BUT WILL
INCREASE CHANCES BACK TO 60% BY MID AFTERNOON IN ASSOC/W DIURNAL
DESTABILIZATION AND PLENTIFUL MOISTURE. HIGHS TODAY ARE SOMEWHAT
CHALLENGING SINCE THEY WILL IN LARGE PART DEPEND ON THE EVOLUTION OF
PRECIPITATION. WITH THE ABOVE IN MIND...WILL INDICATE HIGHS RANGING
FROM THE LOWER 70S NW PIEDMONT TO THE UPPER 70S IN THE COASTAL
PLAIN. RAINFALL AMOUNTS UP TO (POSSIBLY EXCEEDING) AN INCH WILL BE
POSSIBLE IN THE NW PIEDMONT...WITH LESSER AMOUNTS TO THE
SOUTH/EAST...THOUGH CONFIDENCE IN PRECIP AMOUNTS REMAINS RELATIVELY
LOW. A MINOR FLOODING THREAT (PRIMARILY URBAN AREAS) WILL BE PRESENT
WHERE RAINFALL RATES ARE LOCALLY HIGH...MOST LIKELY IN THE W/NW
PIEDMONT.
SEVERE THREAT:
DESPITE EXTENSIVE CLOUD COVER...THE GFS/NAM CONTINUE TO INDICATE
SLIGHTLY STEEPER MID-LEVEL LAPSE RATES ADVECTING INTO THE AREA FROM
THE WEST TODAY...IN THE PRESENCE OF A MOIST AIRMASS (SFC DEWPOINTS
LOWER/MID 60S). AS A RESULT...BOTH MODELS INDICATE ROUGHLY 500-1000
J/KG OF MLCAPE DURING PEAK HEATING. DEEP LAYER (0-6 KM) SHEAR IS
PROGGED TO BE NO HIGHER THAN 20-25 KT TODAY. GIVEN HIGH PWAT VALUES
(~1.50")...DEEP LAYER SHEAR REASONABLY SUPPORTIVE OF MULTICELL
ORGANIZATION...AND 20-25 KT SOUTHERLY LOW-LEVEL FLOW PROGGED THIS
AFTERNOON IN THE PRESENCE OF 500-1000 J/KG MLCAPE...EXPECT A LOW-END
PROBABILITY FOR ISOLD SEVERE STORMS BETWEEN 18Z THIS AFTERNOON AND
03Z THIS EVENING...WITH A PRIMARY THREAT OF DAMAGING WINDS.
TONIGHT:
LITTLE CHANGE IN THE OVERALL PATTERN IS EXPECTED OVERNIGHT...WITH
CONTINUED SW FLOW ALOFT JUST DOWNSTREAM OF AN UPPER LEVEL TROUGH
WEST OF THE MOUNTAINS. EXPECT THE BROAD SURFACE LOW ATTENDANT THE
UPPER TROUGH TO MAKE SLOW PROGRESS EASTWARD INTO THE NC FOOTHILLS BY
12Z TUE. GIVEN A VERY MOIST ATMOSPHERE...STRENGTHENING LOW-LEVEL
SOUTHERLY FLOW/WARM ADVECTION IN ADVANCE OF THE APPROACHING SFC
LOW...AND THE CONTINUED POTENTIAL FOR SHORTWAVES OR SMALL AMPLITUDE
DISTURBANCES IN SW FLOW ALOFT...ONE WOULD EXPECT RELATIVELY HIGH
PRECIPITATION CHANCES. THE LATEST WRF-NMM SHOWS VERY LITTLE COVERAGE
OVERNIGHT (ESPECIALLY AFTER 06Z). IT IS POSSIBLE THAT MEASURABLE
PRECIP MAY BE TOUGH TO COME BY IN THE ABSENCE OF UPPER SUPPORT...AND
CONFIDENCE IN PRECIP CHANCES/COVERAGE REMAINS LOW. WITH THE ABOVE IN
MIND...WILL MAINTAIN 70-80% PRECIP CHANCES THROUGH MIDNIGHT...WITH
CHANCES DECREASING TO THE 50-60% RANGE THEREAFTER. WITH A MOIST
ATMOSPHERE IN PLACE AND CONTINUED SOUTHERLY FLOW...EXPECT LOWS
GENERALLY IN THE LOWER 60S...COOLEST NW PIEDMONT. -VINCENT
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 235 PM SUNDAY...
TUESDAY AND TUESDAY NIGHT:
ONGOING SHOWERS AND STORMS TUESDAY MORNING SHOULD BE MOVING INTO THE
COASTAL PLAIN AS THE AXIS OF DEEPEST MOISTURE FINALLY SHIFTS TOWARD
THE COAST. HOWEVER...THE WEAK SURFACE FRONT IS FORECAST LINGER BACK
TO THE WEST ALONG THE MOUNTAINS WHILE THE UPPER TROUGH ENERGY
CONTINUES TO EVOLVE WEST OF THE MOUNTAINS....EVENTUALLY PUSHING INTO
THE AREA TUESDAY EVENING. WITH SLIGHTLY DRIER AIR FORECAST TO
OVERSPREAD CENTRAL NC...SOME BREAKS IN CLOUD COVER AND STRONGER
DESTABILIZATION ARE EXPECTED. AHEAD OF THE UPPER TROUGH... THE MAY
CONTINUE TO BE SUBTLE DISTURBANCES ALOFT MOVING ACROSS THE
PERSISTENT WARM AND MOIST AIRMASS...LEADING TO A SCATTERED SHOWERS
AND STORMS BY TUESDAY AFTERNOON. THE NAM IS STRONGEST AND SHOWING A
STOUT VORT MAX LIFTING ACROSS THE AREA DURING PEAK HEATING. A
TIGHTER HEIGHT FIELD ASSOCIATED WITH THIS FEATURE LEADS TO STRONGER
DEEP LAYER SHEAR FORECAST BY THE NAM...BUT THE NAM SEEMS TO BE
OVERDONE. THE GFS AND ECMWF SHOW MORE A MORE DIFFUSE WAVE AND
ONLY 20-25KT OF 0-6KM BULK SHEAR...WHICH IS SUPPORTED BY MOST SREF
MEMBERS. THERE IS CONSIDERABLE SPREAD AMONG SREF MEMBERS REGARDING
INSTABILITY...BUT MODIFIED GFS SOUNDINGS FOR TEMPS IN THE UPPER 70S
TO LOWER 80S AND DEWPOINTS IN THE LOWER 60S SHOW 500-1000 J/KG OF
MLCAPE. A FEW ISOLATED SEVERE STORMS MAY BE POSSIBLE...BUT IF THE
UPPER WAVE IS STRONGER...AS THE NAM FORECASTS...THEN THE SEVERE
POTENTIAL WILL BE GREATER. HIGHS 77-82.
AS THE SURFACE FRONT AND MAIN LOW LEVEL CONVERGENCE ZONE PUSHES INTO
THE CWA TUESDAY EVENING...ISOLATED SHOWERS AND STORMS MAY CONTINUE
INTO THE OVERNIGHT HOURS. THE FRONT WILL CONTINUE TO BE RATHER SLOW
MOVING...AND LOWS SHOULD BE FAIRLY PERSISTENT IN THE UPPER 50S TO
LOWER 60S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 210 AM MONDAY...
A BAGGY UPPER TROUGH IS FORECAST TO BE DROPPING OFF THE MOUNTAINS
INTO THE FOOTHILLS AT SUNRISE WEDNESDAY. PROGRESS IS SLOW WITH THE
TROUGH AXIS NO FURTHER EAST THAN HIGHWAY ONE AT SUNSET. THE GFS
CONTINUES TO BE SHARPEST AND MOST PROGRESSIVE WITH UPPER LEVEL
RIDGING IN THE MIDWEST...SLOWING THE EASTWARD PROGRESS OF THE EAST
COAST TROUGH. THE MAJORITY OF MODELS ARE FLATTER AND FURTHER WEST
WITH MIDWEST RIDGING... WITH THE 850 MILLIBAR TROUGH WELL EAST OF
CENTRAL NORTH CAROLINA BY SUNSET. WILL FAVOR THE CONSENSUS WITH
SLIGHT CHANCES FOR SHOWERS WEDNESDAY MORNING... AND SMALL AFTERNOON
CHANCES FOR THUNDERSTORMS IN THE EAST EXITING DURING THE EVENING.
WEAK HIGH PRESSURE ADVANCES TOWARD THE MID ATLANTIC STATES WEDNESDAY
NIGHT AND THURSDAY. MID LEVEL FLOW OVER THE CAROLINAS IS WEAK AND
GENERALLY FROM THE WEST TO NORTHWEST. MEASURABLE RAIN CHANCES APPEAR
MINIMAL IN THIS PATTERN AND WILL PLACE CHANCES AT LESS THAN SLIGHT.
1000 TO 850 MILLIBAR THICKNESSES FORECAST TO BE NEAR CLIMATOLOGY.
EXPECT ENOUGH SUNSHINE BOTH DAYS FOR AFTERNOON HIGH TEMPERATURES
SETTLE NEAR CLIMATOLOGY AS WELL... WITH HIGHS IN THE UPPER 70S TO
LOWER 80S. LOW TEMPERATURES WEDNESDAY AND THURSDAY NIGHTS IN THE MID
TO UPPER 50S.
MID LEVEL HIGH PRESSURE OVER TENNESSEE FRIDAY WILL EXPAND TOWARD NEW
ENGLAND DURING THE WEEKEND. A BROAD AREA OF LOW PRESSURE IS EXPECTED
TO BE CENTERED FAR ENOUGH OFF THE CAROLINA COAST TO LEAVE CENTRAL
NORTH CAROLINA DRY FRIDAY INTO SUNDAY. WITH THE WEATHER PATTERN OVER
THE SOUTHEAST SOMEWHAT STATIC AND LOW LEVEL THICKNESSES NEAR
CLIMATOLOGY... TEMPERATURES WILL FOLLOW SUIT. AFTERNOON HIGH
TEMPERATURES IN THE UPPER 80S TO LOWER 80S AND LOWS IN THE UPPER
50S TO LOWER 60S.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 1205 AM MONDAY...
24-HR TAF PERIOD:
DETERIORATING CONDITIONS ARE EXPECTED THIS MORNING...WITH LITTLE (IF
ANY) IMPROVEMENT THROUGH THE REMAINDER OF THE TAF PERIOD. AN UPPER
LEVEL TROUGH AND ASSOCIATED SURFACE LOW PRESSURE SYSTEM WILL
CONTINUE TO SLOWLY APPROACH THE CAROLINAS FROM THE WEST TODAY AND
TONIGHT. PERIODS OF SHOWERS ARE EXPECTED THIS MORNING...WITH
CEILINGS LOWERING TO IFR/LIFR AT THE INT/GSO TERMINALS AND MVFR/IFR
AT THE RDU/FAY/RWI TERMINALS. PERIODS OF SHOWERS AND THUNDERSTORMS
ARE EXPECTED THIS AFTERNOON...WITH ONLY A MARGINAL IMPROVEMENT IN
CEILINGS DURING PEAK HEATING. EXPECT CEILINGS AND VISBYS TO DECREASE
INTO THE IFR/LIFR RANGE EVERYWHERE BETWEEN SUNSET THIS EVENING AND
SUNRISE TUE MORNING. SE/SSE WINDS AT ~5 KT WILL PERSIST THROUGH
SUNRISE...WITH SE/SSE WINDS INCREASING TO ~10 KT BY THIS AFTERNOON.
LOOKING AHEAD:
LINGERING LOW-LEVEL MOISTURE COMBINED WITH ANOTHER UPPER LEVEL
TROUGH APPROACHING THE AREA FROM THE NORTHWEST WILL ALLOW ADVERSE
AVIATION CONDITIONS TO PERSIST TUE/TUE NIGHT...WITH SCATTERED
SHOWERS AND THUNDERSTORMS POSSIBLE AT ALL TERMINALS. IMPROVING
CONDITIONS ARE EXPECTED WED/WED NIGHT AS THE UPPER LEVEL TROUGH AND
ASSOCIATED SURFACE LOW PROGRESS CLOSER TOWARD THE SOUTHEAST COAST...
THOUGH MVFR CONDITIONS APPEAR LIKELY IN MANY LOCATIONS. UNCERTAINTY
INCREASES TOWARD THE LATTER PORTION OF THE WEEK. AT THIS TIME...
VFR/MVFR CEILINGS (2500-4500 FT AGL) ARE EXPECTED THU/FRI. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...BLS
LONG TERM...99
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
355 PM EDT SUN MAY 13 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM APPROACHING FROM THE SOUTHWEST WILL BRING
INCREASING RAIN CHANCES THIS AFTERNOON AND TONIGHT. A COLD FRONT
WILL STALL NEAR THE AREA THROUGH MID WEEK BRINGING CONTINUED
CHANCES FOR SHOWERS AND THUNDERSTORMS...WITH SIGNIFICANT RAINFALL
POSSIBLE MONDAY INTO TUESDAY. COLD FRONT PUSHES OFFSHORE THURSDAY
BRINGING DRIER CONDITIONS FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM SUNDAY...SHOWERS REMAIN SCATTERED MAINLY OVER SOUTH
CAROLINA THIS AFTERNOON WHERE RICHER DEWPOINT AIR EXISTS WITH
READINGS IN THE MID 60S. DRIER AIR STILL EXISTS FROM CAPE FEAR
NORTH CLOSER TO THE COAST WHERE DEWPOINT TEMPS WERE IN THE MID
50S. HIGHER HRRR CAPE VALUES ALIGNING NICELY WITH SHWR DEVELOPMENT
OVER SC AND INLAND NC ZONES. CLOUD COVER MODERATING TEMPS
OVERALL...ESPECIALLY WHERE PCP OCCURRED THROUGH THE DAY.
MODELS STILL SHOWING SHWR DEVELOPMENT AREA SHIFTING FARTHER INLAND
OVER SC MAINLY THROUGH LATE AFTERNOON WHILE COASTAL NC BECOMES
SLIGHTLY DRIER. MAIN AREA OF PCP MOVING UP THROUGH GA AND SC
AHEAD OF LOW TRACKING NORTH THROUGH TENNESSEE THROUGH TONIGHT.
DEEPEST LAYER MOISTURE WILL REMAIN OVER INLAND SOUTH CAROLINA
TRACKING INTO NC. PCP WATER VALUES WILL REACH UP AROUND 1.5 INCHES
INLAND WHILE STILL REMAINING QUITE DRY FROM CAPE FEAR NORTHWARD
WHERE PCP WATER VALUES REMAIN LESS THAN AN INCH CLOSER TO THE COAST.
EXPECT MOST OF THE SHWR ACTIVITY TO REMAIN SOUTH AND WEST OF CWA
WITH LESS IN THE WAY OF PCP ACROSS COASTAL NC THROUGH MUCH OF
TONIGHT. MOISTURE PROFILES OVER LOCAL AREA SHOWING MOISTURE
THINNING OUT THROUGH THE COLUMN IN THE MID LAYERS THROUGH THIS
EVENING. CAN NOT RULE OUT SOME SHWRS AS SHORTWAVE ROTATES AROUND
PROVIDING SOME MINOR PERTURBATIONS TO SUPPORT SOME CONVECTIVE
DEVELOPMENT BUT OVERALL EXPECT MORE ISOLATED THROUGH THIS EVENING
WITH BETTER CONVECTIVE DEVELOPMENT POSSIBLE LATER TONIGHT ACROSS
THE PEE DEE REGION IN SOUTH CAROLINA AND ALSO ACROSS THE COASTAL
WATERS.
TEMPS WILL ONLY DROP INTO THE LOWER 60S MOST PLACES OVERNIGHT WITH
PLENTY OF MOISTURE PRESENT AND CONSIDERABLE CLOUD COVER.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 340 PM SUNDAY...SFC HIGH PRESSURE TO RETREAT FARTHER OFFSHORE
MONDAY. THIS WILL ALLOW A SFC COLD FRONT ALBEIT WEAK...TO TRACK TO
THE WESTERN CAROLINAS FROM THE GULF COAST STATES BY TUESDAY. THIS
WILL OPEN UP BOTH THE GULF OF MEXICO AND ATLANTIC MOISTURE FEEDS
ACROSS THE FA BY MIDDAY MONDAY...AND CONTINUE THROUGH TUESDAY NIGHT.
THE BEST SHOT FOR POPS FROM CONVECTION WILL RUN FROM MONDAY
AFTERNOON THROUGH DAYBREAK TUESDAY. MID-LEVEL IMPULSES ARE PROGGED
TO WEAKEN AS THEY REACH AND TRACK ACROSS THE FA...NEVERTHELESS THIS
WILL CONTINUE TO BE A FOCUS FOR CONVECTION DEVELOPMENT. PROGGED
NAMBUFR SOUNDINGS INDICATE A NEARLY SATURATED ATM COLUMN ACROSS THE
FA WITH 1.5 TO 1.9 PWS MONDAY NIGHT. COULD OBSERVE WIDESPREAD 3/4 TO
1 1/4 INCHES OF RAINFALL ACROSS THE REGION THROUGH TUESDAY DAYBREAK.
THE DRY GROUNDS AND VEGETATION ACROSS THE REGION WILL ACT LIKE
SPONGES. HOWEVER WILL STILL CONTINUE TO INDICATE IN THE HWO ABOUT
THE POSSIBILITY OF FLOODING RAINS ACROSS ISOLATED LOCALES THAT COULD
EXPERIENCE UP TO 2 INCHES OF RAINFALL. FOR TUESDAY...DIURNALLY
DRIVEN CONVECTION WILL TAKE OVER WITH THE AID OF THE NEARLY STALLED
SFC COLD FRONT AS A TRIGGER. UPPER LEVEL IMPULSES NOT AS PRONOUNCED
THAT WILL AFFECT THE FA LATE MONDAY INTO MONDAY NIGHT. MAX/MIN TEMPS
WILL HOVER WITHIN 3 DEGREES ON EITHER SIDE OF THE CLIMO NORMS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 340 PM SUNDAY...EARLY PORTION OF THE FORECAST IS FAIRLY
STRAIGHT FORWARD. BROAD TROUGHING ALOFT...WITH THE AXIS WEST OF THE
AREA...RESULTS IN DEEP SOUTHWEST FLOW PARALLEL TO SURFACE BOUNDARIES
STALLED IN THE AREA. TYPICALLY THIS YIELDS UNSETTLED...THOUGH NOT
VERY WIDESPREAD...WEATHER. WILL BUMP POP A BIT HIGHER WED BUT STILL
IN THE CHC RANGE AT THIS POINT. TIMING ANY POTENTIAL SHORTWAVES THAT
COULD ENHANCE STORMS AND CREATE MORE COVERAGE AT THIS POINT IS
DIFFICULT AT BEST SO FURTHER POPS REFINEMENTS...BOTH SPATIAL AND
TEMPORAL...WILL BE NEEDED. POTENT SHORTWAVE OUT OF THE WEST HELPS
PUSH THE UPPER TROUGH AND THE STALLED FRONT OFFSHORE WED NIGHT INTO
THU. MOISTURE AND THE THREAT OF PRECIP LINGERS INTO THU WITH TROUGH
AXIS/UPPER LOW OVER HEAD AND SLOW TO MOVE EAST. AT THIS POINT THE
ECMWF/HPC SOLUTION DIFFERS FROM THE GFS/CANADIAN SOLUTION.
00Z ECMWF AND HPC SOLUTIONS DIG THE UPPER TROUGH A BIT DEEPER OVER
THE NORTHERN GOMEX WHICH RESULTS IN A SEMI-CUTOFF UPPER LOW OVER
OVER GA/NORTHERN FL. THIS INDUCES A SURFACE LOW WHICH STARTS OUT
COLD CORE BUT COULD BECOME A HYBRID SYSTEM AS IT MOVES NORTH ALONG
THE COAST. THE 12Z GFS/CANADIAN SOLUTIONS AND A NUMBER OF THE GFS
ENSEMBLE MEMBERS SUPPORT LESS AMPLIFICATION OF THE 5H TROUGH OVER
THE NORTHERN GOMEX...WHICH RESULTS IN THE SYSTEM DEVELOPING MUCH
FARTHER OFF THE COAST. GIVEN BOTH SOLUTIONS SHOW A SYSTEM DEVELOPING
HAVE HIGH CONFIDENCE SOMETHING WILL EXIST OFF THE COAST LATE IN THE
PERIOD...BUT DETAILS REMAIN FUZZY. LOW CONFIDENCE AND THE POTENTIAL
FOR FORECAST FLIP-FLOPPING WILL NOT MAKE MUCH IN THE WAY OF CHANGES
BEYOND THU...KEEPING INHERITED SLIGHT CHC POP. TEMPERATURES WILL BE
WITHIN A DEGREE OR TWO OF CLIMO THROUGH THE PERIOD.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 18Z...A PERSISTENT AREA OF SHOWERS IS MOVING ONSHORE NEAR
GGE/MYR/CRE REACHING AS FAR INLAND AS LBT. FLIGHT CONDITIONS
ASSOCIATED WITH THIS AREA OF SHOWERS HAVE BEEN PREDOMINATELY
MVFR...BUT TEMPO PERIODS OF IFR HAVE OCCURRED. ELSEWHERE...FLO/LBT
HAS EXPERIENCED TEMPO PERIODS OF MVFR CEILINGS...WHILE ILM HAS
REMAINED VFR. SHOWERS WERE DEVELOPING SOUTH OF FLO.
TEMPO PERIODS OF SHOWERS/MVFR CONDITIONS WILL REMAIN POSSIBLE AT ALL
TERMINALS EXCEPT ILM THROUGH MID-LATE AFTERNOON. BY LATE
AFTERNOON/EARLY EVENING SHOWERS SHOULD BE AFFECTING MAINLY THE
FLO/LBT TERMINALS...ALTHOUGH SOME RESIDUAL SHOWERS FROM THE AREA
CURRENTLY NEAR MYR/CRE COULD AFFECT THE ILM TERMINAL BY THEN. EXPECT
ANY ACTIVITY NEAR ILM TO BE VERY LIGHT.
PRECIPITATION WILL BECOME VERY ISOLATED OR WILL END ALL-TOGETHER
DURING THE EVENING AS SIGNIFICANT LIFT DECREASES. THROUGH THE
OVERNIGHT HOURS PERIODS OF MVFR CAN BE EXPECTED. BY SUNRISE SHOWERS
WILL AGAIN INCREASE FROM THE SOUTHWEST WITH GOOD CHANCES OF
SHOWER/MVFR CONDITIONS DURING THE MORNING HOURS.
EXTENDED OUTLOOK...UNSETTLED WEATHER THROUGH THE PERIOD WITH A GOOD
CHANCE FOR SHOWERS/ISOLATED THUNDERSTORMS EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM SUNDAY...LATEST BUOY OBS SHOWING SEAS 2 TO 3 FT THIS
MORNING BUT UP TO 4 FT JUST SOUTH AND EAST OF LOCAL WATERS. SOUTHEAST
WINDS UP AROUND 15 KTS WILL CONTINUE AS GRADIENT TIGHTENS BETWEEN
DEVELOPING LOW PRESSURE OVER TENNESSEE AND HIGH PRESSURE WELL OFF
THE NORTH CAROLINA COAST. WINDS WILL VEER SLIGHTLY THROUGH TONIGHT
BECOMING MORE NORTHERLY AS LOW TRACKS FARTHER NORTH AND EAST. THIS
PERSISTENT ON SHORE FLOW THROUGH TONIGHT WILL BUILD SEAS UP TO 3
TO 4 FT WITH SOME 5 FTERS IN OUTER WATERS.
THE BEST CHANCE OF SHOWER ACTIVITY WILL REMAIN ACROSS THE SC
WATERS...REMAINING ISOLATED THROUGH MOST OF THE NIGHT WITH
POSSIBLE REDEVELOPMENT LATER TONIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 350 PM SUNDAY...HIGH PRESSURE TO RETREAT FURTHER OFFSHORE AND
THE HIGH SEAS THROUGH THE PERIOD. SFC COLD FRONT TO SLOWLY PUSH TO
THE WATERS BY THE END OF THE PERIOD. THIS OPENS UP A SSE TO SSW WIND
DIRECTION MONDAY INTO TUESDAY. THE TIGHTENED SFC PG WILL OCCUR
MONDAY INTO EARLY TUESDAY...BEFORE RELAXING AS THE FRONTAL BOUNDARY
TURTLES ITS WAY EASTWARD BEFORE STALLING JUST INLAND FROM THE COAST
BY EARLY WEDNESDAY. WINDS WILL BE AT THEIR PEAK LATE MONDAY INTO
MONDAY NIGHT...WITH SPEEDS 15 TO 20 KT. AN ESE GROUND SWELL AT 7-8
SECOND PERIODS WILL COMBINE WITH LOCALLY PRODUCED 3 TO 5 SECOND
PERIOD WIND WAVES...TO PRODUCE 3 TO 5 FT SEAS. A FEW 6 FOOTERS
REMAIN POSSIBLE ESPECIALLY THE OUTER WATERS OFF CAPE FEAR AND CAPE
ROMAIN. THE TIME FRAME FOR THIS OCCURRENCE...MONDAY AFTERNOON INTO
TUESDAY NIGHT. NOT ALL THAT CONVINCED THAT SCA CRITERIA WILL BE MET
FOR ANY LENGTH OF TIME. HOWEVER SCEC THRESHOLDS WILL BE MET AND
LIKELY RAISED TONIGHT OR MONDAY UNLESS FUTURE MODEL RUNS INDICATE
INCREASED OCCURRENCE FOR SCA CRITERIA.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 340 PM SUNDAY...SOUTHWEST FLOW OVER THE WATERS WED WITH FRONT
STALLED VERY CLOSE TO THE COAST. PROXIMITY TO THE BOUNDARY WILL KEEP
SOUTHWEST FLOW 10 KT OR LESS ALL DAY. FRONT IS PUSHED OFF THE COAST
LATE WED NIGHT INTO THU WITH WINDS VEERING FROM NORTHWEST
IMMEDIATELY BEHIND THE FRONT TO NORTHEAST BY MID TO LATE MORNING
THU. OFFSHORE FLOW STARTS OUT AROUND 10 KT BUT COLD SURGE LATE THU
NIGHT WILL PUSH SPEEDS CLOSE TO 15 KT AWAY FROM SHORE. FRI COULD BE
QUITE INTERESTING IF THE 00Z ECMWF/HPC SOLUTION VERIFIES. THESE
SOLUTIONS BRING LOW PRESSURE...POTENTIALLY A TROPICAL HYBRID...INTO
THE COASTAL WATERS LATE FRI AND KEEPS IT IN THE AREA SAT. AT THIS
POINT THE EVENT LOOKS LIKE IT WOULD BE A SOLID SCA EVENT...AGAIN IN
THE 00Z ECMWF/HPC SOLUTION VERIFIES. THE 12Z GFS/CANADIAN HAS THE
LOW MUCH FARTHER OFF THE COAST WITH CONTINUED SOLID 15 KT NORTHEAST
FLOW SAT AND SUN. FOR NOW HAVE CONTINUED NORTHEAST FLOW THROUGH THE
END OF THE PERIOD WITH FURTHER ADJUSTMENTS EXPECTED AS THE CORRECT
SOLUTION BECOMES MORE DEFINED.
SEAS 2 TO 4 FT WITH SOME SWAN SUGGESTING A BIT OF SOUTHERLY SWELL
STARTING TO DEVELOP WED. PASSAGE OF COLD FRONT AND RESULTING
NORTHERLY FLOW WILL CREATE CHAOTIC 2 TO 4 FT SEAS WED NIGHT AND THU.
COLD SURGE THU NIGHT WILL INCREASE SEAS FRI...3 TO 4 FT EXCEPT FOR
AREAS BLOCKED TO NORTHEAST FLOW WHERE SEAS WILL BE 1 TO 2 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RGZ
SHORT TERM...DCH
LONG TERM...III
AVIATION...RGZ/MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
330 PM EDT SUN MAY 13 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM APPROACHING FROM THE SOUTHWEST WILL BRING
INCREASING RAIN CHANCES THIS AFTERNOON AND TONIGHT. A COLD FRONT
WILL STALL NEAR THE AREA THROUGH MID WEEK BRINGING CONTINUED
CHANCES FOR SHOWERS AND THUNDERSTORMS...WITH SIGNIFICANT RAINFALL
POSSIBLE MONDAY INTO TUESDAY. COLD FRONT PUSHES OFFSHORE THURSDAY
BRINGING DRIER CONDITIONS FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM SUNDAY...SHOWERS REMAIN SCATTERED MAINLY OVER SOUTH
CAROLINA THIS AFTERNOON WHERE RICHER DEWPOINT AIR EXISTS WITH
READINGS IN THE MID 60S. DRIER AIR STILL EXISTS FROM CAPE FEAR
NORTH CLOSER TO THE COAST WHERE DEWPOINT TEMPS WERE IN THE MID
50S. HIGHER HRRR CAPE VALUES ALIGNING NICELY WITH SHWR DEVELOPMENT
OVER SC AND INLAND NC ZONES. CLOUD COVER MODERATING TEMPS
OVERALL...ESPECIALLY WHERE PCP OCCURRED THROUGH THE DAY.
MODELS STILL SHOWING SHWR DEVELOPMENT AREA SHIFTING FARTHER INLAND
OVER SC MAINLY THROUGH LATE AFTERNOON WHILE COASTAL NC BECOMES
SLIGHTLY DRIER. MAIN AREA OF PCP MOVING UP THROUGH GA AND SC
AHEAD OF LOW TRACKING NORTH THROUGH TENNESSEE THROUGH TONIGHT.
DEEPEST LAYER MOISTURE WILL REMAIN OVER INLAND SOUTH CAROLINA
TRACKING INTO NC. PCP WATER VALUES WILL REACH UP AROUND 1.5 INCHES
INLAND WHILE STILL REMAINING QUITE DRY FROM CAPE FEAR NORTHWARD
WHERE PCP WATER VALUES REMAIN LESS THAN AN INCH CLOSER TO THE COAST.
EXPECT MOST OF THE SHWR ACTIVITY TO REMAIN SOUTH AND WEST OF CWA
WITH LESS IN THE WAY OF PCP ACROSS COASTAL NC THROUGH MUCH OF
TONIGHT. MOISTURE PROFILES OVER LOCAL AREA SHOWING MOISTURE
THINNING OUT THROUGH THE COLUMN IN THE MID LAYERS THROUGH THIS
EVENING. CAN NOT RULE OUT SOME SHWRS AS SHORTWAVE ROTATES AROUND
PROVIDING SOME MINOR PERTURBATIONS TO SUPPORT SOME CONVECTIVE
DEVELOPMENT BUT OVERALL EXPECT MORE ISOLATED THROUGH THIS EVENING
WITH BETTER CONVECTIVE DEVELOPMENT POSSIBLE LATER TONIGHT ACROSS
THE PEE DEE REGION IN SOUTH CAROLINA AND ALSO ACROSS THE COASTAL
WATERS.
TEMPS WILL ONLY DROP INTO THE LOWER 60S MOST PLACES OVERNIGHT WITH
PLENTY OF MOISTURE PRESENT AND CONSIDERABLE CLOUD COVER.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 340 PM SUNDAY...
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 340 PM SUNDAY...EARLY PORTION OF THE FORECAST IS FAIRLY
STRAIGHT FORWARD. BROAD TROUGHING ALOFT...WITH THE AXIS WEST OF THE
AREA...RESULTS IN DEEP SOUTHWEST FLOW PARALLEL TO SURFACE BOUNDARIES
STALLED IN THE AREA. TYPICALLY THIS YIELDS UNSETTLED...THOUGH NOT
VERY WIDESPREAD...WEATHER. WILL BUMP POP A BIT HIGHER WED BUT STILL
IN THE CHC RANGE AT THIS POINT. TIMING ANY POTENTIAL SHORTWAVES THAT
COULD ENHANCE STORMS AND CREATE MORE COVERAGE AT THIS POINT IS
DIFFICULT AT BEST SO FURTHER POPS REFINEMENTS...BOTH SPATIAL AND
TEMPORAL...WILL BE NEEDED. POTENT SHORTWAVE OUT OF THE WEST HELPS
PUSH THE UPPER TROUGH AND THE STALLED FRONT OFFSHORE WED NIGHT INTO
THU. MOISTURE AND THE THREAT OF PRECIP LINGERS INTO THU WITH TROUGH
AXIS/UPPER LOW OVER HEAD AND SLOW TO MOVE EAST. AT THIS POINT THE
ECMWF/HPC SOLUTION DIFFERS FROM THE GFS/CANADIAN SOLUTION.
00Z ECMWF AND HPC SOLUTIONS DIG THE UPPER TROUGH A BIT DEEPER OVER
THE NORTHERN GOMEX WHICH RESULTS IN A SEMI-CUTOFF UPPER LOW OVER
OVER GA/NORTHERN FL. THIS INDUCES A SURFACE LOW WHICH STARTS OUT
COLD CORE BUT COULD BECOME A HYBRID SYSTEM AS IT MOVES NORTH ALONG
THE COAST. THE 12Z GFS/CANADIAN SOLUTIONS AND A NUMBER OF THE GFS
ENSEMBLE MEMBERS SUPPORT LESS AMPLIFICATION OF THE 5H TROUGH OVER
THE NORTHERN GOMEX...WHICH RESULTS IN THE SYSTEM DEVELOPING MUCH
FARTHER OFF THE COAST. GIVEN BOTH SOLUTIONS SHOW A SYSTEM DEVELOPING
HAVE HIGH CONFIDENCE SOMETHING WILL EXIST OFF THE COAST LATE IN THE
PERIOD...BUT DETAILS REMAIN FUZZY. LOW CONFIDENCE AND THE POTENTIAL
FOR FORECAST FLIP-FLOPPING WILL NOT MAKE MUCH IN THE WAY OF CHANGES
BEYOND THU...KEEPING INHERITED SLIGHT CHC POP. TEMPERATURES WILL BE
WITHIN A DEGREE OR TWO OF CLIMO THROUGH THE PERIOD.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 18Z...A PERSISTENT AREA OF SHOWERS IS MOVING ONSHORE NEAR
GGE/MYR/CRE REACHING AS FAR INLAND AS LBT. FLIGHT CONDITIONS
ASSOCIATED WITH THIS AREA OF SHOWERS HAVE BEEN PREDOMINATELY
MVFR...BUT TEMPO PERIODS OF IFR HAVE OCCURRED. ELSEWHERE...FLO/LBT
HAS EXPERIENCED TEMPO PERIODS OF MVFR CEILINGS...WHILE ILM HAS
REMAINED VFR. SHOWERS WERE DEVELOPING SOUTH OF FLO.
TEMPO PERIODS OF SHOWERS/MVFR CONDITIONS WILL REMAIN POSSIBLE AT ALL
TERMINALS EXCEPT ILM THROUGH MID-LATE AFTERNOON. BY LATE
AFTERNOON/EARLY EVENING SHOWERS SHOULD BE AFFECTING MAINLY THE
FLO/LBT TERMINALS...ALTHOUGH SOME RESIDUAL SHOWERS FROM THE AREA
CURRENTLY NEAR MYR/CRE COULD AFFECT THE ILM TERMINAL BY THEN. EXPECT
ANY ACTIVITY NEAR ILM TO BE VERY LIGHT.
PRECIPITATION WILL BECOME VERY ISOLATED OR WILL END ALL-TOGETHER
DURING THE EVENING AS SIGNIFICANT LIFT DECREASES. THROUGH THE
OVERNIGHT HOURS PERIODS OF MVFR CAN BE EXPECTED. BY SUNRISE SHOWERS
WILL AGAIN INCREASE FROM THE SOUTHWEST WITH GOOD CHANCES OF
SHOWER/MVFR CONDITIONS DURING THE MORNING HOURS.
EXTENDED OUTLOOK...UNSETTLED WEATHER THROUGH THE PERIOD WITH A GOOD
CHANCE FOR SHOWERS/ISOLATED THUNDERSTORMS EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM SUNDAY...LATEST BUOY OBS SHOWING SEAS 2 TO 3 FT THIS
MORNING BUT UP TO 4 FT JUST SOUTH AND EAST OF LOCAL WATERS. SOUTHEAST
WINDS UP AROUND 15 KTS WILL CONTINUE AS GRADIENT TIGHTENS BETWEEN
DEVELOPING LOW PRESSURE OVER TENNESSEE AND HIGH PRESSURE WELL OFF
THE NORTH CAROLINA COAST. WINDS WILL VEER SLIGHTLY THROUGH TONIGHT
BECOMING MORE NORTHERLY AS LOW TRACKS FARTHER NORTH AND EAST. THIS
PERSISTENT ON SHORE FLOW THROUGH TONIGHT WILL BUILD SEAS UP TO 3
TO 4 FT WITH SOME 5 FTERS IN OUTER WATERS.
THE BEST CHANCE OF SHOWER ACTIVITY WILL REMAIN ACROSS THE SC
WATERS...REMAINING ISOLATED THROUGH MOST OF THE NIGHT WITH
POSSIBLE REDEVELOPMENT LATER TONIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 340 AM SUNDAY...SFC HIGH PRESSURE TO RETREAT FARTHER OFFSHORE
MONDAY. THIS WILL ALLOW A SFC COLD FRONT ALBEIT WEAK...TO TRACK TO
THE WESTERN CAROLINAS FROM THE GULF COAST STATES BY TUESDAY. THIS
WILL OPEN UP BOTH THE GULF OF MEXICO AND ATLANTIC MOISTURE FEEDS
ACROSS THE FA BY MIDDAY MONDAY...AND CONTINUE THROUGH TUESDAY NIGHT.
THE BEST SHOT FOR POPS FROM CONVECTION WILL RUN FROM MONDAY
AFTERNOON THROUGH DAYBREAK TUESDAY. MID-LEVEL IMPULSES ARE PROGGED
TO WEAKEN AS THEY REACH AND TRACK ACROSS THE FA...NEVERTHELESS THIS
WILL CONTINUE TO BE A FOCUS FOR CONVECTION DEVELOPMENT. PROGGED
NAMBUFR SOUNDINGS INDICATE A NEARLY SATURATED ATM COLUMN ACROSS THE
FA WITH 1.5 TO 1.9 PWS MONDAY NIGHT. COULD OBSERVE WIDESPREAD 3/4 TO
1 1/4 INCHES OF RAINFALL ACROSS THE REGION THROUGH TUESDAY DAYBREAK.
THE DRY GROUNDS AND VEGETATION ACROSS THE REGION WILL ACT LIKE
SPONGES. HOWEVER WILL STILL CONTINUE TO INDICATE IN THE HWO ABOUT
THE POSSIBILITY OF FLOODING RAINS ACROSS ISOLATED LOCALES THAT COULD
EXPERIENCE UP TO 2 INCHES OF RAINFALL. FOR TUESDAY...DIURNALLY
DRIVEN CONVECTION WILL TAKE OVER WITH THE AID OF THE NEARLY STALLED
SFC COLD FRONT AS A TRIGGER. UPPER LEVEL IMPULSES NOT AS PRONOUNCED
THAT WILL AFFECT THE FA LATE MONDAY INTO MONDAY NIGHT. MAX/MIN TEMPS
WILL HOVER WITHIN 3 DEGREES ON EITHER SIDE OF THE CLIMO NORMS.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 340 PM SUNDAY...SOUTHWEST FLOW OVER THE WATERS WED WITH FRONT
STALLED VERY CLOSE TO THE COAST. PROXIMITY TO THE BOUNDARY WILL KEEP
SOUTHWEST FLOW 10 KT OR LESS ALL DAY. FRONT IS PUSHED OFF THE COAST
LATE WED NIGHT INTO THU WITH WINDS VEERING FROM NORTHWEST
IMMEDIATELY BEHIND THE FRONT TO NORTHEAST BY MID TO LATE MORNING
THU. OFFSHORE FLOW STARTS OUT AROUND 10 KT BUT COLD SURGE LATE THU
NIGHT WILL PUSH SPEEDS CLOSE TO 15 KT AWAY FROM SHORE. FRI COULD BE
QUITE INTERESTING IF THE 00Z ECMWF/HPC SOLUTION VERIFIES. THESE
SOLUTIONS BRING LOW PRESSURE...POTENTIALLY A TROPICAL HYBRID...INTO
THE COASTAL WATERS LATE FRI AND KEEPS IT IN THE AREA SAT. AT THIS
POINT THE EVENT LOOKS LIKE IT WOULD BE A SOLID SCA EVENT...AGAIN IN
THE 00Z ECMWF/HPC SOLUTION VERIFIES. THE 12Z GFS/CANADIAN HAS THE
LOW MUCH FARTHER OFF THE COAST WITH CONTINUED SOLID 15 KT NORTHEAST
FLOW SAT AND SUN. FOR NOW HAVE CONTINUED NORTHEAST FLOW THROUGH THE
END OF THE PERIOD WITH FURTHER ADJUSTMENTS EXPECTED AS THE CORRECT
SOLUTION BECOMES MORE DEFINED.
SEAS 2 TO 4 FT WITH SOME SWAN SUGGESTING A BIT OF SOUTHERLY SWELL
STARTING TO DEVELOP WED. PASSAGE OF COLD FRONT AND RESULTING
NORTHERLY FLOW WILL CREATE CHAOTIC 2 TO 4 FT SEAS WED NIGHT AND THU.
COLD SURGE THU NIGHT WILL INCREASE SEAS FRI...3 TO 4 FT EXCEPT FOR
AREAS BLOCKED TO NORTHEAST FLOW WHERE SEAS WILL BE 1 TO 2 FT.
&&
AS OF 300 AM SUNDAY...VERY SLOWLY MOVING COLD FRONT WILL WAVER
ACROSS THE WATERS WEDNESDAY AND MAY TURN WINDS BRIEFLY TO THE WEST
EARLY WEDNESDAY BEFORE BACKING TO THE SW ONCE AGAIN MUCH OF THE DAY.
WITH THE FRONT NEARLY OVERHEAD...WINDS WILL BE RATHER LIGHT...5-10
KTS...BUT WITH LACK OF ANY MEANINGFUL SWELL PRESENT THE SEAS WILL
STILL BE MOSTLY WIND CHOP...AT 2-4 FT. LATE WED NIGHT FROPA FINALLY
OCCURS ACROSS THE WATERS AND WINDS TURN TO THE NW...THEN NE ON
THURSDAY...WITH A DECENT NE SURGE DEVELOPING THURSDAY NIGHT. WINDS
OF 5-10 KTS WILL INCREASE FROM THE NE...BECOMING 10-15 KTS LATE
THURSDAY. AFTER A PERIOD OF CONFUSED SEAS WITH THE WIND SHIFT...NE
WIND WAVES WILL BUILD BACK UP TO 3-4 FT EXCEPT IN THE SHADOWED
REGION SW OF FRYING PAN SHOALS WHERE 1-2 FT SEAS WILL PERSIST.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RGZ
SHORT TERM...DCH
LONG TERM...III
AVIATION...RGZ/MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
303 PM EDT SUN MAY 13 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM APPROACHING FROM THE SOUTHWEST WILL BRING
INCREASING RAIN CHANCES THIS AFTERNOON AND TONIGHT. A COLD FRONT
WILL STALL NEAR THE AREA THROUGH MID WEEK BRINGING CONTINUED
CHANCES FOR SHOWERS AND THUNDERSTORMS...WITH SIGNIFICANT RAINFALL
POSSIBLE MONDAY INTO TUESDAY. COLD FRONT PUSHES OFFSHORE THURSDAY
BRINGING DRIER CONDITIONS FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM SUNDAY...SHOWERS REMAIN SCATTERED MAINLY OVER SOUTH
CAROLINA THIS AFTERNOON WHERE RICHER DEWPOINT AIR EXISTS WITH
READINGS IN THE MID 60S. DRIER AIR STILL EXISTS FROM CAPE FEAR
NORTH CLOSER TO THE COAST WHERE DEWPOINT TEMPS WERE IN THE MID
50S. HIGHER HRRR CAPE VALUES ALIGNING NICELY WITH SHWR DEVELOPMENT
OVER SC AND INLAND NC ZONES. CLOUD COVER MODERATING TEMPS
OVERALL...ESPECIALLY WHERE PCP OCCURRED THROUGH THE DAY.
MODELS STILL SHOWING SHWR DEVELOPMENT AREA SHIFTING FARTHER INLAND
OVER SC MAINLY THROUGH LATE AFTERNOON WHILE COASTAL NC BECOMES
SLIGHTLY DRIER. MAIN AREA OF PCP MOVING UP THROUGH GA AND SC
AHEAD OF LOW TRACKING NORTH THROUGH TENNESSEE THROUGH TONIGHT.
DEEPEST LAYER MOISTURE WILL REMAIN OVER INLAND SOUTH CAROLINA
TRACKING INTO NC. PCP WATER VALUES WILL REACH UP AROUND 1.5 INCHES
INLAND WHILE STILL REMAINING QUITE DRY FROM CAPE FEAR NORTHWARD
WHERE PCP WATER VALUES REMAIN LESS THAN AN INCH CLOSER TO THE COAST.
EXPECT MOST OF THE SHWR ACTIVITY TO REMAIN SOUTH AND WEST OF CWA
WITH LESS IN THE WAY OF PCP ACROSS COASTAL NC THROUGH MUCH OF
TONIGHT. MOISTURE PROFILES OVER LOCAL AREA SHOWING MOISTURE
THINNING OUT THROUGH THE COLUMN IN THE MID LAYERS THROUGH THIS
EVENING. CAN NOT RULE OUT SOME SHWRS AS SHORTWAVE ROTATES AROUND
PROVIDING SOME MINOR PERTURBATIONS TO SUPPORT SOME CONVECTIVE
DEVELOPMENT BUT OVERALL EXPECT MORE ISOLATED THROUGH THIS EVENING
WITH BETTER CONVECTIVE DEVELOPMENT POSSIBLE LATER TONIGHT ACROSS
THE PEE DEE REGION IN SOUTH CAROLINA AND ALSO ACROSS THE COASTAL
WATERS.
TEMPS WILL ONLY DROP INTO THE LOWER 60S MOST PLACES OVERNIGHT WITH
PLENTY OF MOISTURE PRESENT AND CONSIDERABLE CLOUD COVER.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...A WET SHORT TERM ON TAP AS A SLOW MOVING LOW
PRESSURE SYSTEM BRINGS WIDESPREAD SHOWERS AND THUNDERSTORMS TO THE
EASTERN CAROLINAS.
STILL UNCERTAINTY IN TIMING...BUT EXPECT SHOWERS TO BE ONGOING AT
THE START OF THE PERIOD...ESPECIALLY ACROSS THE WESTERN HALF OF THE
ILM CWA...AND BE IMPACTING THE ENTIRE AREA BY MONDAY AFTN. THESE
SHOWERS ARE DUE TO THE ADVANCE OF A SLOWLY MOVING LOW PRESSURE
SYSTEM SPAWNED BY IMPULSES ROTATING DOWN A DEEP...POSITIVELY TILTED
UPPER TROUGH DROPPING OUT OF THE MIDWEST. THE FIRST OF THESE
IMPULSES PUSHES INTO NEW ENGLAND LATE MONDAY AND TRAILS A COLD FRONT
INTO THE REGION. THIS FRONT GETS VERY LITTLE PUSH DUE TO THE
ORIENTATION OF UPPER FEATURES...AND BECOMES STALLED SOMEWHERE ACROSS
THE EASTERN MID-ATLANTIC AND SOUTHEAST. THIS BOUNDARY ACTS A
FOCUSING MECHANISM FOR CONTINUED ROUNDS OF HEAVY RAINFALL AND
THUNDERSTORMS THROUGH TUESDAY.
THE HEAVIEST RAINFALL WILL OCCUR MONDAY AFTN THROUGH TUESDAY
MORNING. THE COMBINATION OF SOME ENHANCED UPPER DIFLUENCE...PWATS
APPROACHING 1.75 INCHES (NEARLY 2 STD DEVIATIONS ABOVE
NORMAL)...RICH THETA-E AIR...10000 FT OF WARM CLOUD DEPTH...AND
CONVERGENCE ALONG THE STALLED BOUNDARY ALL POINT TOWARDS
WIDESPREAD SHOWERS/THUNDERSTORMS WITH HEAVY RAIN. ALTHOUGH BEST
MOISTURE TRANSPORT IS FOCUSED JUST NORTH OF THE ILM CWA...ENHANCED
MOIST ADVECTION FROM SE FLOW OFF THE GULF STREAM SHOULD PROVIDE
SOME HEAVIER RAIN. WILL BUMP POP TO CATEGORICAL MONDAY
AFTN/NIGHT...FALLING TO CHC BY TUE AFTN...WITH TOTAL QPF ABOVE 1
INCH POSSIBLE. WILL NOTE THAT ISOLATED HEAVIER TOTALS ARE
DEFINITELY POSSIBLE...SINCE DEEP SOUTHERLY FLOW BECOMES BOUNDARY
PERPENDICULAR...WHICH FAVORS TRAINING ECHOES FROM SOUTH TO NORTH
AS THE FRONT MAKES VERY LITTLE PROGRESS EASTWARD. SPC DOES HAVE
THE AREA IN A "SEE TEXT" FOR MONDAY...AND DECENT INSTABILITY WILL
EXIST AHEAD OF THE FRONT...BUT OTRW SEVERE PARAMETERS LOOK QUITE
WEAK AND EXPECT MORE OF A HEAVY RAIN THREAT THAN A SEVERE THREAT.
TEMPS WILL BE BELOW CLIMO MONDAY DUE TO CLOUDS AND RAIN...IN THE
UPPER 70S...WITH LOWS WELL ABOVE CLIMO ONLY FALLING INTO THE MID
60S. SIMILAR ON TUESDAY WITH CONTINUED CLOUDS AND SHOWERS...KEEPING
MAX TEMPS JUST BELOW CLIMO AROUND 80 AND MINS ONCE AGAIN FALLING
ONLY INTO THE LOW/MID 60S AT NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 AM SUNDAY...NEARLY STATIONARY FRONT WILL STILL BE OVER THE
AREA EARLY WEDNESDAY AS DEEP UPPER TROUGH AXIS MOVES OVERHEAD. THIS
WILL PROVIDE THE IMPETUS FOR CONTINUED SHOWERS AND
THUNDERSTORMS...ESPECIALLY DURING THE AFTNS OF WED AND THU. THE
KICKER NORTHERN STREAM S/W THEN DROPS SOUTHWARD OUT OF CANADA AND
FINALLY PUSHES THE COLD FRONT OFFSHORE THURSDAY. THIS ALLOWS THE
COLUMN TO BEGIN TO DRY OUT WITH SOME WEAK SUBSIDENCE BEHIND THE
DEPARTING TROUGH...BUT DIURNAL SHOWERS ARE STILL POSSIBLE FRI/SAT.
WILL CARRY CHC POP WED/THU WITH SCHC FRI/SAT...BUT THE ACTIVITY
FRI/SAT SHOULD BE MUCH MORE ISOLATED IN COVERAGE.
BOTH GFS AND EURO DEPICT THE UPPER TROUGH CUTTING OFF NEAR 70 WEST
AND SPAWNING A HYBRID-TYPE SURFACE LOW WELL OFFSHORE. THIS IS
FURTHER EAST THAN PREVIOUS RUNS AND MEANS LESS OF A RAIN CHANCE FOR
THE WKND THAN EARLIER GUIDANCE HAD SUGGESTED. FEEL NO REASON TO
CHANGE INHERITED SCHC ATTM.
TEMPS WILL REMAIN FAIRLY UNIFORM THROUGH THE EXTENDED...WITH HIGHS A
DEGREE OR SO BELOW CLIMO AND MINS AT NIGHT A DEGREE OR TWO ABOVE.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 18Z...A PERSISTENT AREA OF SHOWERS IS MOVING ONSHORE NEAR
GGE/MYR/CRE REACHING AS FAR INLAND AS LBT. FLIGHT CONDITIONS
ASSOCIATED WITH THIS AREA OF SHOWERS HAVE BEEN PREDOMINATELY
MVFR...BUT TEMPO PERIODS OF IFR HAVE OCCURRED. ELSEWHERE...FLO/LBT
HAS EXPERIENCED TEMPO PERIODS OF MVFR CEILINGS...WHILE ILM HAS
REMAINED VFR. SHOWERS WERE DEVELOPING SOUTH OF FLO.
TEMPO PERIODS OF SHOWERS/MVFR CONDITIONS WILL REMAIN POSSIBLE AT ALL
TERMINALS EXCEPT ILM THROUGH MID-LATE AFTERNOON. BY LATE
AFTERNOON/EARLY EVENING SHOWERS SHOULD BE AFFECTING MAINLY THE
FLO/LBT TERMINALS...ALTHOUGH SOME RESIDUAL SHOWERS FROM THE AREA
CURRENTLY NEAR MYR/CRE COULD AFFECT THE ILM TERMINAL BY THEN. EXPECT
ANY ACTIVITY NEAR ILM TO BE VERY LIGHT.
PRECIPITATION WILL BECOME VERY ISOLATED OR WILL END ALL-TOGETHER
DURING THE EVENING AS SIGNIFICANT LIFT DECREASES. THROUGH THE
OVERNIGHT HOURS PERIODS OF MVFR CAN BE EXPECTED. BY SUNRISE SHOWERS
WILL AGAIN INCREASE FROM THE SOUTHWEST WITH GOOD CHANCES OF
SHOWER/MVFR CONDITIONS DURING THE MORNING HOURS.
EXTENDED OUTLOOK...UNSETTLED WEATHER THROUGH THE PERIOD WITH A GOOD
CHANCE FOR SHOWERS/ISOLATED THUNDERSTORMS EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM SUNDAY...LATEST BUOY OBS SHOWING SEAS 2 TO 3 FT THIS
MORNING BUT UP TO 4 FT JUST SOUTH AND EAST OF LOCAL WATERS. SOUTHEAST
WINDS UP AROUND 15 KTS WILL CONTINUE AS GRADIENT TIGHTENS BETWEEN
DEVELOPING LOW PRESSURE OVER TENNESSEE AND HIGH PRESSURE WELL OFF
THE NORTH CAROLINA COAST. WINDS WILL VEER SLIGHTLY THROUGH TONIGHT
BECOMING MORE NORTHERLY AS LOW TRACKS FARTHER NORTH AND EAST. THIS
PERSISTENT ON SHORE FLOW THROUGH TONIGHT WILL BUILD SEAS UP TO 3
TO 4 FT WITH SOME 5 FTERS IN OUTER WATERS.
THE BEST CHANCE OF SHOWER ACTIVITY WILL REMAIN ACROSS THE SC
WATERS...REMAINING ISOLATED THROUGH MOST OF THE NIGHT WITH
POSSIBLE REDEVELOPMENT LATER TONIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...THE WATERS WILL BE SANDWICHED BETWEEN A VERY
SLOWLY ADVANCING COLD FRONT FROM THE WEST...AND HIGH PRESSURE
RETREATING TO THE EAST...THROUGH THE SHORT TERM. THIS CREATES
SOUTHERLY WINDS MONDAY...VEERING SLIGHTLY TO THE SW TUESDAY AS FRONT
GETS CLOSER TO THE AREA...AT 10-15 KTS THROUGHOUT. ALTHOUGH A WEAK
1FT/11SEC EASTERLY SWELL WILL EXIST IN THE WAVE SPECTRUM...THE
SIGNIFICANT WAVE HEIGHTS WILL BE FORCED PRIMARILY BY THE WIND...WITH
3-5 FT SEAS MONDAY FALLING TO 3-4 FT TUESDAY. ADDITIONALLY...THERE
IS A GOOD CHANCE FOR WIDESPREAD SHOWERS AND THUNDERSTORMS WITH
HEAVY RAIN TO IMPACT THE WATERS LATE MONDAY AND TUESDAY.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 300 AM SUNDAY...VERY SLOWLY MOVING COLD FRONT WILL WAVER
ACROSS THE WATERS WEDNESDAY AND MAY TURN WINDS BRIEFLY TO THE WEST
EARLY WEDNESDAY BEFORE BACKING TO THE SW ONCE AGAIN MUCH OF THE DAY.
WITH THE FRONT NEARLY OVERHEAD...WINDS WILL BE RATHER LIGHT...5-10
KTS...BUT WITH LACK OF ANY MEANINGFUL SWELL PRESENT THE SEAS WILL
STILL BE MOSTLY WIND CHOP...AT 2-4 FT. LATE WED NIGHT FROPA FINALLY
OCCURS ACROSS THE WATERS AND WINDS TURN TO THE NW...THEN NE ON
THURSDAY...WITH A DECENT NE SURGE DEVELOPING THURSDAY NIGHT. WINDS
OF 5-10 KTS WILL INCREASE FROM THE NE...BECOMING 10-15 KTS LATE
THURSDAY. AFTER A PERIOD OF CONFUSED SEAS WITH THE WIND SHIFT...NE
WIND WAVES WILL BUILD BACK UP TO 3-4 FT EXCEPT IN THE SHADOWED
REGION SW OF FRYING PAN SHOALS WHERE 1-2 FT SEAS WILL PERSIST.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RGZ
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...MRR
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1242 PM CDT TUE MAY 15 2012
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...THE LATEST MODEL INFO IS A LITTLE UNCERTAIN ABOUT THE
INITIATION OF AN AFTERNOON WEATHER EVENT. NOT SEEING MUCH HAPPEN
YET ACROSS THE CWA...AND THE BRUNT OF THE SHORT WAVE ENERGY LOOKS
LIKE IT WILL ROTATE THROUGH AND OVER CENTRAL AND EAST TEXAS...
WITH LESS ENERGY THIS FAR SOUTH. NONETHELESS...DECIDED TO KEEP THE
CURRENT SCATTERED CONVECTION IN THE FORECAST FOR THIS AFTERNOON...
WITH VCTS IN THE TAFS FOR THE SECOND HALF OF THE AFTERNOON. A FEW
SHOWERS ARE BEGINNING TO DEVELOP IN THE DEL RIO AREA AND EVEN
INLAND ALONG THE MIDDLE TEXAS COAST...AND THE RUC SHOWS ENERGY IN
THAT AREA RIGHT ON SCHEDULE. THUS...NOT OUT OF THE WOODS YET. WILL
GO AHEAD AND EXTEND POP CHANCES INTO EARLY EVENING FOR DELAYED
DEVELOPMENT AND POTENTIAL FOR CONVECTION UPSTREAM TO MOVE
SOUTHEAST INTO THE UPPER VALLEY AND EVENTUALLY DEEPER INTO THE
CWA.
&&
.PREV DISCUSSION... /ISSUED 652 AM CDT TUE MAY 15 2012/
DISCUSSION...TWEAKED MORNING GRIDS AS WEATHER EVENT THAT JUST
PUSHED THROUGH ALL BUT OVER. DO NOT SEE SIGNIFICANT REDEVELOPMENT
IN NEXT SIX HOURS. MAINTAINED ISOLATED SHOWERS THIS MORNING
HOWEVER...BEFORE CONVECTION REDEVELOPS AHEAD OF APPROACHING SHORT
WAVE TROUGH.
UPDATED AVIATION DISCUSSION BELOW.
AVIATION...LOW CLOUDS ARE STILL IN THE AREA AT BRO BUT HRL AND
MFE ARE VFR. EARLY MORNING CONVECTION PUSHED OFF SHORE AND NOT
EXPECTING MUCH ADDITIONAL DEVELOPMENT BEFORE ABOUT NOON. LIGHT
NORTHWEST FLOW SHOULD VEER TO NORTHEAST TODAY. APPROACHING SHORT
WAVE TROUGH AXIS WILL SWING OVERHEAD LATER TODAY...WITH POTENTIAL
FOR AREA WIDE THUNDERSTORMS CAUSING FLIGHT DELAYS. HAZARDS NEAR
THUNDERSTORMS WILL INCLUDE LIGHTNING...SMALL HAIL...GUSTY WINDS
AND TURBULENCE.
PREV DISCUSSION... /ISSUED 427 AM CDT TUE MAY 15 2012/
SHORT TERM /TODAY THROUGH WEDNESDAY/...A POSITIVELY-TILTED 500 MB
TROUGH OVER WEST TEXAS EARLY THIS MORNING WILL MOVE SOUTHEAST
OVER DEEP SOUTH TEXAS TONIGHT. AN MCS MOVING SOUTHEAST ACROSS SOUTH
CENTRAL TEXAS LAST NIGHT HAS BECOME MORE OF A LINEAR FEATURE AS IT
MOVES ACROSS THE RIO GRANDE VALLEY THIS MORNING. THE MODEL GUIDANCE
DID NOT HANDLE THIS PIECE OF SHORTWAVE ENERGY WELL ESPECIALLY IN THE
TIMING OF THE MCS. ONE INTERESTING THING OVERNIGHT WAS THE STRONG
WINDS OCCURRING BEHIND THE THUNDERSTORM COMPLEX. SURFACE
OBSERVATIONS INDICATED AN EAST WIND BETWEEN 25 AND 35 MPH WITH
HIGHER GUSTS. THE WINDS WERE SHORT LIVED ONLY LASTING FOR AN HOUR OR
SO. BRO WSR-88D VELOCITIES ALSO INDICATED 45 TO 55 KNOTS ABOUT 10 TO
12000 FEET ABOVE GROUND BEHIND THUNDERSTORMS.
THE GFS/ECMWF SOLUTIONS ARE PERSISTENT IN BRINGING ANOTHER PIECE OF
SHORTWAVE ENERGY OVER DEEP SOUTH TEXAS LATER TODAY. CONFIDENCE IS
SOMEWHAT LOW THAT MORE WIDESPREAD CONVECTIVE WILL OCCUR
TODAY...SINCE THE ATMOSPHERE HAS BECOME STABLE IN THE WAKE OF THE
PASSING CONVECTIVE COMPLEX AND THE POOR HANDLING THAT THE MODELS DID
ON THIS PREVIOUS THUNDERSTORM ACTIVITY. MODELS DO INDICATE SOME
INSTABILITY OVER THE AREA LATER TODAY. THE LATEST NAM FORECAST
SOUNDING SUGGEST CAPE VALUES OF 1140 J/KG IS POSSIBLE OVER THE AREA
LATER THIS AFTERNOON. HOWEVER ANY SEVERE STORM THREAT APPEARS TO BE
MARGINAL. STRONGER STORMS HAVE THE POSSIBILITY OF PRODUCING SMALL
HAIL AND GUSTY WINDS. HAVE LOWER POPS FOR TODAY BUT HAVE STAYED
CLOSE TO A MAV/MET MOS BLEND. HIGH TEMPERATURES THIS AFTERNOON WILL
BE IN THE MID 80S NEAR THE COAST TO THE UPPER 80S FAR INLAND.
THE MID LEVEL TROUGH AND WEAK SURFACE FRONT MOVES THROUGH THE CWA
LATE TONIGHT INTO WEDNESDAY MORNING. LEFT 20 POPS BEFORE MIDNIGHT
AND 10 POPS AFTER MIDNIGHT. LOW TEMPERATURES WILL BE IN THE UPPER
60S INLAND TO AROUND 70 NEAR THE COAST. CLEARING SKIES EXPECTED ON
WEDNESDAY AS 500 MB RIDGING BUILDS IN OVER THE DEEP SOUTH TEXAS WITH
HIGH PRESSURE AND A WEAK GRADIENT ALSO PREVAILING AT THE SURFACE.
HIGH TEMPERATURES ON WEDNESDAY WILL BE IN THE MID TO UPPER 80S NEAR
THE COAST AND LOWER 90S OVER THE WEST.
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...BENIGN CONDITIONS ARE
EXPECTED THROUGH THE LONG TERM PORTION OF THE FORECAST...WITH DRY
WEATHER AND NEAR TO ABOVE NORMAL TEMPERATURES ANTICIPATED...AS MID-
LEVEL HIGH PRESSURE GRADUALLY SHIFTS EAST FROM THE BAJA PENINSULA
TO NORTH-CENTRAL MEXICO...PRODUCING A PERSISTENT NORTHWEST-TO-
SOUTHEAST MID-LEVEL FLOW OVER DEEP SOUTH TEXAS AND THE RIO GRANDE
VALLEY.
MARINE...TODAY THROUGH WEDNESDAY...BUOY 42020 REPORTED SOUTHEAST
WINDS AROUND 8 KNOTS GUSTING TO AROUND 10 KNOTS WITH SEAS SLIGHTLY
OVER 2.3 FEET WITH A PERIOD OF 7 SECONDS AT 0250 CDT/0750 UTC.
LIGHT SOUTHEAST TO EAST WINDS THIS MORNING BECOMING NORTHEAST THIS
AFTERNOON. WINDS AND SEAS HIGHER IN AND AROUND SHOWERS AND
THUNDERSTORMS. WINDS WILL SHIFT TO THE NORTH LATE TONIGHT INTO
WEDNESDAY MORNING. GENERALLY LOW SEAS AND LIGHT TO MODERATE WINDS
ARE EXPECTED THROUGH WEDNESDAY.
WEDNESDAY NIGHT THROUGH MONDAY...LIGHT TO MODERATE WINDS AND SEAS
WILL PREVAIL ALONG THE LOWER TEXAS COAST THROUGH THE PERIOD...
WITH NO SMALL CRAFT EXERCISE CAUTION OR SMALL CRAFT ADVISORY
EXPECTED...AS HIGH PRESSURE REMAINS THE DOMINANT FEATURE OVER THE
WESTERN GULF OF MEXICO.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
54/68
AREA FORECAST DISCUSSION
NWS AMARILLO TX
332 PM CDT SUN MAY 13 2012
.DISCUSSION...
PRIMARY FOCUS IS ON PRECIPITATION CHANCES THROUGH MONDAY.
AFTERNOON WATER VAPOR IMAGERY SHOWED A MID/UPPER-LEVEL SHORTWAVE
TROUGH SINKING SOUTHEAST ACROSS EASTERN UT TOWARDS THE FOUR CORNERS
REGION. MID TO UPPER-LEVEL FORCING AHEAD OF THIS SHORTWAVE HAS
COMBINED WITH DAYTIME HEATING/DESTABILIZATION AND LOW-LEVEL UPSLOPE
FLOW OVER EASTERN CO AND NM TO GENERATE SHOWERS AND THUNDERSTORMS.
THE GREATEST CONVECTIVE COVERAGE IS CURRENTLY ACROSS NORTHEAST NM
WORKING INTO THE SOUTHWEST TX PANHANDLE...BUT ADDITIONAL SCATTERED
SHOWERS AND THUNDERSTORMS HAVE DEVELOPED FARTHER EAST ACROSS THE
PANHANDLES DUE TO THE COMBINATION OF AFTERNOON DESTABILIZATION AND
BROADER SCALE LIFT AHEAD OF THE SHORTWAVE.
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO IMPACT THE AREA THIS
EVENING AND OVERNIGHT. THE MID/UPPER-LEVEL SHORTWAVE TROUGH WILL
CONTINUE TO DIVE SOUTHEAST...REACHING NORTHERN/CENTRAL NM BY EARLY
MONDAY MORNING. DIFFLUENT/DIVERGENT FLOW ALOFT AHEAD OF THIS WAVE
WILL CONTINUE TO SUPPORT CONVECTION PROPAGATING EAST/SOUTHEAST OUT OF
NM AND CO THIS EVENING AND OVERNIGHT. BEST DYNAMICS WILL BE FOCUSED
ACROSS THE SOUTHWEST HALF OF THE AREA AND HAVE ALIGNED POPS
ACCORDINGLY. ALSO SOME WEAK ISENTROPIC LIFT EVIDENT ON THE 305K THETA
SURFACE ACROSS THE SOUTHWEST TX PANHANDLE THIS EVENING TO FURTHER AID
CONVECTION. LATEST LAPS AND RUC ANALYSIS DATA SHOW MLCAPES IN THE
500-1000 J/KG RANGE ACROSS THE WESTERN PANHANDLES WITH LESSER VALUES
TO THE EAST AND DEEP LAYER SHEAR AROUND 30-35 KTS IN THE SOUTHWEST
TX PANHANDLE...DECREASING TO THE NORTHEAST. THUS COULD SEE A FEW
STRONG STORMS THROUGH THIS EVENING CAPABLE OF PRODUCING SMALL HAIL
AND GUSTY WINDS...BUT NOT REALLY ANTICIPATING ANY SEVERE WEATHER
/ALTHOUGH AN ISOLATED MARGINALLY SEVERE STORM ACROSS THE SOUTHWEST CAN/T
BE RULED OUT/. COULD ALSO SEE SOME LOCALLY HEAVY RAIN GIVEN PWATS IN
THE THREE QUARTERS OF AN INCH TO ONE INCH RANGE AND SOME TRAINING OF
STORMS POSSIBLE. BETTER RAIN CHANCES LOOK TO GRADUALLY SHIFT
SOUTH/SOUTHWEST OF THE AREA LATE TONIGHT IN ASSOCIATION WITH STRONGER
DIVERGENCE ALOFT...AND ALSO AS THE LLJ AND LOW-LEVEL ISENTROPIC LIFT
FOCUS TO OUR SOUTHWEST.
RAIN CHANCES LINGER INTO MONDAY...BUT WILL GRADUALLY END FROM NORTH
TO SOUTH THROUGH THE DAY AS THE SHORTWAVE CONTINUES TO DIVE SOUTHEAST
TO SOUTHEAST NM/SOUTHWEST TX BY EARLY MONDAY EVENING. BETTER RAIN
CHANCES WILL BE FOCUSED ACROSS THE SOUTHERN HALF OF THE CWA ON
MONDAY. WEAKER INSTABILITY AND SHEAR SHOULD PRECLUDE ANY STRONG OR
SEVERE STORMS. WILL ALSO SEE THE COOLEST TEMPS IN THE SOUTH ON MONDAY
DUE TO LINGERING CLOUDS/PRECIP...WITH HIGHS FORECAST TO RANGE FROM
THE UPPER 60S SOUTHWEST TO MID/UPPER 70S NORTH.
DRY CONDITIONS ARE THEN FORECAST BEGINNING MONDAY NIGHT AS SHORTWAVE
UPPER RIDGING BUILDS EAST ACROSS THE SOUTHERN AND CENTRAL ROCKIES.
TEMPS WILL BEGIN TO REBOUND ON TUESDAY DUE TO RISING HEIGHTS...A
RETURN OF WEAK SOUTHERLY WINDS...AND INCREASED SUNSHINE...WITH HIGHS
CLIMBING BACK INTO THE UPPER 70S TO LOWER 80S. A DAMPENING MID-LEVEL
SHORTWAVE WILL WORK ACROSS THE CENTRAL ROCKIES AND PLAINS WEDNESDAY
AND WEDNESDAY NIGHT. THIS COULD POTENTIALLY SPAWN A FEW
SHOWERS/THUNDERSTORMS ACROSS THE NORTHERN PANHANDLES WEDNESDAY NIGHT.
HOWEVER...CHANCES LOOK LOW AT THIS TIME AS BETTER DYNAMICS WILL STAY
TO OUR NORTH AND COME ACROSS AT NIGHT...BY WHICH TIME ELEVATED
INSTABILITY LOOKS MINIMAL. THUS KEPT A DRY FORECAST FOR NOW. THE LEE
TROUGH WILL DEEPEN ON WEDNESDAY...WITH RESULTANT BREEZY SOUTHWEST
WINDS FURTHER CONTRIBUTING TO THE WARM UP.
A ZONAL FLOW/BROAD FLAT RIDGING LATE THIS WEAK WILL TRANSITION TO
SOUTHWESTERLY OVER THE WEEKEND AS AN UPPER TROUGH WORKS ACROSS THE
INTERMOUNTAIN WEST AND ROCKIES EVENTUALLY INTO THE NORTHERN PLAINS.
THIS FLOW ALOFT WILL PROMOTE SURFACE LEE TROUGHING AND SOME
SHARPENING OF THE DRYLINE BY FRIDAY AND SATURDAY. HOWEVER IT
CURRENTLY LOOKS LIKE WARM TEMPS ALOFT AND A LACK OF UPPER FORCING /AS
THE TROUGH IS DEFLECTED WELL TO OUR NORTHWEST/ WILL MAKE IT TOUGH FOR
CONVECTION TO INITIATE. THUS WILL MAINTAIN A DRY FORECAST. ABOVE
NORMAL TEMPERATURES EXPECTED LATE WEEK INTO THE WEEKEND WITH HIGHS IN
THE MID 80S TO LOWER 90S. WILL HAVE TO KEEP AN EYE ON A POTENTIAL
COLD FRONT THAT MAY MOVE IN SUNDAY OR SUNDAY NIGHT.
KB
&&
.FIRE WEATHER...
NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE CURRENTLY
EXPECTED THROUGH THE WEEK. SOUTH/SOUTHWEST WINDS WILL INCREASE TO 15
TO 20 MPH ON WEDNESDAY AND RELATIVE HUMIDITIES MAY FALL TO 15 TO 20
PERCENT ACROSS THE FAR WESTERN PANHANDLES...BUT RECENT RAINFALL AND
RESULTANT GREEN-UP SHOULD MITIGATE ANY FIRE WEATHER CONCERNS. WARMER
TEMPERATURES WILL CONTINUE LATE WEEK INTO THE WEEKEND AND MINIMUM
RELATIVE HUMIDITIES WILL FALL TO 15 TO 20 PERCENT ACROSS WESTERN
AREAS. SOUTH/SOUTHWEST WINDS WILL BE BREEZY AT TIMES AND ELEVATED
FIRE WEATHER CONDITIONS COULD DEVELOP...BUT AGAIN RECENT RAINFALL AND
GREEN-UP WILL HELP MINIMIZE FIRE WEATHER CONCERNS.
KB
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 50 69 50 79 53 / 70 40 10 0 0
BEAVER OK 50 76 51 83 53 / 20 10 5 0 0
BOISE CITY OK 48 73 48 81 51 / 50 20 5 0 0
BORGER TX 52 75 54 82 57 / 50 40 5 0 0
BOYS RANCH TX 52 72 51 82 55 / 70 40 5 0 0
CANYON TX 50 68 48 79 51 / 70 40 10 5 0
CLARENDON TX 53 70 52 79 55 / 50 40 10 5 0
DALHART TX 48 71 46 80 50 / 70 40 5 0 0
GUYMON OK 50 76 50 84 53 / 30 20 5 0 0
HEREFORD TX 49 68 47 78 51 / 80 50 10 5 0
LIPSCOMB TX 50 75 49 81 52 / 20 20 5 0 0
PAMPA TX 50 70 50 79 54 / 40 40 5 0 0
SHAMROCK TX 53 74 51 80 54 / 40 30 10 5 0
WELLINGTON TX 55 75 54 81 55 / 40 30 10 5 0
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
07/08
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
241 PM EDT TUE MAY 15 2012
.SYNOPSIS...
A WEAK FRONTAL BOUNDARY ACROSS THE REGION WILL PROVIDE A FOCUS FOR
SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND THIS EVENING.
THE FRONT WILL SLOWLY PUSH EASTWARD TONIGHT BUT AGAIN PROVIDE
INCREASED CHANCES OF RAIN ACROSS THE EASTERN MIDLANDS ON WEDNESDAY
BEFORE SHIFTING TO THE COAST. SURFACE HIGH PRESSURE WILL BUILD
INTO THE REGION THURSDAY AND PROVIDE DRY WEATHER THROUGH THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...A WEAK FRONTAL BOUNDARY AND LEFT OVER OUTFLOW
BOUNDARIES WILL PROVIDE A FOCUS FOR SHOWER AND THUNDERSTORM
DEVELOPMENT. SPC HAS AREA IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS
THIS AFTERNOON INTO THE EVENING HOURS. THE LATEST RAP SOUNDING FOR
LATE THIS AFTERNOON CONFIRMS THAT THE ATMOSPHERE SHOULD BE UNSTABLE
ENOUGH TO PRODUCE STRONG TO POTENTIALLY SEVERE STORMS. RAP LIS -5
...CAPES OVER 2000 J/KG...TOTALS OVER 50. NAM SOUNDING GIVES
CONVECTIVE TEMPERATURES 82-84 DEGREE THIS AFTERNOON. TEMPERATURES
SHOULD RISE INTO THE LOWER TO MIDDLE 80S DURING THE AFTERNOON.
THIS IS EXPECTED TO ENHANCE SHOWERS AND THUNDERSTORMS...ESPECIALLY
LATE THIS AFTERNOON. WILL START WITH A 20-30 PERCENT CHANCE THIS
AFTERNOON. LOCAL WRF SHOWS INCREASING TREND...ESPECIALLY LATER
THIS AFTERNOON. JUST ISSUED SEVERE THUNDERSTORM WATCH IN EFFECT.
TONIGHT...BEST CHANCES OF SHOWERS AND THUNDERSTORMS WITH CHANCES
INCREASING TO 40-50 PERCENT. AGREE WITH LOCAL 4 KM WRF MODEL GIVING
HIGHEST CHANCES IN THE EVENING. AS TEMPERATURES DROP BY MIDNIGHT...
DECIDED TO GO JUST 20 PERCENT CHANCE REST OF NIGHT AFTER MIDNIGHT.
THERE MAY BE SOME PATCHY FOG AFTER MIDNIGHT AS WELL BUT LEFT OUT
FOR TIME BEING AS SHOWERS MAY LINGER WELL AFTER MIDNIGHT WITH SOME
CLOUDINESS NOT ALLOWING WIDESPREAD FOG LIKE THIS MORNING. WENT ABOVE
GUIDANCE LOWS 1-2 DEGREES AS PREVIOUS RUNS HAVE BEEN A BIT COOL.
SEVERE THUNDERSTORM WATCH IN EFFECT UNTIL 9 PM.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
LOW PRESSURE WILL BE TRACKING FROM NEW ENGLAND INTO THE FAR EASTERN
CANADIAN PROVINCES AS A WEAK FRONTAL BOUNDARY SLOWLY CROSSES THE
FORECAST AREA. ON WEDNESDAY THE FRONT WILL BE OVER THE UPSTATE WITH
ANOTHER UNSTABLE DAY FOR CONVECTIVE ACTIVITY. WITH AROUND 2000 J/KG
CAPE AND LI/S AROUND -5 EXPECT ANOTHER AFTERNOON AND EVENING WITH
SCATTERED SHOWERS AND THUNDERSTORMS. MODELS INDICATE THE BEST
INSTABILITY OVER THE EASTERN MIDLANDS AND...WITH THE POSITION OF THE
FRONT AND HIGHER MOISTURE IN THE EASTERN MIDLANDS...AGREE HIGHEST
POPS TO START IN THAT AREA. WILL EXPAND POPS TO THE REMAINDER OF THE
AREA AS PLENTIFUL INSTABILITY COMBINING WITH OUTFLOWS WILL LIKELY
SPUR ADDITIONAL ACTIVITY. SPC CONTINUES TO KEEP THE REGION IN
GENERAL THUNDER WHICH CURRENTLY SEEMS APPROPRIATE. MAIN THREAT OF
SEVERE ON WEDNESDAY AFTERNOON WILL BE HAIL WITH A LOWER CHANCE FOR
WIND GUSTS. CONVECTIVE ACTIVITY WILL DIMINISH WITH THE LOSS OF
HEATING WEDNESDAY EVENING...HOWEVER WITH OUTFLOW BOUNDARIES REMAINING
OVER THE FORECAST AREA BELIEVE CONVECTION WILL LINGER INTO THE LATE
EVENING/EARLY OVERNIGHT HOURS. AFTERNOON HIGH TEMPERATURES
WEDNESDAY WILL GENERALLY BE IN THE MIDDLE 80S. WITH SOME LINGERING
CLOUDS AND PATCHY FOG EXPECT OVERNIGHT LOWS WEDNESDAY NIGHT IN THE
LOWER 60S.
ON THURSDAY THE FRONT WILL BE OVER THE EASTERN MIDLANDS DURING THE
AFTERNOON AND TRACKING OFFSHORE DURING THE EVENING. INSTABILITY WILL
BE LESS THAN WEDNESDAY...HOWEVER THERE WILL STILL BE ENOUGH TO
INITIATE CONVECTION. BEST INSTABILITY WILL BE CLOSER TO THE FRONT SO
WILL AGAIN INCREASE POPS CLOSEST TO THE FRONT THEN EXPAND A BIT
WESTWARD AS OUTFLOWS TRIGGER SOME ADDITIONAL CONVECTION. SEVERE
THREAT WILL AGAIN BE FROM HAIL WITH LOWER POTENTIAL FOR DAMAGING
WINDS. HIGH TEMPERATURES THURSDAY AFTERNOON WILL GENERALLY BE IN THE
LOWER 80S. CONVECTION WILL DISSIPATE WITH LOSS OF HEATING AND THE
FRONT EDGING OFFSHORE. EXPECT SOME CONVECTION INTO THE EVENING HOURS
AND WITH THE FRONT MOVING OFFSHORE EXPECT CONVECTION TO END BEFORE
THE OVERNIGHT HOURS. LOW TEMPERATURES THURSDAY NIGHT WILL BE A FEW
DEGREES COOLER BEHIND THE FRONT WITH LOWS IN THE UPPER 50S TO LOWER
60S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
MODELS REMAIN IN GOOD AGREEMENT THROUGH THE LONG TERM WITH SOME
TYPICAL TIMING AND INTENSITY DIFFERENCES FOR SUNDAY AND MONDAY.
UPPER LEVEL TROUGH WILL EXIT THE REGION EARLY FRIDAY AS THE UPPER
LEVEL RIDGE BUILDS BACK IN. THIS WILL LEAVE A STATIONARY FRONT
ALONG THE COAST TO JUST SOUTH OF THE AREA. MODELS DIFFER ON THE
LOCATION OF THE FRONT...HOWEVER WITH HIGH PRESSURE DOMINATING THE
SURFACE EXPECT MUCH OF THE CONVECTIVE POTENTIAL TO BE SUPPRESSED
THROUGH THE WEEKEND. AS THE HIGH MOVES OFFSHORE MONDAY THE CHANCE
OF THUNDERSTORMS WILL RETURN. MODELS CONTINUE TO HAVE SIGNIFICANT
RUN TO RUN CHANGES ASSOCIATED WITH A LOW WHICH DEVELOPS ALONG THE
COAST. AS A RESULT HAVE REMAINED PESSIMISTIC CONCERNING THIS
FEATURE. TEMPERATURES THROUGH THE LONG TERM WILL BE NEAR NORMAL.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
UPPER TROUGH STILL TO THE WEST BRINGING MOISTURE TO AREA.
WEAK FRONTAL BOUNDARY ACROSS THE REGION AND LEFT OVER OUTFLOW
BOUNDARIES FROM CONVECTIVE ACTIVITY SHOULD PROVIDE A FOCUS FOR
SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING. MAINLY VFR
CONDITIONS BUT BRIEF IFR-MVFR CONDITIONS ARE POSSIBLE IN CONVECTIVE
ACTIVITY. DECIDED NOT TO INCLUDE IN TAFS SITES DUE TO UNCERTAINTY
AS TO TIMING AND COVERAGE. ACTIVITY IS EXPECTED TO TAPER OFF 03Z-04Z
TIME FRAME BUT MAY LINGER NORTH AND EAST OF TAF SITES. AFTER
MIDNIGHT WITH PLENTY OF MOISTURE AND LEFT OVER CLOUDS...NO AS MUCH
FOG EXPECTED BUT STRATUS WILL PROBABLY DEVELOP AGAIN. EXPECT IFR
CEILINGS TO DEVELOP BEFORE DAYBREAK WEDNESDAY. THE UPPER TROUGH
SHOULD HAVE SHIFTED EASTWARD BY WEDNESDAY BUT THERE WILL STILL BE
ENOUGH MOISTURE AND INSTABILITY FOR SOME AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS. WILL GO VFR BUT LOWER CONDITIONS MAY
OCCUR IN CONVECTIVE ACTIVITY.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT RESTRICTIONS ARE
EXPECTED WEDNESDAY NIGHT THROUGH SUNDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
402 PM CDT TUE MAY 15 2012
.DISCUSSION...
251 PM CDT
FORECAST FOCUS IN NEAR TERM REMAINS COLD FRONTAL PASSAGE THIS
EVENING AND THE POTENTIAL FOR ISOLATED/SCATTERED CONVECTION. AFTER A
MUCH COOLER DAY WEDNESDAY...A WARMING TREND BACK TO SUMMER-LIKE
TEMPERATURES AND EVENTUALLY AND INCREASING POTENTIAL FOR
THUNDERSTORMS IS EXPECTED THROUGH THE WEEKEND.
AT 19Z...SFC ANALYSIS DEPICTS COLD FRONT STRETCHING FROM NEAR GREEN
BAY WISCONSIN...TO AMES IN CENTRAL IOWA. WARM SECTOR AHEAD OF FRONT
IS CHARACTERIZED BY TEMPS IN MID-UPPER 80S FROM NORTHERN IL BACK
INTO EASTERN IA...THOUGH VERY DRY LOW LEVELS AS INDICATED BY SFC DEW
PTS GENERALLY IN THE UPPER 30S TO MID 40S. THIS NOT SURPRISING GIVEN
EXTREMELY DRY LOW-MID LEVELS SEEN IN 12Z RAOBS AT UPSTREAM AT
MPX/OAX...THOUGH THERE IS A NARROW AXIS OF SLIGHTLY HIGHER DWPTS
FROM WESTERN IL INTO NORTHEAST IL. 18Z RAP APPEARS TO HAVE A DECENT
HANDLE ON THE LOW LEVEL MOISTURE FIELD...AND REMAINS CONSISTENT IN
DEVELOPING CONVECTIVE PRECIP AHEAD OF FRONT ACROSS CNTRL/EASTERN WI
AND DEVELOPING IT SOUTHEAST INTO NORTHERN/NORTHEAST IL EARLY THIS
EVENING. DESPITE VIGOROUS MID-LEVEL SHORT WAVE DIGGING SOUTHEAST
ACROSS THE NORTHERN LAKES...STEEP LOW/MID LEVEL LAPSE RATES AND THE
APPROACH OF A RELATIVELY STRONG COLD FRONTAL BOUNDARY...DEARTH OF
LOW LEVEL MOISTURE SUGGESTS IT WILL LIKELY BE DIFFICULT TO DEVELOP
SIGNIFICANT THUNDERSTORM COVERAGE...WITH HIGH LCL/LFC AND FAIRLY
SKINNY CAPE PROFILES OF 200-300 J/KG ALOFT PER RAP SOUNDINGS. THUS
WHILE ISOLATED-SCATTERED STORMS CANT BE RULED OUT COMPLETELY WITH
FROPA EARLY THIS EVENING...CONTINUE TO SUSPECT COVERAGE WILL BE
RELATIVELY LOW AND CONDITIONAL SEVERE THREAT MINIMAL. AS NOTED
PREVIOUSLY...ANY ACTIVITY WHICH DOES DEVELOP SHOULD HAVE A FAIRLY
STRONG DIURNAL COMPONENT AND SHOULD FADE QUICKLY WITH COOLING OF
BOUNDARY LAYER BEYOND SUNSET. WILL CONTINUE TO MAINTAIN ONLY LOW
CHANCE POPS.
HIGH PRESSURE WILL THEN BUILD ACROSS THE GREAT LAKES REGION
WEDNESDAY IN THE WAKE OF THE MID-LEVEL WAVE AND COLD FRONT. MUCH
COOLER TEMPS THAN TODAY CAN BE EXPECTED...RANGING FROM AROUND 60
NEAR THE LAKE MICHIGAN SHORE TO THE LOW 70S IN THE FAR WEST/SOUTH
REACHES OF THE CWA. FLAT UPPER LEVEL RIDGE THEN SPREADS ACROSS THE
MIDWEST THURSDAY...WITH LOW LEVEL WARM ADVECTION FOCUSING ACROSS THE
UPPER MISSISSIPPI VALLEY AND ACROSS THE NORTHERN LAKES FRIDAY. AXIS
OF LOW LEVEL 40-50 KT JET KEEPS THUNDERSTORM FOCUS NORTH/NORTHWEST
OF THE CWA THROUGH THIS TIME. UPPER RIDGE STRENGTHENS OVER THE
MIDWEST INTO THE WEEKEND AS BROAD TROUGH PUSHES EAST ACROSS THE
WESTERN HALF OF THE CONUS. SOUTHEAST/SOUTH FLOW THROUGH THE PERIOD
WILL LEAD TO TEMPS GRADUALLY WARMING FROM THE 70S THURSDAY INTO THE
LOW-MID80S FRI AND MID 80S SAT. LOW LEVEL MOISTURE WILL ALSO
GRADUALLY INCREASE FROM THE WEST/SOUTHWEST OVER THE WEEKEND AS
WESTERN TROUGH AND COLD FRONT SLOWLY APPROACH. GUIDANCE HAS SLOWED
FRONTAL ARRIVAL SOMEWHAT...HOLDING OFF GREATER PRECIP/THUNDERSTORM
THREAT UNTIL SUNDAY NIGHT AND MONDAY. UPPER TROUGH THEN MOVES SLOWLY
ACROSS THE AREA EARLY NEXT WEEK WITH COOLER WEATHER AS LOW LEVEL
FLOW BECOMES NORTHERLY BEHIND THE FRONT.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* GUSTY WSWLY-WLY WINDS TODAY...TURNING NELY LATE TONIGHT.
* CHANCE OF TSRA EARLY THIS EVENING.
KREIN
//DISCUSSION...UPDATED 18Z...
FOR THE REMAINDER OF THE AFTERNOON...THE MAIN CONCERN WILL BE
WINDS. WITH A FRONTAL TROUGH APPROACHING FROM THE NORTH AND HIGH
PRESSURE OVER THE OHIO VALLEY...BRISK WSWLY-WLY WINDS WILL
CONTINUE. UNDER GENERALLY CLEAR SKIES...HIGHER WINDS HAVE BEEN
ABLE TO MIX DOWN TO THE SFC WITH GUSTS TO AROUND 25KT LIKELY TO
CONTINUE THOUGH THE AFTERNOON.
BY EARLY EVENING...THE FOCUS OF CONCERN WILL SHIFT TO THUNDERSTORM
POSSIBILITIES. A COLD FRONT CONTINUES TO DROP SWD THROUGH
WISCONSIN AND IS EXPECTED TO CROSS THE BORDER INTO IL BY ARND 00Z.
WHILE SFC MOISTURE IS RATHER LOW OVER NRN IL/IN...FRONTAL FORCING
AND ADEQUATE WARMTH WILL BE IN PLACE TO GENERATE SHOWERS AND
WIDELY SCATTERED THUNDERSTORMS. THE GREATEST CHANCE FOR THUNDER
WILL BE BEFORE SUNSET...WITH CHANCES DECREASING AFTER SUNSET AND
THROUGH THE EVENING. GIVEN THAT THUNDER COVERAGE IS EXPECTED TO BE
SPARSE...WILL ONLY CARRY A VCTS MENTION IN THE TAFS.
FOLLOWING THE FROPA...WINDS WILL RAPIDLY SHIFT THROUGH NWLY TO NLY
TO NELY OVERNIGHT. WITH HIGH PRESSURE BUILDING IN BEHIND THE
FRONT...WINDS ARE EXPECTED TO REMAIN NELY THROUGH TOMORROW.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM TO HIGH CONFIDENCE REGARDING WIND DIRECTION/SPEEDS/GUSTS
THROUGH THE PERIOD.
* LOW TO MEDIUM CONFIDENCE REGARDING TSRA LATE AFTERNOON THROUGH
EARLY THIS EVENING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT THROUGH SATURDAY...VFR.
* SUNDAY...CHANCE OF TSRA. GUSTY SOUTHWEST WINDS.
* MONDAY...CHANCE OF TSRA.
KJB
&&
.MARINE...
353 PM CDT
A COLD FRONT TRAILING BACK SOUTHWESTWARD FROM LOW PRESSURE OVER
FAR EASTERN ONTARIO BETWEEN JAMES BAY AND GEORGIAN BAY...ACROSS
THE FAR EASTERN UPPER PENINSULA OF MI...CENTRAL WI AND SE IA WILL
CONTINUE TO PUSH SE ACROSS THE UPPER GREAT LAKES AND MID MS VALLEY
THIS EVENING AS THE LOW CONTINUES TO MOVE E TO CENTRAL QUEBEC
DURING THE NIGHT. HIGH PRESSURE CENTERED OVER SOUTHERN MANITOBA
AND EXTENDING S ACROSS THE NORTHERN PLAINS WILL BUILD ACROSS THE
UPPER MIDWEST AND MID MO VALLEY OVERNIGHT BEHIND THE COLD FRONT.
COLD AIR ADVECTION AND A SIGNIFICANT 3 HR PRESSURE RISE CENTER OF
5-6 MB WAS MOVING SE ACROSS CENTRAL LAKE SUPERIOR AND THE U.P. OF
MI GENERATING SOME NW GUSTS TO AROUND 30 KT BEHIND THE COLD FRONT.
THIS PRESSURE RISE CENTER IS EXPECTED TO SWING ACROSS NORTHERN
LAKE MI THIS EVE CAUSING SOME GUSTY NW AND N WINDS MAINLY ON THE N
PORTION OF THE LAKE.
HIGH PRESSURE CENTERED OVER SOUTHERN MANITOBA AND EXTENDING S
ACROSS THE NORTHERN PLAINS WILL BUILD ACROSS THE UPPER MIDWEST AND
MID MO VALLEY OVERNIGHT BEHIND THE COLD FRONT WITH THE PRESSURE
GRADIENT OVER LAKE MI GRADUALLY WEAKENING AND THE RESULTANT WINDS
SLACKING. THIS HIGH THEN MOVES E OVER THE UPPER GREAT LAKES DURING
WED BRINGING LIGHTER WINDS TO THE LAKE. AS THE HIGH SHIFTS FURTHER
E TO THE LOWER GREAT LAKES DURING THU SE WINDS WILL START TO
SLOWLY INCREASE THU NIGHT AND FRI AS LOW PRESSURE MOVES E OVER THE
CENTRAL PLAINS.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
252 PM CDT TUE MAY 15 2012
.DISCUSSION...
251 PM CDT
FORECAST FOCUS IN NEAR TERM REMAINS COLD FRONTAL PASSAGE THIS
EVENING AND THE POTENTIAL FOR ISOLATED/SCATTERED CONVECTION. AFTER A
MUCH COOLER DAY WEDNESDAY...A WARMING TREND BACK TO SUMMER-LIKE
TEMPERATURES AND EVENTUALLY AND INCREASING POTENTIAL FOR
THUNDERSTORMS IS EXPECTED THROUGH THE WEEKEND.
AT 19Z...SFC ANALYSIS DEPICTS COLD FRONT STRETCHING FROM NEAR GREEN
BAY WISCONSIN...TO AMES IN CENTRAL IOWA. WARM SECTOR AHEAD OF FRONT
IS CHARACTERIZED BY TEMPS IN MID-UPPER 80S FROM NORTHERN IL BACK
INTO EASTERN IA...THOUGH VERY DRY LOW LEVELS AS INDICATED BY SFC DEW
PTS GENERALLY IN THE UPPER 30S TO MID 40S. THIS NOT SURPRISING GIVEN
EXTREMELY DRY LOW-MID LEVELS SEEN IN 12Z RAOBS AT UPSTREAM AT
MPX/OAX...THOUGH THERE IS A NARROW AXIS OF SLIGHTLY HIGHER DWPTS
FROM WESTERN IL INTO NORTHEAST IL. 18Z RAP APPEARS TO HAVE A DECENT
HANDLE ON THE LOW LEVEL MOISTURE FIELD...AND REMAINS CONSISTENT IN
DEVELOPING CONVECTIVE PRECIP AHEAD OF FRONT ACROSS CNTRL/EASTERN WI
AND DEVELOPING IT SOUTHEAST INTO NORTHERN/NORTHEAST IL EARLY THIS
EVENING. DESPITE VIGOROUS MID-LEVEL SHORT WAVE DIGGING SOUTHEAST
ACROSS THE NORTHERN LAKES...STEEP LOW/MID LEVEL LAPSE RATES AND THE
APPROACH OF A RELATIVELY STRONG COLD FRONTAL BOUNDARY...DEARTH OF
LOW LEVEL MOISTURE SUGGESTS IT WILL LIKELY BE DIFFICULT TO DEVELOP
SIGNIFICANT THUNDERSTORM COVERAGE...WITH HIGH LCL/LFC AND FAIRLY
SKINNY CAPE PROFILES OF 200-300 J/KG ALOFT PER RAP SOUNDINGS. THUS
WHILE ISOLATED-SCATTERED STORMS CANT BE RULED OUT COMPLETELY WITH
FROPA EARLY THIS EVENING...CONTINUE TO SUSPECT COVERAGE WILL BE
RELATIVELY LOW AND CONDITIONAL SEVERE THREAT MINIMAL. AS NOTED
PREVIOUSLY...ANY ACTIVITY WHICH DOES DEVELOP SHOULD HAVE A FAIRLY
STRONG DIURNAL COMPONENT AND SHOULD FADE QUICKLY WITH COOLING OF
BOUNDARY LAYER BEYOND SUNSET. WILL CONTINUE TO MAINTAIN ONLY LOW
CHANCE POPS.
HIGH PRESSURE WILL THEN BUILD ACROSS THE GREAT LAKES REGION
WEDNESDAY IN THE WAKE OF THE MID-LEVEL WAVE AND COLD FRONT. MUCH
COOLER TEMPS THAN TODAY CAN BE EXPECTED...RANGING FROM AROUND 60
NEAR THE LAKE MICHIGAN SHORE TO THE LOW 70S IN THE FAR WEST/SOUTH
REACHES OF THE CWA. FLAT UPPER LEVEL RIDGE THEN SPREADS ACROSS THE
MIDWEST THURSDAY...WITH LOW LEVEL WARM ADVECTION FOCUSING ACROSS THE
UPPER MISSISSIPPI VALLEY AND ACROSS THE NORTHERN LAKES FRIDAY. AXIS
OF LOW LEVEL 40-50 KT JET KEEPS THUNDERSTORM FOCUS NORTH/NORTHWEST
OF THE CWA THROUGH THIS TIME. UPPER RIDGE STRENGTHENS OVER THE
MIDWEST INTO THE WEEKEND AS BROAD TROUGH PUSHES EAST ACROSS THE
WESTERN HALF OF THE CONUS. SOUTHEAST/SOUTH FLOW THROUGH THE PERIOD
WILL LEAD TO TEMPS GRADUALLY WARMING FROM THE 70S THURSDAY INTO THE
LOW-MID80S FRI AND MID 80S SAT. LOW LEVEL MOISTURE WILL ALSO
GRADUALLY INCREASE FROM THE WEST/SOUTHWEST OVER THE WEEKEND AS
WESTERN TROUGH AND COLD FRONT SLOWLY APPROACH. GUIDANCE HAS SLOWED
FRONTAL ARRIVAL SOMEWHAT...HOLDING OFF GREATER PRECIP/THUNDERSTORM
THREAT UNTIL SUNDAY NIGHT AND MONDAY. UPPER TROUGH THEN MOVES SLOWLY
ACROSS THE AREA EARLY NEXT WEEK WITH COOLER WEATHER AS LOW LEVEL
FLOW BECOMES NORTHERLY BEHIND THE FRONT.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* GUSTY WSWLY-WLY WINDS TODAY...TURNING NELY LATE TONIGHT.
* CHANCE OF TSRA EARLY THIS EVENING.
KREIN
//DISCUSSION...UPDATED 18Z...
FOR THE REMAINDER OF THE AFTERNOON...THE MAIN CONCERN WILL BE
WINDS. WITH A FRONTAL TROUGH APPROACHING FROM THE NORTH AND HIGH
PRESSURE OVER THE OHIO VALLEY...BRISK WSWLY-WLY WINDS WILL
CONTINUE. UNDER GENERALLY CLEAR SKIES...HIGHER WINDS HAVE BEEN
ABLE TO MIX DOWN TO THE SFC WITH GUSTS TO AROUND 25KT LIKELY TO
CONTINUE THOUGH THE AFTERNOON.
BY EARLY EVENING...THE FOCUS OF CONCERN WILL SHIFT TO THUNDERSTORM
POSSIBILITIES. A COLD FRONT CONTINUES TO DROP SWD THROUGH
WISCONSIN AND IS EXPECTED TO CROSS THE BORDER INTO IL BY ARND 00Z.
WHILE SFC MOISTURE IS RATHER LOW OVER NRN IL/IN...FRONTAL FORCING
AND ADEQUATE WARMTH WILL BE IN PLACE TO GENERATE SHOWERS AND
WIDELY SCATTERED THUNDERSTORMS. THE GREATEST CHANCE FOR THUNDER
WILL BE BEFORE SUNSET...WITH CHANCES DECREASING AFTER SUNSET AND
THROUGH THE EVENING. GIVEN THAT THUNDER COVERAGE IS EXPECTED TO BE
SPARSE...WILL ONLY CARRY A VCTS MENTION IN THE TAFS.
FOLLOWING THE FROPA...WINDS WILL RAPIDLY SHIFT THROUGH NWLY TO NLY
TO NELY OVERNIGHT. WITH HIGH PRESSURE BUILDING IN BEHIND THE
FRONT...WINDS ARE EXPECTED TO REMAIN NELY THROUGH TOMORROW.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM TO HIGH CONFIDENCE REGARDING WIND DIRECTION/SPEEDS/GUSTS
THROUGH THE PERIOD.
* LOW TO MEDIUM CONFIDENCE REGARDING TSRA LATE AFTERNOON THROUGH
EARLY THIS EVENING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT THROUGH SATURDAY...VFR.
* SUNDAY...CHANCE OF TSRA. GUSTY SOUTHWEST WINDS.
* MONDAY...CHANCE OF TSRA.
KJB
&&
.MARINE...
219 AM CDT
A COLD FRONT WILL PROGRESS DOWN THE LENGTH OF LAKE MICHIGAN THIS
AFTERNOON AND EVENING. A WIND SHIFT OUT OF THE NORTH CAN BE EXPECTED
FOLLOWING THE PASSAGE OF THIS FRONT. THE FRONT SHOULD BEGIN TO MOVE
ACROSS THE NORTHERN HALF OF THE LAKE LATER THIS AFTERNOON AND THEN
PROGRESS ACROSS THE SOUTHERN HALF OF THE LAKE DURING THE EVENING. IT
APPEARS THAT ONCE THE FRONT PASSES THERE COULD BE A SHORT PERIOD OF
NORTHERLY WINDS UP AROUND 30 KT. THE WINDS WILL BECOME LIGHTER LATER
ON WEDNESDAY AS A SURFACE AREA OF HIGH PRESSURE MOVES ACROSS THE
LAKE. ONCE THIS HIGH SHIFTS EAST OF THE LAKE ON THURSDAY...LOW
PRESSURE ACROSS THE PLAINS WILL ALLOW WINDS TO BECOME SOUTHERLY
AGAIN FOR AN EXTENDED PERIOD THROUGH THE UPCOMING WEEKEND.
FOR THE NEAR SHORE WATERS IT APPEARS WINDS WILL BECOME GUSTY OUT OF
THE WEST SOUTHWEST TODAY AHEAD OF THE AFOREMENTIONED FRONT
DROPPING DOWN LAKE MICHIGAN. IT APPEARS THE WINDS COULD GUST INTO
THE 20 TO 25 KT RANGE UP NEAR THE ILLINOIS AND WISCONSIN
BOARDER...WITH SLIGHTLY LIGHTER GUSTS AROUND 20 KT EXPECTED
FARTHER SOUTH. I WILL HOLD OFF ON A SMALL CRAFT ADVISORY AND
MENTION 15 TO 25 KT WINDS FOR MY FAR NORTHERN MARINE NEAR SHORE
ZONE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
430 PM EDT TUE MAY 15 2012
.SHORT TERM.../TONIGHT-WED NGT/
CDFNT MOVG ACROSS WI/IA THIS AFTN WILL MOVE SE ACROSS OUR CWA
TONIGHT. BKN HIGH BASED CU AND ISOLATED LIGHTNING STRIKES ALONG
FRONT OVER WI/IA ATTM. SFC OBS AND 12Z UPR AIR ANALYSIS SUGGESTS
LATEST NCEP MODELS CONT TO BE TOO MOIST IN LOW LEVELS... THUS
CONFIDENCE IN BKN LINE OF SHOWERS/TSTMS DVLPG FROM MI-SE IA BY 00Z
AS DEPICTED BY LATEST 4KM SPC WRF IS LOW. HRRR INDICATING
CONSIDERABLY LOWER CHC OF CONVECTION REACHING OUR AREA AND APPEARS
TO BE HANDLING THE SFC DWPTS AHEAD OF THE FRONT A LITTLE BETTER. IN
EITHER CASE... ANY SHOWERS/TSTMS WHICH DEVELOP ALONG FRONT LATE
THIS AFTN/EARLY EVE SHOULD BE IN A WKNG/DISSIPATING STAGE UPON
REACHING OUR CWA GIVEN DRY AIRMASS IN PLACE AND DIURNAL
STABILIZATION. ALTHOUGH CONFIDENCE LOW IN CONVECTION REACHING OUR
AREA... FELT GOING LOW CHC OF TSTMS TONIGHT WORTH LEAVING IN FCST
ATTM. GIVEN STEEP LAPSE RATES ABOVE DVLPG SHALLOW NOCTURNAL SFC
BASED INVERSION... POTENTIAL FOR SOME GUSTY WINDS IF CONVECTION
DOES REACH OUR CWA.
HIGH PRESSURE BUILDING INTO THE AREA BEHIND THE FRONT WED WILL
RESULT IN CLEARING SKIES. FAIRLY STRONG CAA SHOULD HOLD TEMPS DOWN
ABOUT 10F FROM TODAYS READINGS DESPITE SUNNY SKIES MOST OF THE DAY.
WITH HIGH MOVG OVERHEAD WED NGT LIGHT WINDS AND DRY AIRMASS WILL
RESULT IN GOOD RADIATIONAL COOLING WITH LOWS IN THE L-M40S ACROSS
THE AREA.
&&
.LONG TERM...
PROGRESSIVE PATTN ALOFT CONTS TO HOLD SWAY THIS PD. LEAD SW TROUGH
OVR SRN ON THIS AFTN WILL RAPIDLY DRIVE EWD UP THROUGH THE ST LAW
VALLEY THU AS SFC RIDGING SHIFTS EWD W/ROBUST WAA DVLPG DURING THE
DAY. MEXMOS APPROXIMATION STILL HOLDS AND SEE NO REASON TO CHG
ANYTHING.
AFT THAT...SIG UPR RIDGING DVLPS EWD OF WRN US TROUGHING AND
INTENSIFIES ACRS THE MID ATL COAST THIS WEEKEND. THERMAL RIDGE
INBTWN WILL BE QUITE WARM FOR MID MAY STANDARDS WITH LOW-MID 80S
XPCD FRI-SUN. EJECTING WRN TROUGH SAT PROGGED TO QUICKLY DEAMPLIFY
EWD MON IN RESPONSE TO DOWNSTREAM UPR RIDGING AND RENEWED FOCUS ON A
MORE SIG WAVE TRAIN ENTERING NWPAC/SW CANADA. IN ADDN...CONTD
SUGGESTION OF A TROPICAL DISTURBANCE OVR THE WRN CARIBBEAN WILL
ELIMINATE ANY SIG GOMEX MSTR RTN. GIVEN CONTD POOR MODEL HANDLING OF
BNDRY LYR MSTR AND XPCD WKNG FNTL SYS...WILL SLASH GOING POPS LWR
MON/MON NIGHT. REMAINDER ON TRACK.
&&
.AVIATION...
VFR CONDITIONS WILL CONT THROUGH THE PERIOD. COLD FRONT WILL CROSS
THE AREA OVERNIGHT WITH WIND SHIFT LATE EVENING TO NORTH AND
EVENTUALLY NORTHEAST. MOISTURE LIMITED ALONG FRONT AND CHANCES FOR
CONVECTION SMALL SO CONTD WITH NO INCLUSION OF PRECIPITATION AT TAF
SITES AT THIS TIME... THOUGH IF CONVECTION DOES DEVELOP AND SURVIVES
LONG ENOUGH INTO THE NIGHT TO REACH THE TERMINALS... COULD BE
ACCOMPANIED BY GUSTY WINDS GIVEN STEEP LAPSE RATES IN PLACE ABOVE
DVLPG SHALLOW SFC BASED NOCTURNAL INVERSION.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 4 PM EDT WEDNESDAY
FOR LMZ043-046.
&&
$$
SHORT TERM...JT
LONG TERM...T
AVIATION...JT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
243 PM MDT TUE MAY 15 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 1249 PM MDT TUE MAY 15 2012
EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOW SHORTWAVE
RIDGE ACROSS CENTRAL ROCKIES...WITH DEEP UPPER LOW UPSTREAM OVER
NORTHERN CALIFORNIA. A COLD FRONT IS CURRENTLY JUST NORTH OF OUR
CWA...WITH TEMPERATURES AHEAD OF THE FRONT OVER OUR CWA IN THE MID
TO UPPER 80S...AND TEMPERATURES BEHIND THE FRONT IN THE MID TO
UPPER 70S.
THE COLD FRONT TO THE NORTH OF THE CWA WILL DROP SOUTH AND EAST
THIS EVENING...WITH INCREASING TD NORTH OF THE FRONT AS WINDS
SHIFT TO THE EAST-SOUTHEAST. IF TD VALUES IN THE LOW-MID 40S WERE
TO ADVECT INTO THE NORTHERN HALF OF OUR CWA...RADIATIONAL FOG
COULDNT BE RULED OUT. GUIDANCE IS CURRENTLY SHOWING BL REMAINING
UNSATURATED THROUGH WED MORNING...SO FOG WAS LEFT OUT OF
FORECAST.
LARGE SCALE SUBSIDENCE AND A VERY DRY/STABLE AIR MASS WILL REMAIN
IN PLACE THROUGH WEDNESDAY AFTERNOON. SHORTWAVE TROUGH BEGINS TO
MOVE EAST INTO THE CENTRAL ROCKIES BY WED AFTERNOON...WHICH
COULD BRING THUNDERSTORM CHANCES TO EASTERN COLORADO COUNTIES BY
LATE WEDNESDAY AFTERNOON. OVERALL TREND IS TO SLOW DOWN THE
ARRIVAL OF LIFT/MOISTURE WITH THIS FEATURE...SO I LIMITED SLIGHT
CHANCE MENTION CLOSER TO 00Z OVER NW PART OF YUMA COUNTY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 239 PM MDT TUE MAY 15 2012
THE NORTHERN PERIPHERY OF AN UPPER LEVEL RIDGE WILL MOVE OVER THE
AREA WEDNESDAY NIGHT. MEANWHILE A SHORT WAVE TROUGH WILL MOVE ALONG
THE PERIPHERY OF THE RIDGE...ENTERING THE NORTHWEST PART OF THE AREA
DURING THE EVENING. SLIGHT CHANCES FOR PRECIPITATION START DURING
THE EARLY EVENING AS POINT SOUNDINGS FROM 550 MB ON UP BEGIN TO
SATURATE OVER THE WESTERN PART OF YUMA COUNTY. WITH 100J/KG OF
700-500MB MOST UNSTABLE CAPE IN THE VICINITY AND CONVECTIVE
TEMPERATURES BEING REACHED DURING THE EARLY EVENING...AN ISOLATED
THUNDERSTORM IS CERTAINLY POSSIBLE AHEAD OF THE SHORT WAVE TROUGH.
WITH MOISTURE INCREASING ABOVE 600MB AND A LOBE OF 500MB VORTICITY
MOVING OVER THE NORTHWEST PART OF THE AREA AROUND MIDNIGHT...HAVE
PRECIPITATION CHANCES PEAKING AT THIS TIME THEN DECLINING TOWARDS
MORNING AS THE 500MB VORTICITY AND SHORT WAVE TROUGH MOVE NORTHEAST
INTO NEBRASKA. WITH A DEEP DRY LAYER IN PLACE...AM NOT TOO
CONFIDENT THAT ANY RAINFALL PRODUCED WILL MAKE IT TO THE
GROUND...BUT CANNOT COMPLETELY RULE OUT MEASURABLE PRECIPITATION
FROM OCCURRING.
THURSDAY ANOTHER SHORT WAVE TROUGH WILL MOVE INTO THE AREA DURING
THE LATE MORNING HOURS...MOVING ACROSS THE AREA THROUGH THE DAY AND
EXITING THE AREA DURING THE LATE EVENING. LATEST NAM HAS SHIFTED THE
TRACK OF THE TROUGH FURTHER SOUTH WHICH IS IN LINE WITH THE GFS. AS
SUCH HAVE SHIFTED THE BULK OF THE PRECIPITATION CHANCES TO AREAS
GENERALLY ALONG AND SOUTH OF HIGHWAY 24 DURING THE AFTERNOON. AS
THE TROUGH MOVES THROUGH...THE AREA OF 500MB VORTICITY BECOMES MORE
DISJOINTED. IN ADDITION THE DEEP DRY LAYER WILL PERSIST THROUGH THE
AFTERNOON AND EVENING...SO DECIDED TO KEEP PRECIPITATION CHANCES IN
THE SLIGHT CATEGORY. PRECIPITATION CHANCES SHIFT TO THE EASTERN
PART OF THE AREA DURING THE MID TO LATE AFTERNOON AS 500MB VORTICITY
SPREADS NORTH WHILE THE SHORT WAVE TROUGH MOVES THROUGH THE EASTERN
HALF OF THE AREA.
LATE THURSDAY MORNING AND THROUGH THE AFTERNOON SOUTH WINDS WILL STRENGTHEN
FOR LOCATIONS GENERALLY EAST OF A RUSSELL SPRINGS TO MCCOOK LINE AHEAD
OF A SURFACE TROUGH OF LOW PRESSURE. 850MB WINDS OF 20 TO 30 KTS
WILL MIX DOWN TO THE SURFACE AHEAD OF THE SURFACE TROUGH PRODUCING
GUSTS UP TO 40 MPH FOR THE ABOVE LOCATIONS. THE WINDS WILL DECLINE
DURING THE LATE AFTERNOON AS THE STRONGER WINDS MOVE EAST OF THE
AREA. SEE FIRE WEATHER SECTION FOR FIRE WEATHER INFORMATION.
FOR THE FRIDAY THROUGH TUESDAY PERIOD AN UPPER LEVEL SHORT WAVE
TROUGH WILL MOVE THROUGH THE AREA SATURDAY WITH ANOTHER ON MONDAY.
THE STRONGEST SHORT WAVE WILL MOVE THROUGH ON SATURDAY ACCOMPANIED
BY A COLD FRONT. AS A RESULT THE BEST CHANCE FOR PRECIPITATION WILL
BE SATURDAY...MAINLY TIED TO THE FRONTAL PASSAGE. A DRY SLOT WILL
MOVE OVER THE SOUTHERN PART OF THE AREA SATURDAY...DIMINISHING
PRECIPITATION CHANCES FOR THAT AREA. A MINOR SHORT WAVE THROUGH
WILL MOVE THROUGH THE AREA MONDAY...SO HAVE SLIGHT CHANCES IN PLACE
ACROSS MOST OF THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1136 AM MDT TUE MAY 15 2012
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD AT BOTH KGLD AND
KMCK. COLD FRONT ALREADY DROPPING SOUTH OVER KMCK WITH WINDS
SHIFTING TO THE NORTHEAST WITH GUSTS 15-17KT THROUGH SUNSET. WINDS
WILL REMAIN VARIABLE AT KGLD THROUGH ABOUT 04Z...WHEN FRONT DROPS
JUST EAST OF TERMINAL AND WINDS SHIFT TO THE SOUTHEAST AROUND
10KT. SURFACE LOW DEVELOPS BY WEDNESDAY AFTERNOON OVER EASTERN
COLORADO...WITH INCREASED GRADIENT LEADING TO GUSTY SOUTH WINDS
DEVELOPING BY 18Z. STRONGEST WINDS SHOULD OCCUR AFTER 18Z...SO I
ONLY SHOWED INCREASING TREND AFTER 15Z IN THE CURRENT TAF
PERIOD.
&&
.FIRE WEATHER...
ISSUED AT 239 PM MDT TUE MAY 15 2012
FIRE WEATHER WATCH FOR WED WAS UPGRADED TO RED FLAG WARNING...WITH
CONFIDENCE HIGH IN RFW CRITERIA BEING MET. WINDS ACROSS THE
WESTERN HALF OF THE AREA SHOULD BE WELL WITHIN CRITERIA WITH GUSTS
AROUND 35 MPH POSSIBLE. THERE WERE SOME QUESTIONS REGARDING TO
RH...WITH SHORTWAVE TROUGH OVER CENTRAL COLORADO POSSIBLY BRINGING
HIGHER TD VALUES INTO WESTERN PARTS OF CWA. EVEN IF MIXING WERE TO
BE LIMITED IN THE WEST AND TD VALUES REMAIN SLIGHTLY HIGHER...RH
VALUES AROUND 15-17% WOULD STILL BE EXPECTED. BASED ON LOWER MODEL
TRENDS AND BETTER MIXING...CURRENT FORECAST SHOWS RH 12-15%. WITH
WINDS GUSTING AROUND 35 MPH...RFW CRITERIA IS LIKELY UNDER EITHER
SCENARIO.
LOW RELATIVE HUMIDITIES OF 15 TO 20 PERCENT AND STRONG SOUTH WINDS
WITH GUSTS UP TO 40 MPH WILL DEVELOP FOR LOCATIONS EAST OF A
RUSSELL SPRINGS TO MCCOOK LINE THURSDAY AFTERNOON. THESE CONDITIONS WILL
CREATE HAZARDOUS FIRE WEATHER CONDITIONS DURING THE AFTERNOON.
LATEST FUEL STATUS FOR THE NORTON AND HILL CITY AREA WHERE WINDS
WILL BE THE STRONGEST INDICATES THE FUELS ARE STILL GREEN ENOUGH
NOT TO BE A CONCERN...SO WILL NOT BE ISSUING A FIRE WEATHER
HIGHLIGHT AT THIS TIME FOR THURSDAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...RED FLAG WARNING FROM 10 AM TO 8 PM MDT WEDNESDAY FOR KSZ013-027.
CO...RED FLAG WARNING FROM 10 AM TO 8 PM MDT WEDNESDAY FOR COZ252>254.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JTL
AVIATION...DR
FIRE WEATHER...DR/JTL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1250 PM MDT TUE MAY 15 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 1249 PM MDT TUE MAY 15 2012
EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOW SHORTWAVE
RIDGE ACROSS CENTRAL ROCKIES...WITH DEEP UPPER LOW UPSTREAM OVER
NORTHERN CALIFORNIA. A COLD FRONT IS CURRENTLY JUST NORTH OF OUR
CWA...WITH TEMPERATURES AHEAD OF THE FRONT OVER OUR CWA IN THE MID
TO UPPER 80S...AND TEMPERATURES BEHIND THE FRONT IN THE MID TO
UPPER 70S.
THE COLD FRONT TO THE NORTH OF THE CWA WILL DROP SOUTH AND EAST
THIS EVENING...WITH INCREASING TD NORTH OF THE FRONT AS WINDS
SHIFT TO THE EAST-SOUTHEAST. IF TD VALUES IN THE LOW-MID 40S WERE
TO ADVECT INTO THE NORTHERN HALF OF OUR CWA...RADIATIONAL FOG
COULDNT BE RULED OUT. GUIDANCE IS CURRENTLY SHOWING BL REMAINING
UNSATURATED THROUGH WED MORNING...SO FOG WAS LEFT OUT OF
FORECAST.
LARGE SCALE SUBSIDENCE AND A VERY DRY/STABLE AIR MASS WILL REMAIN
IN PLACE THROUGH WEDNESDAY AFTERNOON. SHORTWAVE TROUGH BEGINS TO
MOVE EAST INTO THE CENTRAL ROCKIES BY WED AFTERNOON...WHICH
COULD BRING THUNDERSTORM CHANCES TO EASTERN COLORADO COUNTIES BY
LATE WEDNESDAY AFTERNOON. OVERALL TREND IS TO SLOW DOWN THE
ARRIVAL OF LIFT/MOISTURE WITH THIS FEATURE...SO I LIMITED SLIGHT
CHANCE MENTION CLOSER TO 00Z OVER NW PART OF YUMA COUNTY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 323 AM MDT TUE MAY 15 2012
WEDNESDAY NIGHT-THURSDAY NIGHT...STRONG SHORT WAVE TROUGH WILL MOVE
ACROSS THE CWA DURING THE EVENING HOURS...WITH LARGE SCALE ASCENT
INCREASING THROUGH THE EVENING HOURS AS PV ADVECTION INCREASES
THROUGH THE NIGHT. WHILE FORCING LOOKS SUFFICIENT TO SUPPORT A
PRECIPITATION THREAT...HAVE CONCERNS ABOUT COVERAGE/LIKELY HOOD ANY
PORTION OF AIR MASS WILL SATURATE ENOUGH TO SUPPORT PRECIPITATION
GIVEN MEAGER QPF OUTPUT FROM OPERATIONAL MODELS AND OVERALL LOW POPS
FROM ENSEMBLE DATA. WHILE THESE FACTORS LIMIT CONFIDENCE...THINK
SMALL POPS WARRANTED GIVEN THE STRENGTH OF THE SYSTEM. WILL SEE
ANOTHER CHANCE FOR STORMS ON THURSDAY AFTERNOON ALONG FRONTAL ZONE
ASSOCIATED WITH PV ANOMALY...MAINLY ACROSS EASTERN ZONES. POTENTIAL
LOOKS A BIT HIGHER THAN THE NIGHT BEFORE...BUT EXPECTED CLOUD COVER
IN THE MORNING AND EXPECTED POSITION OF UPPER TROUGHS HAVE TO MANY
CONCERNS ABOUT DEGREE OF DESTABILIZATION AND OVERALL LOCATION OF THE
FRONT TO GO MUCH HIGHER THAN THE 30 PERCENT RANGE AT THIS TIME.
SHORTWAVE RIDGING ON FRIDAY WILL ALLOW DAYTIME TEMPERATURES TO CLIMB
WELL ABOVE NORMAL BEFORE A RATHER STRONG SHORTWAVE TROUGH AND
ASSOCIATED COLD FRONT MOVE THROUGH THE REGION SATURDAY. GUSTY SOUTH
TO SOUTHWEST FLOW WILL DEVELOP AHEAD OF THE DEEPENING SURFACE TROUGH
WITH COOLER TEMPERATURES AND NORTHWEST WINDS BEHIND FRONTAL PASSAGE.
THERE MAY BE A CHANCE FOR SCATTERED THUNDERSTORMS TO DEVELOP AS THE
TROUGH MOVES ACROSS THE HIGH PLAINS SATURDAY AFTERNOON AND EVENING.
SURFACE HIGH PRESSURE WILL THEN MOVE INTO THE REGION WITH BROAD
UPPER LEVEL RIDGING BUILDING ACROSS THE HIGH AND CENTRAL PLAINS BY
EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1136 AM MDT TUE MAY 15 2012
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD AT BOTH KGLD AND
KMCK. COLD FRONT ALREADY DROPPING SOUTH OVER KMCK WITH WINDS
SHIFTING TO THE NORTHEAST WITH GUSTS 15-17KT THROUGH SUNSET. WINDS
WILL REMAIN VARIABLE AT KGLD THROUGH ABOUT 04Z...WHEN FRONT DROPS
JUST EAST OF TERMINAL AND WINDS SHIFT TO THE SOUTHEAST AROUND
10KT. SURFACE LOW DEVELOPS BY WEDNESDAY AFTERNOON OVER EASTERN
COLORADO...WITH INCREASED GRADIENT LEADING TO GUSTY SOUTH WINDS
DEVELOPING BY 18Z. STRONGEST WINDS SHOULD OCCUR AFTER 18Z...SO I
ONLY SHOWED INCREASING TREND AFTER 15Z IN THE CURRENT TAF
PERIOD.
&&
.FIRE WEATHER...
ISSUED AT 1249 PM MDT TUE MAY 15 2012
FIRE WEATHER WATCH FOR WED WAS UPGRADED TO RED FLAG WARNING...WITH
CONFIDENCE HIGH IN RFW CRITERIA BEING MET. WINDS ACROSS THE
WESTERN HALF OF THE AREA SHOULD BE WELL WITHIN CRITERIA WITH GUSTS
AROUND 35 MPH POSSIBLE. THERE WERE SOME QUESTIONS REGARDING TO
RH...WITH SHORTWAVE TROUGH OVER CENTRAL COLORADO POSSIBLY BRINGING
HIGHER TD VALUES INTO WESTERN PARTS OF CWA. EVEN IF MIXING WERE TO
BE LIMITED IN THE WEST AND TD VALUES REMAIN SLIGHTLY HIGHER...RH
VALUES AROUND 15-17% WOULD STILL BE EXPECTED. BASED ON LOWER MODEL
TRENDS AND BETTER MIXING...CURRENT FORECAST SHOWS RH 12-15%. WITH
WINDS GUSTING AROUND 35 MPH...RFW CRITERIA IS LIKELY UNDER EITHER
SCENARIO.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...RED FLAG WARNING FROM 10 AM TO 8 PM MDT WEDNESDAY FOR KSZ013-027.
CO...RED FLAG WARNING FROM 10 AM TO 8 PM MDT WEDNESDAY FOR COZ252>254.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JRM/PM
AVIATION...DR
FIRE WEATHER...DR
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
312 PM CDT TUE MAY 15 2012
.DISCUSSION...
A FAIRLY PROGRESSIVE UPPER LEVEL PATTERN WILL BE THE RULE ACROSS
THE NORTHERN CONUS OVER THE UPCOMING WEEK. LATEST WATER VAPOR
IMAGERY AND RAP ANALYSES SHOW A BROAD RIDGE OVER THE WEST... WITH
TROUGHING OVER THE EAST. A HEALTHY SHORTWAVE CAN BE SEEN ROTATING
SOUTHEAST ACROSS THE NORTHERN GREAT LAKES AT THE CURRENT TIME.
THIS FEATURE IS HELPING TO ENHANCE THE CU FIELD ACROSS NORTHEAST
MINNESOTA AND NORTHERN WISCONSIN... BUT ANY SHRA ARE STAYING WELL
NORTH AND EAST OF OUR AREA. THE WESTERN RIDGE WILL MOVE EAST OVER
THE NEXT FEW DAYS... GENERALLY BRINGING DRY WEATHER AND A WARMING
TREND. HOWEVER... CHANCES FOR SHRA/TSRA WILL STEADILY INCREASE
DURING THE SECOND HALF OF THE WEEK INTO THE WEEKEND... WITH AN
UPPER TROUGH EVENTUALLY PUSHING THROUGH TOWARD THE END OF THE
WEEKEND... WHICH WILL HELP PUSH A SURFACE LOW AND FRONTAL BOUNDARY
ACROSS THE REGION. FAVORED THE NAM FOR THE SHORT TERM DETAILS...
THEN TRENDED TOWARD A BLEND OF THE PREVIOUS FORECAST AND ECMWF...
WHICH WAS A BIT SLOWER TO KICK THE RIDGE EASTWARD. THE LATEST
ECMWF IS A BIT FASTER HOWEVER... WHICH MAKES THE WEEKEND FORECAST
TRICKY IN TERMS OF PINPOINTING WHEN PCPN IS MOST LIKELY.
SURFACE RIDGE WILL CONTINUE TO BUILD SOUTHEAST ACROSS THE AREA
TONIGHT... FURTHER DRYING OUT DEWPOINTS THROUGH THE EARLY
EVENING... WITH A REASONABLY COOL NIGHT EXPECTED FOR THE OVERNIGHT
HOURS. THE WESTERN PART OF THE AREA SHOULD MANAGE TO GET ON THE
BACKSIDE OF THE RIDGE BY TOMORROW AFTERNOON... WITH SOME RETURN
FLOW WORKING INTO THAT AREA BY EVENING. A BETTER LOW LEVEL JET AND
WARM ADVECTION LOOK TO SETUP ACROSS THE AREA LATER WEDNESDAY
NIGHT AS LOW PRESSURE EDGED OUT INTO THE HIGH PLAINS. A LOOK AT
FORECAST 850-500MB DIFFERENTIAL THETA-E VALUES... 850MB THETA-E
ADVECTION... AND ISENTROPIC ASCENT ON THE 305K SURFACE SUGGEST
THAT ELEVATED SHRA/TSRA MAY INITIALLY GET GOING OVER THE NORTH
CENTRAL PART OF THE AREA... BUT SHOULD WORK ITS WAY SOUTHEAST
THROUGH THE OVERNIGHT AS SATURATION OCCURS SOUTHWARD ALONG THE
ELEVATED FRONTAL BOUNDARY. SOME ACTIVITY SHOULD REMAIN FOCUSED
NEAR THE FRONTAL BOUNDARY THROUGH THE DAY ON THURSDAY INTO
THURSDAY NIGHT AS WARM ADVECTION PERSISTS IN AN AREA OF CONVECTIVE
INSTABILITY. HOWEVER... BY FRIDAY THROUGH FRIDAY NIGHT THE FOCUS OF
THIS ACTIVITY LOOKS LIKE IT SHOULD SHIFT NORTHEAST OF MOST OF THE
AREA... SO TRIMMED BACK POPS DURING THAT TIME FRAME TO MAINLY
INCLUDE ONLY THE FAR NORTHERN PORTION OF THE CWFA. BY SATURDAY WE
WILL START TO FEEL THE INFLUENCE OF THE APPROACHING SURFACE FRONT
AS THE AIRMASS ACROSS THE REGION CONTINUES TO DESTABILIZE... SO
INCREASED POPS ACROSS MUCH OF THE AREA FROM WEST TO EAST. THE
BOUNDARY ITSELF LOOKS TO MOVE ACROSS THE REGION SATURDAY NIGHT OR
EARLY SUNDAY... BUT AT THIS POINT THAT TIMING COULD EASILY SHIFT
FOR 12-24 HOURS... WHICH WILL CERTAINLY HAVE AN IMPACT ON WHEN
WIDESPREAD SHRA/TSRA IS MOST LIKELY... AS WELL AS WHETHER MUCH IF
ANY SEVERE WEATHER WILL OCCUR. THINGS LOOK TO DRY OUT MONDAY AND
TUESDAY IN THE WAKE OF THE FRONT AND UPPER TROUGH... WITH HIGH
PRESSURE QUICKLY SETTLING IN ON MONDAY... THEN THE PROGRESSIVE
PATTERN BRINGING RETURN FLOW BACK INTO THE REGION BY TUESDAY
AFTERNOON.
&&
.AVIATION.../18Z TAF ISSUANCE/
/ISSUED 1200 PM CDT TUE MAY 15 2012/
SFC HIGH PRESSURE RIDGE BUILDING OVER THE FORECAST AREA DURING THE
PERIOD. NORTHWEST WINDS DIMINISHING TO UNDER 10 KT THIS
EVENING...BECOMING LIGHT AND VARIABLE AFTER MIDNIGHT. WINDS
BECOMING SOUTHERLY 5 TO 10 KNOTS WEDNESDAY. VFR CONDITIONS
PREVAILING THROUGH WEDNESDAY EVENING.
MSP...NO AVIATION PROBLEMS OR CONCERNS DURING THE PERIOD. VFR
CONDITION PREVAILING THROUGH WED EVENING.
OUTLOOK...
THU-SAT...CHANCE OF SHRA/TSRA WITH MVFR CEILINGS POSSIBLE.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
/JVM