Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 03/24/12
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
814 PM EDT Fri Mar 23 2012
.NEAR TERM (THROUGH TONIGHT)...The massive upper low is moving east
across southeastern MO toward the confluence of the OH and MS
Rivers. Isolated severe storms develop today in our forecast area,
which is solidly in the region of upper diffluence. There have been
two reported tornadoes in the area today, both of which resulted in
some damage: one in Geneva County, AL and another in northern Early
County, GA. The activity has diminished significantly. We do see one
MCV approaching Gulf County at this time from earlier convection
over the Gulf. However, no additional severe storms are forecast
this evening with the atmosphere stabilizing with sunset. PoPs will
be adjusted downward accordingly. Round 2 of this severe weather
event will begin Saturday morning, most likely during the mid to
late morning hours. However, there is at least some chance that we
could see some activity firing over the Gulf before sunrise. See
previous discussion below for more details.
&&
.MARINE (TONIGHT THROUGH WEDNESDAY)...
A weak cold front will approach the forecast water tonight and cross
from west to east during the day Saturday. Winds may approach
cautionary levels at times ahead of the front, but we are not
anticipating headlines. The front will exit south of the area
Saturday night turning winds to the northwest for the second half of
the weekend. Again, winds will approach cautionary levels Sunday
night. Winds will veer around to the east by Tuesday and southeast
by Wednesday.
&&
.AVIATION (THROUGH 00Z SUNDAY)...
The line of storms associated with the passing cold front are
quickly dissipating. Overnight...guidance is showing some BR in the
early hours around 08-14 UTC. After that, more TSRA expected
tomorrow everywhere except DHN. After the line passes, there will be
some gusts with the frontal passage.
&&
.FIRE WEATHER...
It is likely that many areas will see a wetting rain ahead of an
approaching cold front between this afternoon and Saturday
afternoon. The cold front will be slow to move across the region on
Saturday. However, it does appear that it will clear our Southeast
AL and inland FL Panhandle counties (along and north of I-10) early
enough to allow afternoon relative humidity to drop below 35
percent. Forecast dispersion indices are not quite high enough to
reach red flag criteria and the new forecast ERC values that will
come in later this afternoon may drop as well. We therefore do not
plan on issuing any red flag products for Saturday at this time. The
front will clear the remainder of the forecast area Saturday night
setting up a dry and breezy day on Sunday. It will not be quite dry
enough to reach red flag criteria across our AL and GA zones.
However, the combination of low RH, high dispersion and high 20-ft
winds will likely produce red flag conditions across inland portions
of FL. Watches and/or warnings will likely be issued by later shifts
for Sunday.
&&
.PREV DISCUSSION (340 PM EDT Fri Mar 23 2012)...
SYNOPSIS...
The 19Z water vapor and H4 RUC analysis shows northern stream upper
level flow arriving over the northern California/Oregon coast before
ridging well to the north over south-central Canada. The main
feature of note to the south of this flow is the large and stubborn
upper level low spinning over the middle of the country. The upper
level ridge that had been in control of our region is being
de-amplified and pushed to the east as the previously mentioned
upper low begins to migration toward the eastern seaboard.
At the surface, forecast are resides between a large area of high
pressure off the SE coast, and a weak cold front currently extending
from the western TN valley to the north-central Gulf of Mexico. Deep
southerly flow is being experienced between these two features into
our zones providing abundant low level moisture. WAA, a slow
increase in synoptic support, and surface focus ahead of the front
are supporting a band of showers and thunderstorms from the open
waters south of Mobile northward to the FL panhandle/eastern
AL/western GA. A few of these storms have shown a tendency to rotate
over the past few hours, and will need to monitored closely.
&&
SHORT TERM (SATURDAY THROUGH SUNDAY NIGHT)...
Saturday,
Late tonight as we approach dawn, the upper low begins to pivot back
Southward and we see slightly better height falls/QG forcing
overspreading the NE gulf. Global guidance and several CAM members
show a resurgence of convection beginning at this time and
continuing into Saturday morning ahead of the front. This seems
reasonable and will show likely rain chances around 60% along and
east of a line roughly from Panama City to Albany. Still expecting a
scattering of showers to the west of this line during the morning
hours, however with the passage of the surface front by early
afternoon will see drier air and falling rain chances for these
western zones.
This will be at least a marginal threat for some strong to severe
thunderstorms over mainly the eastern half of the region during the
daylight hours of Saturday. Currently the most favorable
kinematics/thermodynamics appear to align a bit to our NE tomorrow,
however with 30-40kts of deep layer shear present, the potential for
organized updraft will exist, especially if we experience enough
sunny breaks to add to the instability. Will continue to monitor
this situation, and a more detailed briefing packet on the threat is
available at the following URL.
http://www.srh.noaa.gov/images/tae/briefing/EMBriefingMarch232012.pdf
Saturday Night,
The upper level low begins to make more progressive progress. Energy
rounding the base of the low now looks to give the final push to
accelerate the surface front south and eastward out of our region.
Therefore, will see the last of the showers/storms over the SE Big
Bend zones ending during the pre-dawn hours. The arrival of a drier
airmass will allow temps to drop into the 50s by sunrise.
Sunday/Sunday Night,
A pleasant and dry day is on tap for the second half of the upcoming
weekend. Deep layer NW flow will continue to supply a drier airmass
to the region with just a sct fair weather cumulus field developing
in the afternoon. Despite 850mb temps dropping to between 8-9C,
decent diurnal mixing and the stronger late March sun should still
allow our temperatures to rise to within a couple of degrees of 80.
A secondary trough or dry frontal passage will occur Sunday evening
setting up several days of dry and seasonable weather for the
beginning of next week.
LONG TERM (MONDAY THROUGH NEXT FRIDAY)...
The closed upper low and associated trough will be exiting off the
mid-Atlantic coast Sunday night. A low amplitude upper ridge will
build in from the west early next week. The ridge flattens to nearly
zonal by Thursday as a strong shortwave translates across the
northern tier states into New England. The GFS shows a shortwave
tracking across Texas Thursday lifting into the Missouri/Tennessee
Valleys with a spoke of energy extending SEWD into our region by the
end of the period.
At the surface, high pressure centered north of the Great Lakes
Monday night will drop south-southeast becoming centered east of the
Carolina`s on Wednesday. The high slides east thereafter with the
ridge axis dropping south across the Florida peninsula and allowing
a cold front to drop down from the north. This boundary may slip
into our northern zones Friday before lifting north as a warm front
late in the day in response to the next cold front advancing from
the west. Temperatures will continue above seasonal levels through
the extended period.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 62 82 54 82 50 / 50 60 30 10 0
Panama City 67 80 59 80 58 / 50 60 10 10 0
Dothan 61 83 55 81 53 / 40 40 10 10 0
Albany 61 81 54 79 52 / 50 60 20 10 0
Valdosta 62 80 55 79 53 / 50 60 40 10 0
Cross City 62 81 58 81 51 / 30 60 40 10 0
Apalachicola 67 75 59 77 54 / 50 60 30 10 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.
&&
$$
Aviation...Moore
Marine...Mroczka
Previous Discussions...Barry/Mroczka
Rest of Discussion...Wool
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1045 AM EDT Thu Mar 22 2012
.UPDATE...
14Z water vapor and H4 RUC analysis shows the northern stream flow
well to the north for this time of year, arriving over the Pacific
NW coastline before ridging up into south-central Canada. The main
features south of this flow include the large and stubborn upper low
spinning over the central/southern plains, and the downstream
ridging in place from the eastern Gulf of Mexico northward to the
TN/OH valleys.
At the surface, forecast area is squeezed between a large area of
high pressure centered off the Carolina coast, and a decaying
front/convergent zone across the lower/middle MS valley. The
gradient between these 2 features continues to supply our region
with a deep southeasterly flow. This flow is transporting decent
levels of boundary layer moisture in from the Atlantic and eastern
Gulf of Mexico. KTLH 12Z sounding showed that we are still fairly
dry in the mid-levels overtop this moisture. This profile is rather
conducive to the development of morning status/stratocu seen over
portions of the area. These clouds are expected to begin to mix out
by midday with a general mix of sun and cumulus clouds for the
afternoon/early evening.
Looking to our west, region of deep layer synoptic support/QG
forcing ahead of the upper low combined with the low level
focus/convergence along the front continues to produce a large area
of showers/storms from southern LA into MS and western AL. Little
movement of these features through the day should keep the majority
of this convection west of our zones through the evening hours. Can
not rule out some widely sct convection taking root by late
afternoon, however have decreased rain chances over the western
zones generally below 30% for the rest of the day.
Appears the best chances for deep convection this afternoon will
occur along the Suwannee/River and I-75 corridor (generally after
2pm). High resolution guidance suite all show an eventual veering of
the winds onshore with sea-breeze development along the eastern
shores of Apalachee Bay. This will set up a convergence zone with
the opposing east coast sea-breeze/synoptic flow in the region
described above, and should be enough to force a scattering of
showers and storms into the middle evening hours.
&&
.AVIATION...
Areas of lower stratus that developed around and shortly after
sunrise are beginning to show signs of mixing out. Anticipate period
of MVFR cigs at KTLH...KABY...and KDHN through around midday,
followed by general prevailing VFR conditions through the afternoon
and evening hours. Only exceptions will be associated with any brief
afternoon showers/storms. At this time, the best chances to see the
afternoon convection will be at KVLD (after 19-20z). Continued low
level moisture advection into the region will likely result in
another round (and likely more extensive) of MVFR/IFR CIGS late
tonight into the first few daylight hours of Friday.
&&
.MARINE...
A strong southeast wind fetch across the waters will keep seas
elevated into the afternoon. Winds are then expected to subside
during the later afternoon and seas will follow. A cold front then
approaches later Friday into Saturday switching winds around to the
west and bringing in a better chance of showers and thunderstorms.
The front will then push south on Sunday and conditions will improve
for the later half of the weekend.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 83 62 83 63 81 / 20 10 50 40 60
Panama City 78 67 77 67 76 / 20 20 60 50 60
Dothan 80 65 79 63 80 / 20 20 70 50 60
Albany 82 62 81 63 79 / 30 40 60 50 60
Valdosta 82 59 83 60 84 / 50 60 50 40 70
Cross City 82 60 83 62 79 / 40 40 20 20 60
Apalachicola 76 66 76 68 75 / 10 10 40 30 60
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.
&&
$$
MROCZKA/CAMP
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
713 PM CDT FRI MAR 23 2012
.MESOSCALE DISCUSSION...
710 PM CDT
AREA OF STORMS HAS GENERALLY WEAKENED IN INTENSITY...BUT THE LONG
LIFESPAN TRACKING NORTH AND FAVORABLE LOW-LEVEL PROFILES HAVE
HELPED TO GENERATE A COLD POOL. LEADING EDGE OF THE OUTFLOW HAS
CREATED WIND GUSTS OBSERVED AND ESTIMATED TO AROUND 40 MPH. EVEN
THOUGH THE STORMS HAVE WEAKENED...CONTINUED REPORTS OF FUNNELS
HAVE BEEN RECEIVED. RESIDUAL OUTFLOW BOUNDARIES FROM EARLIER
CONVECTION DO RESIDE OVER COOK COUNTY AND INTO LAKE AND PORTER IN
INDIANA...SO SOME POOLED VORTICITY POTENTIALLY IS PRESENT AND HAS
BEEN ANALYZED BY HIGH RES DIAGNOSTIC MODELS. AT LEAST SOME
STRETCHING OF THIS IS POSSIBLE BY ANY UPDRAFTS...ESPECIALLY THOSE
ALONG THE LEADING EDGE OUTFLOW...AND THAT LIKELY HAS BEEN THE
REASON FOR THE CONTINUED REPORTS. 0-3KM CAPE VALUES OF 50 TO 100
J/KG ARE STILL PRESENT PER LATEST SPC RUC MESOANALYSIS...AND A
VALPARAISO UNIVERSITY SOUNDING ACTUALLY INDICATED OVER 200 J/KG
JUST AHEAD OF THE AREA. THAT CERTAINLY IS MORE THAN ENOUGH TO AID
IN SOME STRETCHING. FURTHER TO THE WEST...GENERALLY WEST OF
ILLINOIS HIGHWAY 47...SOME ISOLATED STORMS ARE POSSIBLE. OVERALL
THOUGH THE CONVECTIVE TRENDS SHOULD CONTINUE DOWNWARD...WITH
POTENTIALLY NOT MUCH LEFT AFTER 9 PM.
DENSE FOG ALONG THE LAKE SHORE HAS BEEN SEEN ON WEB CAMS AND PER
A FEW OBSERVATION SITES. THIS MAY MIX OUT SOME WITH THE
SHOWERS...BUT BEING WITHIN THE SYNOPTIC HIGH DEW POINT
TONGUE...AND AIDED BY THESE SHOWERS...THE FOG SHOULD QUICKLY COME
BACK IN THE LIGHT EASTERLY LOW-LEVEL FLOW. THE DENSE FOG ADVISORY
MAY NEED TO BE EXPANDED SOUTH AND WEST AFTER THE EFFECTS OF THE
SHOWERS ARE SEEN.
MTF
&&
.DISCUSSION...
341 PM CDT
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
THE LARGE UPPER LEVEL LOW IS SLOWLY MAKING ITS WAY EAST ACROSS THE
CENTRAL CONUS WHILE GRADUALLY WEAKENING. MODELS ARE IN GOOD
AGREEMENT WITH THE POSITION OF THIS LOW BY SUNDAY MORNING OVER THE
SOUTHEAST CONUS. FOR SUNDAY THIS WOULD PUT THE LOCAL AREA ON THE
EASTERN EDGE OF A BROAD UPPER RIDGE BUILDING ACROSS THE PLAINS.
WELL WEST AND NORTH OF THE LOW AN UPPER SHORTWAVE AND SURFACE LOW
PRESSURE SYSTEM MOVE QUICKLY ACROSS ONTARIO INTO QUEBEC DURING THIS
SAME TIME PERIOD...DRAGGING A WEAK SURFACE TROUGH ACROSS THE AREA.
BY MONDAY MORNING BOTH OF THESE LOW PRESSURE SYSTEMS HAVE MOVED WELL
EAST OF THE AREA LEAVING A BROAD SURFACE HIGH CENTERED WEST OF
HUDSON BAY. COOL DRY NORTHEAST FLOW AROUND THE SOUTHERN PERIPHERY
OF THE RIDGE WILL PUSH THE HIGHER DEWPOINT AIR AWAY INTO SOUTHERN
ILLINOIS ON MONDAY.
WHAT THIS ALL MEANS FOR THE NEXT THREE DAYS IS MILD BUT UNSETTLED
WEATHER TONIGHT AND TOMORROW...A DAY OF TRANSITION ON SUNDAY...AND
THEN COOLER AND DRY ON MONDAY. HIGH AND LOW TEMPERATURES WILL BE
VERY CHALLENGING THIS WEEKEND AS POCKETS OF WARM AIR SPIN AROUND THE
DEEPLY WRAPPED UP LOW. BASED ON WHAT WE ARE SEEING IN IOWA AND
MISSOURI TODAY...SOME AREAS COULD GET STUCK IN THE 50S AND OTHERS
COULD REACH THE 70S. AND COOLER IS OF COURSE A RELATIVE TERM FOR
MONDAY GIVEN OUR RECENT TRENDS. FOR THE FIRST TIME IN ABOUT TWO
WEEKS A PORTION OF THE AREA SHOULD SEE LOWS DROP INTO THE 30S SUNDAY
AND MONDAY NIGHTS. FREEZING TEMPERATURES APPEAR TO STAY WELL TO OUR
NORTH BOTH NIGHTS...BUT THIS IS A HELPFUL REMINDER THAT WE ARE STILL
ABOUT A MONTH AWAY FROM THE DATE OF THE AVERAGE LAST SPRING FREEZE
ACROSS OUR AREA.
EXTENDED...TUESDAY THROUGH FRIDAY
ON MONDAY AFTERNOON AND TUESDAY A LOW PRESSURE SYSTEM DEVELOPING IN
THE LEE OF THE NORTHERN ROCKIES MOVES INTO THE HIGH PLAINS AHEAD OF
AN UPPER LEVEL NEGATIVELY TILTED TROUGH. WINDS OVER THE LOCAL AREA
VEER FROM NORTHEAST TO SOUTHEAST ON TUESDAY AHEAD OF A PLUME OF
MOISTURE BEING PULLED OUT OF THE GULF TOWARD THE LOW PRESSURE
CENTER. TEMPERATURES AND DEWPOINTS SHOULD CLIMB RAPIDLY DURING THE
DAY TUESDAY AS A WARM FRONT CROSSES THE AREA EARLY IN THE DAY AND A
COLD FRONT APPROACHES LATE. A DISCRETE PERIOD OF SHOWERS AND
THUNDERSTORMS IS POSSIBLE WITH THE PASSAGE OF BOTH BOUNDARIES...BUT
THUNDERSTORMS WOULD APPEAR MOST FAVORABLE DURING THE AFTERNOON AND
EVENING TUESDAY. THE THREAT OF SEVERE IS ALWAYS WORTH CONTEMPLATING
THIS TIME OF YEAR...BUT THE PRESENT TRACK OF THE LOW SUGGESTS THE
BEST CHANCE OF SEVERE WOULD BE NORTHWEST OF THE AREA.
NEXT THURSDAY AND FRIDAY LOOK TO BE A REPEAT OF MONDAY AND TUESDAY
WITH A LARGE HIGH PRESSURE AREA CENTERED OVER ONTARIO
THURSDAY...FOLLOWED BY THE APPROACH OF ANOTHER WARM FRONT ON
FRIDAY.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* THUNDERSTORMS BRINGING CONDITIONS DOWN TO MVFR AND POSSIBLY IFR WITH
PRECEDING GUSTY SOUTHERLY OUTFLOWS THROUGH 01Z TO 02Z.
* FOG AND IFR/LIFR STRATUS ALONG THE LAKE SHORE CREEPING
EASTWARD...ESPECIALLY IN THE WAKE OF THE RAIN ACTIVITY FROM MID-
EVENING FORWARD.
* WIND DIRECTION BEING VARIABLE AT TIMES THIS EVENING IN THE
CHAOTIC WIND FIELD AROUND THE EVENING SHOWERS/STORMS...THEN
VARIABLE OVERNIGHT INTO EARLY SATURDAY MORNING.
* WINDS SWINGING TOWARDS DUE NORTH BY MIDDAY SATURDAY.
//DISCUSSION...UPDATED 00Z...
AN AREA OF SHOWERS WITH EMBEDDED THUNDERSTORMS WILL LIFT NORTH
THROUGH THE CHICAGOLAND TERMINALS THROUGH 02Z. AHEAD OF
THIS...SOUTH TO SOUTHWEST OUTFLOW WITH WIND GUSTS OF 25 TO 35 KTS
HAS BEEN REPORTED OR ESTIMATED. FOR MDW AND GYY...EXPECT WINDS TO
TURN AROUND TO THIS DIRECTION FOR 30 TO 60 MIN...AND GUST UP TO
THE 25 TO 35 KT LEVEL AT FIRST. FOR ORD AND DPA...THE OUTFLOW MAY
LOSE STEAM...BUT SHOULD STILL TURN WINDS BRIEFLY TO THE
SOUTH/SOUTHWEST AROUND 01Z. AS FOR THE THUNDERSTORMS
THEMSELVES...EXPECT A PERIOD OF HEAVY DOWNPOURS REDUCING
VISIBILITY TO 2 TO 4 SM BASED ON UPSTREAM OBSERVATIONS. SOME SMALL
HAIL CANNOT BE RULED OUT NEAR MDW AND GYY. THE OVERALL CLOUD-TO-
GROUND LIGHTNING TREND HAS SHOWN A SLIGHT DECREASE OVER THE PAST
HOUR.
WEBCAMS AND REPORTS INDICATE THAT FOG/LOW STRATUS HAS CREPT INTO
FAR NORTHEAST IL AND NORTHWEST IN. THIS MAY MIX OUT SOME WITH THE
SHOWERS THROUGH 03Z...BUT THEN SHOULD SETTLE IN FOR THE DURATION
OF THE NIGHT WITH LIGHT EAST NORTHEAST FLOW AND MOIST BOUNDARY
LAYER CONDITIONS. IT IS POSSIBLE THAT STRATUS IS MORE DOMINANT
DURING THE LATER EVENING INTO OVERNIGHT...BUT OVERALL THIS SHOULD
AT LEAST LOWER/SATURATE DOWN TO THE GROUND TO REDUCE VISIBILITY TO
UNDER ONE MILE. DISSIPATION TIME OF THE FOG ON SATURDAY MORNING IS
TRICKY...AS THE LOW-LEVEL FLOW WILL REMAIN LIGHT THROUGH THE
MORNING. IT IS POSSIBLE THAT DENSE FOG MAY PERSIST LONGER THAN
CURRENTLY FORECAST. WINDS WILL TURN MORE NORTHERLY BY AFTERNOON
SATURDAY...WITH LIKELY LINGERING STRATOCU.
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN OUTFLOW REACHING THE CHICAGOLAND
TERMINALS...WITH THE HIGHER GUSTS AT MDW AND GYY.
* MEDIUM CONFIDENCE IN HOW REDUCED VISIBILITY WILL DROP UNDER THE
RAIN. ANY IFR VISIBILITY IS LIKELY TO BE TEMPORARY WITHIN THE
RAIN...HOWEVER FOG LATER IN THE EVENING SHOULD BRINGING
VISIBILITY BACK DOWN.
* HIGH CONFIDENCE IN FOG SETTLING IN BY OVERNIGHT. LOW CONFIDENCE
ON START TIME...AND MAY BE MUCH EARLIER DEPENDING ON HOW THE
SHOWERS IMPACT THE BOUNDARY LAYER. MEDIUM CONFIDENCE IN
DISSIPATION TIME.
* HIGH CONFIDENCE IN WINDS BEING LIGHT AND VARIABLE AT TIMES AFTER
THE SHOWERS THROUGH MID MORNING SATURDAY.
* LOW CONFIDENCE ON WHETHER WINDS AT OHARE ON SATURDAY AFTERNOON WILL
SWING TO WEST OF NORTH.
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...VFR.
MONDAY...VFR.
TUESDAY...VFR. PSBL MVFR CIGS WITH CHC SHRA/ISO TS.
WEDNESDAY...MVFR EARLY TRENDING VFR. CHC RA/TS EARLY.
THURSDAY...VFR.
MTF
&&
.MARINE...
321 PM CDT
WHILE THERE MAY BE SOME PATCHY DENSE FOG NEAR THE WESTERN
SHORE THROUGH TONIGHT...THE PRIMARY CONCERN IS A PERIOD OF UNSTABLE
CONDITIONS LATE SUNDAY INTO EARLY MONDAY...WHICH WILL LEAD TO
STRONGER NORTHERLY WINDS. THEN ON TUESDAY...STRONG SOUTHERLY FLOW
WILL DEVELOP...BUT THE AIR MASS IS EXPECTED TO BECOME INCREASINGLY
STABLE OVER THE LAKE.
INITIALLY...BROAD LOW PRESSURE OVER THE OHIO VALLEY WILL SHIFT
SLOWLY EAST ACROSS THE OHIO VALLEY THROUGH LATE SATURDAY...WITH
WINDS TURNING NORTHERLY BUT REMAINING FAIRLY LIGHT AS THE AIR MASS
OVER THE LAKE WILL STILL BE MILD...LEADING TO STABLE CONDITIONS.
HOWEVER...ON SUNDAY...A COLD FRONT PASSAGE WILL LEAD TO A SHOT OF
REINFORCING COLD AIR AS STRONG HIGH PRESSURE PRESSES DOWN FROM
NORTHERN ONTARIO. THIS WILL BE THE FIRST PUSH OF COLD AIR OVER THE
LAKE IN QUITE A WHILE...SO THE LAKE IS EXCEPTIONALLY MILD FOR LATE
MARCH. THUS...AIR TEMPERATURES BELOW FREEZING ALOFT MOVING OVER THE
MILD LAKE WILL ENABLE MIXING DOWN OF STRONGER WINDS AS THE STRONG
HIGH PRESSURE BUILDING IN RESULTS IN A TIGHT NORTHERLY PRESSURE
GRADIENT. THE COLD AIR WILL TAKE SOME TIME TO DEEPEN...SO THE TARGET
PERIOD FOR STRONGEST NORTHERLY WINDS IS SUNDAY NIGHT INTO EARLY
MONDAY...STARTING WITH THE NORTH HALF...THEN TRANSITIONING DOWN THE
LAKE. HAVE PEGGED THIS TIME FRAME FOR NORTH AND NORTHEAST WINDS UP
TO 30 KT...BUT CANNOT RULE OUT LOW END GALES...SO THIS PERIOD WILL
NEED TO BE MONITORED. THE STRONG NORTHERLY WINDS AND BUILDING WAVES
WILL ALSO LEAD TO A HIGH LIKELIHOOD OF CONDITIONS HAZARDOUS TO SMALL
CRAFT FOR THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS LATE
SUNDAY NIGHT OR EARLY MONDAY MORNING INTO MONDAY EVENING. WINDS WILL
BRIEFLY SUBSIDE AND TURN SOUTHEAST LATE MONDAY NIGHT AS THE HIGH
QUICKLY MOVES EAST.
STRONG LOW PRESSURE WILL APPROACH THE UPPER GREAT LAKES FROM THE
NORTHERN PLAINS ON TUESDAY...STRENGTHENING THE SOUTHERLY FLOW...BUT
AT THIS POINT...THE AIR MASS MOVING ACROSS THE LAKE WILL BE
MILD...AND GUSTS WILL BE LIMITED BY INCREASINGLY STABLE CONDITIONS.
WILL CERTAINLY NEED TO MONITOR THIS PERIOD AS WELL...AS THE WINDS
NOT FAR ABOVE THE STABLE LAYER WILL BE QUITE STRONG. COLDER...UNSTABLE
CONDITIONS AND STRONGER WESTERLY WINDS WILL RETURN ON WEDNESDAY
AFTER THE COLD FRONT TRAILING FROM THE LOW PRESSURE SWEEPS ACROSS
THE LAKE.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ006-ILZ014 UNTIL 9 AM SATURDAY.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ080-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-LMZ743-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 9 AM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
334 PM EDT THU MAR 22 2012
.SHORT TERM.../TONIGHT THROUGH FRIDAY NIGHT/
MOSTLY SUNNY TO SUNNY SKIES HAS ALLOWED TEMPS TO CLIMB INTO THE
UPPER 70S TO LOWER 80S ONCE AGAIN ACROSS THE AREA. LARGE UPPER LOW
THAT HAS BEEN RESPONSIBLE IN PART FOR THE MASSIVE WARMTH WAS
BEGINNING ITS TREK TOWARDS THE OHIO VALLEY. A BAND OF PRECIPITATION
EXTENDED FROM THE GULF STATES INTO PORTIONS OF EASTERN IOWA. MODELS
HAVE BEEN STRUGGLING TO DETERMINE THE TIMING OF THIS BAND SHIFTING
NORTHEAST AND IMPACTING THE AREA. SEVERAL OF THE HRRR RUNS DEPICTED
DEVELOPMENT OF WIDELY SCT TO SCT SHOWERS AND A FEW STORMS MID
AFTERNOON INTO EARLY EVENING. ACCAS FIELD HAS QUICKLY FORMED NE OF
THE MAIN BAND OF PRECIP AND CONVECTION HAS NOW BEGAN TO FIRE FROM NE
ILLINOIS INTO WHITE COUNTY AND TOWARDS INDY. IN ADDITION...CU FIELD
EXPANDING ACROSS SOUTHERN LWR MICHIGAN ALONG AND IN ADVANCE OF LAKE
BREEZE WHICH HAS WORKED WELL INLAND WITH ONE SHOWER NOTED OVER
HILLSDALE COUNTY. HAVE OPTED FOR PRE 1ST PERIOD SLGT CHC/CHC WITH
HIGHEST IN SW AREAS TO COVER TRENDS. BAND OF PRECIP SHOULD BEGIN TO
WORK CLOSER TO THE AREA LATER THIS EVENING INTO THE OVERNIGHT HOURS
ALLOWING FOR INCREASING CHANCES FOR SHOWERS AND MAYBE AN EVENING
STORM. HAVE TRIED TO ADD SOME TIMING DETAIL INTO THE OVERNIGHT HOURS
AND WENT CATEGORICAL LATER TONIGHT IN SW AREAS. CLOUD COVER AND
PRECIP WILL KEEP TEMPS AOA 60 FOR OVERNIGHT LOWS.
UPPER LOW WILL APPROACH THE OHIO RIVER FRI/FRI NGT. LARGE DRY SLOW
NOTED BEHIND BAND OF SHOWERS AND AHEAD OF THE MAIN UPPER LOW. TIMING
OF THIS WILL BE CRUCIAL TO CONVECTIVE DEVELOPMENT FRI AFTN/EVE AND
ALSO SEVERE POTENTIAL. TRENDS WOULD SUGGEST THAT CLEARING WILL
ARRIVE DURING THE MORNING FROM SW TO NE...ALLOWING TEMPS TO JUMP
INTO THE 70S PRIOR TO ARRIVAL OF SERIES OF WAVES WHICH WILL MOVE
AROUND THE LOW AND HELP EXPAND COVERAGE OF SHOWERS AND STORMS.
SWODY2 HAS SOUTHERN HALF OR SO OF AREA IN SLGT RISK. RISK FOR SEVERE
MAY EXTEND ACROSS ENTIRE AREA DEPENDING ON TIMING OF CLEARING AND
AMOUNT OF HEATING. LEFT LIKELY POPS ALONE FOR FRI MORNING WITH
POTENTIAL FOR DRY PERIOD THAT WILL NEED TO BE BETTER TIMED OUT WITH
THE OVERNIGHT PACKAGE. SEVERAL OFFICES HAVE INCREASED TO HIGH LIKELY
OR LOW END CAT POPS FRI AFTERNOON AND GIVEN SEVERAL SIGNALS IN
MODELS AND RECENT TRENDS...HAVE FOLLOWED SUIT AND INCREASED TO CAT
POPS NE HALF IN THE AFTERNOON.
FRIDAY NIGHT PRECIP WILL STILL LINGER IN THE EVENING SO HAVE KEPT
LIKELY POPS NE TRENDING TO CHC OVERNIGHT. LOWS WILL DROP BACK INTO
THE LOW TO MID 50S.
&&
.LONG TERM...
RETURN TO MORE SEASONABLE WEATHER STILL EXPECTED BEGINNING SATURDAY.
TEMPS STILL EXPECTED TO BE ABOVE NORMAL BUT IT WILL CERTAINLY FEEL
MORE LIKE LATE MARCH THAN LATE MAY.
UPPER LEVEL LOW WILL BE SLOWLY MOVING BY TO OUR SOUTH ON SATURDAY
WITH PLENTY OF WRAP AROUND MOISTURE AND WEAK LIFT. EXPECT A CLOUDY
DAY WITH SCATTERED SHOWERS. ENOUGH INSTABILITY IN AFTERNOON FOR SOME
THUNDERSTORM DEVELOPMENT SO LEFT SLIGHT CHANCE MENTION IN FOR THAT.
AS MENTIONED YESTERDAY...SYNOPTIC PATTERN STILL FAVORABLE FOR WEAK
CLOSED LOW FUNNEL CLOUDS...WHICH RARELY TOUCHDOWN BUT DO DEVELOP IN
THIS PATTERN.
UPPER LOW DRIFTS SOUTHEAST ON SUNDAY WITH DRIER AND COOLER AIR
MOVING IN. THIS HIGH WILL SETTLE INTO MICHIGAN MONDAY WITH COOL
EASTERLY FLOW OVER OUR AREA. MODELS HAVE BEEN TRENDING COOLER MONDAY
NIGHT WITH SURFACE RIDGE NOSING INTO NORTHEAST AREAS. HAVE CONTINUED
TREND OF GRADUALLY LOWERING TEMPS WITH LOWS NOW INTO MIDDLE 40S
SOUTHWEST TO MID 30S NORTHEAST. PATCHY FROST BECOMING MORE PLAUSIBLE
NORTHEAST IF WINDS DECOUPLE AND SKIES REMAIN CLEAR. RETURN FLOW
LOOKS TO QUICKLY SETUP EARLY TUESDAY AND THIS MAY HELP INCREASE
WINDS TUESDAY MORNING. MUCH TOO EARLY AND TOO MUCH UNCERTAINTY FOR
ANY INCLUSION OF FROST INTO FORECAST BUT CERTAINLY WORTH WATCHING
GIVEN THE SUSCEPTIBLE STATE OF MOST VEGETATION.
BRIEF WARMUP THROUGH WEDNESDAY BEFORE NEXT FRONT PUSHES THROUGH
BRINGING RAIN CHANCES BACK TO THE AREA. ACCEPTED ALLBLEND POPS FOR
THIS PERIOD WITH MID CHANCE RANGE AND STILL ISSUES WITH TIMING OF
BEST LIFT THROUGH THE AREA.
&&
.AVIATION... /18Z TAFS/
FEW CHANGES MADE TO 18Z TAFS AS SWATH OF SHOWER ACTIVITY CONTINUES
TO EXPAND TO THE WEST ACROSS CENTRAL ILLINOIS INTO WESTERN
KENTUCKY. SOME SLIGHT EASTWARD TREND HAS OCCURRED BUT STILL NO
CLEAR SIGNS OF ITS ARRIVAL HERE. ONE OF THE HI RES MODELS SHOWS
WIDELY SCT SHOWERS BREAKING OUT THIS AFTERNOON WHICH MAY IMPACT
BOTH TAF SITES. VIS SAT SHOWS CU BEGINNING TO POP SO TRENDS WILL
NEED TO BE MONITORED...BUT VFR CONDITIONS SHOULD PREVAIL. IN TERMS
OF BAND TO THE WEST. HAVE INTRODUCED LIGHT SHOWERS DURING THE
OVERNIGHT HOURS TO TRY TO PROVIDE SOME TIMING. FURTHER REFINEMENTS
WILL BE NEEDED.
DRY SLOT WILL MOVE THROUGH SOMETIME ON FRIDAY WHICH WILL ALLOW FOR
AT LEAST SOME HEATING AND LIKIHOOD OF INCREASE IN CONVECTION AS
UPPER LOW DRAWS CLOSER. ADDITIONAL CHANCES FOR CONVECTION WILL
NEED TO BE ADDED WITH BEST TIMING AFTER 18Z FRI.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...FISHER
LONG TERM...LASHLEY
AVIATION...FISHER
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
148 PM EDT THU MAR 22 2012
.AVIATION... /18Z TAFS/
FEW CHANGES MADE TO 18Z TAFS AS SWATH OF SHOWER ACTIVITY CONTINUES
TO EXPAND TO THE WEST ACROSS CENTRAL ILLINOIS INTO WESTERN
KENTUCKY. SOME SLIGHT EASTWARD TREND HAS OCCURRED BUT STILL NO
CLEAR SIGNS OF ITS ARRIVAL HERE. ONE OF THE HI RES MODELS SHOWS
WIDELY SCT SHOWERS BREAKING OUT THIS AFTERNOON WHICH MAY IMPACT
BOTH TAF SITES. VIS SAT SHOWS CU BEGINNING TO POP SO TRENDS WILL
NEED TO BE MONITORED...BUT VFR CONDITIONS SHOULD PREVAIL. IN TERMS
OF BAND TO THE WEST. HAVE INTRODUCED LIGHT SHOWERS DURING THE
OVERNIGHT HOURS TO TRY TO PROVIDE SOME TIMING. FURTHER REFINEMENTS
WILL BE NEEDED.
DRY SLOT WILL MOVE THROUGH SOMETIME ON FRIDAY WHICH WILL ALLOW FOR
AT LEAST SOME HEATING AND LIKIHOOD OF INCREASE IN CONVECTION AS
UPPER LOW DRAWS CLOSER. ADDITIONAL CHANCES FOR CONVECTION WILL
NEED TO BE ADDED WITH BEST TIMING AFTER 18Z FRI.
&&
.UPDATE...
UPDATE SENT TO BUMP UP HIGHS...ESPECIALLY ALONG LAKE WHERE STRONG
HEATING AND DELAY IN LAKE SHADOW HAS ALLOWED TEMPS TO CLIMB INTO
THE UPPER 70S. SFC OBS SHOWING WINDS NOW BECOMING CALM OR LIGHT NW
WHICH SHOULD ALLOW TEMPS TO STEADY OUT ALONG THE LAKE SHORE.
SLOWED ARRIVAL OF CLOUD COVER SOMEWHAT WITH MAIN CLOUD SHIELD WELL
TO THE WEST IN ILLINOIS. WILL NEED TO MONITOR TRENDS FOR SHOWERS
THIS AFTERNOON AS LAST FEW FRAMES OF VIS SAT SHOWS CU BEGINNING TO
POP IN SW AREAS. SEVERAL RUNS OF THE HRRR HAVE LEANED TOWARDS
WIDELY SCT SHOWERS POPPING UP AND AFFECTING MUCH OF THE AREA
THROUGH LATE AFTERNOON. HAVE MADE MINOR TWEAKS TO POPS TO INCREASE
IN SW AREAS WHERE HRRR HINTS AT BEST CHANCE OF INITIATION AND
UPDATE IF NEEDED.
&&
.PREV DISCUSSION... /ISSUED 348 AM EDT THU MAR 22 2012/
SHORT TERM...
HGT PATTN ALOFT HAS CHGD LTL OVR THE LAST 24HRS W/DEEP CUTOFF
CYCLONE STUCK OVR N TX WWD OF LG BLOCKING RIDGE CNTRD THROUGH THE
ERN OH VALLEY. AS IS TYPICAL IN HIGHLY AMPLIFIED FLW PATTNS SUCH AS
THIS...MODEL BIASES CONT WRT TO BREAKDOWN OF MID LVL RIDGE AND AS
SUCH ARE AGAIN DECIDEDLY SLWR W/EWD ARRIVAL OF DEEPER MSTR SURGE THU
NIGHT COINCIDENT W/EWD PROGRESSION OF RAPIDLY WKNG MID LVL ASCENT
PLUME.
PREFERENCE THIS MORNING LIES W/HIGHRES INDICATIONS THROUGHOUT BUT
ESP W/RENEWED DEEP TROPOSPHERIC ASCENT DVLPG ON FRI ALG NE
SEMICIRCLE OF DEEP LYRD TROUGH CONCURRENT W/DIURNAL DESTABILIZATION
UPSWING. THUS ISOLD THUNDER MENTION CONFINED TO AFTN PDS BOTH LT THIS
AFTN/EVE FAR WEST AND NE HALF FRI AFTN TIMED W/XPCD GREATER SFC
BASED DESTABILIZATION AS LL THETA-E RIDGE AND LACKLUSTER MID LVL
LAPSE RATES SUGGEST OTHERWISE OUTSIDE THESE PDS. MOST SIG CHG SHRT TERM
WAS TO BACK POPS WWD THIS AFTN THROUGH EVENING W/SLWR BREAKDOWN OF
MID LVL RIDGE.
OTHERWISE SLWR EWD RETREAT/BREAKDOWN OF LL THERMAL RIDGE TDA SHLD
AGAIN YIELD RECORD HIGHS ONCE AGAIN. KFWA RECORD OF 75 IN JEOPARDY
FRI PENDING COVERAGE/EXTENT OF PCPN AND CLD CVR BUT CERTAINLY
ATTAINABLE W/BINOVC PATTN OBSVD IN IR IMAGERY THIS MORNING.
LONG TERM... / SATURDAY THROUGH WEDNESDAY /
CLOSED NEGATIVE HEIGHT ANOMALY DESCRIBED IN THE SHORT TERM WILL
DRIFT SEWD THROUGH CENTRAL/SOUTHERN INDIANA ON SATURDAY. AN
ASSOCIATED SINKING LOW LEVEL CONVERGENT BOUNDARY...AND VORT LOBES
ROTATING AROUND THE CUT-OFF UPPER LOW...WILL PROVIDE THE FOCUS FOR
SCATTERED SHOWERS. COVERAGE/INTENSITY OF SHOWERS WILL LIKELY
INCREASE A BIT DURING THE AFTERNOON GIVEN SOME SFC HEATING UNDER THE
COLD POCKET ALOFT...WITH ISO THUNDER POSSIBLE. ALSO...AS MENTIONED
BY THE DAY SHIFT...THIS SYNOPTIC SETUP DOES SUPPORT A LOW RISK FOR
COLD AIR FUNNELS MAINLY SATURDAY AFTERNOON. TEMPS WILL FALL BACK A
BIT BUT STILL REMAIN AROUND 15 DEGREES ABOVE NORMAL FOR THIS TIME OF
YEAR.
SUBSIDENCE AND DRYING ALOFT WILL SALVAGE A DRY SECOND HALF OF THE
WEEKEND AS THE CLOSED LOW DROPS INTO THE MID ATLANTIC. MODEL 925-850
HPA RH`S ABOVE 80 PERCENT SUNDAY MORNING SUGGEST THAT A BKN/OVC
STRATOCU DECK WILL HANG ON FOR MUCH OF THE DAY BEFORE
MIXING/THINNING OUT IN THE AFTERNOON. BUMPED UP SKY COVER TO ACCOUNT
FOR THIS TREND. WEAK NORTHERLY FLOW AND CLOUD COVER WILL SUPPRESS
MIXING A BIT...LEADING TO HIGHS GENERALLY A LITTLE COOLER THAN
SATURDAY (LOW/MID 60S).
BEYOND THIS WEEKEND THE MAIN FOCUS WILL SHIFT TO THE
TIMING/TRACK/AMPLITUDE OF NORTHERN STREAM SHORTWAVE ENERGY EMANATING
OUT OF A NORTHEAST PACIFIC MEAN TROUGH. ONE SUCH WAVE WILL LIFT NEWD
INTO CENTRAL CANADA AND THEN DROP INTO THE NORTHEAST CONUS EARLY
NEXT WEEK...POSSIBLY PHASING WITH THE AFOREMENTIONED CLOSED LOW.
ASSOCIATED HEIGHT FALLS WILL FORCE A BACKDOOR COLD FRONT THROUGH THE
AREA...WITH GUIDANCE CONTINUED TO STRUGGLE A BIT WITH TIMING AND
STRENGTH (ECMWF QUICKER AND COOLER COMPARED TO THE GFS/GEFS). GIVEN
THESE DIFFERENCES OPTED TO CONTINUE CLOSE TO THE PREV FCST SUNDAY
NIGHT THROUGH MONDAY NIGHT. OTHERWISE...NOT EXPECTING ANY RAINFALL
OR EVEN MUCH IN THE WAY OF CLOUD COVER WITH THE BACKDOOR FRONT.
WARM ADVECTION REGIME IS EXPECTED ACROSS THE REGION TUESDAY INTO
WEDNESDAY AS THE FLOW VEERS SOUTHWESTERLY. THIS WILL BE IN RESPONSE
TO A SECOND SHORTWAVE THAT GUIDANCE HAS APPROACHING THE NORTHERN
GREAT LAKES. SYSTEM WARM FRONT SHOULD LIFT THROUGH ON TUESDAY WITH
NOTHING MORE THAN SOME MID LVL CLOUDS. LAST SEVERAL MODEL CYCLES
HAVE BEEN RELATIVELY CONSISTENT IN DROPPING A COLD FRONT THROUGH THE
FA AROUND WEDNESDAY. FORCING/MOISTURE APPEARS SUFFICIENT FOR
SHOWERS/STORMS ALONG THIS FEATURE WITH THE PRIMARY QUESTION THIS FAR
IN ADVANCE BEING TIMING. AS FOR DAYS 6/7 TEMPS...DECIDED TO CONTINUE
WITH TREND OF GOING WARMER THAN CONSALL GIVEN CLIMO BIAS IN MOS AND
RECENT COOL BIAS IN THIS WARM PATTERN.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...T
LONG TERM...STEINWEDEL
AVIATION...FISHER
UPDATE...FISHER
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
348 PM CDT THU MAR 22 2012
...UPDATED SYNOPSIS AND SHORT TERM SECTIONS...
.SYNOPSIS...
ISSUED AT 343 PM CDT THU MAR 22 2012
THE UPPER LOW WHICH WAS RESPONSIBLE FOR THE WIDESPREAD HEAVY
RAINFALL AMOUNTS WAS CENTERED ALONG THE KANSAS-OKLAHOMA BORDER EARLY
THIS AFTERNOON. MORNING RAOB AND RUC ANALYSIS INDICATED A -28C
CENTER AT 500MB OVER NORTHERN OKLAHOMA. A FAIRLY FOCUSED CENTER OF
ROTATION WAS EVIDENT BOTH ON RADAR AND 1KM VISIBLE SATELLITE JUST
EAST OF KIOWA, KS. SOME SMALL SHOWERS WERE ROTATING AROUND THE
CENTER AND AFFECTED MAINLY PRATT AND BARBER COUNTY AS OF 20Z. A
MORE GENERAL LIGHT RAIN SHOWER AXIS EXTENDED FROM GREAT BEND TO
KINSLEY TO BUCKLIN TO NEAR ASHLAND AND COLDWATER. THIS WAS THE
WESTERNMOST AREA OF PRECIPITATION...WHICH HAS NOT MOVED WESTWARD AT
ALL AS THE GENERAL MOTION OF THE SHOWER ACTIVITY WAS FROM
NORTH-NORTHEAST TO SOUTH-SOUTHWEST. TEMPERATURES WERE REMAINING
STEADY IN THE MID TO UPPER 40S WITH THE COOLEST TEMPS AT DODGE CITY
AND PRATT AT 20Z.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 343 PM CDT THU MAR 22 2012
MAIN SHORT TERM CHALLENGES TONIGHT WILL BE THE TIMING OF THE END OF
PRECIPITATION. INDICATIONS FROM THE RUC, HRRR, AND NAM12 WOULD SEEM
TO INDICATE THAT THE SHOWER ACTIVITY WILL BE WANING OVER THE NEXT
COUPLE OF HOURS. POPS WILL BE RAPIDLY DECREASING IN THE GRIDS WITH
SLIGHT CHANCE POPS GONE BY 01-02Z OR SO IN THE SOUTHEAST ZONES. THE
FOCUS THEN WILL TURN TO THE FOG DEVELOPMENT. SKIES ARE EXPECTED TO
CLEAR (OR AT LEAST BECOME MOSTLY CLEAR)...ESPECIALLY AFTER 06Z
TONIGHT...AND WITH LIGHT WINDS AT 6 KNOTS OR LESS AND SATURATED
GROUNDS...THE STAGE WILL BE SET FOR FOG FORMATION AS TEMPERATURES
FALL INTO THE MID TO UPPER 30S. WILL BE ADDING AREAS OF FOG TO THE
GRIDS FOR THE 09-14Z TIME FRAME. ON FRIDAY...ONCE THE FOG CLEARS
(IF IT DEVELOPS AS FORECAST) SHORTWAVE RIDGING WILL ADVANCE ON THE
WESTERN PLAINS FROM THE ROCKIES. THE LOW LEVEL RIDGE AXIS WILL
REMAIN OVER WESTERN KANSAS THROUGH THE DAY FRIDAY AND THIS WILL
YIELD LIGHT WINDS ALL DAY AT 6 KNOTS OR LESS. LOW LEVEL THICKNESSES
WILL STILL BE FAIRLY LOW WITH THE UPPER LOW NOT ALL THAT FAR REMOVED
FROM THE PLAINS...SO TEMPERATURES WILL MAX OUT IN THE MID 60S FOR
MOST LOCATIONS...AND LOWER 70S ACROSS FAR SOUTHWEST ZONES WHERE
THICKNESSES WILL BE INCREASING AT A QUICKER RATE WITH THE SHORTWAVE
RIDGE APPROACHING.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 131 PM CDT THU MAR 22 2012
MUCH WARMER AIR WILL RETURN TO WESTERN KANSAS FRIDAY AS THE
UPPER-LEVEL LOW DISCUSSED IN THE SHORT TERM DISCUSSION MOVES INTO
MISSOURI AND SUNSHINE RETURNS. HIGHS SHOULD WARM INTO THE LOWER
TO MID 70S. THE WARM TEMPERATURES WILL PERSIST THROUGH NEXT WEEK
AS UPPER-LEVEL TROUGHING DEVELOPS ACROSS THE WESTERN UNITED
STATES, AND SURFACE LEE TROUGHING DEVELOPS ACROSS THE HIGH PLAINS.
A SHORTWAVE TROUGH WILL PASS ACROSS THE NORTHERN PLAINS BY MONDAY
NIGHT AND TUESDAY. THE GFS/GEM AND ECMWF WERE GENERALLY FOLLOWED
WITH THIS SYSTEM. DESPITE SOME SUBTLE MODEL DIFFERENCES, THE
BOTTOM LINE IS THAT THE UPPER-LEVEL SYSTEM WILL PASS TO OUR NORTH,
WITH LITTLE IN THE WAY OF SYNOPTIC SCALE LIFT OVER WESTERN KANSAS.
TEMPERATURES COULD POSSIBLY REACH INTO THE MID 80S BEHIND THE
DRYLINE IN FAR WESTERN KANSAS MONDAY. RICH LOW-LEVEL MOISTURE
WILL BE DRAWN NORTHWARD ALONG AND EAST OF THE 100TH MERIDIAN IN
ADVANCE OF THE SYSTEM. OFTENTIMES IN MARCH, STRONG FRONTS PUSH THE
LOW-LEVEL MOISTURE DEEP INTO THE TROPICS. BUT SO FAR THIS MARCH WE
HAVE HAD NO PROBLEM GETTING RICH MOISTURE BACK FROM THE GULF IN
THE ABSENCE OF STRONG FRONTAL PASSAGES. A DRYLINE WILL SET UP
ACROSS WESTERN KANSAS MONDAY, WITH AN UNSTABLE AIRMASS DEVELOPING
IMMEDIATELY AHEAD OF IT. HOWEVER, THUNDERSTORMS MAY NOT DEVELOP
SINCE THE ASSOCIATED UPPER-LEVEL JET AND MID-LEVEL COOLING WILL
PASS TO OUR NORTH. BUT AN ISOLATED LATE DAY THUNDERSTORM CANNOT BE
COMPLETELY RULED OUT. AFTER THIS SYSTEM PASSES, THE ASSOCIATED
WEAK COLD FRONT WILL MOVE THROUGH SOUTHWEST KANSAS, KNOCKING
TEMPERATURES DOWN ONLY A FEW DEGREES. IN FACT, TEMPERATURES OUGHT
TO REMAIN ABOVE CLIMATOLOGICAL AVERAGES ALL WEEK AS LEE TROUGHING
QUICKLY REDEVELOPS GIVEN THE FAIRLY ZONAL MID-LEVEL FLOW. A
THUNDERSTORM OR TWO COULD DEVELOP ALONG THE TRAILING COLD FRONT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1259 PM CDT THU MAR 22 2012
THE LOW STRATUS CEILING WAS INCREASING SLOWLY THROUGH THE MVFR
CATEGORY AS OF MIDDAY WITH 2000 TO 3000 FOOT BROKEN/OVERCAST BEING
REPORTED. VISIBLE SATELLITE CONFIRMS SOME BREAKS IN THE OVERCAST
AROUND THE GCK AREA...HOWEVER IT IS DOUBTFUL THAT CEILING WILL
ERODE UNTIL EARLY THIS EVENING. WILL BE MAINTINING A MVFR CEILING
THROUGH ABOUT 20Z...WITH CEILINGS LIKELY 2500 TO 3000 FEET BY LATE
AFTERNOON. WILL ALSO BE CARRYING VICINITY SHOWERS AT DDC AND HYS
CLOSER TO THE DEPARTING UPPER LOW FROM 20Z TO 01Z. SKIES WILL
CLEAR THIS EVENING...AND WINDS WILL REMAIN LIGHT...ALLOWING FOR
RADIATIONAL COOLING AND POTENTIAL FOG DEVELOPMENT GIVEN THE
MOISTURE-LADEN GROUND. AT THIS TIME WILL BE FORECASTING IFR IN
LIGHT FOG FROM 09Z TO 14Z FRIDAY MORNING...HOWEVER SOME DENSE
GROUND FOG CANNOT BE RULED OUT ESPECIALLY AROUND DAYBREAK.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 37 67 41 74 / 10 0 0 0
GCK 36 68 40 76 / 0 0 0 0
EHA 36 72 42 77 / 0 0 0 0
LBL 37 71 41 77 / 0 0 0 0
HYS 40 66 41 76 / 10 0 0 0
P28 42 68 43 74 / 20 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM....FINCH
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS TOPEKA KS
325 AM CDT THU MAR 22 2012
.DISCUSSION...
A CLOSED OFF UPPER LOW WAS LOCATED OVER WESTERN OK EARLY THIS
MORNING. THE UPPER LOW WILL MOVE NORTHEAST INTO SOUTH CENTRAL KS
THIS AFTERNOON. SHORTER WAVE LENGTH TROUGHS ROTATING AROUND THE
UPPER LOW WILL PROVIDE ENOUGH ASCENT FOR SCATTERED TO NUMEROUS
SHOWERS TO DEVELOP ACROSS THE CWA THIS AFTERNOON. IF THE STRATUS
BREAKS UP LATER THIS MORNING...ALLOWING FOR SURFACE HEATING INTO THE
EARLY AFTERNOON...THEN THE INSTABILITY WILL INCREASE ENOUGH FOR
ISOLATED THUNDERSTORMS TO DEVELOP. SBCAPE MAY REACH 400 TO 600 J/KG
ALONG WITH UNIDIRECTIONAL SPEED SHEAR TO PRODUCE SOME STRONGER
STORMS THAT MAY PRODUCE SMALL HAIL AND 40 TO 50 MPH WIND GUSTS
DURING THE AFTERNOON HOURS. IF WE KEEP THE CLOUD COVER THROUGH THE
DAY WE MAY REMAIN STABLE ENOUGH TO PREVENT THUNDERSTORMS FROM
DEVELOPING. HIGHS WILL REACH THE UPPER 50S TO LOWER 60S...MAY BE MID
60S IN AREAS WITH MORE INSOLATION.
TONIGHT THROUGH FRIDAY...THE UPPER LOW WILL TRACK EASTWARD ACROSS
SOUTHEAST KS INTO SOUTH CENTRAL MO BY LATE FRIDAY AFTERNOON. THERE
WILL CONTINUE TO BE ENOUGH ASCENT FOR SCATTERED TO NUMEROUS SHOWERS
THROUGH THE NIGHT. THE SHOWERS SHOULD DIMINISH FROM WEST TO EAST
ACROSS THE CWA FRIDAY AS THE UPPER LOW MOVES EAST OF THE CWA. HIGHS
ON FRIDAY WILL REACH THE LOWER 60S ACROSS THE EASTERN COUNTIES AND
MID 60S ACROSS THE WESTERN COUNTIES...WHERE SKIES MAY BECOME PARTLY
CLOUDY BY AFTERNOON.
SATURDAY THROUGH MONDAY...AN H5 TROUGH WILL MOVE INTO THE WESTERN
CONUS WHILE A DOWN STREAM H5 RIDGE AMPLIFIES ACROSS PLAINS INTO THE
MS RIVER VALLEY. SOUTHWESTERLY FLOW ALOFT OVER THE ROCKIES WILL
CAUSE A LEE SFC TROUGH TO DEEPEN ACROSS THE HIGH PLAINS. SOUTHERLY
LOW-LEVEL WINDS WILL WARM TEMPERATURES INTO THE MID AND UPPER 70S
THIS WEEKEND AND AROUND 80 BY MONDAY. DEEPER GULF MOISTURE WILL ALSO
BE ADVECTED NORTHWARD ACROSS THE CWA SUNDAY AND MONDAY.
MONDAY NIGHT THROUGH WEDNESDAY...THE WESTERN CONUS H5 TROUGH WILL
LIFT NORTHEAST ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST. THIS
WILL CAUSE A SURFACE COLD FRONT TO MOVE SOUTHEAST INTO THE NORTHERN
CWA LATE MONDAY NIGHT. THE FRONT MAY BECOME STATIONARY ALONG I-70
AND RETREAT NORTH AS A WARM FRONT ON WEDNESDAY...AS ANOTHER H5
TROUGH MOVES INTO THE WESTERN CONUS. THE SFC FRONT MAY PROVIDE
CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE CWA MONDAY NIGHT
THROUGH WEDNESDAY. HIGHS WILL COOL SLIGHTLY INTO THE 70S.
GARGAN
&&
.AVIATION...
CIGS OVERNIGHT AND WHETHER FOG WILL DEVELOP ARE THE MAIN
UNCERTAINTIES. FORCING FOR PRECIP SHOULD CONTINUE TO MOVE WEST.
THE NAM FORECAST SOUNDINGS SUGGEST FOG WILL FORM BETWEEN 08 AND
09Z. THE RUC AT LEAST HAS IFR STRATUS. WITH RECENT RAINS AND A
NEARLY SATURATED BOUNDARY LAYER...IF SKIES CLEAR OUT DENSE FOG
WILL BE POSSIBLE. MODELS CONTINUE TO SHOW THE BOUNDARY LAYER
SOMEWHAT MIXED FAVORING A STRATUS DECK. HAVE MORE CONFIDENCE IN
STRATUS FORMING SO WILL STAY WITH PERSISTENCE AND ONLY MENTION
SOME MVFR VSBY AND BR. THE BOUNDARY LAYER SHOULD MIX OUT BY NOON
WITH SOME INSTABILITY DEVELOPING AS THE UPPER LOW MOVES CLOSER.
TIMING OF ANY TS WILL BE DIFFICULT SO WILL CONTINUE WITH A MENTION
OF CB AT THIS TIME.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
216 AM MDT THU MAR 22 2012
.UPDATE...
ISSUED AT 904 PM MDT WED MAR 21 2012
TONIGHT-THURSDAY NIGHT...AT 03Z RADAR SHOWING AN AREA OF LIGHT TO
MODERATE RAIN FROM MCCOOK TO COLBY TO TRIBUNE MOVING WEST AT 20-25
MPH. LATEST 00Z NAM AND RUC HAVE A GOOD HANDLE ON THIS BAND AND
CONTINUE TO MOVE IT WEST THROUGH THE NIGHT WHILE FURTHER EAST
DRIER AIR MOVES IN PRODUCING A QUICK DECREASE IN PRECIPITATION
CHANCES. HAVE UPPED THE POPS TO CATEGORICAL WITH THE BAND MOVING
WEST. ALSO INCLUDED AREAS OF FOG GIVEN THE RICH LOW LEVEL MOISTURE
AND LOW T/TD SPREADS. AREAS FURTHER EAST THAT MAY NOT SEE RAIN
DURING THE MORNING WEDNESDAY WILL STILL HAVE A THREAT FOR FOG.
WINDS TONIGHT GUSTY FROM THE NORTH. OVERNIGHT LOWS GENERALLY IN
THE 40S WITH HIGH TEMPERATURES THURSDAY MID 50S TO AROUND 60.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 218 PM MDT WED MAR 21 2012
WATER VAPOR IMAGERY SHOWS THAT TEXAS 500 MB LOW HAS MOVED NORTHEAST
THE PAST FEW HOURS. DRY AIR IS CURRENTLY WORKING ITS WAY THROUGH
SOUTHERN KANSAS...BUT EXPECT MOISTURE TO ADVECT OVER THE AREA LATER
THIS EVENING...ESPECIALLY AFTER 03Z. BEST SYNOPTIC LIFT PER Q VECTOR
CONVERGENCE IS PROGGED OVER THE AREA BETWEEN 00Z-06Z. ALTHOUGH LOW
LEVEL TRAJECTORIES WILL HAVE A LONG WAY TO TRAVEL BEFORE THEY ARRIVE
HERE...FEEL THE POTENTIAL FOR DECENT RAINS IS HIGH ESPECIALLY AS THE
CLOSED LOW MOVES CLOSER TO THE AREA. MODELS ARE IN GENERAL AGREEMENT
WITH THIS SCENARIO. WILL KEEP POPS ON THE LOW SIDE EARLY THIS
EVENING...THEN INCREASE THEM AFTER 03Z. HAVE INTRODUCED SOME FOG
TO THE EASTERN ZONES WHERE DEW POINTS WILL BE THE HIGHEST.
LOW WILL STALL OVER OKLAHOMA THURSDAY PROVIDING THE AREA WITH ANOTHER
CHANCE OF PRECIPITATION THROUGH THE MORNING. MOISTURE GETS SHUNTED
TO THE NORTH BY THE AFTERNOON...SO THE AIR MASS WILL DRY BY THE LATE
AFTERNOON.
EXPECT LOW LEVEL DEW POINTS TO INCREASE TONIGHT WHICH WILL KEEP MINIMUM
TEMPERATURES IN THE UPPER 30S TO THE MID 40S. MAXIMUM TEMPERATURES
FRIDAY WILL BE HIGH DEPENDENT ON CLOUD COVER. EXPECT CLOUDS TO
DECREASE BY THE AFTERNOON WHICH WILL ALLOW HIGHS TO REACH INTO THE
50S...VERY SIMILAR TO THE TEMPERATURES REACH TODAY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 210 AM MDT THU MAR 22 2012
FRIDAY NIGHT-SATURDAY NIGHT...PERSISTENT CUT OFF LOW THAT HAS BEEN
IMPACTING AREA FOR SEVERAL DAYS WILL CONTINUE TO MOVE EAST OF THE
AREA AS NEXT TROUGH BEGINS TO DIG INTO THE WESTERN CONUS. WHILE
MODELS HAVE STRUGGLED WITH THIS PATTERN...AVAILABLE
OPERATIONAL/ENSEMBLE DATA INCREASES CONFIDENCE ENOUGH TO THINK THIS
SOLUTION VERY REASONABLE. CWA WILL FIND ITSELF BETWEEN STRENGTHENING
TROUGH OVER THE WEST COAST AND DEPARTING TROUGH ACROSS THE EASTERN
CONUS WITH FAIRLY AMPLIFIED RIDGE IN PLACE ACROSS THE PLAINS.
OVERALL...EXPECT FAIRLY QUIET CONDITIONS THROUGH THE PERIOD. SOME
POTENTIAL FOR ELEVATED INSTABILITY TO DEVELOP ALONG DEVELOPING LLJ
ON SATURDAY NIGHT...BUT MODELS SPLIT WITH HOW STRONG THIS WILL BE
AND THINK OVERALL PROBABILITIES FOR ANY PRECIP ARE TOO LOW TO
MENTION AT THIS TIME WITH ONLY SOME OVERNIGHT PATCHY FOG BEING THE
ONLY WX CONCERNS. OVERALL EXPECT WELL ABOVE NORMAL TEMPERATURES TO
RETURN TO THE AREA WITH HIGHS REACHING THE UPPER 70S AND LOW
TEMPERATURES IN THE UPPER 30S FRIDAY NIGHT AND THE LOWER TO MID 40S
ON SATURDAY NIGHT.
SUNDAY-WEDNESDAY...MEDIUM RANGE MODELS ARE IN REASONABLE AGREEMENT THROUGH
THE PERIOD WITH GEFS SPAGHETTI PLOTS NOT INDICATING ALOT OF SPREAD
THROUGH MUCH OF THE PERIOD AND WITH MODELS BEING IN DECENT AGREEMENT
THINK OVERALL CONSENSUS PRODUCTS A PRETTY GOOD PLACE TO START WITH.
WHILE PERIOD WILL START WITH LARGE SCALE H5 RIDGE IN PLACE BRINGING
CONTINUED WARM AND DRY WEATHER...SHORT WAVE TROUGH WILL SWEEP ACROSS
NORTHERN PLAINS ON MONDAY...FORCING COLD FRONT ACROSS THE REGION
BREAKING DOWN RIDGE AND BRINGING MORE PROGRESSIVE/ZONAL FLOW TO THE
PLAINS FOR THE REST OF THE PERIOD. THINK THERE MAY BE A SMALL WINDOW
FOR THUNDERSTORMS BEFORE FRONTAL PASSAGE ON MONDAY AND MONDAY
EVENING...BUT THINK OVERALL CHANCES PRETTY LOW. EVEN BEHIND
FRONT...TEMPS WILL REMAIN ABOVE NORMAL THROUGH THE PERIOD. COULD
POTENTIALLY SEE A FIRE WX THREAT ON MONDAY GIVEN VERY WARM TEMPS AND
INCREASING WINDS IN THE AFTERNOON...BUT WITH WIDESPREAD RAINFALL
OCCURRING...WANT TO WAIT AND SEE IMPACT ON FUELS BEFORE HIGHLIGHTING
THREAT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1045 PM MDT WED MAR 21 2012
WIDESPREAD LIGHT TO MODERATE RAIN WITH MVFR/IFR CIGS AND VIS TO
IMPACT BOTH KGLD AND KMCK FROM 06Z TONIGHT THROUGH ROUGHLY 15Z
THURSDAY MORNING. AS THIS BAND OF PRECIPITATION MOVES WEST AFTER
15Z CIGS AND VIS WILL SLOWLY IMPROVE TO VFR BETWEEN 21Z-00Z AND
REMAIN SO THROUGH THE REST OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
KS...NONE.
NE...NONE.
&&
$$
UPDATE...007
SHORT TERM...MENTZER
LONG TERM....JRM
AVIATION...007
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1255 AM CDT THU MAR 22 2012
...UPDATED AVIATION SECTION...
.UPDATE...
ISSUED AT 1239 AM CDT THU MAR 22 2012
RAIN HAS ENDED ACROSS SOUTH CENTRAL AND CENTRAL KANSAS AS A
SURFACE LOW MOVES SOUTHWEST ACROSS SOUTHWEST KANSAS. I HAVE
UPDATED THE POPS, WX, AND QPF GRIDS WITH THE HRRR WHICH SEEMS TO
HAVE A GOOD HANDLE ON THE SITUATION. ALSO ADJUSTED TEMPERATURES
OVER THE NEXT COUPLE OF HOURS KEEPING TEMPS UP ACROSS AREAS THAT
WILL RECEIVE ADDITIONAL RAIN. ALL OTHER GRIDS AND FORECAST
THINKING REMAIN ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 309 PM CDT WED MAR 21 2012
AS PRECIPITATION CONTINUES TO EXPAND AND INTENSIFY ACROSS SOUTHWEST
KANSAS...HOURLY PRECIPITATION RATES OF 0.25 TO 0.35 INCHES/HR WILL
COVER A MUCH LARGER AREA INCLUDING GARDEN CITY, DODGE CITY, LIBERAL,
GREENSBURG, KINSLEY AREAS. AS MUCH AS 0.5 TO 0.75 INCHES ARE
POSSIBLE THROUGH LATE EVENING. THE DEFORMATION AXIS WILL SHIFT
SLOWLY TO THE WEST/NORTHWEST LATE TONIGHT SUCH THAT AREAS LIKE
DIGHTON, NESS CITY, AND WAKEENEY WILL RECEIVE FAIRLY DECENT RAINFALL
AMOUNTS IN EXCESS OF THREE-QUARTERS OF AN INCH (THROUGH 12Z
THURSDAY). MODERATE RAIN WILL BE ONGOING AT THE END OF THE TONIGHT
PERIOD 12Z THURSDAY)...WITH THE MOST LIKELY AREAS FOR HEAVIEST RAIN
BEING FROM GARDEN CITY TO WAKEENEY BY THAT TIME. TEMPERATURE
WISE...WILL BE KEEPING TEMPERATURES MAINLY IN THE LOWER TO MID 40S
THROUGH THE EVENING AND OVERNIGHT HOURS WITHOUT ANY ADVECTION
OCCURRING.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 351 PM CDT WED MAR 21 2012
THE UPPER-LEVEL LOW PRESSURE CENTER DISCUSSED IN THE SHORT TERM
FORECAST WILL SLOWLY FILL OVER THE NEXT 24 HRS, WITH
ADVECTIONS/ISENTROPIC LIFT DIMINISHING BY 12Z THURSDAY. HOWEVER THE
ASSOCIATED MID-LEVEL COLD POOL WILL BE PROGRESSING INTO
SOUTHWESTERN KANSAS BY THURSDAY. THUS, THE LOW TO MID-LEVEL LAPSE
RATES WILL BE INCREASING. WITH PLENTY OF LOW LEVEL MOISTURE IN
PLACE, SMALL AMOUNTS OF CAPE WILL LEAD TO SCATTERED SHOWERS AND
POSSIBLY A THUNDERSTORM OR TWO THURSDAY, ESPECIALLY IN SOUTH CENTRAL
KANSAS. TEMPERATURES WILL STILL BE FAIRLY COOL IN THE 50S THURSDAY
GIVEN THE WIDESPREAD CLOUDINESS AND PERSISTENCE OF THE LOW-LEVEL COLD
POOL. THE UPPER-LOW WILL GRADUALLY EXIT INTO MISSOURI BY THURSDAY
NIGHT AND FRIDAY. SO THE PRECIPITATION OUGHT TO EXIT SOUTHWEST AND
SOUTH CENTRAL KANSAS BY 7 PM THURSDAY.
FRIDAY WILL BE MUCH WARMER AS SUNSHINE RETURNS AND THE LOW-LEVEL COLD
POOL EXITS. TEMPERATURES OUGHT TO REACH INTO THE 60S TO LOWER 70S. IN
FACT, THE WARM TEMPERATURES WILL PERSIST THROUGH EARLY NEXT WEEK AS
UPPER-LEVEL TROUGHING DEVELOPS ACROSS THE WESTERN UNITED STATES,
AND LEE TROUGHING DEVELOPS ACROSS THE HIGH PLAINS. A SHORTWAVE
TROUGH WILL PASS ACROSS THE NORTHERN PLAINS BY MONDAY NIGHT AND
TUESDAY. MEANWHILE, RICH LOW LEVEL MOISTURE WILL BE POISED TO MAKE A
RAPID RETURN ALONG AND EAST OF THE 100TH MERIDIAN SINCE THE PREVIOUS
FRONT WILL NOT PASS VERY FAR INTO THE GULF OF MEXICO AND SINCE THE
GULF WATER IS ALREADY NEAR EQUILIBRIUM WITH THE OVERLYING AIR.
OFTENTIMES IN MARCH THERE ARE STRONG FRONTS THAT PUSH THE LOW LEVEL
MOISTURE DEEP INTO THE TROPICS, WITH INSUFFICIENT TIME TO DRAW THIS
MOISTURE NORTHWESTWARD AHEAD OF UPPER-LEVEL TROUGHS. A DRYLINE WILL
SET UP ACROSS WESTERN KANSAS MONDAY WITH DECENT CAPE LIKELY IMMEDIATELY
AHEAD OF IT. HOWEVER, THUNDERSTORMS MAY NOT DEVELOP SINCE THE
ASSOCIATED UPPER-LEVEL JET AND MID-LEVEL COOLING WILL PASS TO OUR
NORTH. THAT SAID, THE LATEST RUN OF THE ECMWF SHOWS THUNDERSTORMS
ALONG THE DRYLINE IN WESTERN KANSAS. SO SMALL STORM CHANCES WERE
MAINTAINED. AFTER THIS SYSTEM PASSES, THE ASSOCIATED WEAK COLD FRONT
WILL MOVE THROUGH SOUTHWEST KANSAS, KNOCKING TEMPERATURES DOWN FROM
THE 70S/80S MONDAY AND TUESDAY INTO THE 60S AND 70S BY WEDNESDAY.
THERE COULD BE A FEW THUNDERSTORMS ALONG THE TRAILING COLD FRONT
TUESDAY NIGHT OR WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1239 AM CDT THU MAR 22 2012
IFR CONDITIONS WILL CONTINUE OVER THE NEXT COUPLE OF HOURS ACROSS
THE GARDEN CITY TERMINAL AS RAIN CONTINUES. MVFR TO VFR CONDITIONS
ARE ANTICIPATED ACROSS THE DODGE CITY AND HAYS TERMINALS AS AN
AREA OF SURFACE LOW PRESSURE MOVES TO THE SOUTHWEST. WINDS ARE
SHIFTING TO THE SOUTHEAST BEHIND THIS SURFACE LOW AT LESS THAN 10
KNOTS. WITH THE MOIST SURFACE AND UPSLOPE FLOW RETURNING, AREAS OF
DENSE FOG MAY FORM TOWARDS SUNRISE. THIS COULD LOWER VISIBILITIES
TO AROUND A QUARTER OF A MILE IN SOME PLACES. THE UPPER LEVEL
SYSTEM STARTS TO MOVE TO THE EAST TOMORROW WITH RAIN CHANCES
ENDING FROM WEST TO EAST. VFR CONDITIONS SHOULD PREVAIL BY
TOMORROW AFTERNOON WITH CLOUDS AOA060.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 35 67 41 77 / 0 0 0 0
GCK 34 68 40 77 / 0 0 0 0
EHA 34 70 42 79 / 0 0 0 0
LBL 35 69 41 78 / 0 0 0 0
HYS 39 66 41 75 / 0 10 0 0
P28 37 68 43 74 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HOVORKA 42
SHORT TERM...UMSCHEID
LONG TERM....FINCH
AVIATION...HOVORKA 42
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1051 PM MDT WED MAR 21 2012
.UPDATE...
ISSUED AT 904 PM MDT WED MAR 21 2012
TONIGHT-THURSDAY NIGHT...AT 03Z RADAR SHOWING AN AREA OF LIGHT TO
MODERATE RAIN FROM MCCOOK TO COLBY TO TRIBUNE MOVING WEST AT 20-25
MPH. LATEST 00Z NAM AND RUC HAVE A GOOD HANDLE ON THIS BAND AND
CONTINUE TO MOVE IT WEST THROUGH THE NIGHT WHILE FURTHER EAST
DRIER AIR MOVES IN PRODUCING A QUICK DECREASE IN PRECIPITATION
CHANCES. HAVE UPPED THE POPS TO CATEGORICAL WITH THE BAND MOVING
WEST. ALSO INCLUDED AREAS OF FOG GIVEN THE RICH LOW LEVEL MOISTURE
AND LOW T/TD SPREADS. AREAS FURTHER EAST THAT MAY NOT SEE RAIN
DURING THE MORNING WEDNESDAY WILL STILL HAVE A THREAT FOR FOG.
WINDS TONIGHT GUSTY FROM THE NORTH. OVERNIGHT LOWS GENERALLY IN
THE 40S WITH HIGH TEMPERATURES THURSDAY MID 50S TO AROUND 60.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 218 PM MDT WED MAR 21 2012
WATER VAPOR IMAGERY SHOWS THAT TEXAS 500 MB LOW HAS MOVED NORTHEAST
THE PAST FEW HOURS. DRY AIR IS CURRENTLY WORKING ITS WAY THROUGH
SOUTHERN KANSAS...BUT EXPECT MOISTURE TO ADVECT OVER THE AREA LATER
THIS EVENING...ESPECIALLY AFTER 03Z. BEST SYNOPTIC LIFT PER Q VECTOR
CONVERGENCE IS PROGGED OVER THE AREA BETWEEN 00Z-06Z. ALTHOUGH LOW
LEVEL TRAJECTORIES WILL HAVE A LONG WAY TO TRAVEL BEFORE THEY ARRIVE
HERE...FEEL THE POTENTIAL FOR DECENT RAINS IS HIGH ESPECIALLY AS THE
CLOSED LOW MOVES CLOSER TO THE AREA. MODELS ARE IN GENERAL AGREEMENT
WITH THIS SCENARIO. WILL KEEP POPS ON THE LOW SIDE EARLY THIS
EVENING...THEN INCREASE THEM AFTER 03Z. HAVE INTRODUCED SOME FOG
TO THE EASTERN ZONES WHERE DEW POINTS WILL BE THE HIGHEST.
LOW WILL STALL OVER OKLAHOMA THURSDAY PROVIDING THE AREA WITH ANOTHER
CHANCE OF PRECIPITATION THROUGH THE MORNING. MOISTURE GETS SHUNTED
TO THE NORTH BY THE AFTERNOON...SO THE AIR MASS WILL DRY BY THE LATE
AFTERNOON.
EXPECT LOW LEVEL DEW POINTS TO INCREASE TONIGHT WHICH WILL KEEP MINIMUM
TEMPERATURES IN THE UPPER 30S TO THE MID 40S. MAXIMUM TEMPERATURES
FRIDAY WILL BE HIGH DEPENDENT ON CLOUD COVER. EXPECT CLOUDS TO
DECREASE BY THE AFTERNOON WHICH WILL ALLOW HIGHS TO REACH INTO THE
50S...VERY SIMILAR TO THE TEMPERATURES REACH TODAY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 218 PM MDT WED MAR 21 2012
LARGE SCALE RIDGE BUILDS ACROSS THE CENTRAL US AS UPPER LOW SHIFTS
TO THE EAST COAST. THIS RIDGE WILL BRING UNSEASONABLY WARM
TEMPERATURES BACK TO THE REGION ALONG WITH A RETURN TO DRY
CONDITIONS. TEMPERATURES ALOFT WILL BEGIN MODERATING FRIDAY AS THE
UPPER LOW PULLS EAST...WITH HIGHS GENERALLY IN THE MID-UPPER 60S.
MUCH WARMER TEMPERATURES ARRIVE THIS WEEKEND...WITH WIDESPREAD UPPER
70S AND MANY LOCATIONS AROUND 80F. MONDAY LOOKS TO BE THE WARMEST
DAY OF THE FORECAST PERIOD...WITH WIDESPREAD 80F TEMPS AND LOW-MID
80S POSSIBLE.
A SHORTWAVE TROUGH WILL PASS THROUGH THE NORTHERN PLAINS ON
MONDAY/MONDAY NIGHT...WITH A COLD FRONT DROPPING SOUTH OVER THE CWA
MONDAY NIGHT. A DRY LINE WILL BE IN PLACE ACROSS THE CWA WITH WITH
HIGH TD VALUES AND GOOD INSTABILITY BUILDING EAST OF THIS FEATURE. A
DEEP DRY AIRMASS WILL REMAIN IN PLACE OVER THE CWA ALONG WITH STRONG
CIN...AND THE BEST LARGE SCALE ASCENT WILL BE WELL NORTH OF THE
AREA. WITH THIS IN MIND IVE KEPT THE FORECAST DRY. IT IS WORTH
MENTIONING THE ECMWF FOR THE LAST TWO RUNS HAS PRODUCED QPF EAST OF
THE FORECAST DRY LINE...SO A STORM OR TWO ACROSS WESTERN/CENTRAL
KANSAS IS NOT OUT OF THE QUESTION IF THE CAP WERE TO WEAKEN. THE
COLD FRONT MONDAY NIGHT WILL BRING COOLER TEMPERATURES FOR TUESDAY
AND WEDNESDAY...THOUGH THEY WILL STILL BE 10-20F ABOVE NORMAL WITH
HIGHS IN THE UPPER 60S/LOW 70S.
LOOKING BEYOND THE CURRENT FORECAST PERIOD ENSEMBLE GUIDANCE ALONG
WITH CPC 6-10 DAY OUTLOOK GENERALLY SUPPORTS DRY CONDITIONS AND
ABOVE NORMAL TEMPERATURES. UNFORTUNATELY WE MAY HAVE AWHILE TO WAIT
FOR A MEANINGFUL SHOT OF MEASURABLE PRECIPITATION AFTER OUR CURRENT
SYSTEM EXITS THE REGION TOMORROW EVENING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1045 PM MDT WED MAR 21 2012
WIDESPREAD LIGHT TO MODERATE RAIN WITH MVFR/IFR CIGS AND VIS TO
IMPACT BOTH KGLD AND KMCK FROM 06Z TONIGHT THROUGH ROUGHLY 15Z
THURSDAY MORNING. AS THIS BAND OF PRECIPITATION MOVES WEST AFTER
15Z CIGS AND VIS WILL SLOWLY IMPROVE TO VFR BETWEEN 21Z-00Z AND
REMAIN SO THROUGH THE REST OF THE TAF PERIOD.
&&
.FIRE WEATHER...
ISSUED AT 218 PM MDT WED MAR 21 2012
CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE EACH SATURDAY
THROUGH NEXT WEDNESDAY AFTERNOON WITH VERY WARM TEMPERATURES IN
PLACE. THERE ARE STILL QUESTIONS REGARDING THE EXACT POSITION OF THE
DRY LINE OVER THE CWA EACH DAY...WITH A LARGE TD GRADIENT POSSIBLE
FROM THE WEST TO THE EAST. WINDS WILL ALSO BE A QUESTION MARK EACH
AFTERNOON WITH MONDAY AND TUESDAY MOST LIKELY TO REACH CRITERIA ON
WINDS. AT THIS POINT IN TIME...LOCATIONS ACROSS THE WESTERN HALF OF
OUR FORECAST AREA HAVE THE BEST CHANCE OF REACHING RFW CRITERIA
NEXT MONDAY AND TUESDAY. THERE IS A LOT THAT CAN CHANGE IN REGARDS
TO TD AND WINDS EACH AFTERNOON BEFORE WE ARE CLOSE ENOUGH IN TIME TO
ISSUE A WATCH/WARNING...SO THIS WILL NEED TO BE MONITORED.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
KS...NONE.
NE...NONE.
&&
$$
UPDATE...007
SHORT TERM...MENTZER
LONG TERM....DR
AVIATION...007
AREA FORECAST DISCUSSION
NWS JACKSON KY
1043 PM EDT FRI MAR 23 2012
.UPDATE...
ISSUED AT 1043 PM EDT FRI MAR 23 2012
NDFD AND ASSOCIATED PRODUCTS HAVE BEEN UPDATED FOR LATEST
OBSERVATIONAL TRENDS. PREVIOUS TIMING ON CONVECTION FOR THE REMAINDER
OF THE NIGHT STILL LOOKS GOOD BASED ON LATEST RADAR TRENDS AND SHORT
RANGE MODEL DATA. CONVECTION IS NEARING THE SOUTHWEST PART OF THE
FORECAST AREA AT THIS TIME. LATEST HRRR SEEMS TO HAVE A PRETTY GOOD
HANDLE ON THE CONVECTION...AND EXPECT INTENSITY OF SHOWERS AND
THUNDERSTORMS TO DECREASE OVERNIGHT PER THE 23Z HRRR. HAVE CONTINUE
WITH THE IDEA OF SCATTERED SHOWERS AND THUNDERSTORMS. SOME REPORTS OF
FOG IN LOCAL VALLEY AREAS AND WILL ADD THIS TO THE HWO.
UPDATE ISSUED AT 747 PM EDT FRI MAR 23 2012
SCATTERED SHOWERS CURRENTLY EAST OF A LINE FROM MOREHEAD TO
WHITESBURG CONTINUE TO DIMINISH IN COVERAGE AND INTENSITY AS THEY
MOVE NORTHEAST AT 40 MPH. ALSO AN SHOWER MOVING INTO WAYNE COUNTY AT
THIS TIME. FOR THE MOST PART EXPECT DRY WEATHER TO PREVAIL FOR THE
REST OF THE EVENING WITH ONLY ISOLATED SHOWERS AND THUNDERSTORMS
POSSIBLE. SHOWERS AND THUNDERSTORMS CURRENTLY INCREASING FROM NORTH
OF BOWLING GREEN INTO CENTRAL INDIANA. AS LOW AND SURFACE FRONT MOVE
EAST TONIGHT EXPECT SHOWERS AND THUNDERSTORMS TO ONCE AGAIN BECOME
MORE NUMEROUS IN EASTERN KY...GENERALLY AFTER MIDNIGHT. THIS IS IN
AGREEMENT WITH CURRENT TRENDS AND THE LATEST HRRR AND NAM. FOR NOW
WILL KEEP PRECIPITATION SCATTERED IN NATURE LATER TONIGHT WITH 50
PERCENT PROBABILITIES. HAVE ALSO MADE SOME MINOR UPDATES TO NDFD FOR
LATEST SURFACE OBSERVATIONAL TRENDS.
UPDATE ISSUED AT 441 PM EDT FRI MAR 23 2012
HAVE UPDATED NDFD OUT THROUGH THE NEXT SEVERAL HOURS FOR LATEST
OBSERVATIONAL TRENDS. LATEST SHORT RANGE GUIDANCE STILL POINTS
TOWARDS A DECREASING CHANCE OF SHOWERS AND THUNDERSTORMS AFTER 00Z AS
THE CURRENT ACTIVITY NOW AFFECTING EASTERN KY MOVES NORTHEAST OF THE
AREA. THE CHANCE WILL THEN RAMP UP AGAIN LATER TONIGHT AS THE CLOSED
UPPER LOW MOVES EAST.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 306 PM EDT FRI MAR 23 2012
SAT IMAGERY AND SFC ANALYSIS AS OF 18Z SHOWS THE CENTER OF A BROAD
STACKED LOW NOW MOVING FROM MO INTO IL. CONVECTION OVER ERN KY HAS
BEEN RATHER ANEMIC THUS FAR LARGELY DUE TO THE EXTENSIVE CLOUD COVER
INHIBITING INSTABILITY. HOWEVER...BLENDED PWAT PRODUCT SHOWS THE AXIS
OF AMPLE MOISTURE TRANSPORT FROM THE GOMEX STILL ALIGNED FROM SRN AL
UP THRU MIDDLE TN AND INTO CENTRAL KY....FUELING WIDESPREAD SHOWERS
OVER ERN KY WITH LIGHTNING JUST NOW STARTING TO PICK UP OVER OUR
AREA...ALONG WITH A HINT OF ROTATION IN A CELL MOVING INTO LESLIE
COUNTY SUGGESTING AT LEAST A POTENTIAL FOR HAIL MAY STILL EXIST
THROUGH THE REMAINDER OF THE FIRST PERIOD AS WELL.
CURRENT RADAR TRENDS OVER WRN KY WHERE CONVECTION HAS BEEN NOTABLY
DEEPER SUGGEST 12Z MODELS MAY NOT BE TOO FAR OFF THE MARK WITH THE
IDEA OF A SOLID LULL IN ACTIVITY OVERNIGHT. HOWEVER...STILL WOULD NOT
RULE OUT A STRONG TSTM OR TWO THRU THIS EVENING WITH IR INDICATING
SOME ENHANCEMENT IN THE CONVECTION MOVING UP FROM ERN TN. GUIDANCE
REMAINS IN GOOD AGREEMENT FOR SATURDAY BRINGING LOWERING HEIGHTS
ALOFT AS THE BROAD LOW APPROACHES WITH STEEPENING LAPSE RATES THROUGH
THE AFTERNOON IN RESPONSE...WARRANTING ANOTHER ROUND OF CHANCE TSTMS
THRU THE MORNING AND INTO THE AFTERNOON...THOUGH WITH SIGNIFICANTLY
LESS SEVERE POTENTIAL THAN TODAY.
BY SATURDAY NIGHT...MODELS BEGIN TO DIVERGE WITH THE TRACK OF THE
UPPER LOW AND THIS WILL UNDOUBTEDLY HAVE AN INFLUENCE ON THE SFC
TRACK AND POPS AS WELL. HAVE LEANED MORE TOWARDS THE ECMWF AFTER 00Z
SUNDAY FOR THE SYNOPTIC PICTURE AS IT APPEARS TO HAVE THE MORE
CONSISTENT SOLUTION. THIS WOULD MOVE THE CORE OF THE UPPER LOW INTO
SERN KY BY SUNDAY MORNING BEFORE EXITING THE COMMONWEALTH...LEAVING A
DEEP NW FLOW OVERHEAD WITH A POTENTIAL FOR A GOOD FETCH OF MOISTURE
OFF THE GREAT LAKES AND POSSIBLY JUST ENOUGH RESIDUAL MID LEVEL
ENERGY ON THE BACKSIDE OF THE DEPARTING SYSTEM TO AFFECT A FEW
SHOWERS ACROSS THE CWA ON SUNDAY. BUFR SOUNDINGS ATTM INDICATE
MINIMAL INSTABILITY THROUGH THE DAY AND HAVE KEPT SLIGHT CHANCE
WORDING FOR TSTMS FOR THE MOMENT...THOUGH IF MODEL TRENDS CONTINUE
THEN THE NEXT ISSUANCE COULD PROBABLY PULL THUNDER FROM SUNDAY AND
JUST LEAVE ISOLATED SHOWERS.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 306 PM EDT FRI MAR 23 2012
PATTERN IS QUITE PROGRESSIVE THROUGH THE EXTENDED PERIOD. ALSO...
MODELS ARE IN GOOD AGREEMENT UNTIL DY7 WHEN SOLUTIONS DISPLAY A
SIGNIFICANT DEPARTURE...ESPECIALLY THE GFS. HOWEVER...TREND HAS BEEN
TOWARDS THE ECMWF SOLUTION. A FAST MOVING SHORT WAVE RIDGE TRANSITS
OUR AREA AT THE START OF THE EXTENDED BEHIND EXITING LOW OFF THE
ATLANTIC COAST. BUT SHORT WAVE ENERGY DIGGING SOUTHEASTWARD ACROSS
THE GREAT LAKES LATE MONDAY NIGHT INTO TUESDAY MORNING WILL SEND A
BACK DOOR SFC FRONT INTO THE CWA. BUT THIS FEATURE STALLS OUT ACROSS
OUR AREA TUESDAY BEFORE SHOOTING BACK TO OUR NORTH AS OUR NEXT
WEATHER MAKER ROLLS OUT OF THE NORTHERN PLAINS...PULLING A COLD
FRONT THROUGH EASTERN KENTUCKY MID WEEK...PROBABLY WEDNESDAY. DRY
WEATHER TAKES OVER AS CANADIAN HIGH PRESSURE NOSES ITS WAY INTO THE
OHIO VALLEY REGION TO CLOSE OUT THE WEEK.
IN GENERAL TEMPERATURES WILL COOL THROUGH THE PERIOD AS COMPARED TO
OUR RECENT RECORD HIGHS...BUT STILL REMAIN ABOVE NORMAL. LOOK FOR
HIGHS AROUND 70...EXCEPT MID 70S ON WEDNESDAY AND LOWS IN THE UPPER
40S TO LOWER 50S THROUGH THE FORECAST PERIOD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 747 PM EDT FRI MAR 23 2012
THERE WILL BE A LULL IN SHOWER AND THUNDERSTORM ACTIVITY FOR MUCH OF
THE EVENING...WITH VFR CONDITIONS PREVAILING. AS LOW PRESSURE MOVES
EAST AN OCCLUDED FRONT CURRENTLY IN CENTRAL KY WILL MOVE EAST INTO
OUR AREA...WITH SHOWERS AND THUNDERSTORMS INCREASING IN COVERAGE
AFTER 04Z. MVFR TO IFR CONDITIONS ARE EXPECTED IN SHOWERS AND
THUNDERSTORMS LATER TONIGHT...WITH VFR CONDITIONS PREVAILING OUTSIDE
OF PRECIPITATION AREAS.
CONVECTION EXPECTED TO THEN DECREASE AGAIN BY DAWN...WITH MORE
SHOWERS AND THUNDERSTORMS DEVELOPING SATURDAY AFTERNOON. EXPECT VFR
CONDITIONS TO PREVAIL ON SATURDAY...WITH MVFR TO IFR CONDITIONS IN
PRECIPITATION.
ONE PART OF THE FORECAST WHERE THERE IS UNCERTAINTY IS FOG FOR
TONIGHT. RAIN HAS FALLEN OVER MUCH OF THE AREA TODAY SO THE STAGE IS
SET. THE EXTENT OF FOG FORMATION WILL BE DEPENDENT ON AMOUNT OF
CLEARING...AND HOW LONG SKIES REMAIN CLEAR. BROKEN TO OVERCAST SKIES
WILL GIVE WAY TO SCATTERED TO BROKEN SKIES THIS EVENING...BUT THEN
CLOUDS WILL BE ON THE INCREASE AGAIN AFTER MIDNIGHT. FOR NOW HAVE
LEFT FOG OUT OF TAFS...BUT THIS WILL NEED TO BE MONITORED.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...MB
LONG TERM....RAY
AVIATION...SBH
AREA FORECAST DISCUSSION
NWS JACKSON KY
748 PM EDT FRI MAR 23 2012
.UPDATE...
ISSUED AT 747 PM EDT FRI MAR 23 2012
SCATTERED SHOWERS CURRENTLY EAST OF A LINE FROM MOREHEAD TO
WHITESBURG CONTINUE TO DIMINISH IN COVERAGE AND INTENSITY AS THEY
MOVE NORTHEAST AT 40 MPH. ALSO AN SHOWER MOVING INTO WAYNE COUNTY AT
THIS TIME. FOR THE MOST PART EXPECT DRY WEATHER TO PREVAIL FOR THE
REST OF THE EVENING WITH ONLY ISOLATED SHOWERS AND THUNDERSTORMS
POSSIBLE. SHOWERS AND THUNDERSTORMS CURRENTLY INCREASING FROM NORTH
OF BOWLING GREEN INTO CENTRAL INDIANA. AS LOW AND SURFACE FRONT MOVE
EAST TONIGHT EXPECT SHOWERS AND THUNDERSTORMS TO ONCE AGAIN BECOME
MORE NUMEROUS IN EASTERN KY...GENERALLY AFTER MIDNIGHT. THIS IS IN
AGREEMENT WITH CURRENT TRENDS AND THE LATEST HRRR AND NAM. FOR NOW
WILL KEEP PRECIPITATION SCATTERED IN NATURE LATER TONIGHT WITH 50
PERCENT PROBABILITIES. HAVE ALSO MADE SOME MINOR UPDATES TO NDFD FOR
LATEST SURFACE OBSERVATIONAL TRENDS.
UPDATE ISSUED AT 441 PM EDT FRI MAR 23 2012
HAVE UPDATED NDFD OUT THROUGH THE NEXT SEVERAL HOURS FOR LATEST
OBSERVATIONAL TRENDS. LATEST SHORT RANGE GUIDANCE STILL POINTS
TOWARDS A DECREASING CHANCE OF SHOWERS AND THUNDERSTORMS AFTER 00Z AS
THE CURRENT ACTIVITY NOW AFFECTING EASTERN KY MOVES NORTHEAST OF THE
AREA. THE CHANCE WILL THEN RAMP UP AGAIN LATER TONIGHT AS THE CLOSED
UPPER LOW MOVES EAST.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 306 PM EDT FRI MAR 23 2012
SAT IMAGERY AND SFC ANALYSIS AS OF 18Z SHOWS THE CENTER OF A BROAD
STACKED LOW NOW MOVING FROM MO INTO IL. CONVECTION OVER ERN KY HAS
BEEN RATHER ANEMIC THUS FAR LARGELY DUE TO THE EXTENSIVE CLOUD COVER
INHIBITING INSTABILITY. HOWEVER...BLENDED PWAT PRODUCT SHOWS THE AXIS
OF AMPLE MOISTURE TRANSPORT FROM THE GOMEX STILL ALIGNED FROM SRN AL
UP THRU MIDDLE TN AND INTO CENTRAL KY....FUELING WIDESPREAD SHOWERS
OVER ERN KY WITH LIGHTNING JUST NOW STARTING TO PICK UP OVER OUR
AREA...ALONG WITH A HINT OF ROTATION IN A CELL MOVING INTO LESLIE
COUNTY SUGGESTING AT LEAST A POTENTIAL FOR HAIL MAY STILL EXIST
THROUGH THE REMAINDER OF THE FIRST PERIOD AS WELL.
CURRENT RADAR TRENDS OVER WRN KY WHERE CONVECTION HAS BEEN NOTABLY
DEEPER SUGGEST 12Z MODELS MAY NOT BE TOO FAR OFF THE MARK WITH THE
IDEA OF A SOLID LULL IN ACTIVITY OVERNIGHT. HOWEVER...STILL WOULD NOT
RULE OUT A STRONG TSTM OR TWO THRU THIS EVENING WITH IR INDICATING
SOME ENHANCEMENT IN THE CONVECTION MOVING UP FROM ERN TN. GUIDANCE
REMAINS IN GOOD AGREEMENT FOR SATURDAY BRINGING LOWERING HEIGHTS
ALOFT AS THE BROAD LOW APPROACHES WITH STEEPENING LAPSE RATES THROUGH
THE AFTERNOON IN RESPONSE...WARRANTING ANOTHER ROUND OF CHANCE TSTMS
THRU THE MORNING AND INTO THE AFTERNOON...THOUGH WITH SIGNIFICANTLY
LESS SEVERE POTENTIAL THAN TODAY.
BY SATURDAY NIGHT...MODELS BEGIN TO DIVERGE WITH THE TRACK OF THE
UPPER LOW AND THIS WILL UNDOUBTEDLY HAVE AN INFLUENCE ON THE SFC
TRACK AND POPS AS WELL. HAVE LEANED MORE TOWARDS THE ECMWF AFTER 00Z
SUNDAY FOR THE SYNOPTIC PICTURE AS IT APPEARS TO HAVE THE MORE
CONSISTENT SOLUTION. THIS WOULD MOVE THE CORE OF THE UPPER LOW INTO
SERN KY BY SUNDAY MORNING BEFORE EXITING THE COMMONWEALTH...LEAVING A
DEEP NW FLOW OVERHEAD WITH A POTENTIAL FOR A GOOD FETCH OF MOISTURE
OFF THE GREAT LAKES AND POSSIBLY JUST ENOUGH RESIDUAL MID LEVEL
ENERGY ON THE BACKSIDE OF THE DEPARTING SYSTEM TO AFFECT A FEW
SHOWERS ACROSS THE CWA ON SUNDAY. BUFR SOUNDINGS ATTM INDICATE
MINIMAL INSTABILITY THROUGH THE DAY AND HAVE KEPT SLIGHT CHANCE
WORDING FOR TSTMS FOR THE MOMENT...THOUGH IF MODEL TRENDS CONTINUE
THEN THE NEXT ISSUANCE COULD PROBABLY PULL THUNDER FROM SUNDAY AND
JUST LEAVE ISOLATED SHOWERS.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 306 PM EDT FRI MAR 23 2012
PATTERN IS QUITE PROGRESSIVE THROUGH THE EXTENDED PERIOD. ALSO...
MODELS ARE IN GOOD AGREEMENT UNTIL DY7 WHEN SOLUTIONS DISPLAY A
SIGNIFICANT DEPARTURE...ESPECIALLY THE GFS. HOWEVER...TREND HAS BEEN
TOWARDS THE ECMWF SOLUTION. A FAST MOVING SHORT WAVE RIDGE TRANSITS
OUR AREA AT THE START OF THE EXTENDED BEHIND EXITING LOW OFF THE
ATLANTIC COAST. BUT SHORT WAVE ENERGY DIGGING SOUTHEASTWARD ACROSS
THE GREAT LAKES LATE MONDAY NIGHT INTO TUESDAY MORNING WILL SEND A
BACK DOOR SFC FRONT INTO THE CWA. BUT THIS FEATURE STALLS OUT ACROSS
OUR AREA TUESDAY BEFORE SHOOTING BACK TO OUR NORTH AS OUR NEXT
WEATHER MAKER ROLLS OUT OF THE NORTHERN PLAINS...PULLING A COLD
FRONT THROUGH EASTERN KENTUCKY MID WEEK...PROBABLY WEDNESDAY. DRY
WEATHER TAKES OVER AS CANADIAN HIGH PRESSURE NOSES ITS WAY INTO THE
OHIO VALLEY REGION TO CLOSE OUT THE WEEK.
IN GENERAL TEMPERATURES WILL COOL THROUGH THE PERIOD AS COMPARED TO
OUR RECENT RECORD HIGHS...BUT STILL REMAIN ABOVE NORMAL. LOOK FOR
HIGHS AROUND 70...EXCEPT MID 70S ON WEDNESDAY AND LOWS IN THE UPPER
40S TO LOWER 50S THROUGH THE FORECAST PERIOD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 747 PM EDT FRI MAR 23 2012
THERE WILL BE A LULL IN SHOWER AND THUNDERSTORM ACTIVITY FOR MUCH OF
THE EVENING...WITH VFR CONDITIONS PREVAILING. AS LOW PRESSURE MOVES
EAST AN OCCLUDED FRONT CURRENTLY IN CENTRAL KY WILL MOVE EAST INTO
OUR AREA...WITH SHOWERS AND THUNDERSTORMS INCREASING IN COVERAGE
AFTER 04Z. MVFR TO IFR CONDITIONS ARE EXPECTED IN SHOWERS AND
THUNDERSTORMS LATER TONIGHT...WITH VFR CONDITIONS PREVAILING OUTSIDE
OF PRECIPITATION AREAS.
CONVECTION EXPECTED TO THEN DECREASE AGAIN BY DAWN...WITH MORE
SHOWERS AND THUNDERSTORMS DEVELOPING SATURDAY AFTERNOON. EXPECT VFR
CONDITIONS TO PREVAIL ON SATURDAY...WITH MVFR TO IFR CONDITIONS IN
PRECIPITATION.
ONE PART OF THE FORECAST WHERE THERE IS UNCERTAINTY IS FOG FOR
TONIGHT. RAIN HAS FALLEN OVER MUCH OF THE AREA TODAY SO THE STAGE IS
SET. THE EXTENT OF FOG FORMATION WILL BE DEPENDENT ON AMOUNT OF
CLEARING...AND HOW LONG SKIES REMAIN CLEAR. BROKEN TO OVERCAST SKIES
WILL GIVE WAY TO SCATTERED TO BROKEN SKIES THIS EVENING...BUT THEN
CLOUDS WILL BE ON THE INCREASE AGAIN AFTER MIDNIGHT. FOR NOW HAVE
LEFT FOG OUT OF TAFS...BUT THIS WILL NEED TO BE MONITORED.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...MB
LONG TERM....RAY
AVIATION...SBH
AREA FORECAST DISCUSSION
NWS GAYLORD MI
155 PM EDT THU MAR 22 2012
.SYNOPSIS...
A WEAK RIDGE OF HIGH PRESSURE THAT STRETCHES FROM OVER THE ATLANTIC
COAST BACK INTO ALBERTA CANADA...WILL CONTINUE TO FORCE WARMER THAN
NORMAL AIR INTO THE GREAT LAKES AGAIN TODAY...RESULTING IN CONTINUED
RECORD BREAKING WARMTH ACROSS NORTHERN MICHIGAN. HOWEVER...THE
TEMPERATURES WILL BE 10 TO 15 DEGREES COOLER THAN YESTERDAY.
THERE WILL ALSO BE CHANCES OF SHOWERS TODAY THROUGH SATURDAY...AS AN
UPPER LEVEL LOW TRACKS FROM THE SOUTHERN PLAINS...INTO THE OHIO
VALLEY. THE LOW WILL CONTINUE THE COOLING TREND ACROSS THE STATE
THROUGH THE WEEKEND. HIGH TEMPERATURES WILL BE RETREATING INTO THE
50S OVER THE WEEKEND.
&&
.UPDATE...
ISSUED AT 137 PM EDT THU MAR 22 2012
GOING FORECAST IN GOOD SHAPE AS OF THIS HOUR WITH ZONE OF SHOWERS
BECOMING INCREASINGLY CONFINED TO EASTERN UPPER MICHIGAN ALONG
NEARLY STATIONARY BAND OF MID LEVEL FRONTOGENESIS FORCING. AS WE
HEAD THROUGH THE AFTERNOON...EXPECT SOME SHOWER ACTIVITY TO LINGER
OVER EASTERN UPPER...WITH BEST CHANCES OF REDEVELOPMENT OVER
NORTHERN LOWER BEING CONFINED TO AREAS WEST OF US 131 WHERE
THE GREATEST AMOUNT OF DESTABILIZATION IS EXPECTED. MUCAPE VALUES
ARE ALREADY REACHING 500 J/KG IN THIS AREA...WITH A RUN TOWARDS
1000 J/KG POSSIBLE NEAR MY SOUTHWEST BOARDER OVER THE NEXT FEW
HOURS. LACKING MUCH FORCING FOR ASCENT IN THIS REGION AS FRONTAL
ZONE NOW HAS PUSHED INTO SOUTHERN LOWER. HOWEVER...IT MAY ATTEMPT
TO MIX BACK NORTH AS SKIES CLEAR OVER MY SOUTHWESTERN
ZONES...WHICH WILL PROVIDE THE BEST CHANCE /ALONG WITH LAKE BREEZE
DEVELOPMENT FROM MANSITEE TO SLEEPING BEAR POINT/ FOR CONVECTIVE
INITIATION. THE HRRR SUGGESTS THAT THIS WILL HAPPEN BUT AM NOT
COMPLETELY SOLD ON THIS...AND WILL GO NO HIGHER THAN CHANCE POPS
THROUGH THE EVENING.
TOOK TEMPS DOWN JUST A TAD BASED ON EARLY AFTERNOON TRENDS...BUT
CLEARLY ANOTHER VERY WARM DAY...PARTICULARLY SOUTH OF M-72.
UPDATE ISSUED AT 938 AM EDT THU MAR 22 2012
SHOWERS AND THUNDERSTORMS CONTINUE TO TRAVERSE MUCH OF NORTHERN
MICHIGAN THIS MORNING AS RIGHT REAR QUADRANT OF 130KT JET STREAK
NEAR THE SOUTHERN EDGE OF JAMES BAY MOVES OVERHEAD PROVIDING
ASSISTANCE FOR LIFT IN THE VICINITY OF SURFACE COLD FRONT /WHICH
BISECTS NORTHERN LOWER/ WITH A BAND OF MID LEVEL FGEN CENTERED
OVER EASTERN UPPER. THIS HAS FORCED THE PRIMARY BAND OF SHOWERS
OVER NORTHERN AREAS...WITH ADDITIONAL THUNDERSTORMS POPPING TO THE
SOUTH AND EAST AS SOUTHERLY FLOW OVER THE COLD DOME RELEASES 3-500
J/KG OF ELEVATED CAPE AS EVIDENCED BY THE 12Z RAOB FROM APX. THESE
STORMS HAVE PRODUCED A LITTLE PEA SIZED HAIL...AND HEAVY
DOWNPOURS...BUT THAT/S ABOUT IT. EXPECT THIS ACTIVITY TO CONTINUE
TO PULL EAST AND NORTH WHILE WANING AS THE AFOREMENTIONED JET
STREAK SHIFTS EAST AND THE JET TO OUR NORTH REORIENTS ITSELF. BAND
OF MID LEVEL FGEN HANGS AROUND THROUGH THE AFTERNOON...HOWEVER
...SO AM LESS CERTAIN ABOUT THE AMOUNT OF IMPROVEMENT OVER EASTERN
UPPER WHERE SHOWERS WILL LIKELY CONTINUE THROUGH THE AFTERNOON.
HAVE LOWERED HIGHS A FEW DEGREES HERE AS A RESULT.
BACK SOUTH OVER NORTHERN LOWER...INSTABILITY WILL GRADUALLY RETURN
THIS AFTERNOON AS SOME PARTIAL CLEARING ALLOWS FOR US TO START TO
TAKE ADVANTAGE OF CONTINUED SUMMER-LIKE WARMTH ALOFT /+14C AT H85
THIS MORNING ON THE APX RAOB/. SO...WILL MAINTAIN WARM
TEMPERATURES HERE AND HIGHLIGHT AFTERNOON TSRA CHANCES IN THE
VICINITY OF SURFACE BOUNDARY. WILL FOCUS MORE ON THIS POTENTIAL IN
THE NEXT FORECAST UPDATE...BUT FOR NOW LATE AFTERNOON CHANCE POPS
LOOK GOOD.
UPDATE ISSUED AT 657 AM EDT THU MAR 22 2012
SHALLOW SFC FRONT NOW ACROSS THE SE CWA...BUT SHORTWAVE IMPULSE
LIFTING THROUGH UPPER MICHIGAN IS ALLOWING FOR AN UPTICK IN
SHOWERS AND EMBEDDED THUNDERSTORMS. THIS IS OCCURRING WELL NORTH
OF THE FRONT...EVEN IN EASTERN UPPER MICHIGAN WHERE THE ACTIVITY
IS SEEMINGLY BEING ASSISTED BY MID LEVEL FGEN. FORECAST IS FAIRLY
ON TRACK. DO BELIEVE THERE WILL BE A DECREASE IN COVERAGE BY
MID/LATE MORNING AS THE SHORTWAVE EXITS EAST.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 445 AM EDT THU MAR 22 2012
UPPER LEVEL RIDGE THAT HAS BEEN OVER US FOR DAYS IS NOW GETTING
FLATTENED WITH NRN STREAM SHORTWAVE RIPPING THROUGH ONTARIO. A
SHORTWAVE IMPULSE LIFTING THROUGH NRN WISCONSIN...OUT OF A CLOSED
LOW OVER OKLAHOMA...IS RESULTING IN SOME MID LEVEL FGEN ACROSS
EASTERN UPPER BEHIND A WEAK COLD FRONT NOW DRAPED OVER NRN LOWER.
COMBINED WITH A CONFLUENT LOW LEVEL WIND FLOW...THE RADAR IS
STARTING TO LIGHT UP A BIT MORE WITH SHOWERS. MORE RETURNS ARE
POPPING UP OVER NRN LK MICHIGAN AS WELL...ALSO AHEAD OF THE
SHORTWAVE. THIS WITHIN AXIS OF 1.2" PWATS...HIGH THETA-E AIR AND
INSTABILITY ACROSS NRN LOWER (MUCAPES ARE ONLY A FEW HUNDRED J/KG
RIGHT NOW...BUT RESPECTABLE 6.5C/KM H7-H5 LAPSE RATES ARE LEADING
TO ISOLATED THUNDERSTORMS).
SHALLOW FRONTAL BOUNDARY DROPS THROUGH NRN LOWER THIS
MORNING...BUT THE DEEP MOISTURE/THETA-E REMAIN OVER NRN LOWER
MICHIGAN...COINCIDENT WITH THE 850MB FRONT. AS THE IMPULSE OVER
NRN WISCONSIN WORKS ITS WAY INTO NRN MICHIGAN THIS MORNING...AM
EXPECTING ADDITIONAL SHOWERS AND STORMS TO FIRE OFF AND TRACK
ACROSS THE STRAITS SOUTHWARD. MOST OF THE THUNDER SHOULD BE IN NRN
LOWER AS THE AIR MASS STABILIZES QUITE WELL ACROSS CHIPPEWA
COUNTY. LOW LEVEL WINDS ARE NOT ALL THAT STRONG...AND EXTENT OF
HEATING WILL GOVERN HOW MUCH OF A LAKE BREEZE WE CAN GENERATE THIS
AFTERNOON. THAT SAID...SOME OF THE HIGHER RES DATA SUGGESTS THAT
IN AND AROUND THE GTV BAY REGION WE COULD SEE DEVELOPING
CONVERGENCE ASSOCIATED WITH LAKE BREEZES. THE CLOSED UPPER LOW
WILL CONTINUE TO SEND WEAK IMPULSES UP THROUGH LAKE MICHIGAN AS IT
LIFTS NORTHWARD...AND BACKING LOW TO MID LEVEL WINDS THROUGH
TONIGHT WILL ALIGN THE WEAKLY UNSTABLE AIR MASS JUST ABOVE THE
SFC...INTO MORE OF A SE TO NW ORIENTATION. THE OVERALL FORCING IS
LESS THAN IMPRESSIVE...BUT CAN SEE PERIODIC SHOWERS (SCATTERED)
WITH EMBEDDED THUNDERSTORMS ACROSS NRN LOWER THROUGH ALL OF
TONIGHT...AND EVEN INTO FRIDAY MORNING. LAPSE RATES WILL BECOME
MORE AND MORE MARGINAL WITH TIME...SO THUNDER WILL GRADUALLY
BECOME LESS COMMON BY FRIDAY AFTERNOON. CHANCES FOR SEEING
RAINFALL HOWEVER WILL BE INCREASING THROUGH FRIDAY...AS DEEPER
MOISTURE ARRIVES AHEAD OF THE SFC/UPPER LOW`S OCCLUDED FRONT.
EXTENT OF CLOUDS BOTH TODAY AND FRIDAY WILL BE A SIGNIFICANT
PLAYER IN HIGH TEMPERATURES. MAX READINGS CAN CERTAINLY APPROACH
80 DEGREES IN AND AROUND GTV/SAG BAYS TODAY...WHILE THE INFLUX OF
COOLER AIR/CLOUDS BEHIND THE FRONTAL ZONE WILL BE FELT ACROSS
EASTERN UPPER WITH HIGHS IN THE MIDDLE 60S. STILL WELL ABOVE
NORMAL. CLOUDIER SKIES EXPECTED ALL AREAS FRIDAY...WITH ALL
LOCALES IN THE 60S. ANY SUNSHINE BOTH DAYS WILL BE ABLE TO RESULT
IN MUCH WARMER READINGS THOUGH (70S/LOW 80S POTENTIAL).
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 445 AM EDT THU MAR 22 2012
FRIDAY NIGHT...THE 500 MB CUT OFF LOW BEGINS TO MOVE INTO C INDIANA
ALLOWING MOISTURE TO PINWHEEL AROUND THE LOW AND BRING RAIN TO THE
REGION. ALTHOUGH E UPPER LOOKS LIKE IT COULD ESCAPE THE BULK OF THE
RAIN AS MOST OF IT FALLS CLOSER TO THE LOW CENTER.
SATURDAY...WILL CONTINUE THE CHANCE POPS AS THE 500 MB CUTOFF LOW
MOVES SOUTH OF THE FORECAST AREA. HOWEVER, AS THE 500 MB LOW MOVES
OVER THE REGION, THE LAPSE RATES FOR THE 700-500 MB LAYER BEGIN TO
STEEPEN TO BETTER THAN 6 C/KM, WHICH IS WHAT I USED AS A ROUGH CUT
OFF FOR THUNDER. SO ADDED A RUMBLE OF THUNDER FOR THE MORNING IN NE
LOWER, THEN AS THE COOLER 500 MB TEMPERATURES ROTATE WEST HAVE
THUNDER POSSIBLE EVERYWHERE SOUTH OF THE STRAITS. OVERNIGHT, IT
LOOKS LIKE THE RAIN MOVES OUT OF THE REGION, GRADUALLY. HOWEVER, THE
ONE CONCERN IS THAT THERE IS A LOT OF MOISTURE TRAPPED UNDER THE
INVERSION, WHICH IS QUITE DEEP THE REST OF THE NIGHT. SO HAVE ADDED
PATCHY DRIZZLE, ALTHOUGH IT MAY BE MORE WIDESPREAD THAN THAT.
EXTENDED (SUNDAY THROUGH WEDNESDAY)...SUNDAY, THE HEIGHTS BUILD
SLIGHTLY. THE ECMWF CLEARS THINGS OUT FOR A TIME, WHILE THE GFS
KEEPS IT CLOUDY. SO WILL KEEP THE TIME DRY. MONDAY, WILL LEAVE THE
DAY DRY AS A WARM FRONT, ASSOCIATED WITH A SFC LOW IN CANADA, MOVES
MOVES INTO W UPPER BY THE AFTERNOON AND THE HUDSON BAY HIGH IS STILL
DRYING THE REGION. TUESDAY, AS THE SYSTEM CONTINUES TO MOVE ACROSS
THE FORECAST AREA, WILL CONTINUE THE CHANCE FOR RAIN SHOWERS. THERE
IS SOME WARMING OVERNIGHT AS THE WARM SECTOR MOVES INTO THE REGION,
HOWEVER, THE GFS IS +12C AND ECMWF IS +6C. LIKE YESTERDAY, WILL
CONTINUE THE COOLER TEMPERATURES. WEDNESDAY, BOTH MODELS WERE
SHOWING A CHANCE FOR RAIN NOW, IT IS ONLY THE GFS, WITH THE 00Z
ECMWF SHOWING DRY WEATHER AS THE HIGH AGGRESSIVELY BUILDS INTO THE
REGION. WILL LEAVE THE LOW CHANCE POPS FOR NOW, BUT THE LATER PART
OF THE FORECAST MAY BE CHANGED LATER TODAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 137 PM EDT THU MAR 22 2012
VFR CONDITIONS DOMINATING THE TERMINALS EARLY THIS AFTERNOON SAVE
SOME PESKY 1KFT STRATUS THAT HAS BEEN FLOATING AROUND PLN...AND
ALSO APN. FEEL THAT RESTRICTIONS DUE TO THIS WILL BE THE EXCEPTION
RATHER THAN THE RULE...SO THROUGH EARLY EVENING EXPECT GENERALLY
VFR CONDITIONS TO PERSIST. COULD SEE SOME SHRA/TSRA DEVELOPMENT
THIS EVENING SOUTH OF TVC /PERHAPS IMPACTING MBL/ AND WILL CARRY A
CB GROUP FOR THIS POSSIBILITY.
TONIGHT...EXPANSIVE AREA OF LOW PRESSURE OVER THE MID MISSISSIPPI
VALLEY WILL GRADUALLY LIFT NORTH AND EAST...WITH SLOWLY
DETERIORATING CONDITIONS EXPECTED. FIRST...EXPECT THAT WE/LL SEE
SOME FOG DEVELOPMENT LATE TONIGTH AT PLN...FOLLOWED AFTER MIDNIGHT
AT EACH OF THE OTHER TERMINALS AS WINDS SLACKEN IN VERY MOIST
AIRMASS. EXPECT FOG TO GENERALLY BE OF THE MVFR VARIETY...AND
GIVEN AFTERNOON OBSERVATIONS...THERE COULD BE SOME STRATUS AS
WELL. EXPECT ANY FOG TO BE THICKEST AT PLN...WHERE A PERIOD OF IFR
VSBYS TOWARDS DAYBREAK IS LIKELY...WITH IFR A POSSIBILITY AT EACH
OF THE OTHER TERMINALS.
BAND OF SHOWERS /MUCH LIKE WHAT IS SEEN OVER ILLINOIS THIS
AFTERNOON/ WILL LIKELY REACH MBL AND PERHAPS TVC DURING MORNING ON
FRIDAY...WITH JUST A CHANCE OF SHOWERS ELSEWHERE. THUS...EXPECT
MVFR CONDITIONS TO PERSIST AT MBL...WITH GRADUAL IMPROVEMENT BACK
TO VFR /WITH LIGHT FOG-HAZE BURNING OFF/ AT THE OTHER TERMINALS.
EAST-NORTHEAST WINDS AROUND 10KTS THIS AFTERNOON WILL DIMINISH TO
5KTS OR LESS TONIGHT BEFORE SHIFTING MORE EASTERLY AND REACHING
BACK TOWARDS 10KTS BY LATE MORNING FRIDAY.
&&
.MARINE...
ISSUED AT 445 AM EDT THU MAR 22 2012
SCATTERED SHOWERS AND THUNDERSTORMS WILL ROAM THROUGH LAKES
MICHIGAN AND HURON...MAINLY THIS MORNING AS A WEAK COLD FRONT
PASSES. WINDS WILL BE BE LIGHT AND VARIABLE AROUND THIS FRONT
UNTIL WINDS SHIFT OUT OF THE NE BEHIND THE FRONT. WINDS CONTINUE
TO VEER TO OUT OF THE EAST LATER TODAY. THE EAST WINDS WILL
INCREASE FRIDAY...AND MAY RESULT IN SMALL CRAFT ADVISORY GUSTS
ENHANCED BY FUNNELING THROUGH THE STRAITS...AND BY COASTAL
CONVERGENCE ON THE NRN SHORE OF LAKES MICHIGAN AND HURON.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JA
SYNOPSIS...JL
SHORT TERM...SD
LONG TERM....JL
AVIATION...JA
MARINE...SD
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1201 AM CDT THU MAR 22 2012
.UPDATE...
ISSUED AT 844 PM CDT WED MAR 21 2012
CONTINUING TO UPDATE POPS AS SHOWERS JUST REFUSE TO FORM OVER OUR
AREA. HAVE CUT BACK ACROSS THE AREA THROUGH MIDNIGHT...BUT ALLOWED
POPS TO RAMP UP OVER THE NEXT 3-4 HOURS IN CENTRAL AND SOUTHERN
SECTIONS OF THE CWFA AS THE RAIN BAND OVER SOUTH CENTRAL MO
ROTATES NORTHEAST. SHORT RANGE GUIDANCE CONTINUES TO SHOW A
GENERAL INCREASE IN SHOWER ACTIVITY AFTER 06Z...SO HAVE KEPT
LIKELY/CATEGORICAL POPS GOING FOR LATE TONIGHT.
ISSUED AT 650 PM CDT WED MAR 21 2012
HAVE DECREASED POPS FOR MUCH OF THE AREA FOR AT LEAST THE EARLY
PART OF THE EVENING. CURRENT RADAR TRENDS SHOW THAT THE NEXT BAND
OF PRECIP TO AFFECT THE AREA IS STILL SEVERAL HOURS AWAY DOWN IN
SOUTH CENTRAL MISSOURI. SHORT RANGE MODELS GUIDANCE INCLUDING THE
RUC AND THE HRRR CONTINUE TO SHOW INCREASING AREAL COVERAGE AND
INTENSITY AFTER 06Z SO HAVE BASICALLY LEFT THE PRECIP TRENDS AFTER
MIDNIGHT UNTOUCHED.
CARNEY
&&
.SHORT TERM...
ISSUED AT 355 PM CDT WED MAR 21 2012
(TONIGHT)
THE DEEP UPPER LOW HAS BEEN MEANDERING NNEWD TODAY AND PROFILER AND
WATER VAPOR IMAGERY INDICATE IT IS OVER EXTREME SW OK AT MID
AFTERNOON. BROKEN BANDS OF SHOWERS HAVE BEEN ROTATING CYCLONICALLY
THROUGH MID MO TODAY PRODUCING LIGHT RAINFALL AMOUNTS OF GENERALLY
LESS THAN A QUARTER INCH. THE PRECIPITATION HASNT MADE ANY IN-ROADS
FURTHER EAST. THE MODELS ARE IN RELATIVELY GOOD AGREEMENT SHOWING
THE UPPER LOW WILL CONTINUE TO CHUG NNEWD TONIGHT MOVING TO NEAR THE
CENTRAL OK/KS BORDER BY 12Z. IN THE PROCESS...A VORT LOBE WILL
ROTATE NNEWD INTO THE AREA...AND A MUCH LARGER AND MORE SOLID BAND
OF SHOWERS/RAIN THAT HAS BEEN LOCATED FROM SRN KS THROUGH SW MO INTO
AR MUCH OF THE DAY WILL PROGRESS EASTWARD ACROSS THE AREA TONIGHT.
AT THIS TIME WE ARE NOT EXPECTING HEAVY RAINFALL AMOUNTS WITH THIS
BAND. HOWEVER THERE ARE SOME MINOR FLOOD CONCERNS IN A SMALL PORTION
OF CENTRAL MO. THE PERSIST SHOWERS/RAIN LAST NIGHT THROUGH DAYBREAK
THIS MORNING GENERATED RAINFALL AMOUNTS OF 1-3 INCHES...WITH THE
GREATEST AMOUNTS ACROSS MONITEAU COUNTY WHERE SOME MINOR FLOODING
HAS BEEN REPORTED. GIVEN THIS ONGOING FLOODING AND THE ADDITIONAL
RAINFALL TONIGHT...I HAVE ISSUED A FLOOD WATCH...THINKING THE
ADDITIONAL RAINFALL WILL POTENTIALLY AGGRAVATE ANY ONGOING PROBLEMS.
GLASS
&&
.LONG TERM...
ISSUED AT 355 PM CDT WED MAR 21 2012
(THURSDAY THROUGH WEDNESDAY)
THE UPPER LOW WILL CONTINUE TO SLOWLY LIFT OUT TO THE EAST
NORTHEAST THROUGH THE END OF THE WORK WEEK. THE WIDESPREAD RAIN
THAT DEVELOPED TONIGHT...WILL EXIT THE FORECAST AREA BY THURSDAY
AFTERNOON. HOWEVER...EXPECT ANOTHER ROUND OF SHOWERS WITH MAIN
UPPER LOW TO DEVELOP AND INCREASE IN COVERAGE THURSDAY NIGHT AND
FRIDAY...WITH AN ADDITIONAL QUARTER INCH OR SO OF PCPN WITH THIS
ROUND. MODELS CONTINUE TO BE A BIT SLOWER WITH SYSTEM EXITING...SO
KEPT CHANCE POPS IN FOR PORTIONS OF THE AREA THROUGH SATURDAY.
AS FOR TEMPS THROUGH THE PERIOD...COLDER AIR TO FILTER IN ON
THURSDAY AS THE RAIN INCREASES IN COVERAGE. HIGHS ON THURSDAY WILL
ONLY BE IN THE MID TO UPPER 60S...BUT STILL ABOVE AVERAGE FOR THIS
TIME OF YEAR. LOWS THURSDAY NIGHT WILL BE IN THE UPPER 40S TO LOW
50S...THEN HIGHS ON FRIDAY AND SATURDAY WILL REMAIN IN THE MID TO
UPPER 60S.
DRY AND MILDER WEATHER TO RETURN TO THE AREA FOR THE LAST HALF OF
THE WEEKEND AND INTO EARLY NEXT WEEK. HIGHS ON SUNDAY WILL BE IN
THE LOW TO MID 70S...WARMING UP INTO THE MID TO UPPER 70S FOR
MONDAY AND TUESDAY.
THE NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS WILL MOVE INTO THE AREA
TUESDAY NIGHT AND WEDNESDAY AS A STRONG COLD FRONT APPROACHES THE
REGION.
BYRD
&&
.AVIATION...
ISSUED AT 1154 PM CDT WED MAR 21 2012
SHOWERS HAVE BEEN SLOWER TO DEVELOP AND SPREAD NWD THAN PREVIOUSLY
EXPECTED HOWEVER LATEST RADAR TRENDS STILL SUPPORT THE IDEA OF A
PROLONGED PERIOD OF RAIN SHOWERS AT THE TAF SITES OVERNIGHT AND
THROUGH PART OF TOMORROW AS A LOW PRESSURE SYSTEM OVER OKLAHOMA
SLOWLY MOVES NEWD. INITIALLY VFR CONDITIONS WILL PROBABLY LOWER TO
MVFR HOWEVER THERE IS LOW CONFIDENCE IN THE TIMING OF MVFR ONSET.
SPECIFICS FOR KSTL...SHOWERS HAVE BEEN SLOWER TO DEVELOP AND
SPREAD NWD THAN PREVIOUSLY EXPECTED HOWEVER LATEST RADAR TRENDS
STILL SUPPORT THE IDEA OF A PROLONGED PERIOD OF RAIN SHOWERS AT
KSTL OVERNIGHT AND THROUGH PART OF TOMORROW AS A LOW PRESSURE
SYSTEM OVER OKLAHOMA SLOWLY MOVES NEWD. INITIALLY VFR CONDITIONS
WILL PROBABLY LOWER TO MVFR HOWEVER THERE IS LOW CONFIDENCE IN THE
TIMING OF MVFR ONSET.
KANOFSKY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...FLOOD WATCH UNTIL 4 AM CDT THURSDAY FOR BOONE MO-COLE MO-
MONITEAU MO.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
802 PM MDT FRI MAR 23 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
UPDATED THE FORECAST TO REFLECT CURRENT CONDITIONS THIS EVENING.
SNOW SHOWERS ACROSS CENTRAL MONTANA HAVE MOVED INTO OUR CWA THIS
EVENING ACROSS THE NORTHWEST AND WESTERN ZONES. SO RAISED POPS AND
CHANGED THE PRECIPITATION OVER FROM RAIN SHOWERS WITH SPOTS OF
SNOW MIXED IN TO ALL SNOW. WESTERN PHILLIPS AND NORTHERN PHILLIPS
MOSTLY ALONG WITH NORTHERN VALLEY WILL SEE MOSTLY SNOW THIS
EVENING AND OVERNIGHT AND ACCUMULATIONS WILL BE LESS THEN ONE INCH.
PLACES JUST TO THE EAST OF THE ALL SNOW ZONE WILL SEE A WINTERY
MIX AND THEN AS YOU HEAD EASTWARD IT WILL TRANSITION INTO
ISOLATED RAIN SHOWERS. WE STILL HAVE A FRONTAL BOUNDARY SET UP
ACROSS OUR EASTERN ZONES AND THE WARM SECTOR BETWEEN THIS FRONT
AND THE NORTH DAKOTA BORDER COULD SEE ISOLATED THUNDER ALONG WITH
THE ISOLATED RAIN SHOWERS. ALL OF THIS UPDATE WAS BASED MOSTLY OFF
THE HRRR AND SOME OF THE 18Z GFS MODELS. REST OF THE SHORT TERM
LOOKS GOOD. RSMITH
PREVIOUS DISCUSSION...SYNOPTIC SET UP... A CUT OFF LOW RESIDES
OVER THE CENTRAL MISSISSIPPI VALLEY WHILE A RIDGE RUNS UP THE HIGH
PLAINS FROM NEW MEXICO THROUGH COLORADO AND INTO SOUTHEASTERN
MONTANA. TO THE WEST A TROUGH SPANS THROUGH YUKON OVER THE BRITISH
COLUMBIAN COAST AND OFF THE COAST OF THE PACIFIC NORTHWEST.
FURTHER WEST... A SMALL RIDGE IS PRESENT FROM THE NORTH PACIFIC
INTO THE GULF OF ALASKA WITH ANOTHER TROUGH OVER THE BEARING SEA.
TONIGHT... NORTHEASTERN MONTANA WILL BE CAUGHT IN SOUTHWEST FLOW
BETWEEN THE TROUGH TO THE WEST AND THE HIGH PLAINS RIDGE JUST TO
THE SOUTHEAST. A SHORTWAVE HAS EJECTED OFF THE FRONT RANGE THIS
AFTERNOON AND IS GENERATING RAIN AND ISOLATED SNOW SHOWERS ACROSS
NORTHERN CENTRAL MONTANA AS EVIDENT ON RADAR. THESE SHOWERS WILL
CONTINUE TO MOVE TO THE NORTH AND EAST BUT MIGHT BE ABLE TO SPILL
OVER INTO PHILLIPS AND NORTHERN VALLEY COUNTY THIS EVENING BRIEFLY
BEFORE EXITING DURING THE MORNING HOURS. NAM APPEARS TO BE HAVING
A TOUGHER TIME WITH THESE SHOWERS DUE TO JET IN THE MID LEVELS NOT
BEING PICKED UP PROPERLY. PREFER THE GFS SOLUTIONS FOR MOST ITEMS
DURING THIS TIME. GFS ALSO IS POINTING TOWARD GUSTY WINDS
OVERNIGHT FROM CAA BEHIND A PASSING COLD FRONT.
SATURDAY THROUGH SUNDAY... FLOW WILL BECOME MORE ZONAL SATURDAY
FROM THE ENTERING COLD AIRMASS OVERNIGHT AND THEN SLOWLY BEGIN TO
RIDGE BY SUNDAY. THIS WILL MAKE FOR A SLIGHTLY COOLER START
SATURDAY MORNING HOWEVER RIDGING SHOULD SHOULD MODIFY THE AIRMASS
AND RAISE TEMPERATURES INTO THE 60S BY SUNDAY. CONDITIONS SHOULD
REMAIN DRY... A WEAK DISTURBANCE IS PRESENT IN THE EC ON SUNDAY
MORNING BUT NOT DISPLAYED IN ANY OTHER MODELS. THEREFORE... HAVE
DISREGARDED EC OVER THIS LIMITED POP FOR NOW.
PREFERRED MODEL FOR HIGHS WERE THE MOSBC WITH MET BC IN THE
SHORT RUN AND MEXBC ON SUNDAY WHILE OVERNIGHT LOWS WAS DOMINATE LY
THE SREFBC DATA. GAH
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
UPPER TROF REMAINS ENTRENCHED OVER THE EASTERN PACIFIC RESULTING
IN CONTINUED ACTIVE SOUTHWEST FLOW INTO MONTANA. MAIN SHORTWAVE OF
INTEREST LIFTS THROUGH THE GREAT BASIN AND INTO THE NORTHERN
PLAINS AT THE BEGINNING OF NEXT WEEK. MODELS HAVE SHIFTED THIS
SYSTEM TO THE SOUTHEAST...TRACKING IT THROUGH WYOMING INTO SOUTH
DAKOTA. EVEN THOUGH THIS TRACK PUSHES MOST OF THE PRECIPITATION
OUT OF EASTERN MONTANA FOR MONDAY THROUGH TUESDAY...MADE SOMEWHAT
SMALL CHANGES TO GOING FORECAST...GIVEN THE MODEL CHANGES. THIS
CHANGE ALSO BRINGS A LITTLE RIDGING INTO EASTERN MONTANA...FOR
WARMING FROM TUESDAY INTO WEDNESDAY. ANOTHER WEAK WAVE SLIDES
THROUGH ON THURSDAY TO KNOCK DOWN THIS RIDGE. EBERT
PREVIOUS LONG TERM DISCUSSION...LONG TERM FORECAST PERIOD WILL
FOCUS MAINLY ON THE STORM SYSTEM SET TO BEGIN TO IMPACT NORTHEAST
MONTANA SOMETIME MONDAY AFTERNOON THROUGH TUESDAY NIGHT. A SHORT
WAVE WILL TRANSVERSE THE SIERRA NEVADA MOUNTAIN RANGE AND MOVE
INTO THE GREAT BASIN ON IT`S WAY TO THE NORTHERN PLAINS. A PERIOD
OF SHOWERS AND COOLER TEMPERATURES ARE EXPECTED TO ACCOMPANY THIS
SYSTEM MONDAY AFTERNOON THROUGH TUESDAY AFTERNOON.
THE GFS...DGEX AND ECMWF MODELS ARE IN BETTER AGREEMENT WITH THIS
MORNINGS 00Z MODEL RUNS. THESE THREE MODELS HAVE THIS SYSTEM
CROSSING NORTHERN WYOMING AND INTO CENTRAL NORTH DAKOTA BECOMING
VERTICALLY STACKED. THE GEM ON THE OTHER HAND IS SLOWER AND IT HAS
THE SYSTEM PASSING FARTHER TO THE SOUTH OVER SOUTH DAKOTA...AND
IS MORE OF AN OPEN WAVE. SO WENT WITH THE FIRST THREE MODELS AND
DECIDED TO RAISE POPS INTO THE UPPER CHANCE RANGE. KEPT EVERYTHING
IN THE FORM OF RAIN SHOWERS AS 850 MB TEMPERATURES COMBINED
THICKNESS VALUES SUGGEST TO DO. WOULD NOT RULE OUT AS SNOW FLAKE OR
TWO ON THE BACK SIDE OF THIS SYSTEM AS IT EXITS MONTANA TUESDAY
MORNING BUT STILL LOOKS LIKE MOSTLY RAIN. EXPECT SOME WIND MONDAY
NIGHT AND TUESDAY MORNING ALONG WITH THE RAIN FROM THIS SYSTEM AS
WELL. THE MODELS SHOW THE STRONGEST WINDS WILL BE SOUTH OF THE
MISSOURI RIVER AND ACROSS SOUTHEAST MONTANA.
TUESDAY AND WEDNESDAY WILL BE THE COOL DAYS OF THE FORECAST.
GIVEN THAT SPRING HAS ARRIVED...AT LEAST BY THE CALENDAR...THE
COLD AIR INTRUSION WITH THIS EARLY NEXT WEEK SYSTEM WILL BE SHORT
LIVED AS TEMPERATURES ARE EXPECTED TO QUICKLY REBOUND BACK ABOVE
NORMAL. THE UPPER TROUGH OVER THE GULF OF ALASKA WILL SEND ANOTHER
SHORTWAVE ACROSS THE NORTHERN ROCKIES ON THURSDAY SO INTRODUCED A
SLIGHT CHANCE OF RAIN SHOWERS TO THE ZONES FOR THURSDAY. THE
ECMWF IS WETTER THEN THE OTHER TWO MODELS BUT THOUGHT A SLIGHT
CHANCE OF RAIN SHOWERS WAS JUSTIFIED. RSMITH
&&
.AVIATION...
MAINLY VFR THROUGH THE TAF CYCLE. A FRONTAL SYSTEM WILL MOVE
THROUGH THE REGION THIS EVENING...TURNING WINDS TO THE NORTHWEST
AND CAUSING THEM TO INCREASE TO 15 TO 25 KTS. THERE MAY BE A
SHOWER OR TWO BEHIND THE FRONT...MAINLY IMPACTING KGGW OR KOLF
LATE TONIGHT. RAE
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
648 PM MDT FRI MAR 23 2012
.SHORT TERM...VALID FOR SAT AND SUN...
ISSUED A QUICK EARLY UPDATE TO ADD A SLIGHT CHANCE OF SHOWERS IN
THE EAST. RADAR STARTING TO PICK UP SOME ECHOES AND SATELLITE
IMAGERY SHOWING A BIT OF COOLING CLOUD TOPS. WILL PROBABLY TURN
OUT TO BE JUST VIRGA OR SPRINKLES FOR THE MOST PART...BUT HRRR IS
INDICATING SOME ENHANCEMENT POSSIBLE THIS EVENING AND THERE IS
SOME WEAK 850MB FRONTOGENESIS AND DIVERGENCE ALOFT OCCURRING. BT
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
MODELS HAVE BEEN TRENDING INTO BETTER AGREEMENT FOR THE PACIFIC
SYSTEM THAT WILL AFFECT THE REGION MON INTO TUE AND HAVE AGREED ON A
QUICKER SYSTEM MOVEMENT...SO CONFIDENCE WAS GROWING FOR THE FORECAST FOR
THESE PERIODS.
A PACIFIC TROUGH WILL ROTATE INTO THE WESTERN U.S. BY 12Z MON.
MODELS BROUGHT THE SOUTHERN WAVE OF THE SYSTEM INTO WY BY 00Z
TUE...THEN ROTATED THIS FEATURE INTO THE DAKOTAS BY 12Z TUE. THE
SYSTEM QUICKLY EXITED THE AREA TUE MORNING. THERE WAS A STRONG AREA
OF Q-VECTOR CONVERGENCE ACCOMPANYING THE WAVE MON AFTERNOON AND
EVENING. THIS LIFT AFFECTED MAINLY THE SE HALF OF THE AREA. THE
DEEPEST MOISTURE WAS FORECAST TO BE OVER THE WESTERN MOUNTAINS AND
KLVM AREA ON MON. ADDITIONAL MOISTURE INCREASED OVER FAR SE MT DUE
TO A LOW-LEVEL JET. A COLD FRONT WILL CROSS THE AREA LATE MON
THROUGH MON NIGHT. ON MON...THE HIGH POPS OVER THE FAR W WERE IN
GOOD SHAPE BASED ON THE ABOVE...WITH POPS TAPERING DOWN TOWARD KBIL.
HAVE ADDED A SLIGHT CHANCE OF SHOWERS AND AFTERNOON THUNDERSTORMS TO
AREAS E AND S OF KBIL FOR MON. THE LOW-LEVEL JET...APPROACHING COLD
FRONT AND Q-VECTOR CONVERGENCE WILL PROVIDE LIFT OVER THIS AREA. E
FLOW AHEAD OF THE SYSTEM SHOULD HELP MOISTEN UP THE LOW-LEVELS AS
WELL. MODELS WERE INDICATING NEGATIVE LIFTED INDICES MON AFTERNOON
AND MODEL SOUNDINGS SHOWED ELEVATED INSTABILITY OVER A LARGE PART OF
THE AREA WHICH SUPPORTED THUNDER. ADDED A SLIGHT CHANCE OF AFTERNOON
THUNDER TO THE REMAINDER OF THE REGION AS WELL.
ADJUSTED MON HIGH TEMPERATURES TO WARM UP PORTIONS OF THE E IN THE
WARM SECTOR AND TO COOL DOWN FAR SE MT DUE TO THE LOW-LEVEL JET
CREATING A LOW-LEVEL INVERSION. ALSO LOWERED TEMPERATURES A LITTLE
IN THE FAR WESTERN ZONES DUE TO AN EARLY FRONTAL PASSAGE. POPS MON
NIGHT LOOKED GOOD WITH A CHANCE ACROSS THE ENTIRE AREA. A STRONG
SURFACE PRESSURE GRADIENT BEHIND THE SYSTEM WILL SUPPORT WINDY
CONDITIONS MON NIGHT INTO TUE. DRIED OUT TUE QUITE A BIT AS THE
FASTER MODEL TRENDS HAD UPPER RIDGING MOVING IN QUICKLY OVER THE
AREA. TEMPERATURES WERE IN GOOD SHAPE. THE REMAINDER OF THE
EXTENDED PERIOD WILL FEATURE W TO SW FLOW ALOFT WITH WEAK WAVES
MOVING THROUGH THE FLOW. THE INHERITED POPS WERE IN GOOD SHAPE.
RAISED TEMPERATURES ON WED BASED ON 700 MB TEMPERATURES FROM ZERO TO
+2 DEGREES C FROM KBIL E AND S. ALSO RAISED FRI TEMPERATURES. ARTHUR
&&
.AVIATION...
A STRONG...MAINLY DRY...COLD FRONT WILL SWEEP SE THROUGH THE AREA
LATE THIS AFTERNOON THROUGH THIS EVENING. THE FRONT WILL USHER IN
A PERIOD OF STRONG GUSTY N TO NW SURFACE WINDS FROM 20 TO 30 KT
THAT WILL MOVE E ACROSS THE AREA TONIGHT. THESE STRONG WINDS WILL
AFFECT AREAS TO THE N AND NW OF KBIL...AS WELL AS E OF KBIL
INCLUDING KMLS. SURFACE WINDS WILL TURN E DURING SAT AND INCREASE
TO 10 TO 20 KT OVER KLVM. VFR WILL PREVAIL OVER THE AREA THROUGH
SAT. HOWEVER...A FEW AREAS OF STRATUS AND FOG WILL BE POSSIBLE IN
THE YELLOWSTONE RIVER VALLEY FROM KBIL W LATE TONIGHT INTO EARLY
SAT WITH LOCALIZED LIFR CONDITIONS. EXPECT LOCALIZED MOUNTAIN
OBSCURATION THROUGH SAT OVER THE CRAZYS...BEARTOOTHS AND
ABSAROKAS. ARTHUR
&&
.PRELIMINARY POINT TEMP/POPS...
SAT SUN MON TUE WED THU FRI
-----------------------------------------------------------
BIL 033/057 038/071 044/078 040/061 039/067 040/064 039/067
00/B 10/B 02/T 40/B 11/B 22/W 21/B
LVM 031/058 036/066 042/070 039/055 039/062 038/060 036/061
20/B 10/B 05/T 50/B 11/B 22/W 21/B
HDN 036/061 036/075 040/080 037/062 038/071 036/069 035/072
00/B 10/B 02/T 40/B 11/B 12/W 21/B
MLS 036/061 037/074 041/078 038/059 035/070 038/067 038/072
20/B 10/B 02/T 44/W 11/B 12/W 21/B
4BQ 038/063 038/074 042/082 037/059 036/071 037/068 037/073
20/B 10/B 02/T 42/W 11/B 12/W 21/B
BHK 037/059 035/068 039/072 038/059 038/067 036/066 036/072
20/B 11/B 02/T 44/W 11/B 12/W 21/B
SHR 036/062 037/073 041/077 035/059 036/068 036/066 036/069
10/B 00/B 02/T 40/B 11/B 12/W 21/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
315 PM MDT THU MAR 22 2012
.SHORT TERM...VALID FOR FRI AND SAT...
SOUTHWEST FLOW ALOFT IS IN PLACE OVER MT TODAY...AND WILL CONTINUE
INTO THE WEEKEND. HOWEVER...SOME SHORT WAVE ENERGY PEELING OFF THE
MEAN TROUGH LOCATED NEAR THE WEST COAST IS EXPECTED TO SEND A COLD
FRONT THROUGH THE AREA BY FRI NIGHT. THE 12 UTC NAM REMAINS A FAST
OUTLIER WITH THE TIMING OF THAT SURFACE FRONT...SO ITS SOLUTION IS
NOT BEING USED IN THE FORECAST...WHICH INSTEAD LEANS ON THE 12 UTC
GFS AND ECMWF RUNS. CONFIDENCE IN THIS DECISION WAS INCREASED BY A
TREND BY THE 18 UTC NAM TOWARD THE SLOWER SET OF SOLUTIONS.
AT 21 UTC...A WEAK SURFACE LOW IS NORTH OF LEWISTOWN...WITH A WEAK
COLD FRONT EXTENDING TO ITS SOUTHWEST TOWARD BOZEMAN. THE RUC FROM
18 UTC REMAINS ON TRACK IN PUSHING THIS FRONT SOUTHEAST TO ABOUT A
MILES CITY AND HARDIN LINE BY 06 UTC. THE ONLY SENSIBLE WEATHER IS
GOING TO BE A WEAK WIND SHIFT THOUGH...ESPECIALLY SINCE WE BELIEVE
THE FRONT WILL IN EFFECT WASH OUT BY FRI MORNING AS PRESSURE FALLS
BECOME MORE ESTABLISHED EAST OF THE FRONT RANGE. THAT PROCESS WILL
KEEP SOUTHEAST LOW-LEVEL FLOW IN THE BAKER AREA...WHICH COULD HELP
PULL SOME MORE SUBSTANTIAL BOUNDARY LAYER MOISTURE INTO THAT AREA.
SURFACE DEWPOINTS IN THE 40S F HAVE ACTUALLY MADE IT UP INTO RAPID
CITY AS OF MID AFTERNOON...SO IT IS CERTAINLY POSSIBLE THESE MOIST
READINGS COULD APPROACH BAKER BY 12 UTC. SOME FOG...OR AT THE VERY
LEAST A BIT OF STRATUS...COULD ACCOMPANY THIS MOISTURE...JUST LIKE
THE 12 UTC MET GUIDANCE INDICATES. HOWEVER...GIVEN DRY TOP SOIL...
AND INDICATIONS OF MODEST LOW-LEVEL WINDS...WE HAVE REFRAINED FROM
INCLUDING FOG IN THE FORECAST FOR NOW.
ON FRI...850-HPA TEMPERATURES OF +16 TO +20 C WILL EXIST OUT AHEAD
OF THE NEXT /AND STRONGER/ COLD FRONT. FORECAST SOUNDINGS ACTUALLY
ONLY MIX TO AROUND 750-HPA GIVEN THE WARM AIR ADVECTION ALOFT...SO
WE WERE HESITANT TO DEVIATE MUCH FROM THE MULTI-MODEL CONSENSUS AT
THIS POINT...WHICH STILL HAS HIGHS WELL INTO THE 70S F. WE NEED TO
NOTE THAT A PRE-FRONTAL ENVIRONMENT LIKE THIS ONE COULD EASILY END
UP WARMER...AND WITH THAT IN MIND WE CANNOT ENTIRELY DISCOUNT WHAT
THE 12 UTC BIAS-CORRECTED ECMWF SHOWS WITH ITS 80+ F HIGHS ACROSS
SOME PARTS OF SOUTHEASTERN MT. EITHER WAY...DAILY RECORDS COULD BE
IN EASY REACH AT BOTH SHERIDAN /76 F...SET IN 1993/ AND MILES CITY
/78 F...ALSO SET IN 1993/. HUMIDITY WILL DROP TO AROUND 20 PERCENT
OR SO ON THE PLAINS...SO THERE WILL ONCE AGAIN BE AN ELEVATED RISK
OF GRASSLAND FIRES...WHICH IS CURRENTLY EXPECTED TO BE TEMPERED BY
A LACK OF STRONG PRE-FRONTAL WINDS.
BY FRI EVENING...LOW- AND MID-LEVEL COLD AIR ADVECTION DEVELOPS IN
THE WAKE OF THE FRONT...WITH A PRETTY SUBSTANTIAL SURFACE PRESSURE
RISE TO GO WITH IT. SIMILAR FRONTS LAST WEEK WERE ABLE TO GENERATE
A PERIOD OF VERY GUSTY WINDS...ESPECIALLY SINCE LIKE THIS UPCOMING
ONE THEY PASSED WHEN THE BOUNDARY LAYER WAS STILL WELL-MIXED AFTER
A VERY WARM AFTERNOON. THE 500 M AGL WINDS FROM THE 12 UTC GFS ARE
ON THE ORDER OF 20 TO 25 KT FROM 00 TO 06 UTC AS WELL...WHICH ALSO
SUPPORTS A PERIOD OF AT LEAST 20 TO 30 MPH SURFACE WINDS. IT LOOKS
LIKE HUMIDITY INCREASES QUICKLY BEHIND THE FRONT...SO WE WILL HOLD
OFF ANY KIND OF FIRE HEADLINES...BUT THE FRONTAL PASSAGE SHOULD BE
EMPHASIZED FOR FIRE WEATHER CONCERNS. A DRY FORECAST IS IN PLAY AS
THE FRONT PASSES...BUT STEEP MID-LEVEL LAPSE RATES MAY YIELD A BIT
OF CONVECTION LIKE THE 15 UTC SREF SHOWS. WE DO NOT HAVE ENOUGH IN
THE WAY OF CONFIDENCE TO ADVERTISE POPS AT THIS POINT THOUGH SINCE
THE AMBIENT AIR MASS WILL BE RELATIVELY DRY.
BY SAT...LOW-LEVEL EAST-NORTHEAST FLOW WILL BE IN PLACE...WHICH IS
A SCENARIO THAT CAN HAVE LIMITED MIXING. FORECAST SOUNDINGS MIX TO
ONLY ABOUT 850-HPA. THUS...ADVERTISED HIGHS ARE CLOSER TO 60 F. WE
ARE ACTUALLY PROBABLY OPTIMISTIC WITH THESE HIGHS IN SOME AREAS AS
2 M TEMPERATURE GUIDANCE IS MAINLY FROM 50 TO 55 F. SCHULTZ
.LONG TERM...VALID FOR SUN...MON...TUE...WED...THU...
MON THROUGH TUE WILL BE THE MOST CHALLENGING PORTION OF THE EXTENDED
FORECAST WHICH BEGINS ON SUN. SUN THROUGH SUN NIGHT WILL BE DRY AND
WARM AS RIDGING ALOFT TRANSITIONS INTO SW FLOW AHEAD OF A POTENT
SHORTWAVE. ON MON...THE WAVE WILL ROTATE NE TOWARD THE FORECAST AREA
WITH THE ECMWF MOVING THE WAVE FASTER THAN THE GFS. THIS DIFFERENCE
IN THE SPEED OF THE WAVE CONTINUED THROUGH TUE. THE GFS HAS BEEN
MORE CONSISTENT FROM RUN-TO-RUN WITH THE WAVE SO HAVE LEANED TOWARD
IT FOR PARTS OF THE FORECAST. BOTH MODELS BROUGHT A GOOD SHOT OF
MOISTURE THROUGH THE AREA MON NIGHT THROUGH TUE WITH VARYING SPEEDS.
HAVE ADJUSTED THE POPS TO SHOW AT LEAST A CHANCE OF PRECIPITATION
ACROSS THE REGION FOR BOTH THESE PERIODS. THE TIMING AND CHANCES OF
PRECIPITATION WILL BECOME BETTER REFINED IN LATER SHIFTS AS THE
MODELS CLOSE IN ON THE TIMING OF THE SYSTEM. MON LOOKED VERY WARM
AHEAD OF THE SYSTEM WITH 700 MB TEMPERATURES OF +2 TO +4 DEGREES C
OVER THE AREA AND DRY ADIABATIC MIXING TO NEAR 500 MB. HAVE RAISED
TEMPERATURES E OF KBIL. LOW RELATIVE HUMIDITIES AND GUSTY SOUTHERLY
WINDS WILL COMBINE WITH THE UNSEASONABLE WARMTH TO CREATE HAZARDOUS
FIRE WEATHER CONDITIONS. OLDER MODEL RUNS HAD SHOWN THE POSSIBILITY
OF HIGH TEMPERATURES NOT MAKING IT OUT OF THE 40S ON TUE. GIVEN THAT
THE LAST FEW RUNS OF BOTH THE GFS AND ECMWF HAVE TRENDED
WARMER...HAVE RAISED TEMPERATURES TO THE CONSALL GUIDANCE. THE
SYSTEM WILL MOVE OUT OF THE AREA TUE NIGHT LEAVING LINGERING LOW
PRECIPITATION CHANCES OVER FAR SE MT. WEAK SHORTWAVES WILL MOVE
THROUGH A WSW FLOW WITH LIMITED MOISTURE THROUGH THE REMAINDER OF
THE PERIOD SO EXPECT WED THROUGH THU TO BE MOSTLY DRY WITH ABOVE
NORMAL TEMPERATURES. ARTHUR
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL OVER THE AREA THROUGH FRI. A FEW
SHOWERS WILL BE POSSIBLE FRI AFTERNOON FROM KLVM NE TO HARLOWTON.
ALSO EXPECT LOCALIZED OBSCURATION OVER THE CRAZYS...BEARTOOTH AND
ABSAROKAS DUE TO THE SHOWERS. GUSTY SW SURFACE WINDS FROM ROUNDUP
TO KBIL TO PRYOR W WILL DIMINISH THIS EVENING. GUSTY SW WINDS
WILL REDEVELOP FROM ROUNDUP TO KBIL TO PRYOR W FRI AFTERNOON.
ARTHUR
&&
.PRELIMINARY POINT TEMP/POPS...
FRI SAT SUN MON TUE WED THU
-----------------------------------------------------------
BIL 039/071 039/059 039/069 044/078 037/059 036/061 036/064
00/B 11/B 10/B 02/W 33/W 11/B 11/B
LVM 040/064 039/056 039/064 042/071 035/053 035/057 033/060
02/W 22/W 10/B 03/W 55/W 11/B 11/B
HDN 037/075 040/063 037/073 040/078 035/060 034/063 032/069
00/B 11/B 10/B 01/B 33/W 11/B 11/B
MLS 039/079 040/060 038/072 043/078 036/057 033/060 035/067
00/U 11/B 10/B 01/B 33/W 11/B 11/B
4BQ 040/079 043/062 040/075 043/081 037/058 035/062 034/068
00/U 01/B 10/B 01/B 33/W 11/B 11/B
BHK 041/075 040/061 037/070 043/076 040/053 032/057 033/066
00/B 11/B 10/B 01/N 34/W 21/B 11/B
SHR 039/075 039/064 039/071 040/074 034/057 034/061 033/066
00/U 01/B 10/B 01/B 33/W 11/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
609 PM CDT FRI MAR 23 2012
.AVIATION...00Z TAF. QUIET WEATHER WILL PREVAIL THROUGH THE TAF
PERIOD AS AN UPPER LEVEL RIDGE OF HIGH PRESSURE SETTLES ACROSS THE
CENTRAL PLAINS. A FEW MID TO HIGH CLOUDS WILL GIVE WAY TO MAINLY
CLEAR SKIES TONIGHT AND SATURDAY. LIGHT AND VARIABLE WINDS WILL
GRADUALLY TRANSITION SOUTHWESTERLY.
&&
.PREV DISCUSSION... /ISSUED 354 PM CDT FRI MAR 23 2012/
SHORT TERM...THROUGH SATURDAY AFTERNOON. NEEDLESS TO SAY...THE
NEXT 24 HOURS CONTINUE THE RETURN TO INCREDIBLY NICE LATE MARCH
WEATHER...WITH HIGH TEMPS ON SATURDAY FORECAST TO BE RIGHT AROUND
CLIMATOLOGICAL NORMALS FOR LATE MAY/EARLY JUNE.
STARTING OFF AT 20Z THIS AFTERNOON...A LIGHT AND SOMEWHAT VARIABLE
WIND REGIME IS IN PLACE ACROSS THE CWA...THANKS TO A BROAD DIFFUSE
RIDGE AXIS. THE COMBINATION OF MODEST BOUNDARY LAYER
MOISTURE...ALONG WITH SOME COOLER MID LEVEL AIR ON THE BACK SIDE
OF THE DEPARTING CLOSED LOW OVER SOUTH CENTRAL MISSOURI...HAS
RESULTED IN A LEGITIMATE SCATTERED FAIR WEATHER CUMULUS FIELD
ESPECIALLY ACROSS THE EASTERN HALF OF THE CWA. ALTHOUGH THIS
SCATTERED TO LOCALLY BROKEN DECK WAS A BIT MORE CLOUD COVER THAN
EARLIER EXPECTED...TEMPS HAVE HAD STILL HAD NO PROBLEMS MAKING IT
INTO AT LEAST THE MID-UPPER 60S AT THIS HOUR...WITH SOME PLACES
POSSIBLY TOUCHING 70 BY DAYS END. AS MENTIONED...WATER VAPOR
IMAGERY AND SHORT TERM MODEL DATA CLEARLY REVEAL THE DEPARTING
CLOSED LOW AS THE MAIN MID/UPPER FEATURE OF INTEREST...WITH
SHORTWAVE RIDGING NOW BUILDING ALONG AN AXIS FROM THE SOUTHERN
ROCKIES TO NORTHERN PLAINS...AND THE NEXT LOW PRESSURE SYSTEM OF
INTEREST STILL WELL OFF THE PACIFIC COAST.
FOR LATE THIS AFTERNOON...HAVE KEPT THE FORECAST DRY...ALTHOUGH
THE HRRR CONTINUES TO INSIST THAT A FEW SPRINKLES COULD FLIRT WITH
FAR SOUTHEAST EDGES OF THE CWA. BASED ON LATEST VIS SATELLITE
TRENDS...ANY SLIGHTLY ENHANCED CUMULUS GROWTH POTENTIALLY
CONDUCIVE TO SPRINKLES/LIGHT RAIN SHOULD REMAIN JUST EAST OF THESE
COUNTIES.
THIS EVENING/TONIGHT...BOUNDARY LAYER CUMULUS DEVELOPMENT SHOULD
QUICKLY FADE AWAY...RESULTING IN ESSENTIALLY CLEAR SKIES AS
SHORTWAVE RIDGING CONTINUES TO NOSE OVERHEAD IN THE WAKE OF THE
DEPARTING LOW...WHICH WILL BE NEAR THE IL/IN/KY BORDER AREA BY
12Z. BREEZES WILL REMAIN LIGHT OVERNIGHT...BUT THE DIRECTION WILL
PREVAIL FROM THE WEST/SOUTHWEST. ONLY POTENTIAL ISSUE IS FOG
DEVELOPMENT OVERNIGHT. VARIOUS MODEL BOUNDARY LAYER RELATIVE
HUMIDITY PROGS...ALONG WITH MET/MAV VISIBILITY GUIDANCE...SUGGEST
THAT THIS LIGHT WESTERLY LOW LEVEL FLOW WILL NOT BE VERY CONDUCIVE
TO FOG DEVELOPMENT. THAT BEING SAID...AT LEAST LIGHT FOG HAS
DEVELOPED HERE AND THERE ACROSS THE CWA THE PAST FEW NIGHTS
LARGELY DUE TO MOIST GROUND IN THE WAKE OF RECENT RAINFALL. GIVEN
THAT PATCHY FOG WORDING HAS ALREADY BEEN IN THE FORECAST FOR OVER
24 HOURS NOW IN SOME AREAS...WILL LET IT RIDE...BUT WOULD BE VERY
SURPRISED TO SEE MORE THAN PATCHY LIGHT VISIBILITY RESTRICTIONS.
FOR LOW TEMPS...KEPT SIMILAR TO PREVIOUS FORECAST IN EASTERN
ZONES...BUT BUMPED DOWNWARD A FEW DEGREES IN THE WEST...RESULTING
IN A RANGE FROM MID-UPPER 30S WEST...LOW 40S CENTRAL...MID 40S
SOUTHEAST. BASED ON WHAT HAPPENED THIS MORNING WITH LOWS TUMBLING
INTO THE LOW 30S WEST...WOULD NOT BE SURPRISED IF TONIGHTS LOWS
END UP A BIT LOWER THAN FORECAST. HOWEVER...THE LIGHT WESTERLY
BREEZES SHOULD HELP HOLD THINGS UP A BIT VERSUS LAST NIGHT.
SATURDAY...THE MID/UPPER PATTERN REMAINS QUITE TRANQUIL...AS THE
HEART OF THE 700-500MB RIDGE BUILDS OVER THE PLAINS...WELL TO THE
EAST OF THE DEEP TROUGH AXIS OFF THE PACIFIC COAST...AND THE
PRIMARY 300MB JET AXIS SNAKING FROM NORTHERN CA THEN EASTWARD
ACROSS SOUTHERN CANADA. AS A SURFACE HIGH PRESSURE SYSTEM WORKS
INTO SOUTHERN CANADA INTO THE DAKOTAS...A VERY WEAK COLD FRONT
WILL PUSH SOUTHWARD TOWARD/INTO THE NORTHWEST CWA DURING THE
AFTERNOON. OTHERWISE...LIGHT SOUTHWEST BREEZES WILL PREVAIL ACROSS
MOST OF THE CWA FOR THE MAJORITY OF THE DAY. WITH FORECAST
SOUNDINGS A BIT DRIER IN THE BOUNDARY LAYER COMPARED TO
TODAY...NOT ANTICIPATING MUCH CUMULUS DEVELOPMENT...AND IN FACT
VERY LITTLE CLOUD COVER. TEMP WISE...GIVEN THE WIDESPREAD SUN AND
850MB TEMPS CLIMBING WELL INTO THE 14-17C RANGE...A NOTABLE JUMP
IN AFTERNOON HIGHS IN LIKELY. DIDN/T GET TOO CARRIED AWAY...BUT
NUDGED UP PREVIOUS FORECAST TOWARD HIGHER END OF MET/MAV GUIDANCE
CONSENSUS...WITH MOST OF THE CWA INTO THE 78-80 RANGE.
LONG TERM...SATURDAY NIGHT THROUGH FRIDAY. WE KICK THINGS OFF
SATURDAY NIGHT WITH A PROMINENT UPPER RIDGE OVER THE PLAINS AND A
HIGHLY AMPLIFIED TROUGH ON ENTERING THE WEST COAST OF THE UNITED
STATES. WEATHER SHOULD REMAIN DRY INTO SUNDAY THANKS TO BEING
UNDER THE INFLUENCE OF NOT ONLY THE UPPER LEVEL RIDGE BUT A
SURFACE RIDGE AS WELL. THERE WILL BE A SURFACE TROUGH DEVELOPING
IN THE LEE OF THE ROCKIES BY SUNDAY NIGHT WITH A HEALTHY FAIRLY
STRONG LOW-LEVEL JET INCREASING OVER PARTS OF WESTERN AND CENTRAL
KANSAS...WITH THE NOSE OF THE JET MAKING ITS WAY INTO SOUTHERN AND
CENTRAL PARTS OF THE CWA BY LATE SUNDAY NIGHT...WITH THE NAM A BIT
STRONGER HERE...INDICATING A 50 KT JET...AS OPPOSED TO NEAR 40 KTS
FOR THE GFS AND ECMWF. AT THIS POINT...THERE DOES NOT APPEAR TO BE
ENOUGH MOISTURE TO GET ANY CONVECTION GOING...BUT IF THERE
WERE...STRONG TO SEVERE THUNDERSTORMS WOULD CERTAINLY NOT BE OUT
OF THE QUESTION. CONFIDENCE IS NOT HIGH ENOUGH TO INTRODUCE
CHANCES OF RAIN AT THIS POINT.
A POTENT NEGATIVELY TILTED SHORTWAVE TROUGH WILL EJECT NORTHEAST OUT
OF THE CENTRAL ROCKIES MONDAY NIGHT AND HAS BEEN PROJECTED TO DO SO
FOR SOME TIME. THERE ARE SOME STRENGTH AND TIMING DIFFERENCES
BETWEEN MEDIUM TO LONG RANGE MODELS...BUT THE GENERAL SCENARIO IS
SIMILAR. THE ECMWF CONTINUES TO PROJECT A STRONGER WAVE THAT EJECTS
INTO THE PLAINS SOONER THAN THE GFS SOLUTION. SURFACE PRESSURE
GRADIENTS WILL INCREASE ALONG WITH INCREASED MIXING AND WE COULD BE
GETTING CLOSE TO WIND ADVISORY WITH HEALTHY WIND FROM THE
SOUTH...ESPECIALLY IN THE WESTERN CWA. MODELS GENERALLY PRODUCE THE
NOSE OF THE LOW-LEVEL JET WELL NORTH OF THE CWA...ALONG WITH THE
BEST MID TO UPPER LEVEL FORCING TO THE NORTH AS WELL. AT THE
SURFACE...BY MONDAY EVENING...THE DRY LINE SHOULD STILL BE WELL TO
THE WEST OF THE CWA...WHILE A WARM FRONT IS EXPECTED TO HAVE PASSED
TO THE NORTHEAST OF THE CWA BY THEN. SEVERE PARAMETERS SUGGEST
POSSIBLE SEVERE WEATHER NEAR THESE BOUNDARIES...BUT WE MAY WIGGLE
OUT OF MOST OF THE SEVERE WEATHER BY BEING BETWEEN THESE BOUNDARIES
WHILE SEVERE WEATHER INITIATES TOWARD EVENING...GIVEN THAT SOUNDINGS
SUGGEST WE WILL BE TOO CAPPED TO PRODUCED MUCH OF ANYTHING IN THE
REGION UNTIL LATE AFTERNOON AND QUITE LIKELY IN THE EVENING...AND
FOR THIS REASON...I HAVE ALL BUT PULLED CHANCES OF PRECIPITATION
FROM MONDAY AFTERNOON...SAVE PERHAPS THE FAR NORTHEASTERN CORNER OF
THE CWA IF THE WARM FRONT DOES NOT GET OUT OF THE CWA FAST
ENOUGH...AND HAVE LIMITED THAT SMALL AREA TO LATE
AFTERNOON...DESPITE THE FACT THAT THE LATEST ECMWF PAINTS SOME QPF
OVER THE NORTHWEST. THIS DOES NOT LOOK PROBABLE AS IT APPEARS THAT
THE WARM FRONT SHOULD CLEAR THE CWA BEFORE CONVECTION BEGINS AND
THERE IS NO OTHER FOCUS FOR CONVECTION IN THE AFTERNOON TO REALLY
GET THINGS GOING FROM WHAT IT LOOKS LIKE FOR NOW. THIS LOOKS LIKE A
SCENARIO WHERE WE MAY WIND UP GETTING SOME NOCTURNAL HIGH PLAINS
CONVECTION AS THE THETA E AXIS WILL MOVE FROM WEST TO EAST ACROSS
THE CWA BETWEEN 03Z AND 08Z TUESDAY (MONDAY EVENING)...BUT THIS MAY
BE MORE OF A WEAKER LEFTOVER EVENT...GIVING US ELEVATED
STRONGER/HEAVY RAINER STORMS...BUT PERHAPS NO LONGER SEVERE. I AM
NOT CONFIDENT ENOUGH TO PULL SEVERE POTENTIAL OUT OF THE HWO...AS
TIMING DIFFERENCES COULD MAKE A HUGE DIFFERENCE...AND BEING SO FAR
OUT IN THE FORECAST...IT WOULD BE PRUDENT TO KEEP SEVERE POTENTIAL
MENTIONED IN THE HWO.
AFTER THE WAVE PASSES MONDAY NIGHT...THERE WILL BE LITTLE MORE
CHANCE OF PRECIPITATION FOR A COUPLE OF DAYS WITH RIDGING TAKING
PLACE. TUESDAY COULD BE GETTING CLOSE TO RED FLAG POTENTIAL IN THE
FAR WESTERN CWA WITH RELATIVE HUMIDITY POSSIBLY GETTING NEAR 20
PERCENT AND WEST WINDS APPROACHING SUSTAINED 20 MPH. THE ECMWF
INDICATES A SMALL PERTURBATION RIDING THE RIDGE BY WEDNESDAY NIGHT
ALONG OUR SOUTHERN FRINGE WITH PERHAPS THE AID OF SOME CONVERGENCE
AT 850 MB...BUT EVEN WITH QPF ADVERTISED BY THE ECMWF...PROBABILITY
OF PRECIPITATION FOR RUSSEL AND CONCORDIA ARE AROUND 20
PERCENT...AND LOWER THAN THIS IN OUR CWA TO THE NORTH. FOR THE REST
OF THE EXTENDED...I LEFT LOW CHANCES OF PRECIPITATION AS FLOW COULD
CONTAIN POTENTIAL SMALL WAVES OF ENERGY...ALTHOUGH TEMPERATURES WILL
REMAIN WELL ABOVE NORMAL.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1234 PM CDT THU MAR 22 2012
.AVIATION...18Z TAFS FOR KOMA...KLNK AND KOFK.
COMPLEX AVIATION FORECAST AS UPPER LOW OVER SRN PLAINS SPINS MIX
OF CLOUDS AND SUN OVER THE TAF SITES. WITH HEATING DURING THE
DAYTIME HOURS...WILL LIKELY DEVELOP LARGER CU FIELD THUS HAVE A
TEMPO GROUP OF MVFR CIGS IN DURING THE AFTERNOON HOURS. FORECAST
MODELS BRING SHOWERS ALONG WITH FOG AND IFR CIGS INTO KLNK
OVERNIGHT SO DID HINT AT THAT IN THE TAF. FOR BOTH KOMA AND
KOFK...DID LEAVE THESE IN VFR CATEGORY AS FORECAST MODELS SUGGEST
BUT WILL NEED TO MONITOR CLOSELY AS THEY COULD DEVELOP BOTH FOG
AND LOW CLOUDS OVERNIGHT AS LOW LEVEL MOISTURE REMAINS HIGH.
&&
PREV DISCUSSION... /ISSUED 258 AM CDT THU MAR 22 2012/
DISCUSSION...
DEALING WITH UPPER LOW OVER THE SOUTHERN PLAINS AND ITS
MOVEMENT OUT OF THE REGION WILL CONTINUE TO BE THE PRIMARY
FORECAST CONCERN.
AT 07Z UPPER LOW WAS OVER CENTRAL OKLAHOMA WITH SURFACE LOW
IN SOUTHWEST KANSAS. NEXT ARM OF SHOWERS PIVOTING AROUND
THE UPPER LOW WAS MOVING ACROSS SOUTHEAST NEBRASKA AND SOUTHWEST
IOWA. HRRR MODEL LIFTS THE SHOWERS NORTHEAST ACROSS THE AREA
THROUGH 12Z WITH SHOWERS CONFINED TO NORTHEAST NEBRASKA FOR MUCH
OF THE REMAINDER OF THE MORNING. IN THE AFTERNOON SHOWERS EXPECTED
TO END IN THE NORTHEAST BUT SPREAD BACK INTO SOUTHERN PARTS OF THE
CWA AS UPPER LOW STARTS TO MOVE TOWARD THE LOWER MISSOURI VALLEY.
RAIN CHANCES CONFINED TO SOUTHEAST NEBRASKA AND SOUTHWEST IOWA
TONIGHT WITH UPPER LOW MOVING TO NORTHEAST KANSAS BY FRIDAY
MORNING. A LINGERING CHANCE OF SHOWERS CONTINUES YET ON FRIDAY FOR
SOUTHEAST AREAS AS THE LOW TRACKS SLOWLY EAST ACROSS MISSOURI. LOW
FINALLY MOVES FAR ENOUGH EAST FRIDAY NIGHT TO END RAIN THREAT FOR
THE AREA WITH SKIES CLEARING. WARMER TEMPERATURES RETURN SATURDAY
WITH SUNNY SKIES AS UPPER RIDGE MOVES INTO THE PLAINS REGION.
THE WARM TEMPERATURES CONTINUE AT THE BEGINNING OF THE EXTENDED
FORECAST PERIOD ON SUNDAY AND MONDAY. AN INCREASING CHANCE OF
THUNDERSTORMS DEVELOPS MONDAY NIGHT INTO TUESDAY AS A COLD FRONT
APPROACHES THE AREA WITH MODELS STALLING THE FRONT JUST SOUTH OF
THE AREA ACROSS NORTHEAST KANSAS TUESDAY NIGHT AND WEDNESDAY.
HAVE KEPT THE LATE PERIOD STARTING ON WEDNESDAY DRY FOR NOW BUT
WITH STALLED FRONT NEARBY TO THE SOUTH LATER ADJUSTMENTS ARE
LIKELY.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
610 AM CDT THU MAR 22 2012
.AVIATION...
12Z TAFS FOR KOFK...KOMA AND KLNK.
BAND OF RAIN ALONG WITH LOWER CIGS CONTINUED TO LIFT NORTH ACROSS
EASTERN NEBRASKA WITH MOST OF ANY RAIN NOW EXPECTED N OF KOMA AND
KLNK THIS MORNING. ALTHOUGH BULK OF LOW CLOUDS WERE LIFTING NORTH
WITH PRECIP AREA...POCKETS OF IFR CIGS REMAINED TO THE SOUTH...AND
THESE COULD TRACK ACROSS TAF SITES FOR SEVERAL HOURS AFTER PRECIP
SHIFTS EVEN FARTHER N. OTHERWISE HEATING BY NOON COULD BRING AN
FURTHER INCREASE IN CLOUDS TO ERN NEBRASKA...ALTHOUGH ANY CIGS LIKELY
ABOVE 3K FT AGL. AS UPPER LOW LIFTS TOWARD REGION LATER
TONIGHT...LOWER CIGS AND A CHANCE OF RAIN WILL RETURN...ALTHOUGH
WITH 12Z TAF MENTION OF RAIN WAS JUST MADE AT KLNK. IF CLOUDS
INCREASE SLOWER THAN EXPECTED FOG COULD BECOME MORE OF AN ISSUE
LATE TONIGHT.
CHERMOK
&&
.PREV DISCUSSION... /ISSUED 258 AM CDT THU MAR 22 2012/
DISCUSSION...
DEALING WITH UPPER LOW OVER THE SOUTHERN PLAINS AND ITS
MOVEMENT OUT OF THE REGION WILL CONTINUE TO BE THE PRIMARY
FORECAST CONCERN.
AT 07Z UPPER LOW WAS OVER CENTRAL OKLAHOMA WITH SURFACE LOW
IN SOUTHWEST KANSAS. NEXT ARM OF SHOWERS PIVOTING AROUND
THE UPPER LOW WAS MOVING ACROSS SOUTHEAST NEBRASKA AND SOUTHWEST
IOWA. HRRR MODEL LIFTS THE SHOWERS NORTHEAST ACROSS THE AREA
THROUGH 12Z WITH SHOWERS CONFINED TO NORTHEAST NEBRASKA FOR MUCH
OF THE REMAINDER OF THE MORNING. IN THE AFTERNOON SHOWERS EXPECTED
TO END IN THE NORTHEAST BUT SPREAD BACK INTO SOUTHERN PARTS OF THE
CWA AS UPPER LOW STARTS TO MOVE TOWARD THE LOWER MISSOURI VALLEY.
RAIN CHANCES CONFINED TO SOUTHEAST NEBRASKA AND SOUTHWEST IOWA
TONIGHT WITH UPPER LOW MOVING TO NORTHEAST KANSAS BY FRIDAY
MORNING. A LINGERING CHANCE OF SHOWERS CONTINUES YET ON FRIDAY FOR
SOUTHEAST AREAS AS THE LOW TRACKS SLOWLY EAST ACROSS MISSOURI. LOW
FINALLY MOVES FAR ENOUGH EAST FRIDAY NIGHT TO END RAIN THREAT FOR
THE AREA WITH SKIES CLEARING. WARMER TEMPERATURES RETURN SATURDAY
WITH SUNNY SKIES AS UPPER RIDGE MOVES INTO THE PLAINS REGION.
THE WARM TEMPERATURES CONTINUE AT THE BEGINNING OF THE EXTENDED
FORECAST PERIOD ON SUNDAY AND MONDAY. AN INCREASING CHANCE OF
THUNDERSTORMS DEVELOPS MONDAY NIGHT INTO TUESDAY AS A COLD FRONT
APPROACHES THE AREA WITH MODELS STALLING THE FRONT JUST SOUTH OF
THE AREA ACROSS NORTHEAST KANSAS TUESDAY NIGHT AND WEDNESDAY.
HAVE KEPT THE LATE PERIOD STARTING ON WEDNESDAY DRY FOR NOW BUT
WITH STALLED FRONT NEARBY TO THE SOUTH LATER ADJUSTMENTS ARE
LIKELY.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
258 AM CDT THU MAR 22 2012
.DISCUSSION...
DEALING WITH UPPER LOW OVER THE SOUTHERN PLAINS AND ITS
MOVEMENT OUT OF THE REGION WILL CONTINUE TO BE THE PRIMARY
FORECAST CONCERN.
AT 07Z UPPER LOW WAS OVER CENTRAL OKLAHOMA WITH SURFACE LOW
IN SOUTHWEST KANSAS. NEXT ARM OF SHOWERS PIVOTING AROUND
THE UPPER LOW WAS MOVING ACROSS SOUTHEAST NEBRASKA AND SOUTHWEST
IOWA. HRRR MODEL LIFTS THE SHOWERS NORTHEAST ACROSS THE AREA
THROUGH 12Z WITH SHOWERS CONFINED TO NORTHEAST NEBRASKA FOR MUCH
OF THE REMAINDER OF THE MORNING. IN THE AFTERNOON SHOWERS EXPECTED
TO END IN THE NORTHEAST BUT SPREAD BACK INTO SOUTHERN PARTS OF THE
CWA AS UPPER LOW STARTS TO MOVE TOWARD THE LOWER MISSOURI VALLEY.
RAIN CHANCES CONFINED TO SOUTHEAST NEBRASKA AND SOUTHWEST IOWA
TONIGHT WITH UPPER LOW MOVING TO NORTHEAST KANSAS BY FRIDAY
MORNING. A LINGERING CHANCE OF SHOWERS CONTINUES YET ON FRIDAY FOR
SOUTHEAST AREAS AS THE LOW TRACKS SLOWLY EAST ACROSS MISSOURI. LOW
FINALLY MOVES FAR ENOUGH EAST FRIDAY NIGHT TO END RAIN THREAT FOR
THE AREA WITH SKIES CLEARING. WARMER TEMPERATURES RETURN SATURDAY
WITH SUNNY SKIES AS UPPER RIDGE MOVES INTO THE PLAINS REGION.
THE WARM TEMPERATURES CONTINUE AT THE BEGINNING OF THE EXTENDED
FORECAST PERIOD ON SUNDAY AND MONDAY. AN INCREASING CHANCE OF
THUNDERSTORMS DEVELOPS MONDAY NIGHT INTO TUESDAY AS A COLD FRONT
APPROACHES THE AREA WITH MODELS STALLING THE FRONT JUST SOUTH OF
THE AREA ACROSS NORTHEAST KANSAS TUESDAY NIGHT AND WEDNESDAY.
HAVE KEPT THE LATE PERIOD STARTING ON WEDNESDAY DRY FOR NOW BUT
WITH STALLED FRONT NEARBY TO THE SOUTH LATER ADJUSTMENTS ARE
LIKELY.
&&
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
A DRY PUNCH/LOBE WORKING AROUND UPPER LOW OVER SOUTHERN PLAINS
SHOULD BRING IMPROVING CONDITIONS TO TAF SITES BY MID TO LATE
THURSDAY MORNING. HOWEVER...BEFORE THEN VARIABLE CONDITIONS WITH
CIGS/VSBYS FROM VFR TO IFR CAN BE EXPECTED AS BANDS OF
SHOWERS/DRIZZLE PIVOT NORTH/NORTHWEST ACROSS EASTERN NEBRASKA. THE
RAIN AND LOWER CIGS/VSBYS SHOULD IMPROVE FROM S TO N THROUGH THE
MORNING AS BRISK E/NE SFC WINDS BECOME SSE AND DECREASE.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
FOBERT/CHERMOK
AREA FORECAST DISCUSSION
NWS RALEIGH NC
315 PM EDT THU MAR 22 2012
.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE ALOFT WILL MOVE AWAY FROM CENTRAL NC
TODAY. HIGH PRESSURE ALOFT WILL EXTEND ACROSS THE REGION TONIGHT AND
FRIDAY. AN AREA OF LOW PRESSURE WILL APPROACH FROM THE WEST FRIDAY
NIGHT AND SATURDAY...BRINGING UNSETTLED WEATHER TO CENTRAL NC
THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1010 AM THURSDAY...
LINGERING FOG HAS BECOME CONFINED TO THE SOUTHERN PIEDMONT THIS
MORNING...BUT EVEN REPORTING STATIONS IN THAT AREA ARE BEGINNING TO
SHOW SIGNS OF VSBYS AT OR ABOVE 1/2 MILE. STRATUS IS FAIRLY
WIDESPREAD WEST OF US HWY 1 BUT NEAR TERM GUIDANCE SUGGEST CLOUDS
WILL BREAK BY NOON AND SHOULD NOT HAVE A SIGNIFICANT IMPACT ON
AFTERNOON HEATING. MAIN CONCERN FOR THIS AFTERNOON WILL AGAIN BE
CONVECTIVE CONVERGE. THE WATER VAPOR CHANNEL APPEARS RELATIVELY
QUIET UPSTREAM OVER VA THIS MORNING WITH LITTLE IN THE WAY OF
OBVIOUS DISTURBANCES AND MUCH DRIER AIR ALOFT PENETRATING INTO
CENTRAL NC. THE MAIN CYCLONIC CIRCULATIONS OF THE UPPER LOW IS NOW
RIGHT ALONG THE OBX COAST. RUC DYNAMIC TROPOPAUSE FORECASTS SUGGEST
THERE MAY BE A WEAK JET AND SHALLOW DISTURBANCE OVER EASTERN PA/MD
THAT WILL DROP SOUTH ACROSS NORTHEAST NC THIS AFTERNOON. SPC
MESOANALYSIS SHOWS EARLY SIGNS OF AN INSTABILITY AXIS DEVELOPING
OVER NORTHEAST NC AND SOUTHEAST VA WHERE MID LEVEL TEMPS ARE
COOLEST. HI-RES MODELS ARE NOT PARTICULARLY ACTIVE WITH REGARDS TO
CONVECTION OVER THE NORTHEAST...BUT GIVEN THE ABOVE
OBSERVATIONS...WE WILL KEEP POPS HIGHEST OVER THE NORTHEAST CWA. TO
THE SOUTH...SEABREEZE AND SCATTERED CONVECTION OVER INLAND SC WHERE
DEEP MOISTURE IS GREATER MAY DRIFT NORTH AND WEST INTO THE SANDHILLS
AND SOUTHERN PIEDMONT LATER THIS AFTERNOON...BUT WEAK MID LEVEL
LAPSE RATES AND WIND FIELDS SHOULD LIMIT ANY MORE THAN AN ISOLATED
SEVERE STORM. HIGHS IN THE UPPER 70S TO AROUND 80. -SMITH
AS UPPER LEVEL LOW MOVES FARTHER AWAY FROM CENTRAL NC
TONIGHT...NARROW UPPER RIDGE WILL EXTEND N-S ACROSS THE REGION. THE
PRESENCE OF THE RIDGE ALOFT WILL RESULT IN CLEAR-PARTLY CLOUDY
SKIES. LIGHT WIND REGIME NEAR THE SURFACE ALONG WITH A RELATIVELY
MOIST AIR MASS IN THE BOUNDARY LAYER WILL CREATE CONDITIONS OPTIMAL
FOR FOG DEVELOPMENT. CONFIDENCE NOT HIGH ENOUGH TO MENTION DENSE FOG
IN THE FORECAST AT THIS TIME. MIN TEMPS UPPER 50S TO NEAR 60.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 315 PM THURSDAY...
...AN ACTIVE PERIOD OF WEATHER EXPECTED ON FRIDAY NIGHT THROUGH
SUNDAY NIGHT...
THE BEGINNING OF THE SHORT TERM PERIOD FEATURES AN AMPLIFIED PATTERN
WITH A DEEP CLOSED VORTEX OVER THE MID MISSISSIPPI VALLEY AND A
DECAYING RIDGE OF HIGH PRESSURE OVER THE MID-ATLANTIC AND CAROLINAS.
THE UPPER LOW SLOWLY FILLS AS IT MOVES SLOWLY NORTHEAST AND
INTERACTS WITH THE POLAR JET TO THE NORTH. AHEAD OF THE UPPER LOW
AND A MODEST COLD FRONT...A PLUME OF DEEP MOISTURE WITH PW VALUES
RANGING BETWEEN 1.25 AND 1.5 INCHES EXTENDS NORTHWARD FROM THE GULF.
THIS ENVIRONMENT IS LIKELY TO INITIATE CONVECTION ACROSS THE DEEP
SOUTH AND MISS VALLEY ON FRIDAY AFTERNOON THAT WILL MOVE EAST AND
OVERSPREAD THE WESTERN PIEDMONT ON FRIDAY EVENING. THIS CONVECTION
WILL LIKELY SHIFT EAST ACROSS THE REMAINDER OF CENTRAL NC OVERNIGHT
AND WILL NECESSITATE CHANCE TO LIKELY POPS. WITH MOSTLY CLOUDY SKIES
AND AREA OF PRECIPITATION...EXPECT OVERNIGHT LOWS FRIDAY NIGHT IN
THE LOWER 60S.
THE UPPER LOW MOVES INTO THE OH VALLEY ON SATURDAY WITH THE
ASSOCIATED COLD FRONT REACHING THE SOUTHERN APPALACHIANS BY MIDDAY.
THE LOW AND MID LEVEL FLOW STRENGTHENS DURING THE AFTERNOON WITH
0-6KM BULK SHEAR INCREASING TO BETWEEN 25 AND 35 KTS BY LATE IN THE
DAY. AS THE UPPER LOW APPROACHES...THE MID LEVELS SHOULD COOL
SOMEWHAT RESULTING IN LIMITED BUT SUFFICIENT INSTABILITY FOR
CONVECTION. SPC HAS MUCH OF VA AND THE CAROLINAS IN A SLIGHT RISK ON
SATURDAY WITH THE PRIMARY THREAT FROM MARGINAL SEVERE HAIL AND
LOCALLY DAMAGING WIND GUSTS. ONE LIMITING FACTOR WILL BE THE AMOUNT
OF DRYING ALOFT AND RESULTANT INSOLATION THAT COULD ENHANCE
INSTABILITY. WITH LINGERING SHOWERS IN THE AREA IN THE MORNING AND
PLENTY OF CLOUD COVER...THE AMOUNT OF LOW LEVEL HEATING WILL BE
LIMITED. WILL KEEP HIGH CHC TO LIKELY POPS IN THE FORECAST WITH A
PERIOD OF SHOWERS/POSSIBLE THUNDERSTORM IN THE MORNING...THEN A BIT
OF A LULL AROUND MIDDAY AND THEN PERHAPS A MORE ORGANIZED LINE OF
CONVECTION IN THE AFTERNOON AND EVENING. HIGHS IN THE LOW AND MID
70S LOOK GOOD.
THE 12Z GFS AND ECMWF ARE IN BETTER AGREEMENT WITH THE TIMING OF THE
COLD FRONTAL PASSAGE IN CENTRAL NC AROUND MIDNIGHT. THE THREAT OF
SEVERE WEATHER WILL DIMINISH OVERNIGHT AS THE FRONT AND A MORE
WESTERLY/NORTHWESTERLY FLOW ARRIVES. WITH THE VORTEX JUST TO THE
WEST OF THE REGION OVERNIGHT EXPECT SCT SHOWERS OR THUNDERSTORMS TO
CONTINUE OVERNIGHT. LOW TEMPS IN THE LOW AND MID 50S LOOK GOOD.
UNSETTLED WEATHER WILL CONTINUE ON SUNDAY AND SUNDAY NIGHT AS THE
COLD VORTEX MOVES OVERHEAD AND THE VARIOUS DISTURBANCES ROTATING
AROUND THE UPPER LOW INITIATE SCT CONVECTION. WITH FREEZING LEVELS
AROUND 7-8KFT...SOME SMALL HAIL IS POSSIBLE IN THE STRONGER
THUNDERSTORMS. WITH THE CLOUD COVER AND PRECIPITATION EXPECT HIGH
TEMPS IN THE LOW 70S AND LOWS IN THE LOWER 50S -BLAES
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 315 PM THURSDAY...
THE UPPER AIR PATTERN DURING THIS PERIOD CAN BE CHARACTERIZED AS
PROGRESSIVE AND RATHER AMPLIFIED. A PHASING AND DEEPENING TROUGH
MOVES OFF THE ATLANTIC COAST ON MONDAY AS A HIGH PRESSURE RIDGE
ALOFT AND AT THE SURFACE BUILDS INTO THE REGION. THE UPPER RIDGE
DEAMPLIFIES ON WEDNESDAY AS HIGH PRESSURE MOVES OFFSHORE AND A COLD
FRONT APPROACHES THE REGION FROM THE MISSISSIPPI AND OHIO VALLEYS.
WILL ADD/EXTEND SLIGHT CHC POPS INTO MONDAY MORNING ACROSS THE
COASTAL PLAIN AS THE 12Z CANADIAN AND 00Z ECMWF HOLDS ONTO PRECIP
IN THE EAST AND EVEN THE 12Z GFS SHOWS SOME RESIDUAL LOW LEVEL
MOISTURE BUT NO PRECIP.
GENERALLY FAIR WEATHER WITH TEMPERATURES NEAR TO SLIGHTLY ABOVE
NORMAL ARE EXPECTED ON TUESDAY AND WEDNESDAY. WITH THE SFC HIGH
MOVING OFFSHORE AND AN INCREASINGLY DEEP VEERING LOW LEVEL FLOW..
EXPECT LOW STRATUS TO DEVELOP TUESDAY NIGHT AND EARLY WEDNESDAY WITH
A CONSIDERABLE AMOUNT OF CLOUDINESS ON WEDNESDAY. THE 12Z GFS EVEN
SUGGESTS SOME PRECIPITATION ACROSS THE UPSLOPE REGION OF THE
SOUTHERN APPALACHIANS. WILL OMIT POPS FOR NOW BUT INCREASE CLOUD
COVER NOTABLY.
THE NEXT SHORT WAVE AND THE ASSOCIATED COLD FRONT MOVES ACROSS THE
GREAT LAKES AND OH VALLEY LATE WEDNESDAY AND APPROACHES THE REGION
WEDNESDAY NIGHT AND THURSDAY. THE 12 GFS IS MUCH STRONGER WITH THE
SYSTEM THAN THE 00Z ECMWF WITH THE 12Z CANADIAN IN BETWEEN. NOT
SURPRISINGLY THE GFS GENERATES A LOT MORE PRECIPITATION UPSTREAM AND
ACROSS THE AREA ON WEDNESDAY NIGHT AND THURSDAY. BOTH THE GFS AND
ECMWF SUGGEST THAT THE SFC FRONT/TROUGH SHOULD REACH THE AREA ON
THURSDAY AFTERNOON. WILL INCLUDE SLIGHT CHANCE POPS FOR THURSDAY
WITH THUNDERSTORMS. -BLAES
&&
.AVIATION /18Z THURSDAY THROUGH MONDAY/...
AS OF 205 PM THURSDAY...
THIS MORNINGS FOG AND STRATUS HAS LIFTED TO VFR LEVEL CUMULUS
EVERYWHERE EXCEPT FOR THE TRIAD WHERE KGSO/KINT STILL REPORT 2-3K FT
CEILINGS. SATELLITE TRENDS SUGGEST CEILINGS THERE SHOULD SCATTER
OUT BY 20Z...WITH LESS CHANCE OF A SHOWER OR STORM THAN AREAS TO THE
EAST. OVER THE PIEDMONT AND COASTAL PLAIN...ISOLATED TO SCATTERED
SHOWERS WILL DEVELOP AND MAY IMPACT ANY TERMINAL. CONFIDENCE IN A
SHOWER WITH BRIEF HEAVY RAIN AND MVFR CEILINGS IS GREATEST AT KFAY
AND KRWI. CONVECTION WILL DIE OFF AFTER SUNSET...WITH STRATUS AND
FOG POSSIBLE AGAIN FRIDAY MORNING. BASED ON PREVIOUS
MORNINGS...PROBABILITY OF RAINFALL THIS EVENING...AND STATISTICAL
GUIDANCE..CONFIDENCE IS HIGHEST AT KRDU/KFAY/KRWI.
OUTLOOK....SHOWERS AND STORMS...POSSIBLY SEVERE...LATER FRIDAY NIGHT
INTO SATURDAY AS A COLD FRONT MOVES ACROSS THE AREA. SHOWERS AND
ISOLATED STORMS WILL THEN BE POSSIBLE AGAIN ON SUNDAY AS THE
ASSOCIATED UPPER LOW CROSSES CENTRAL NC. CONDITIONS SHOULD IMPROVE
TO VFR FOR MONDAY AND TUESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS/SMITH
SHORT TERM...BLAES
LONG TERM...BLAES
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
205 PM EDT THU MAR 22 2012
.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE ALOFT WILL MOVE AWAY FROM CENTRAL NC
TODAY. HIGH PRESSURE ALOFT WILL EXTEND ACROSS THE REGION TONIGHT AND
FRIDAY. AN AREA OF LOW PRESSURE WILL APPROACH FROM THE WEST FRIDAY
NIGHT AND SATURDAY...BRINGING UNSETTLED WEATHER TO CENTRAL NC
THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1010 AM THURSDAY...
LINGERING FOG HAS BECOME CONFINED TO THE SOUTHERN PIEDMONT THIS
MORNING...BUT EVEN REPORTING STATIONS IN THAT AREA ARE BEGINNING TO
SHOW SIGNS OF VSBYS AT OR ABOVE 1/2 MILE. STRATUS IS FAIRLY
WIDESPREAD WEST OF US HWY 1 BUT NEAR TERM GUIDANCE SUGGEST CLOUDS
WILL BREAK BY NOON AND SHOULD NOT HAVE A SIGNIFICANT IMPACT ON
AFTERNOON HEATING. MAIN CONCERN FOR THIS AFTERNOON WILL AGAIN BE
CONVECTIVE CONVERGE. THE WATER VAPOR CHANNEL APPEARS RELATIVELY
QUIET UPSTREAM OVER VA THIS MORNING WITH LITTLE IN THE WAY OF
OBVIOUS DISTURBANCES AND MUCH DRIER AIR ALOFT PENETRATING INTO
CENTRAL NC. THE MAIN CYCLONIC CIRCULATIONS OF THE UPPER LOW IS NOW
RIGHT ALONG THE OBX COAST. RUC DYNAMIC TROPOPAUSE FORECASTS SUGGEST
THERE MAY BE A WEAK JET AND SHALLOW DISTURBANCE OVER EASTERN PA/MD
THAT WILL DROP SOUTH ACROSS NORTHEAST NC THIS AFTERNOON. SPC
MESOANALYSIS SHOWS EARLY SIGNS OF AN INSTABILITY AXIS DEVELOPING
OVER NORTHEAST NC AND SOUTHEAST VA WHERE MID LEVEL TEMPS ARE
COOLEST. HI-RES MODELS ARE NOT PARTICULARLY ACTIVE WITH REGARDS TO
CONVECTION OVER THE NORTHEAST...BUT GIVEN THE ABOVE
OBSERVATIONS...WE WILL KEEP POPS HIGHEST OVER THE NORTHEAST CWA. TO
THE SOUTH...SEABREEZE AND SCATTERED CONVECTION OVER INLAND SC WHERE
DEEP MOISTURE IS GREATER MAY DRIFT NORTH AND WEST INTO THE SANDHILLS
AND SOUTHERN PIEDMONT LATER THIS AFTERNOON...BUT WEAK MID LEVEL
LAPSE RATES AND WIND FIELDS SHOULD LIMIT ANY MORE THAN AN ISOLATED
SEVERE STORM. HIGHS IN THE UPPER 70S TO AROUND 80. -SMITH
AS UPPER LEVEL LOW MOVES FARTHER AWAY FROM CENTRAL NC
TONIGHT...NARROW UPPER RIDGE WILL EXTEND N-S ACROSS THE REGION. THE
PRESENCE OF THE RIDGE ALOFT WILL RESULT IN CLEAR-PARTLY CLOUDY
SKIES. LIGHT WIND REGIME NEAR THE SURFACE ALONG WITH A RELATIVELY
MOIST AIR MASS IN THE BOUNDARY LAYER WILL CREATE CONDITIONS OPTIMAL
FOR FOG DEVELOPMENT. CONFIDENCE NOT HIGH ENOUGH TO MENTION DENSE FOG
IN THE FORECAST AT THIS TIME. MIN TEMPS UPPER 50S TO NEAR 60.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 305 AM THURSDAY...
FRIDAY...MID/UPPER LEVEL RIDGE OVER THE SE U.S. FRIDAY MORNING WILL
DRIFT EWD AS A DEEP UPPER LEVEL LOW OVER THE CENTRAL-SOUTHERN PLAINS
DRIFTS ENE INTO THE LOWER OH VALLEY. AS UPPER RIDGE AXIS MOVES
EWD....EXPECT TO SEE AN INCREASE IN MID/HIGH LEVEL CLOUDS OCCURRING
OUT AHEAD OF THE DEEP CENTRAL U.S. LOW. BELIEVE INITIAL SURGE OF
MID/HIGH LEVEL CLOUDS WILL BE OPAQUE ENOUGH TO ALLOW AT LEAST
FILTERED SUNSHINE IN THE PIEDMONT DURING THE AFTERNOON. LOW LEVEL
SLY FLOW WILL LIKELY AID TO INITIATE ISOLATED/SCATTERED CONVECTION
OVER THE HIGHER TERRAIN OF WESTERN NC. DEVELOPING SSW FLOW SHOULD
KEEP BULK OF CONVECTION OVER THE TERRAIN AND NOT CREEP INTO THE
PIEDMONT. THUS...HAVE TRIMMED/DELAYED PRECIP ONSET IN THE WEST
FRIDAY AFTERNOON. LOW LEVEL THICKNESSES REMAIN AROUND 1390M FRIDAY
AFTERNOON. WITH DEVELOPING SW SURFACE FLOW ON THE BACK SIDE OF THE
HIGH AIDING TO BRING ADDITIONAL WARMTH ...AFTERNOON TEMPS AROUND
80/LOWER 80S HIGHLY PROBABLE.
FRIDAY NIGHT...UPPER LEVEL LOW WILL CONTINUE TO ADVANCE SLOWLY ESE
TOWARD THE CAROLINAS. BEGINNING TO SEE MODEL DIFFERENCES IN THE
TIMING WITH THE NAM NOTICEABLY SLOWER COMPARED TO THE GFS/ECMWF.
APPEARS BULK OF DEEPER MOISTURE AND LIFT WILL HOLD OFF UNTIL LATE
FRIDAY NIGHT WITH LOCALES ALONG AND EAST OF HIGHWAY 1 LIKELY
REMAINING DRY UNTIL DAYBREAK SATURDAY. HAVE ADJUSTED PRECIP TIMING A
TAD IN THE WESTERN PIEDMONT...DELAYING LIKELY POPS UNTIL AFTER
MIDNIGHT OR 2 AM. REMAINING MILD WITH OVERNIGHT TEMPS IN THE UPPER
50S TO LOWER 60S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 250 AM THURSDAY...
SATURDAY THROUGH SUNDAY NIGHT:
A POTENT UPPER LOW AND ASSOCIATED SURFACE COLD FRONT ARE EXPECTED TO
AFFECT CENTRAL NC THIS WEEKEND... RESULTING IN A GOOD CHANCE FOR
SHOWERS AND THUNDERSTORMS.
MODELS CONTINUE TO DIFFER SOME ON THE TRACK OF THE UPPER LOW... BUT
THE OVERALL TREND HAS BEEN TO THE SOUTHERN EDGE OF THE GUIDANCE FROM
A COUPLE OF DAYS AGO. THE 12Z ECMWF APPEARS TO BE A GOOD COMPROMISE
BETWEEN THE 00Z NAM (THROUGH 12Z SUNDAY... 84 HOURS) AND THE 00Z
GFS... LIFTING THE UPPER LOW ACROSS THE AREA IN A SW TO NE FASHION
ON SUNDAY. HOWEVER... AHEAD OF THIS FEATURE... AN ASSOCIATED SURFACE
COLD FRONT IS EXPECTED TO TRACK ACROSS THE AREA ON SATURDAY
AFTERNOON. MODELS DIFFER ON THE AMOUNT OF CONVECTION ALONG AND AHEAD
OF THIS FRONT. WHICH APPEARS TO BE TIED TO SEVERAL FACTORS... HOW
MUCH SURFACE HEATING WILL WE REALIZE (INSTABILITY) AND HOW POSSIBLE
CONVECTION SOUTH OF THE AREA MAY DISRUPT MOISTURE TRANSPORT (STILL A
BIT FAR OUT TO MAKE A GOOD ASSESSMENT ON THIS YET WITH ANY
CONFIDENCE). IN FACT THE LATEST MAV AND MET GUIDANCE HAS A GOOD 5-10
DEGREE SPREAD IN HIGHS FOR SATURDAY. HOWEVER... WITH INCREASING DEEP
LAYER SHEAR (~30-50 KTS) AS THE SYSTEM APPROACHES AND THE POTENTIAL
FOR MODEST SURFACE INSTABILITY (UPWARDS OF 1500 J/KG) ON SATURDAY
AFTERNOON ALONG WITH FALLING HEIGHTS ALOFT EXPECT WE MAY SEE SOME
KIND OF ORGANIZED SEVERE THREAT DEVELOP ACROSS THE AREA... WITH THE
MAIN THREAT FROM DAMAGING WINDS AND HAIL. WILL CONTINUE LIKELY POPS
FOR SATURDAY... WHICH LOOKS LIKE A GOOD BET AT THIS TIME. POPS FOR
SATURDAY NIGHT AND SUNDAY... WILL DEPEND ON THE TIMING AND TRACK OF
THE UPPER LOW. FOR NOW WILL CONTINUE CHANCE POPS FOR BOTH PERIODS
(GFS ATTEMPTS TO DRY SLOT US SATURDAY NIGHT). GIVEN THE UPPER LOW IS
EXPECTED TO TRACK ACROSS THE AREA ON SUNDAY... RESULTING IN
STEEPENING LAPSE RATES AND LOWERING FREEZING LEVELS... EXPECT WE
COULD SEE SOME INSTABILITY SHOWERS AND STORMS DURING PEAK HEATING.
WITH THIS TYPE OF A SETUP WE MAY SEE SOME OF THE STRONGER STORMS
SUNDAY AFTERNOON PRODUCE AT LEAST MARGINALLY SEVERE HAIL. THUS...
WILL MENTION THE POTENTIAL FOR SEVERE STORMS FOR BOTH SATURDAY AND
SUNDAY IN THE HWO.
HIGH TEMPS ON SATURDAY WILL DEPEND ON THE AMOUNT OF CLOUD COVER AND
PRECIP. FOR NOW WILL CONTINUE TO GO WITH HIGH IN THE 73-77 DEGREE
RANGE ACROSS THE AREA FROM NW TO E. EXPECT LOWS SUNDAY MORNING WILL
BE GENERALLY IN THE MID TO UPPER 50S. GIVEN THE UPPER LOW TRACKING
ACROSS THE AREA AND THE POTENTIAL FOR SHOWERS AND STORMS ON
SUNDAY... WILL CONTINUE TO TREND HIGH TEMPS BELOW STATISTICAL
GUIDANCE THEN... GENERALLY LOWER 70S... WITH POSSIBLY SOME MID 70S
SOUTH. LOWS MONDAY MORNING ARE EXPECTED TO GENERALLY BE IN THE LOWER
50S... AS THE MID/UPPER LOW BEGINS TO LIFT OFF TO THE NORTHEAST AND
RAIN CHANCES COME TO AN END.
MONDAY THROUGH WEDNESDAY:
MID/UPPER LEVEL RIDGING IS EXPECTED TO BUILD BACK INTO THE AREA FOR
EARLY NEXT WEEK... WHILE SURFACE HIGH PRESSURE BUILDS ACROSS THE
AREA. THIS WILL RESULT IN A RETURN TO DRY WEATHER WITH LOWER
DEWPOINTS. HOWEVER... HAVE LOWERED TEMPS A BIT FROM PREVIOUS
FORECASTS... GIVEN THE POTENTIAL FOR A DRY BACKDOOR CLOUD DROPPING
SOUTHWARD INTO THE AREA AS A NORTHERN STREAM S/W TRACKS ESE`WARD
ACROSS SOUTHERN CANADA AND NEW ENGLAND EARLY NEXT WEEK. THUS... WILL
GO WITH HIGH TEMPS GENERALLY IN THE LOWER 70S DURING THIS PERIOD...
WITH POSSIBLY SOME 60S ACROSS OUR NORTHEAST ON TUESDAY AND/OR
WEDNESDAY. LOW TEMPS DURING THE PERIOD ARE EXPECTED TO BE IN THE 40S
TO AROUND 50.
&&
.AVIATION /18Z THURSDAY THROUGH MONDAY/...
AS OF 205 PM THURSDAY...
THIS MORNINGS FOG AND STRATUS HAS LIFTED TO VFR LEVEL CUMULUS
EVERYWHERE EXCEPT FOR THE TRIAD WHERE KGSO/KINT STILL REPORT 2-3K FT
CEILINGS. SATELLITE TRENDS SUGGEST CEILINGS THERE SHOULD SCATTER
OUT BY 20Z...WITH LESS CHANCE OF A SHOWER OR STORM THAN AREAS TO THE
EAST. OVER THE PIEDMONT AND COASTAL PLAIN...ISOLATED TO SCATTERED
SHOWERS WILL DEVELOP AND MAY IMPACT ANY TERMINAL. CONFIDENCE IN A
SHOWER WITH BRIEF HEAVY RAIN AND MVFR CEILINGS IS GREATEST AT KFAY
AND KRWI. CONVECTION WILL DIE OFF AFTER SUNSET...WITH STRATUS AND
FOG POSSIBLE AGAIN FRIDAY MORNING. BASED ON PREVIOUS
MORNINGS...PROBABILITY OF RAINFALL THIS EVENING...AND STATISTICAL
GUIDANCE..CONFIDENCE IS HIGHEST AT KRDU/KFAY/KRWI.
OUTLOOK....SHOWERS AND STORMS...POSSIBLY SEVERE...LATER FRIDAY NIGHT
INTO SATURDAY AS A COLD FRONT MOVES ACROSS THE AREA. SHOWERS AND
ISOLATED STORMS WILL THEN BE POSSIBLE AGAIN ON SUNDAY AS THE
ASSOCIATED UPPER LOW CROSSES CENTRAL NC. CONDITIONS SHOULD IMPROVE
TO VFR FOR MONDAY AND TUESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS/SMITH
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1010 AM EDT THU MAR 22 2012
.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE ALOFT WILL MOVE AWAY FROM CENTRAL NC
TODAY. HIGH PRESSURE ALOFT WILL EXTEND ACROSS THE REGION TONIGHT AND
FRIDAY. AN AREA OF LOW PRESSURE WILL APPROACH FROM THE WEST FRIDAY
NIGHT AND SATURDAY...BRINGING UNSETTLED WEATHER TO CENTRAL NC
THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1010 AM THURSDAY...
LINGERING FOG HAS BECOME CONFINED TO THE SOUTHERN PIEDMONT THIS
MORNING...BUT EVEN REPORTING STATIONS IN THAT AREA ARE BEGINNING TO
SHOW SIGNS OF VSBYS AT OR ABOVE 1/2 MILE. STRATUS IS FAIRLY
WIDESPREAD WEST OF US HWY 1 BUT NEAR TERM GUIDANCE SUGGEST CLOUDS
WILL BREAK BY NOON AND SHOULD NOT HAVE A SIGNIFICANT IMPACT ON
AFTERNOON HEATING. MAIN CONCERN FOR THIS AFTERNOON WILL AGAIN BE
CONVECTIVE CONVERGE. THE WATER VAPOR CHANNEL APPEARS RELATIVELY
QUIET UPSTREAM OVER VA THIS MORNING WITH LITTLE IN THE WAY OF
OBVIOUS DISTURBANCES AND MUCH DRIER AIR ALOFT PENETRATING INTO
CENTRAL NC. THE MAIN CYCLONIC CIRCULATIONS OF THE UPPER LOW IS NOW
RIGHT ALONG THE OBX COAST. RUC DYNAMIC TROPOPAUSE FORECASTS SUGGEST
THERE MAY BE A WEAK JET AND SHALLOW DISTURBANCE OVER EASTERN PA/MD
THAT WILL DROP SOUTH ACROSS NORTHEAST NC THIS AFTERNOON. SPC
MESOANALYSIS SHOWS EARLY SIGNS OF AN INSTABILITY AXIS DEVELOPING
OVER NORTHEAST NC AND SOUTHEAST VA WHERE MID LEVEL TEMPS ARE
COOLEST. HI-RES MODELS ARE NOT PARTICULARLY ACTIVE WITH REGARDS TO
CONVECTION OVER THE NORTHEAST...BUT GIVEN THE ABOVE
OBSERVATIONS...WE WILL KEEP POPS HIGHEST OVER THE NORTHEAST CWA. TO
THE SOUTH...SEABREEZE AND SCATTERED CONVECTION OVER INLAND SC WHERE
DEEP MOISTURE IS GREATER MAY DRIFT NORTH AND WEST INTO THE SANDHILLS
AND SOUTHERN PIEDMONT LATER THIS AFTERNOON...BUT WEAK MID LEVEL
LAPSE RATES AND WIND FIELDS SHOULD LIMIT ANY MORE THAN AN ISOLATED
SEVERE STORM. HIGHS IN THE UPPER 70S TO AROUND 80. -SMITH
AS UPPER LEVEL LOW MOVES FARTHER AWAY FROM CENTRAL NC
TONIGHT...NARROW UPPER RIDGE WILL EXTEND N-S ACROSS THE REGION. THE
PRESENCE OF THE RIDGE ALOFT WILL RESULT IN CLEAR-PARTLY CLOUDY
SKIES. LIGHT WIND REGIME NEAR THE SURFACE ALONG WITH A RELATIVELY
MOIST AIR MASS IN THE BOUNDARY LAYER WILL CREATE CONDITIONS OPTIMAL
FOR FOG DEVELOPMENT. CONFIDENCE NOT HIGH ENOUGH TO MENTION DENSE FOG
IN THE FORECAST AT THIS TIME. MIN TEMPS UPPER 50S TO NEAR 60.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 305 AM THURSDAY...
FRIDAY...MID/UPPER LEVEL RIDGE OVER THE SE U.S. FRIDAY MORNING WILL
DRIFT EWD AS A DEEP UPPER LEVEL LOW OVER THE CENTRAL-SOUTHERN PLAINS
DRIFTS ENE INTO THE LOWER OH VALLEY. AS UPPER RIDGE AXIS MOVES
EWD....EXPECT TO SEE AN INCREASE IN MID/HIGH LEVEL CLOUDS OCCURRING
OUT AHEAD OF THE DEEP CENTRAL U.S. LOW. BELIEVE INITIAL SURGE OF
MID/HIGH LEVEL CLOUDS WILL BE OPAQUE ENOUGH TO ALLOW AT LEAST
FILTERED SUNSHINE IN THE PIEDMONT DURING THE AFTERNOON. LOW LEVEL
SLY FLOW WILL LIKELY AID TO INITIATE ISOLATED/SCATTERED CONVECTION
OVER THE HIGHER TERRAIN OF WESTERN NC. DEVELOPING SSW FLOW SHOULD
KEEP BULK OF CONVECTION OVER THE TERRAIN AND NOT CREEP INTO THE
PIEDMONT. THUS...HAVE TRIMMED/DELAYED PRECIP ONSET IN THE WEST
FRIDAY AFTERNOON. LOW LEVEL THICKNESSES REMAIN AROUND 1390M FRIDAY
AFTERNOON. WITH DEVELOPING SW SURFACE FLOW ON THE BACK SIDE OF THE
HIGH AIDING TO BRING ADDITIONAL WARMTH ...AFTERNOON TEMPS AROUND
80/LOWER 80S HIGHLY PROBABLE.
FRIDAY NIGHT...UPPER LEVEL LOW WILL CONTINUE TO ADVANCE SLOWLY ESE
TOWARD THE CAROLINAS. BEGINNING TO SEE MODEL DIFFERENCES IN THE
TIMING WITH THE NAM NOTICEABLY SLOWER COMPARED TO THE GFS/ECMWF.
APPEARS BULK OF DEEPER MOISTURE AND LIFT WILL HOLD OFF UNTIL LATE
FRIDAY NIGHT WITH LOCALES ALONG AND EAST OF HIGHWAY 1 LIKELY
REMAINING DRY UNTIL DAYBREAK SATURDAY. HAVE ADJUSTED PRECIP TIMING A
TAD IN THE WESTERN PIEDMONT...DELAYING LIKELY POPS UNTIL AFTER
MIDNIGHT OR 2 AM. REMAINING MILD WITH OVERNIGHT TEMPS IN THE UPPER
50S TO LOWER 60S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 250 AM THURSDAY...
SATURDAY THROUGH SUNDAY NIGHT:
A POTENT UPPER LOW AND ASSOCIATED SURFACE COLD FRONT ARE EXPECTED TO
AFFECT CENTRAL NC THIS WEEKEND... RESULTING IN A GOOD CHANCE FOR
SHOWERS AND THUNDERSTORMS.
MODELS CONTINUE TO DIFFER SOME ON THE TRACK OF THE UPPER LOW... BUT
THE OVERALL TREND HAS BEEN TO THE SOUTHERN EDGE OF THE GUIDANCE FROM
A COUPLE OF DAYS AGO. THE 12Z ECMWF APPEARS TO BE A GOOD COMPROMISE
BETWEEN THE 00Z NAM (THROUGH 12Z SUNDAY... 84 HOURS) AND THE 00Z
GFS... LIFTING THE UPPER LOW ACROSS THE AREA IN A SW TO NE FASHION
ON SUNDAY. HOWEVER... AHEAD OF THIS FEATURE... AN ASSOCIATED SURFACE
COLD FRONT IS EXPECTED TO TRACK ACROSS THE AREA ON SATURDAY
AFTERNOON. MODELS DIFFER ON THE AMOUNT OF CONVECTION ALONG AND AHEAD
OF THIS FRONT. WHICH APPEARS TO BE TIED TO SEVERAL FACTORS... HOW
MUCH SURFACE HEATING WILL WE REALIZE (INSTABILITY) AND HOW POSSIBLE
CONVECTION SOUTH OF THE AREA MAY DISRUPT MOISTURE TRANSPORT (STILL A
BIT FAR OUT TO MAKE A GOOD ASSESSMENT ON THIS YET WITH ANY
CONFIDENCE). IN FACT THE LATEST MAV AND MET GUIDANCE HAS A GOOD 5-10
DEGREE SPREAD IN HIGHS FOR SATURDAY. HOWEVER... WITH INCREASING DEEP
LAYER SHEAR (~30-50 KTS) AS THE SYSTEM APPROACHES AND THE POTENTIAL
FOR MODEST SURFACE INSTABILITY (UPWARDS OF 1500 J/KG) ON SATURDAY
AFTERNOON ALONG WITH FALLING HEIGHTS ALOFT EXPECT WE MAY SEE SOME
KIND OF ORGANIZED SEVERE THREAT DEVELOP ACROSS THE AREA... WITH THE
MAIN THREAT FROM DAMAGING WINDS AND HAIL. WILL CONTINUE LIKELY POPS
FOR SATURDAY... WHICH LOOKS LIKE A GOOD BET AT THIS TIME. POPS FOR
SATURDAY NIGHT AND SUNDAY... WILL DEPEND ON THE TIMING AND TRACK OF
THE UPPER LOW. FOR NOW WILL CONTINUE CHANCE POPS FOR BOTH PERIODS
(GFS ATTEMPTS TO DRY SLOT US SATURDAY NIGHT). GIVEN THE UPPER LOW IS
EXPECTED TO TRACK ACROSS THE AREA ON SUNDAY... RESULTING IN
STEEPENING LAPSE RATES AND LOWERING FREEZING LEVELS... EXPECT WE
COULD SEE SOME INSTABILITY SHOWERS AND STORMS DURING PEAK HEATING.
WITH THIS TYPE OF A SETUP WE MAY SEE SOME OF THE STRONGER STORMS
SUNDAY AFTERNOON PRODUCE AT LEAST MARGINALLY SEVERE HAIL. THUS...
WILL MENTION THE POTENTIAL FOR SEVERE STORMS FOR BOTH SATURDAY AND
SUNDAY IN THE HWO.
HIGH TEMPS ON SATURDAY WILL DEPEND ON THE AMOUNT OF CLOUD COVER AND
PRECIP. FOR NOW WILL CONTINUE TO GO WITH HIGH IN THE 73-77 DEGREE
RANGE ACROSS THE AREA FROM NW TO E. EXPECT LOWS SUNDAY MORNING WILL
BE GENERALLY IN THE MID TO UPPER 50S. GIVEN THE UPPER LOW TRACKING
ACROSS THE AREA AND THE POTENTIAL FOR SHOWERS AND STORMS ON
SUNDAY... WILL CONTINUE TO TREND HIGH TEMPS BELOW STATISTICAL
GUIDANCE THEN... GENERALLY LOWER 70S... WITH POSSIBLY SOME MID 70S
SOUTH. LOWS MONDAY MORNING ARE EXPECTED TO GENERALLY BE IN THE LOWER
50S... AS THE MID/UPPER LOW BEGINS TO LIFT OFF TO THE NORTHEAST AND
RAIN CHANCES COME TO AN END.
MONDAY THROUGH WEDNESDAY:
MID/UPPER LEVEL RIDGING IS EXPECTED TO BUILD BACK INTO THE AREA FOR
EARLY NEXT WEEK... WHILE SURFACE HIGH PRESSURE BUILDS ACROSS THE
AREA. THIS WILL RESULT IN A RETURN TO DRY WEATHER WITH LOWER
DEWPOINTS. HOWEVER... HAVE LOWERED TEMPS A BIT FROM PREVIOUS
FORECASTS... GIVEN THE POTENTIAL FOR A DRY BACKDOOR CLOUD DROPPING
SOUTHWARD INTO THE AREA AS A NORTHERN STREAM S/W TRACKS ESE`WARD
ACROSS SOUTHERN CANADA AND NEW ENGLAND EARLY NEXT WEEK. THUS... WILL
GO WITH HIGH TEMPS GENERALLY IN THE LOWER 70S DURING THIS PERIOD...
WITH POSSIBLY SOME 60S ACROSS OUR NORTHEAST ON TUESDAY AND/OR
WEDNESDAY. LOW TEMPS DURING THE PERIOD ARE EXPECTED TO BE IN THE 40S
TO AROUND 50.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 730 AM THURSDAY...
SIMILAR TO THE PAST FEW MORNINGS...A MOIST AIR MASS NEAR THE SURFACE
COUPLED WITH LIGHT WINDS AND CLEAR SKIES ALOFT HAS ALLOWED FOG TO
DEVELOP WITH POCKETS OF DENSE FOG AND LOW STRATUS. THE FOG AND
STRATUS WILL BEGIN TO LIFT/DISSIPATE BETWEEN 8-10 AM INTO A BROKEN
STRATUS DECK BETWEEN 1000-2000FT...THEN INTO A SCATTERED CU FIELD BY
MID DAY WITH BASES 3500-4500FT.
THE PASSAGE OF A MID LEVEL TROUGH EARLY THIS MORNING MAY TRIGGER A
FEW SHOWERS TO THE NORTH OF KGSO/KRDU AND KRWI. OTHERWISE...THE
HIGHEST THREAT FOR AFTERNOON SCATTERED CONVECTION WILL BE ALONG AND
EAST OF I-95 WITH ONLY ISOLATED CONVECTION ANTICIPATED OVER THE
PIEDMONT. IN ANTICIPATION OF LIMITED COVERAGE...WILL NOT MENTION ANY
CONVECTION IN THE TAF FORECAST AT THIS TIME.
AN AREA OF HIGH PRESSURE ALOFT WILL EXTEND ACROSS THE REGION TONIGHT
INTO FRIDAY. THIS WILL RESULT IN CLEAR-PARTLY CLOUDY SKIES AND NO
CONVECTION. AGAIN...A MOIST NEAR SURFACE AIR MASS AND CLEAR SKIES
ALOFT SHOULD ALLOW FOG TO DEVELOP EARLY FRIDAY MORNING WITH 3-4
HOURS OF IFR/LIFR VISIBILITY PROBABLE AT MOST TAF SITES.
AN AREA OF LOW PRESSURE WILL APPROACH FROM THE WEST LATE FRIDAY AND
INFLUENCE OUR WEATHER THROUGH THE WEEKEND. EXPECT PERIODS OF SHOWERS
AND T-STORMS ALONG WITH EXTENDED STRETCHES OF MVFR/IFR CEILING AND
VISIBILITY. WEATHER CONDITIONS SHOULD IMPROVE ON MONDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS/SMITH
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1000 AM EDT THU MAR 22 2012
.SYNOPSIS...
MILD TEMPERATURES ACCOMPANIED BY SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS CAN BE EXPECTED THE NEXT FEW DAYS AS BERMUDA HIGH
PRESSURE CIRCULATES MOIST AIR ONSHORE. SATURDAY WILL BRING A GOOD
CHANCE OF RAINFALL AND POSSIBLY STRONG THUNDERSTORMS...AS AN UPPER
LOW AND COLD FRONT APPROACH THE AREA. COOLER AND DRIER CONDITIONS
ARE EXPECTED SUNDAY THROUGH EARLY NEXT WEEK AS HIGH PRESSURE BUILDS
INTO THE REGION...WITH A GRADUAL WARMING TREND THROUGH MID WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM THURSDAY...WEAK OUTFLOW BOUNDARY WILL SLIP SOUTH ALONG
THE NORTH COAST THROUGH LATE MORNING...LIKELY TRIPPING OFF A FEW
SHOWERS FROM 10 MILE BOX-CARS TO FIGURE 8 ISLAND INTO PARTS OF
PENDER COUNTY INTO MIDDAY. DRY AIR ALOFT EVIDENCED IN SOUNDINGS AND
VAPOR TRENDS WILL LIMIT CONVECTIVE STRENGTH TODAY...BUT ENOUGH
MOISTURE...INSTABILITY AND BOUNDARIES WILL EXIST TO SUSTAIN SCT
SHOWERS AND ISOLATED TSTMS THROUGH THE AFTERNOON. SLIGHTLY COOLER
AIR ALOFT OVER NC SEEMS LIKELY TO SLIP FARTHER SOUTHWARD AS THE
UPPER CIRCULATION OVER THE OUTER BANKS SAGS SE. STORMS TODAY WILL
EXHIBIT SLUGGISH MOTION...PERHAPS A SLOW DRIFT TO THE SE AS THE
TOWER CORES EXCEED 700 MB. SO THERE IS A POTENTIAL FOR LOCALIZED
FLOODING TODAY AND HAIL...IN AND JUST AFTER PEAK DIURNAL HEATING.
THE SEA BREEZE IS ALSO EXPECTED TO PLAY A ROLE IN THE CONVECTION
TODAY...FOCUSING ACTIVITY INLAND AS THE DAY PROGRESSES.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...FRI LOOKS RATHER DRY AS BERMUDA HIGH WEAKLY
HOLDS ON UNDER NARROW 5H RIDGE. WEAK SUBSIDENCE UNDER THE RIDGE
AXIS...WHICH WILL BE OVERHEAD DURING FRI...AND LACK OF ANY
SIGNIFICANT UPPER FEATURE LIMITS AFTERNOON CONVECTION. ANTICIPATE
SOME ISOLATED STORMS FIRING OFF THE SEA BREEZE. CURRENT SLIGHT
CHANCE POP IS MORE THAN ADEQUATE. UPPER RIDGE AXIS SHIFTS OFFSHORE
FRI NIGHT AS STACKED LOW OVER THE CENTRAL MISSISSIPPI VALLEY MOVES
EAST. DEEP GULF MOISTURE STARTS TO SPREAD OVER THE AREA FRI NIGHT AS
FLOW ALOFT STARTS TO BACK TO SOUTHWESTERLY.
SAT AND SAT NIGHT LOOKING LIKE A SIGNIFICANT RAIN EVENT WITH THE
POTENTIAL FOR RAINFALL TOTALS EXCEEDING 1 INCH ACROSS MUCH OF THE
AREA. DEEP SOUTHWEST FLOW CONTINUES TO PUMP GULF MOISTURE INTO THE
SOUTHEAST WITH PRECIPITABLE WATER VALUES EXCEEDING 1.5 INCH.
ADDITIONALLY THE LOCATION OF THE UPPER LOW PLACES THE CAROLINAS IN A
AN AREA OF FAVORABLE DIVERGENCE ALOFT. ALTHOUGH FAIRLY DEEP
CONVECTION IS EXPECTED DOES NOT LOOK LIKE MUCH OF A SEVERE THREAT.
MID LEVEL LAPSE RATES REMAIN UNDER 6C/KM AND WINDS DO NOT CHANGE
MUCH WITH HEIGHT...HELICITY VALUES STAY UNDER 50 FOR MOST OF SAT.
WHILE THERE IS A LOW LEVEL JET IT IS NOT VERY STRONG...35 TO 40 KT.
CANNOT RULE OUT THUNDER GIVEN THE DEEPER CONVECTION...BUT LACK OF
STRONG UPWARD MOTION WILL LIMIT STRONG/SEVERE STORM POTENTIAL. BEST
CHANCE OF THUNDER MAY COME WITH PASSAGE OF COLD FRONT LATE SAT
NIGHT...THOUGH THE LOSS OF DIURNAL INSTABILITY MAY OFFSET THE
INCREASE IN LIFT PROVIDED BY THE FRONT. LOW LEVELS START TO DRY OUT
BEHIND THE FRONT...BUT WITH THE UPPER LOW TRAILING THE FRONT MID
LEVEL REMAIN MOIST. LIMITED FORCING ALOFT LATE SAT NIGHT MAY KEEP
PRECIP FROM FALLING THROUGH THE END OF THE PERIOD BUT SKIES REMAIN
CLOUDY.
TEMPERATURES WELL ABOVE CLIMO FRI/FRI NIGHT WILL DROP A BIT FOR
SAT/SAT NIGHT...THOUGH BOTH HIGHS AND LOWS WILL STILL BE SEVERAL
DEGREES ABOVE CLIMO.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 3 AM THURSDAY...UPPER LOW OVER CENTRAL NC AT THE START OF THE
PERIOD SLOWLY SHIFTS EAST...MOVING OFF THE COAST SUN NIGHT.
PROXIMITY TO THE UPPER LOW AND ITS DEEP MOISTURE WARRANTS CARRYING A
POP ALL DAY SUN DESPITE THE LOW LEVELS STARTING TO DRY OUT. WILL
CARRY HIGHEST POP SUN MORNING WHERE PRECIP ASSOCIATED WITH THE FRONT
MAY LINGER...ESPECIALLY IF THE FRONT SLOWS DOWN. WILL HAVE LOWER POP
IN THE AFTERNOON...LOW CHANCE VS THE MORNING HIGH CHANCE. EXIT OF
UPPER LOW SUN NIGHT ALLOWS DEEP NORTHWEST FLOW TO DEVELOP...DRYING
THE AREA OUT. 5H RIDGE STARTS TO BUILD EAST MON AS SURFACE HIGH
BUILDS DOWN THE EAST COAST. SURFACE HIGH MIGRATES OFFSHORE SETTING
UP SHOP NEAR BERMUDA WITH UPPER RIDGE REMAINING IN PLACE THROUGH
WED. GUIDANCE DOES SHOW THE UPPER RIDGE STARTING FLATTEN LATE
WED...BUT THIS MAY BE PREMATURE. TEMPERATURES WILL REMAIN ABOVE
CLIMO THROUGH THE PERIOD...THOUGH ONLY BY A FEW DEGREES INSTEAD OF 8
TO 10 DEGREES.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 12Z...FOG IS NOT AS DEEP AS IN PAST DAYS. ANY FOG LEFTOVER AT
TAF ISSUANCE SHOULD QUICKLY BURN OFF. MODERATE CONFIDENCE FOR
CONVECTION BY EARLY AFTERNOON...EXCEPT FOR THE IMMEDIATE COAST AS
THE SEA BREEZE RESULTANT WILL PUSH CONVECTION WESTWARD. HIGH
PRESSURE ANCHORED OFFSHORE WILL CONTINUE TO GIVE US A SOUTHERLY
GRADIENT...A BIT MORE SOUTHEASTERLY ALONG THE COAST IN THE
AFTERNOON. HRRR MODEL ADVERTISING A GOOD BIT OF CONVECTION FOR FLO
AND LBT AFTER 17Z. LIGHT WINDS TONIGHT WITH POSSIBLE LIGHT FOG.
EXTENDED OUTLOOK...SCATTERED SHOWERS/THUNDERSTORMS WITH TEMPO
MVFR/IFR POSSIBLE THROUGH SUNDAY. THE BEST CHANCE FOR
THUNDERSTORMS WILL BE SATURDAY. VFR MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM THURSDAY...BERMUDA HIGH PRESSURE OFFSHORE WILL MAINTAIN
A WEAK SOUTHERLY GRADIENT OVER THE WATERS TODAY...BECOMING MORE
SOUTHWEST OVERNIGHT AS HIGH PRESSURE SHIFTS SOUTHWARD. WINDS WILL
GENERALLY STAY ON THE LIGHT SIDE...AROUND 10 KTS. SEAS WILL BE A
BIT HIGHER THAN EXPECTED GIVEN THE LOW WIND SPEEDS. THIS WILL BE DUE
TO THE INCREASING SWELL HEIGHT CONTRIBUTION TO THE TOTAL SEA STATE.
EXPECT SEAS MAINLY IN THE 3 TO 4 FT RANGE THROUGH THE NEAR TERM.
ISOLATED SHOWERS AND TSTMS CAN BE EXPECTED ON THE WATERS AS WELL.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...LIGHT SOUTHERLY FLOW ON FRI WILL INCREASE FRI
NIGHT AS GRADIENT TIGHTENS UP AHEAD OF A COLD FRONT. SPEEDS STARTING
OUT AROUND 10 KT WILL INCREASE TO 10 TO 15 KT FRI NIGHT. WINDS
CONTINUE TO INCREASE SAT AS GRADIENT TIGHTENS FURTHER. SPEEDS TOP
OUT CLOSE TO 20 KT LATE SAT EVENING...JUST AHEAD OF THE COLD FRONT.
ONCE FRONT PUSHES EAST OF THE WATERS...CLOSE TO THE END OF THE
PERIOD...OFF SHORE FLOW DEVELOPS. NOT REALLY ANY COLD ADVECTION TO
SPEAK OF SO WINDS AT THE END OF THE PERIOD WILL BE DRIVEN BY THE
GRADIENT. SEAS AROUND 3 FT FRI INCREASE TO 3 TO 5 FT SAT IN RESPONSE
TO WINDS PICKING UP. SEAS MAY BRIEFLY TOUCH 6 FT AWAY FROM THE COAST
LATE SAT...POTENTIALLY REQUIRING A SHORT DURATION SCA AS THE PERIOD
ENDS.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 3 AM THURSDAY...WESTERLY FLOW WILL DEVELOP BEHIND THE COLD
FRONT SUN WITH WINDS BECOMING NORTHWEST SUN NIGHT. GRADIENT WILL
KEEP SPEEDS AROUND 15 KT WITH WINDS VEERING TO NORTHERLY ON MON.
GRADIENT STARTS TO RELAX LATE MONDAY WITH WINDS DROPPING TO 10 KT.
OFFSHORE COMPONENT TO WINDS KNOCKS SEAS BACK TO 3 TO 4 FT SUN.
FURTHER DECREASE IN SPEEDS MON WILL RESULT IN SEAS DROPPING TO 3 FT
LATE IN THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MJC
SHORT TERM...III
LONG TERM...III
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
650 AM EDT THU MAR 22 2012
.SYNOPSIS...
AN UPPER LEVEL LOW PRESSURE SYSTEM OVER VIRGINIA WILL SHIFT SOUTHWARD
TOWARD THE CAROLINAS PROVIDING AN INCREASED CHANCE OF THUNDERSTORMS
TODAY. HIGH PRESSURE WILL RETURN BRIEFLY ON FRIDAY BEFORE GIVING
WAY TO A COLD FRONT ON SATURDAY WITH INCREASED CHANCES FOR
THUNDERSTORMS. HIGH PRESSURE WILL RETURN EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 6:30 AM THURSDAY...CUT BACK TO SILENT POPS FOR MUCH OF OUR
INLAND SITES THIS MORNING...SLIGHT CHANCE ELSEWHERE. ALSO REMOVED
MENTION OF FOG AS IT HAS BEEN QUITE SPOTTY THIS MORNING. NO
CHANGES TO THE GOING FORECAST FOR THIS AFTERNOON AS DESCRIBED IN
PREVIOUS DISCUSSION BELOW:
OVERALL PATTERN WILL FINALLY SHOW SOME SIGNS OF EVOLUTION DURING
THE NEAR TERM. THE BERMUDA HIGH ANCHORED WELL OFFSHORE WILL BEGIN
TO BECOME DEPRESSED SOUTHWARD AS A CUT- OFF UPPER LOW CENTERED
OVER OKLAHOMA STARTS TRACKING NORTHEAST. A BROAD WEAKNESS IN THE
UPPER RIDGE OVER EASTERN CONUS/WESTLANT WILL PUSH EASTWARD TODAY
AND TONIGHT.
SEE NO TRIGGERS FOR STRONG OR WIDESPREAD CONVECTION TODAY.
HOWEVER...WITH ABOUT AN INCH AN A QUARTER OF P/W
AVAILABLE...DEWPOINTS OF AROUND 60 AND ABOVE NORMAL TEMPERATURES WE
WOULD EXPECT ISOLATED TO SCATTERED CONVECTION THIS AFTERNOON AND
EVENING. ISOLATED LIGHT SHOWER ACTIVITY IS ALSO POSSIBLE THIS
MORNING AS GUIDANCE DOES SHOW SOME MODEST FORCING IN THE CURRENT
JUICY...ALMOST TROPICAL...AIRMASS.
AS OVERALL PATTERN HAS NOT CHANGED THAT MUCH EXPECT TEMPERATURES
WILL CONTINUE TO RUN WELL ABOVE NORMAL. HIGHS RANGING FROM THE UPPER
70S TO AROUND 80 THIS AFTERNOON...LOWS IN THE UPPER 50S.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...FRI LOOKS RATHER DRY AS BERMUDA HIGH WEAKLY
HOLDS ON UNDER NARROW 5H RIDGE. WEAK SUBSIDENCE UNDER THE RIDGE
AXIS...WHICH WILL BE OVERHEAD DURING FRI...AND LACK OF ANY
SIGNIFICANT UPPER FEATURE LIMITS AFTERNOON CONVECTION. ANTICIPATE
SOME ISOLATED STORMS FIRING OFF THE SEA BREEZE. CURRENT SLIGHT
CHANCE POP IS MORE THAN ADEQUATE. UPPER RIDGE AXIS SHIFTS OFFSHORE
FRI NIGHT AS STACKED LOW OVER THE CENTRAL MISSISSIPPI VALLEY MOVES
EAST. DEEP GULF MOISTURE STARTS TO SPREAD OVER THE AREA FRI NIGHT AS
FLOW ALOFT STARTS TO BACK TO SOUTHWESTERLY.
SAT AND SAT NIGHT LOOKING LIKE A SIGNIFICANT RAIN EVENT WITH THE
POTENTIAL FOR RAINFALL TOTALS EXCEEDING 1 INCH ACROSS MUCH OF THE
AREA. DEEP SOUTHWEST FLOW CONTINUES TO PUMP GULF MOISTURE INTO THE
SOUTHEAST WITH PRECIPITABLE WATER VALUES EXCEEDING 1.5 INCH.
ADDITIONALLY THE LOCATION OF THE UPPER LOW PLACES THE CAROLINAS IN A
AN AREA OF FAVORABLE DIVERGENCE ALOFT. ALTHOUGH FAIRLY DEEP
CONVECTION IS EXPECTED DOES NOT LOOK LIKE MUCH OF A SEVERE THREAT.
MID LEVEL LAPSE RATES REMAIN UNDER 6C/KM AND WINDS DO NOT CHANGE
MUCH WITH HEIGHT...HELICITY VALUES STAY UNDER 50 FOR MOST OF SAT.
WHILE THERE IS A LOW LEVEL JET IT IS NOT VERY STRONG...35 TO 40 KT.
CANNOT RULE OUT THUNDER GIVEN THE DEEPER CONVECTION...BUT LACK OF
STRONG UPWARD MOTION WILL LIMIT STRONG/SEVERE STORM POTENTIAL. BEST
CHANCE OF THUNDER MAY COME WITH PASSAGE OF COLD FRONT LATE SAT
NIGHT...THOUGH THE LOSS OF DIURNAL INSTABILITY MAY OFFSET THE
INCREASE IN LIFT PROVIDED BY THE FRONT. LOW LEVELS START TO DRY OUT
BEHIND THE FRONT...BUT WITH THE UPPER LOW TRAILING THE FRONT MID
LEVEL REMAIN MOIST. LIMITED FORCING ALOFT LATE SAT NIGHT MAY KEEP
PRECIP FROM FALLING THROUGH THE END OF THE PERIOD BUT SKIES REMAIN
CLOUDY.
TEMPERATURES WELL ABOVE CLIMO FRI/FRI NIGHT WILL DROP A BIT FOR
SAT/SAT NIGHT...THOUGH BOTH HIGHS AND LOWS WILL STILL BE SEVERAL
DEGREES ABOVE CLIMO.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 3 AM THURSDAY...UPPER LOW OVER CENTRAL NC AT THE START OF THE
PERIOD SLOWLY SHIFTS EAST...MOVING OFF THE COAST SUN NIGHT.
PROXIMITY TO THE UPPER LOW AND ITS DEEP MOISTURE WARRANTS CARRYING A
POP ALL DAY SUN DESPITE THE LOW LEVELS STARTING TO DRY OUT. WILL
CARRY HIGHEST POP SUN MORNING WHERE PRECIP ASSOCIATED WITH THE FRONT
MAY LINGER...ESPECIALLY IF THE FRONT SLOWS DOWN. WILL HAVE LOWER POP
IN THE AFTERNOON...LOW CHANCE VS THE MORNING HIGH CHANCE. EXIT OF
UPPER LOW SUN NIGHT ALLOWS DEEP NORTHWEST FLOW TO DEVELOP...DRYING
THE AREA OUT. 5H RIDGE STARTS TO BUILD EAST MON AS SURFACE HIGH
BUILDS DOWN THE EAST COAST. SURFACE HIGH MIGRATES OFFSHORE SETTING
UP SHOP NEAR BERMUDA WITH UPPER RIDGE REMAINING IN PLACE THROUGH
WED. GUIDANCE DOES SHOW THE UPPER RIDGE STARTING FLATTEN LATE
WED...BUT THIS MAY BE PREMATURE. TEMPERATURES WILL REMAIN ABOVE
CLIMO THROUGH THE PERIOD...THOUGH ONLY BY A FEW DEGREES INSTEAD OF 8
TO 10 DEGREES.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 12Z...FOG IS NOT AS DEEP AS IN PAST DAYS. ANY FOG LEFTOVER AT
TAF ISSUANCE SHOULD QUICKLY BURN OFF. MODERATE CONFIDENCE FOR
CONVECTION BY EARLY AFTERNOON...EXCEPT FOR THE IMMEDIATE COAST AS
THE SEA BREEZE RESULTANT WILL PUSH CONVECTION WESTWARD. HIGH
PRESSURE ANCHORED OFFSHORE WILL CONTINUE TO GIVE US A SOUTHERLY
GRADIENT...A BIT MORE SOUTHEASTERLY ALONG THE COAST IN THE
AFTERNOON. HRRR MODEL ADVERTISING A GOOD BIT OF CONVECTION FOR FLO
AND LBT AFTER 17Z. LIGHT WINDS TONIGHT WITH POSSIBLE LIGHT FOG.
EXTENDED OUTLOOK...SCATTERED SHOWERS/THUNDERSTORMS WITH TEMPO
MVFR/IFR POSSIBLE THROUGH SUNDAY. THE BEST CHANCE FOR
THUNDERSTORMS WILL BE SATURDAY. VFR MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 6:30 AM THURSDAY...BERMUDA HIGH PRESSURE OFFSHORE WILL KEEP
A WEAK SOUTHERLY GRADIENT OVER THE WATERS TODAY...BECOMING MORE
SOUTHWEST OVERNIGHT AS HIGH SHIFT SOUTHWARDS. WINDS WILL GENERALLY
STAY ON THE LIGHT SIDE...AROUND 10 KTS OR LESS. SEAS WILL BE A BIT
HIGHER THAN EXPECTED GIVEN THE LOW WIND SPEEDS. THIS WILL BE DUE
TO THE INCREASING SWELL HEIGHT CONTRIBUTION TO THE TOTAL SEA
STATE. EXPECT SEAS MAINLY IN THE 3 TO 4 FT RANGE THROUGH THE NEAR
TERM.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...LIGHT SOUTHERLY FLOW ON FRI WILL INCREASE FRI
NIGHT AS GRADIENT TIGHTENS UP AHEAD OF A COLD FRONT. SPEEDS STARTING
OUT AROUND 10 KT WILL INCREASE TO 10 TO 15 KT FRI NIGHT. WINDS
CONTINUE TO INCREASE SAT AS GRADIENT TIGHTENS FURTHER. SPEEDS TOP
OUT CLOSE TO 20 KT LATE SAT EVENING...JUST AHEAD OF THE COLD FRONT.
ONCE FRONT PUSHES EAST OF THE WATERS...CLOSE TO THE END OF THE
PERIOD...OFF SHORE FLOW DEVELOPS. NOT REALLY ANY COLD ADVECTION TO
SPEAK OF SO WINDS AT THE END OF THE PERIOD WILL BE DRIVEN BY THE
GRADIENT. SEAS AROUND 3 FT FRI INCREASE TO 3 TO 5 FT SAT IN RESPONSE
TO WINDS PICKING UP. SEAS MAY BRIEFLY TOUCH 6 FT AWAY FROM THE COAST
LATE SAT...POTENTIALLY REQUIRING A SHORT DURATION SCA AS THE PERIOD
ENDS.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 3 AM THURSDAY...WESTERLY FLOW WILL DEVELOP BEHIND THE COLD
FRONT SUN WITH WINDS BECOMING NORTHWEST SUN NIGHT. GRADIENT WILL
KEEP SPEEDS AROUND 15 KT WITH WINDS VEERING TO NORTHERLY ON MON.
GRADIENT STARTS TO RELAX LATE MONDAY WITH WINDS DROPPING TO 10 KT.
OFFSHORE COMPONENT TO WINDS KNOCKS SEAS BACK TO 3 TO 4 FT SUN.
FURTHER DECREASE IN SPEEDS MON WILL RESULT IN SEAS DROPPING TO 3 FT
LATE IN THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...REK
SHORT TERM...III
LONG TERM...III
AVIATION...43
MARINE...REK/III
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
144 AM EDT THU MAR 22 2012
.SYNOPSIS...
AN UPPER LEVEL LOW PRESSURE SYSTEM OVER VIRGINIA WILL SHIFT SOUTHWARD
TOWARD THE CAROLINAS PROVIDING AN INCREASED CHANCE OF THUNDERSTORMS
TROUGH THURSDAY. HIGH PRESSURE WILL RETURN BRIEFLY ON FRIDAY BEFORE
GIVING WAY TO A COLD FRONT ON SATURDAY WITH INCREASED CHANCES FOR
THUNDERSTORMS. HIGH PRESSURE WILL RETURN EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1030 PM WEDNESDAY...NO SIGNIFICANT CHANGES FROM THE PREVIOUS
UPDATE. I MADE A FEW MINOR UPWARD TWEAKS TO HOURLY TEMPERATURES AND
DEWPOINTS TO REFLECT LATEST OBSERVATIONS. PREVIOUS DISCUSSION FROM
730 PM FOLLOWS...
SURFACE HIGH PRESSURE OVER 500 MILES EAST OF THE NORTH CAROLINA
COAST IS ADVECTING A MILD & MOIST AIRMASS ONSHORE WITH TEMPERATURES
AND DEWPOINTS WELL ABOVE MID-MARCH CLIMATOLOGICAL NORMALS. THE UPPER
LEVEL PATTERN REMAINS VERY AMPLIFIED WITH A NARROW RIDGE AXIS ALONG
THE WESTERN SLOPES OF THE APPALACHIANS AND A SMALL UPPER LOW ACROSS
COASTAL VIRGINIA. THIS IS PRODUCING A NORTHWEST UPPER FLOW OVER THE
EASTERN CAROLINAS. COOL MID-LEVEL TEMPERATURES HAVE PREVENTED THE
DEVELOPMENT OF ANY KIND OF INVERSION ALOFT FOR DAYS NOW...AND THE
SURFACE AIRMASS HAS SUFFICIENT ENERGY TO GENERATE CONVECTION ANY
TIME SUFFICIENT SYNOPTIC LIFT EXISTS FROM A PASSING SHORTWAVE
DISTURBANCE ALOFT.
ONE UPPER DISTURBANCE HAS HELPED CREATE THE AREA OF THUNDERSTORMS
CURRENTLY ONGOING ACROSS EAST-CENTRAL NORTH CAROLINA. THIS
DISTURBANCE WILL PUSH OFFSHORE LATER THIS EVENING BUT WILL HAVE
TROUBLE INITIATING NEW CONVECTION CLOSER TO THE COAST WITH THE
COOLER MARINE AIRMASS IN PLACE BEHIND THE SEABREEZE FRONT. A SECOND
DISTURBANCE ALOFT WILL APPROACH FROM THE NORTHWEST JUST AFTER
DAYBREAK THURSDAY...AND WE`LL SHOW AN INCREASING TREND IN POPS AT
DAYBREAK LEADING INTO WHAT WILL PROBABLY BE A LATE MORNING ROUND OF
SHOWERS AND STORMS THURSDAY.
DEWPOINTS ARE RUNNING AS MUCH AS 5-6 DEGREES ABOVE GFS OR NAM MOS
BULLETINS INLAND...AND WITH THIS EXCESS BOUNDARY LAYER MOISTURE WE
ARE FORECASTING LOW TEMPERATURES SEVERAL DEGREES ABOVE MOS CONSENSUS
TONIGHT. LOWS SHOULD RANGE FROM THE UPPER 50S TO LOWER 60S. FAIRLY
LIGHT BOUNDARY LAYER WINDS AND AT LEAST SOME PERIODS OF CLEAR SKIES
OVERNIGHT MAY ALLOW FOR AREAS OF FOG TO DEVELOP. SOME FOG COULD
BECOME DENSE AFTER MIDNIGHT...ESPECIALLY WHERE RAIN FELL EARLIER
TODAY. WE`LL WATCH VISIBILITY TRENDS CLOSER FOR THE POSSIBLE
ISSUANCE OF DENSE FOG ADVISORIES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
AS OF 2:25 PM WEDNESDAY...MID LEVEL LOW WILL
CONTINUE TO AFFECT THE AREA AT LEAST THURSDAY. A SUBTLE DEFORMATION
ZONE WILL KEEP ACTIVITY OFFSHORE EARLY TRANSLATING TO INLAND LATE
MORNING THROUGH THE AFTERNOON MUCH LIKE IS TAKING PLACE TODAY. THE
LOW GETS BOOTED OFF TO THE EAST FRIDAY AS THE SYSTEM OUT WEST IS
FINALLY ON THE MOVE. STILL HAVE SLIGHT CHANCE POPS VIA SEA BREEZE
BUT VALUES ARE LESS THAN THURSDAY. VIA PERSISTENCE...ADDED AREAS OF
FOG FOR THURSDAY AND FRIDAY MORNING. REGARDING
TEMPERATURES...NUMERICAL GUIDANCE IS CLOSE BUT RECENT VERIFICATION
NUMBERS LEAN TOWARD THE MAV AND GENERALLY USED THESE NUMBERS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 2:25 PM WEDNESDAY...SIGNIFICANT PATTERN ANOMALIES CREATE THE
POTENTIAL FOR A WIDESPREAD RAIN EVENT FOR THE WKND. DRIER AIR AND
MORE SEASONABLE WEATHER WILL TAKE HOLD FOR THE BEGINNING OF THE
WEEK...BEFORE A WARMING TREND RETURNS BY WEDNESDAY.
STRONG UPPER RIDGE WHICH HAS BEEN DOMINATING THE EASTERN HALF OF THE
COUNTRY FINALLY BREAKS DOWN SATURDAY...AND ALL IT TAKES IS THE
EASTWARD PROGRESSION OF A -3 STANDARD DEVIATION UPPER LOW! THIS
LOW WILL BE IN THE OHIO VALLEY AT THE START OF THE PERIOD...AND THEN
PUSH SOUTHEAST TO BE OVER THE COASTAL CAROLINAS BY SUNDAY AFTN...AND
OFFSHORE BY MONDAY MORNING. SURFACE CYCLOGENESIS OCCURS ACROSS THE
MID ATLANTIC BENEATH THIS UPPER LOW WHICH THEN TRAILS A COLD FRONT
THROUGH THE AREA SUNDAY MORNING. DEEP SOUTHERLY FLOW AHEAD OF THIS
SYSTEM RAISES PWATS TO 1.5 INCHES...OR +2 STANDARD
DEVIATIONS...WHICH WILL PROVIDE THE JUICE FOR POTENTIAL PERIODS OF
HEAVY RAIN. AT THE SAME TIME...IMPULSES ROTATING AROUND THE UPPER
LOW AND THE APPROACH OF AN 80 KT UPPER JET WILL TAP THE HIGHER
THETA-E AIR SO EXPECT TSTMS MUCH OF SATURDAY AND HALF OF
SUNDAY...BEFORE DRYING OCCURS SUNDAY EVE. BEST RAIN CHANCES WILL
OCCUR SATURDAY NIGHT AND WILL BUMP POP TO JUST BELOW
CATEGORICAL...WITH LIKELY POP BOOK-ENDING THAT PERIOD.
BY SUNDAY NIGHT...DRIER NW FLOW DEVELOPS IN THE COLUMN AND UPPER
RIDGE BEGINS TO REBUILD ACROSS THE EAST. WILL CONTINUE SCHC POP
THROUGH MONDAY MORNING AS WEAK UPPER IMPULSES ROTATE AROUND
DEPARTING UPPER LOW...BUT LACK OF MOISTURE WILL PRECLUDE MUCH IN THE
WAY OF RAIN. SURFACE HIGH PRESSURE BUILDING DOWN FROM THE NORTH
CREATES COOL NORTH FLOW THROUGH TUESDAY...BEFORE THIS HIGH DRIFTS
OFFSHORE AND SOUTHERLY FLOW RETURNS ON WEDNESDAY.
TEMPS THROUGH THE PERIOD REMAIN ABOVE NORMAL. EVEN WITH CLOUDS AND
RAIN DURING THE WKND...TEMPS RISE AT LEAST INTO THE MID 70S AWAY
FROM THE COAST...ALTHOUGH HAVE GONE BELOW GUIDANCE MAXES. NEAR TO
JUST SLIGHTLY ABOVE CLIMO MON/TUE...REBOUNDING TO THE UPPER 70S BY
WEDNESDAY. MINS THROUGH THE PERIOD WILL REMAIN ABOVE CLIMO.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...POSSIBLE MVFR/IFR DURING THE EARLY MORNING HOURS DUE
TO FOG DEVELOPMENT. CURRENT RADAR IMAGERY DEPICTS SOME LEFTOVER
LIGHT RAIN SHOWERS ACROSS THE AREA WHICH WILL LIKELY LINGER
THROUGH A PORTION OF THE OVERNIGHT HOURS. ANTICIPATE CLOUDS TO
BUILD MORE ALONG THE COAST VERSUS THE INLAND SITES WHICH COULD
INHIBIT INTENSE FOG DEVELOPMENT. SFC WINDS WILL BE LIGHT
OVERNIGHT...AND THIS WITH LOW LEVEL MOISTURE FROM EARLIER RAINFALL
COULD ENHANCE FOG DEVELOPMENT ...ESPECIALLY AT THE INLAND
TERMINALS. FOR NOW HAVE KEPT MVFR/POTENTIAL IFR AT THE COASTAL
SITES...WITH MVFR/IFR AT THE INLAND SITES. BY MID
MORNING...ANTICIPATE ANY LINGERING FOG TO QUICKLY DISSIPATE GIVING
WAY TO VFR...WITH CLOUDS GIVING WAY TO BKN SKIES. WINDS THROUGHOUT
THE DAY WILL BE SOUTH-SOUTHEAST...WITH SUSTAINED WINDS AOB 12 KTS
THROUGH THE AFTERNOON...BECOMING LIGHT AFTER SUNSET. CANNOT RULE
OUT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS LATER
THROUGHOUT THE DAY SIMILAR TO THE PAST COUPLE OF DAYS.
EXTENDED OUTLOOK...SCATTERED SHOWERS/THUNDERSTORMS WITH TEMPO
MVFR/IFR POSSIBLE THROUGH SUNDAY. THE BEST CHANCE FOR
THUNDERSTORMS WILL BE SATURDAY. VFR MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM WEDNESDAY...NO SIGNIFICANT CHANGES FROM THE PREVIOUS
FORECAST UPDATE. THE LATEST FEW RUNS OF THE HRRR MODEL SHOW A
CLUSTER OF SHOWERS MAY DEVELOP 50-100 MILES SOUTH OF CAPE FEAR AFTER
MIDNIGHT AND APPROACH CAPE FEAR AROUND SUNRISE. PREVIOUS DISCUSSION
FROM 730 PM FOLLOWS...
HIGH PRESSURE IS CENTERED OVER 500 MILES EAST OF THE NORTH CAROLINA
COAST...WITH A MILD SOUTHEAST WIND BLOWING ACROSS THE COASTAL WATERS
THIS EVENING. DESTABILIZATION OF THE ATMOSPHERE PROVIDED BY THE WARM
GULF STREAM HAS HELPED CREATE OCCASIONAL SHOWERS 60+ MILES OFFSHORE.
THESE SHOWERS HAVE REMAINED QUITE SHALLOW SO FAR AND ARE THEREFORE
BEING STEERED BY THE LOW-LEVEL FLOW BELOW THE 700 MB LEVEL. THE
AVERAGE WIND VECTOR FROM THE SURFACE UP THROUGH 700 MB SHOULD VEER
MORE SOUTHWESTERLY WITH TIME TONIGHT...KEEPING THE BULK OF THESE
SHOWERS OUT OVER THE OFFSHORE WATERS. WE ARE INCLUDING CHANCES OF
SHOWERS MAINLY AFTER MIDNIGHT...WITH THE BEST CHANCE IN THE CAPE
FEAR REGION.
SEAS ARE MUCH HIGHER THAN ONE MIGHT EXPECT FROM JUST THE WIND ALONE
DUE TO A SUBSTANTIAL SOUTHEASTERLY SWELL PUSHING ONSHORE. SEA
HEIGHTS AT THE FRYING PAN SHOALS BUOY ARE 4 FEET WITH 7-8 SECOND
PERIOD. LITTLE CHANGE IS EXPECTED OVERNIGHT.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 2:25 PM WEDNESDAY...SUMMER LIKE PATTERN WILL CONTINUE
ACROSS THE WATERS WITH A SOUTH TO SOUTHEASTERLY FLOW. SPEEDS OF
TEN KNOTS OR SO INCREASING WITH THE SEA BREEZE. DO NOTICE A SUBTLE
INCREASE IN WINDS LATE FRIDAY/EARLY SATURDAY AS THE SYSTEM OUT
WEST INCHES CLOSER. SWAN SEAS ARE CONSISTENT IN A RANGE OF 2-4
FEET.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 2:25 PM WEDNESDAY...PREFRONTAL REGIME SATURDAY INTO SUNDAY
CREATES INCREASING SOUTHERLY WINDS AND BUILDING WAVE HEIGHTS.
PRESSURE GRADIENT TIGHTENS ON SATURDAY AHEAD OF AN APPROACHING COLD
FRONT...CAUSING WINDS TO JUMP FROM AROUND 10 KTS SATURDAY
MORNING...TO 15-20 KTS BY SATURDAY NIGHT. THIS IN TURN FORCES WAVES
TO BUILD TO 5-6 FT SATURDAY NIGHT AND SUNDAY MORNING...AND A SMALL
CRAFT ADVISORY MAY BE NEEDED FOR AT LEAST A SHORT DURATION SATURDAY
NIGHT. COLD FRONT PUSHES ACROSS THE WATERS BY SUNDAY EVE...AND WINDS
VEER RAPIDLY TO THE WEST THEN NORTH ON MONDAY. SPEEDS REMAIN AROUND
15 KTS BEFORE EASING LATE MONDAY TO 10 KTS. THIS OFFSHORE FLOW
PUSHES THE HIGHEST SEAS AWAY FROM THE COASTAL WATERS...SO WAVE
HEIGHTS WILL DIMINISH TO 3-4 FT BY SUNDAY EVE...AND PERSIST THERE
THROUGH MONDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
757 PM EDT FRI MAR 23 2012
.SYNOPSIS...
AN UPPER LEVEL LOW PRESSURE SYSTEM OVER THE MID MISSISSIPPI VALLEY
WILL MOVE SOUTHEAST THROUGH THE WEEKEND. HIGH PRESSURE WILL BUILD
IN EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
SHOWERS CONTINUE TO LIFT NORTH NORTHEAST ACROSS THE REGION. IT
APPEARS THAT THEY WILL GET OUT OF THE FORECAST AREA BY 03Z. BUT
ATTENTION TURNS TO BROKEN LINE OF STORMS FROM CENTRAL INDIANA INTO
CENTRAL KENTUCKY. THESE WILL SLOWLY PROGRESS INTO THE AREA LATE
THIS EVENING. LATEST AVAILABLE HRRR RUN SEEMS TO HAVE A PRETTY
GOOD HANDLE ON THIS. SO EXPECT SHOWERS AND THUNDERSTORMS TO SPREAD
ACROSS THE WESTERN ZONES AND THEN WEAKEN AS THEY PROGRESS ACROSS
THE REST OF THE AREA LATER TONIGHT AS INSTABILITY DECREASES.
0-1 KM SHEAR COINCIDENT WITH THESE STORMS IS FORECAST TO REMAIN
FAIRLY RESPECTABLE FOR THE NEXT SEVERAL HOURS AND THEN DIMINISH AS
ACTIVITY MOVES INTO OHIO.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
UPPER LOW APPROACHING THE REGION AT THE BEGINNING OF THE PERIOD
WILL START MOVING SOUTHEAST WHICH WILL MEAN THAT THE CENTER OF THE
SYSTEM WILL PASS JUST TO THE SOUTH. COMBINATION OF COLD
TEMPERATURES ALOFT AND DAYTIME HEATING WILL BRING ADDITIONAL
CONVECTION ON SATURDAY WITH THE GREATER COVERAGE IN SOUTHERN
ZONES. THIS WILL DIMINISH SATURDAY EVENING.
A SECONDARY TROUGH AXIS WILL MOVE FROM NORTHWEST TO SOUTHEAST ON
SUNDAY. AND WHILE THIS LOOKS PRETTY WEAK...CANNOT COMPLETELY RULE
OUT A FEW SHOWERS DEVELOPING ALONG IT. SO KEPT SLIGHT CHANCE POPS
FOR THE DAY. HIGH PRESSURE WILL START TO BUILD IN SUNDAY NIGHT.
GENERALLY LEANED TOWARDS NAM MOS FOR TEMPERATURES THROUGHOUT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL START OUT THE LONG TERM. WITH COOL NORTHERLY
FLOW HIGH TEMPERATURES ON MONDAY WILL BE IN THE MIDDLE 50S ACROSS
CENTRAL OHIO TO THE MIDDLE 60S ACROSS NORTHERN KENTUCKY. COOL
CONDITIONS WILL CONTINUE MONDAY NIGHT AND EXPECT LOW TEMPERATURES TO
DROP DOWN INTO THE 30S. TEMPERATURES HAVE THE POTENTIAL TO DROP
DOWN NEAR FREEZING MONDAY NIGHT ACROSS THE EASTERN PORTIONS OF THE
FA ACROSS CENTRAL OHIO WHERE CLOUD COVER AND WINDS WILL BE LESS.
WILL ADD FROST MENTION TO THE HWO FOR MONDAY NIGHT. TEMPERATURES
WILL INCREASE INTO THE 60S ACROSS MOST OF FA DURING THE DAY ON
TUESDAY AS SOUTHERLY FLOW BRINGS WARMER AIR INTO THE REGION. A COLD
FRONT WILL APPROACH THE AREA TUESDAY NIGHT AND MOVE THROUGH THE FA
WEDNESDAY MORNING. THE BEST CHANCE FOR THUNDERSTORM ACTIVITY WILL
BE AFTER MIDNIGHT TUESDAY NIGHT THROUGH THE MORNING HOURS ON
WEDNESDAY. PRECIPITATION WILL TAPER OFF BY WEDNESDAY AFTERNOON AND
DRY CONDITIONS WILL BE PRESENT FOR THE REMAINDER OF THE LONG TERM.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
GENERALLY VFR CONDITIONS FORECAST TO PERSIST THROUGH THE TAF
PERIOD. SHOWERS WILL CONTINUE TO AFFECT ALL BUT THE CINCINNATI
TERMINALS FOR THE NEXT HOUR OR TWO BEFORE MOVING OFF. BROKEN LINE
OF THUNDERSTORMS OFF TO THE WEST WILL SWING INTO THE REGION AND
START AFFECTING THE TERMINALS AFTER 02Z. HAVE ONLY INCLUDED
TEMPORARY MVFR CONDITIONS WITH THESE STORMS ALTHOUGH IT COULD BE
BRIEFLY LOWER IN ANY STRONGER CORES. EXPECT THIS LINE TO WEAKEN AS
IT MOVES EAST OVERNIGHT SO HAVE ONLY INCLUDED VCTS IN THE COLUMBUS
TERMINALS.
CANNOT RULE OUT SOME MIST DEVELOPING LATE TONIGHT IN A MOIST
ENVIRONMENT AND LIGHT WINDS. BUT CONFIDENCE WAS NOT HIGH ENOUGH TO
REDUCE VISIBILITIES IN THE TAFS. EXPECT VFR CEILINGS TO DEVELOP
WITH HEATING TOMORROW. THERE WILL BE SCATTERED SHOWERS AND
THUNDERSTORMS. BUT PROBABILITY OF AFFECTING ANY PARTICULAR
LOCATION WAS NOT HIGH ENOUGH TO INCLUDE IN THE TAFS THIS FAR OUT
IN TIME.
OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...NOVAK
AVIATION...
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
424 PM EDT THU MAR 22 2012
.SYNOPSIS...
A SLOW MOVING UPPER LEVEL LOW PRESSURE SYSTEM WILL PUSH TOWARDS
THE REGION THROUGH THE REST OF THE WEEK. THIS LOW WILL SLIDE OFF
TO THE SOUTHEAST SUNDAY WITH HIGH PRESSURE BUILDING BACK IN EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
ISOLATED SHOWERS HAVE DEVELOP ACROSS PARTS OF THE AREA. SOME
THUNDER WILL BE POSSIBLE. THESE CELLS WILL LIKELY DIMINISH WITH
THE LOSS OF HEATING. BUT BAND OF SHOWERS OFF TO THE WEST WILL
START TO PUSH INTO THE WESTERN PART OF THE FORECAST AREA LATER
TONIGHT. CANNOT RULE OUT SOME EMBEDDED THUNDER WITH THIS.
EXPECT ANOTHER VERY WARM NIGHT WITH FORECAST LOWS AT OR ABOVE
WARMER MOS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
INITIAL BAND OF PRECIPITATION IN ADVANCE OF AN UPPER LOW WILL MAKE
ITS WAY ACROSS THE FORECAST AREA ON FRIDAY INTO FRIDAY EVENING.
THIS WILL NOT BE AN ALL DAY EVENT AT ANY ONE LOCATION BUT DO
EXPECT JUST ABOUT EVERYWHERE TO GET MEASURABLE RAINFALL. THERE IS
SOME WEAK INSTABILITY ASSOCIATED WITH THIS. BUT GIVEN THE THE LACK
OF LIGHTNING STRIKES WITHIN THE BAND TODAY BACK TO OUT WEST...HAVE
PLAYED DOWN THUNDER AND ONLY INCLUDED A CHANCE.
ADDITIONAL SCATTERED SHOWERS WILL OCCUR OVERNIGHT FRIDAY NIGHT AS
THE UPPER SYSTEM GETS CLOSER. WITH HEATING AND COLD TEMPERATURES
ALOFT THERE SHOULD BE AN INCREASE IN COVERAGE ON SATURDAY WITH
SOME THUNDER POSSIBLE AS WELL. ACTIVITY WILL DIMINISH SATURDAY
NIGHT WITH THE LOSS OF INSOLATION AND AS BETTER FORCING WITH THE
LOW MOVE OFF TO THE SOUTHEAST.
TEMPERATURES WILL BE NOT AS WARM. HAVE USED A MOS BLEND FOR HIGHS
FRIDAY LEANING SOMEWHAT TOWARDS COOLER NAM MOS. WENT SLIGHTLY
ABOVE MOS CONSENSUS FOR LOWS BOTH NIGHTS AND SLIGHTLY BELOW MOS
FOR SATURDAY HIGHS.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE UPPER LEVEL LOW WILL CONTINUE TO MOVE TO THE EAST ON SUNDAY.
RAIN CHANCES WILL GRADUALLY DECREASE THROUGH THE DAY ON SUNDAY AS
THE UPPER LOW MOVES FURTHER TO THE EAST. DRY CONDITIONS WILL RETURN
TO THE FA BY SUNDAY EVENING. HIGH PRESSURE WILL KEEP DRY CONDITIONS
ACROSS THE REGION THROUGH TUESDAY. THE NEXT SYSTEM WILL BEGIN TO
BRING SHOWERS AND THUNDERSTORMS INTO WESTERN PORTIONS OF THE FA LATE
TUESDAY NIGHT WITH A BETTER CHANCE OF THUNDERSTORM ACTIVITY ON
WEDNESDAY. A COLD FRONT WILL MOVE THROUGH WEDNESDAY NIGHT AND
PRECIPITATION WILL END ACROSS THE FA BY THURSDAY MORNING.
ALTHOUGH TEMPERATURES WILL NOT BE AS WARM AS THE PAST FEW
DAYS...TEMPERATURES WILL CONTINUE TO RUN ABOVE NORMAL. THE COOLEST
TEMPERATURES WILL BE TUESDAY MORNING WHEN TEMPERATURES DROP DOWN
INTO THE UPPER 30S TO THE LOW 40S. THE WARMEST TEMPERATURES WILL
OCCUR ON WEDNESDAY IN ADVANCE OF THE COLD FRONT.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
AS UPPER LEVEL LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS WILL
PUSH EAST INTO THE LOWER OHIO VALLEY THROUGH FRIDAY. AN INITIAL
BAND OF SHOWERS ASSOCIATED WITH THIS LOW IS CURRENTLY PIVOTING UP
ACROSS SOUTHERN ILLINOIS AND WESTERN KENTUCKY. THE EASTWARD
PROGRESSION OF THIS HAS BEEN VERY SLOW AND THE LATEST RUC IS NOT
BRINGING IT TO THE SOUTHWESTERN TAF SITES UNTIL LATER TONIGHT. THIS
SEEMS REASONABLE AND AS A RESULT HAVE TRENDED THE TAFS TOWARD THE
SLOWER GFS SOLUTION. AHEAD OF THIS BAND...SUPPOSE WE COULD SEE AN
ISOLATED SHOWER OR THUNDERSTORM POP UP LATER THIS AFTERNOON OR
EVENING BUT CHANCE IS LOW ENOUGH TO LEAVE MENTIONS OUT OF THE
TAFS.
WE ARE NOT SEEING MUCH IN THE WAY OF LIGHTNING WITH THE CURRENT
BAND OF SHOWERS PUSHING INTO THE LOWER OHIO VALLEY. INSTABILITY IS
MARGINAL OVERNIGHT SO THINK ANY THUNDER WILL REMAIN LIMITED
THROUGH THE OVERNIGHT HOURS. WILL THEREFORE JUST SPREAD A
PREVAILING -SHRA IN FROM THE SOUTHWEST LATER TONIGHT. WE SHOULD
DESTABILIZE BETTER THROUGH FRIDAY AFTERNOON AND THIS MAY EVENTUALLY
ALLOW FOR SOME SCATTERED THUNDERSTORM ACTIVITY AFTER 18Z.
OUTLOOK...THUNDERSTORMS POSSIBLE INTO SATURDAY. MVFR CIGS POSSIBLE
ON SUNDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...NOVAK
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
150 PM EDT THU MAR 22 2012
.SYNOPSIS...
HIGH PRESSURE OFF OF THE EAST COAST WILL BE PUSHED ASIDE AS LOW
PRESSURE IN THE PLAINS MAKES ITS WAY TO THE OHIO VALLEY FOR THE
WEEKEND. THIS LOW WILL EXIT ON SUNDAY AND HIGH PRESSURE WILL
ESTABLISH ITSELF OVER THE CENTRAL U.S. FOR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WE HAD SOME AC ACROSS PARTS OF OUR AREA EARLIER THIS MORNING BUT
THIS HAS SINCE DISSIPATED WITH SKIES MAINLY SUNNY ATTM. WE SHOULD
SEE A GRADUAL INCREASE LATER TODAY IN MAINLY HIGH AND MID LEVEL
CLOUDS AS MOISTURE ASSOCIATED WITH UPPER LEVEL LOW WORKS ITS WAY
SLOWLY EAST. STILL THOUGH...EXPECT A FAIR AMOUNT OF SUNSHINE
ACROSS THE AREA AT LEAST INTO EARLY AFTERNOON SO WILL NUDGE TEMPS
UP A BIT WITH HIGHS IN THE LOW TO MID 80S TODAY. AS WE WARM
UP...SOME WEAK INSTABILITIES WILL DEVELOP THROUGH THE AFTERNOON
HOURS. THIS COULD LEAD TO AN ISOLATED THUNDERSTORM ONCE
AGAIN...WITH THE BEST CHANCE BEING ACROSS OUR SOUTHWEST WHERE
LIMITED FORCING SHOULD BE A LITTLE BETTER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
CLOUD COVER AND SOUTHERLY WINDS WILL KEEP UNSEASONABLY MILD
READINGS OVER THE OHIO VALLEY FOR ANOTHER NIGHT. SHOWERS AND
THUNDERSTORMS WILL OVERSPREAD THE REGION FROM THE WEST EARLY ON
FRIDAY...AND THE APPROACHING LOW WILL NECESSITATE THUNDERSTORMS IN
THE FORECAST AS IT MOVES EAST.
I REMOVED THUNDER FROM THE FORECAST SATURDAY AND BEYOND AS THE
AIRMASS WILL HAVE BEEN WORKED OVER AND THERE SHOULD BE LITTLE IF
ANY DIRECT SUNSHINE TO INSTIGATE SURFACE BASED CONVECTION.
TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH THE FORECAST PERIOD
BUT BE A BIT COOLER THAN THE RECENT RECORD-BREAKING SPELL THESE
PAST FEW DAYS DUE TO CLOUD COVER AND EXPECTED RAINFALL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
TEMPERATURES WILL GRADUALLY BE ON THE INCREASE MONDAY THROUGH
WEDNESDAY AS A RIDGE BUILDS INTO THE AREA. A COLD FRONT WILL BEGIN
TO APPROACH THE AREA ON WEDNESDAY ALLOWING FOR SHOWERS AND
THUNDERSTORMS TO MOVE INTO THE REGION WEDNESDAY AFTERNOON INTO
WEDNESDAY NIGHT.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS UPPER LEVEL LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS WILL
PUSH EAST INTO THE LOWER OHIO VALLEY THROUGH FRIDAY. AN INITIAL
BAND OF SHOWERS ASSOCIATED WITH THIS LOW IS CURRENTLY PIVOTING UP
ACROSS SOUTHERN ILLINOIS AND WESTERN KENTUCKY. THE EASTWARD
PROGRESSION OF THIS HAS BEEN VERY SLOW AND THE LATEST RUC IS NOT
BRINGING IT TO THE SOUTHWESTERN TAF SITES UNTIL LATER TONIGHT. THIS
SEEMS REASONABLE AND AS A RESULT HAVE TRENDED THE TAFS TOWARD THE
SLOWER GFS SOLUTION. AHEAD OF THIS BAND...SUPPOSE WE COULD SEE AN
ISOLATED SHOWER OR THUNDERSTORM POP UP LATER THIS AFTERNOON OR
EVENING BUT CHANCE IS LOW ENOUGH TO LEAVE MENTIONS OUT OF THE
TAFS.
WE ARE NOT SEEING MUCH IN THE WAY OF LIGHTNING WITH THE CURRENT
BAND OF SHOWERS PUSHING INTO THE LOWER OHIO VALLEY. INSTABILITY IS
MARGINAL OVERNIGHT SO THINK ANY THUNDER WILL REMAIN LIMITED
THROUGH THE OVERNIGHT HOURS. WILL THEREFORE JUST SPREAD A
PREVAILING -SHRA IN FROM THE SOUTHWEST LATER TONIGHT. WE SHOULD
DESTABILIZE BETTER THROUGH FRIDAY AFTERNOON AND THIS MAY EVENTUALLY
ALLOW FOR SOME SCATTERED THUNDERSTORM ACTIVITY AFTER 18Z.
OUTLOOK...THUNDERSTORMS POSSIBLE INTO SATURDAY. MVFR CIGS POSSIBLE
ON SUNDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...JGL
SHORT TERM...FRANKS
LONG TERM...NOVAK
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS TULSA OK
1232 PM CDT THU MAR 22 2012
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
CONVECTION IS BEGINNING TO INCREASE IN AREAL COVERAGE AND WILL
MAINTAIN A WIDESPREAD IMPACT THROUGH THE MID EVENING HOURS.
ADDITIONALLY THUNDERSTORM POTENTIAL WILL INCREASE BY MID AFTERNOON
AND PERSIST UNTIL THE RAIN ENDS FROM WEST TO EAST THIS EVENING.
OVERALL VFR/MVFR CONDITIONS WILL PREVAIL BEFORE TURNING VFR
OVERNIGHT. LOWER CLOUDS WILL WORK INTO NORTHERN LOCATIONS TOMORROW
WITH SCATTERED SHOWERS AGAIN DEVELOPING.
&&
.PREV DISCUSSION... /ISSUED 1052 AM CDT THU MAR 22 2012/
..UPDATE...
DISCUSSION...
REGIONAL PROFILER AND VWP DATA HAVE SAMPLED A STRONG LOW TO MID
LEVEL JET MAX ACROSS NORTHWEST INTO NORTH CENTRAL TEXAS. THIS
FEATURE WILL CONTINUE TO ROTATE E-NE AROUND THE PERIPHERY OF THE
UPPER LOW THROUGH THE AFTERNOON AND EVENING HOURS. ASSOCIATED
FORCING HAS PRODUCED WIDESPREAD LOW TO MID CLOUD ALONG WITH A
REGION OF LIGHT RAIN WHICH WILL ACCOMPANY THE SPEED MAX INTO THE
FORECAST AREA. ALL SHORT RANGE DATA IS IN GOOD AGREEMENT ON
INCREASING THE COVERAGE OF PRECIP ACROSS E OK/NW AR THIS AFTERNOON
AND THE UPDATED FORECAST WILL SIMPLY REFINE PRECIP CHANCES TO
FOLLOW THE SCENARIO. THE SEVERE WEATHER CONCERN WILL CONTINUE TO
FOCUS ACROSS SE OK / NW AR WHERE THE AFOREMENTIONED WIND FIELDS
PRODUCE AMPLE SHEAR TO SUPPORT SEVERE WEATHER. THE LARGEST
UNCERTAINTY WILL BE THE RECOVERY OF TEMPS AND ASSOCIATED
INSTABILITY ALONG THE SOUTHERN PERIPHERY OF THE CLOUD SHIELD.
WHERE THE AIRMASS DOES RECOVERY ENOUGH INSTABILITY LATE THIS
AFTERNOON A MIX OF SUPERCELLS AND BOWING LINE SEGMENTS ARE LIKELY
TO EVOLVE. LOCAL WRF RUNS ALONG WITH HRRR DATA SUGGEST THIS IS
MOST LIKELY ACROSS EXTREME SE OK AND POINTS FURTHER EAST. THE
UPDATED FORECAST WILL FOLLOW THIS SCENARIO SUPPORTED BY OBSERVED
CLOUD / TEMP TRENDS THIS MORNING ACROSS NORTH TEXAS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 60 44 68 46 / 80 40 40 10
FSM 64 45 67 45 / 80 80 30 10
MLC 60 42 70 46 / 80 30 10 10
BVO 60 42 65 42 / 80 50 50 10
FYV 64 42 62 41 / 80 80 50 10
BYV 65 46 61 45 / 80 80 60 10
MKO 61 43 66 44 / 80 40 20 10
MIO 62 45 63 46 / 80 80 60 10
F10 60 44 68 48 / 80 30 10 10
HHW 64 43 72 48 / 80 50 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...07
AREA FORECAST DISCUSSION
NWS TULSA OK
1052 AM CDT THU MAR 22 2012
...UPDATE...
.DISCUSSION...
REGIONAL PROFILER AND VWP DATA HAVE SAMPLED A STRONG LOW TO MID
LEVEL JET MAX ACROSS NORTHWEST INTO NORTH CENTRAL TEXAS. THIS
FEATURE WILL CONTINUE TO ROTATE E-NE AROUND THE PERIPHERY OF THE
UPPER LOW THROUGH THE AFTERNOON AND EVENING HOURS. ASSOCIATED
FORCING HAS PRODUCED WIDESPREAD LOW TO MID CLOUD ALONG WITH A
REGION OF LIGHT RAIN WHICH WILL ACCOMPANY THE SPEED MAX INTO THE
FORECAST AREA. ALL SHORT RANGE DATA IS IN GOOD AGREEMENT ON
INCREASING THE COVERAGE OF PRECIP ACROSS E OK/NW AR THIS AFTERNOON
AND THE UPDATED FORECAST WILL SIMPLY REFINE PRECIP CHANCES TO
FOLLOW THE SCENARIO. THE SEVERE WEATHER CONCERN WILL CONTINUE TO
FOCUS ACROSS SE OK / NW AR WHERE THE AFOREMENTIONED WIND FIELDS
PRODUCE AMPLE SHEAR TO SUPPORT SEVERE WEATHER. THE LARGEST
UNCERTAINTY WILL BE THE RECOVERY OF TEMPS AND ASSOCIATED
INSTABILITY ALONG THE SOUTHERN PERIPHERY OF THE CLOUD SHIELD.
WHERE THE AIRMASS DOES RECOVERY ENOUGH INSTABILITY LATE THIS
AFTERNOON A MIX OF SUPERCELLS AND BOWING LINE SEGMENTS ARE LIKELY
TO EVOLVE. LOCAL WRF RUNS ALONG WITH HRRR DATA SUGGEST THIS IS
MOST LIKELY ACROSS EXTREME SE OK AND POINTS FURTHER EAST. THE
UPDATED FORECAST WILL FOLLOW THIS SCENARIO SUPPORTED BY OBSERVED
CLOUD / TEMP TRENDS THIS MORNING ACROSS NORTH TEXAS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 60 44 68 46 / 100 40 20 0
FSM 64 45 67 45 / 70 60 20 10
MLC 60 42 71 46 / 90 30 10 10
BVO 60 42 66 42 / 100 40 20 0
FYV 64 42 62 41 / 70 80 40 10
BYV 65 46 62 45 / 70 80 40 10
MKO 61 43 66 44 / 90 40 10 10
MIO 62 45 64 46 / 90 80 40 0
F10 60 44 69 48 / 90 30 10 0
HHW 64 43 73 48 / 80 30 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...07
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1021 PM EDT FRI MAR 23 2012
.SYNOPSIS...
A WARM AND MOIST AIR MASS WILL LINGER ACROSS THE REGION TONIGHT
AHEAD OF A COLD FRONT. THE FRONT WILL CROSS THE CAROLINAS AND
NORTHEAST GEORGIA ON SATURDAY...FOLLOWED BY AN UPPER LEVEL LOW ON
SUNDAY. DRY HIGH PRESSURE WILL BUILD ACROSS THE REGION SUNDAY NIGHT
AND WILL REMAIN THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 1020 PM EDT...PATCH AREAS OF HIGH BASED LIGHT RAIN AND A FEW
HEAVIER SHRA HAVE BEEN INCREASING IN COVERAGE OVER THE
UPSTATE...BACK ACROSS THE UPPER SAVANNAH RIVER VALLEY. THE CHANCES
OF MEASURABLE PCPN IN THIS AREA STILL LOOKS FAIRLY LOW...AND I/VE
RAISED POPS A LITTLE...BUT ONLY INTO THE LOW CHANCE RANGE. THERE IS
STILL A FAIR AMOUNT OF ELEVATED INSTABILITY LOOKING AT THE 00 UTC
FFC SOUNDING...BUT THERE IS A SFC TEMPERATURE MINIMUM OVER THE ERN
UPSTATE AND INTO WRN NC WHERE WIDESPREAD RAIN FEEL EARLIER.
THEREFORE I DON/T SEE THIS AREA OF RAIN BECOMING MUCH
HEAVIER...THOUGH AN ISOLATED TSTM IS STILL POSSIBLE.
FARTHER TO THE WEST...STRONG PVA IS MOVING ACROSS MIDDLE AND ERN TN.
TSTMS ARE BEGINNING TO DEVELOP A LITTLE TO THE NORTHEAST OF
HUNTSVILLE. THE RUC 0-3KM BULK SHEAR VALUES ACROSS ERN TN INCREASE
DRAMATICALLY OVER THE NEXT THREE HOURS. THE NAM SHOWS CAPE VALUES
ACTUALLY INCREASING A BIT INTO THE GREAT VALLEY AREA THE NEXT FEW
HOURS. THIS IS ALSO ALONG A SFC COLD FRONT. SO DEEP LAYER
FORCING...STRONG SHEAR AND SFC CONVERGENCE SHOULD HELP THE
CONVECTION TO RAPIDLY INCREASE IN COVERAGE. HOWEVER...IT/S STILL
SEVERAL HOURS AWAY FROM THE FA. BY AROUND 0600 UTC CONVECTION SHOULD
BEGIN TO AFFECT THE SW NC MTNS. HOWEVER...IT SHOULD WEAKEN BY THIS
TIME. A STRONG OR SEVERE STORM CANNOT BE RULED OUT OVER THE
MTNS...BUT I DON/T THINK ITS LIKELY. POPS HAVE BEEN INCREASED TO
HIGH CHANCE RANGE IN THESE AREAS LATER TONIGHT.
AS OF 755 PM EDT...THE MCS OVER THE I-77 CORRIDOR IS RAPIDLY
WEAKENING...BUT THE HIGHEST POPS WILL REMAIN IN THIS PART OF THE FA
FOR ANOTHER HOUR OR SO. SCT SHRA ARE DEVELOPING AGAIN...ESPECIALLY
OVER THE NC MTNS AND THE NRN PART OF THE UPSTATE. A SHORT WAVE WILL
SLOWLY CROSS THE WRN ZONES THIS EVENING...AND CHANCE POPS WILL BE
RETAINED ACROSS THE ENTIRE FA AWAY FROM THE CATEGORICAL POPS IN THE
NC PIEDMONT.
AS OF 5 PM EDT...UPDATED THE FORECAST TO INCREASE POPS AHEAD OF THE
DEVELOPING MCS OVER THE UPSTATE AND WRN NC FOOTHILLS...AND DECREASE
POPS BEHIND IT. ADDITIONAL CONVECTION WILL PROBABLY MOVE BACK INTO
NE GA AND THE WRN UPSTATE IN A CPL HOURS...BUT POPS WILL BE KEPT LOW
UNTIL THE STORMS START TO SHOW SOME ORGANIZATION.
PREVIOUS DISCUSSION...
UPPER LOW AND ASSOC SHORTWAVE TROFS CONTINUE MOVG E TOWARD THE
REGION WHILE MOIST S LL FLOW INCREASES OVER THE AREA. SHWRS AND
TSTMS WILL CONTINUE TO DEVELOP AND MOVE NE ACROSS THE CWA THIS
EVE...TAPERING OFF SOMEWHAT OVERNIGHT...THEN REDEVELOPING SAT AS THE
UPPER LOW TRACKS E ACROSS THE CWA ON THE WAY TO THE CAROLINA COAST.
FCST SOUNDINGS SHOW SOME CAPE AND SHEAR THRU THIS EVE BUT SVR THREAT
IS SOMEWHAT LIMITED DUE TO MOIST PROFILES AND WEAK SHEAR. AS THE
UPPER LOW MOVES IN SAT SHEAR/CAPE INCREASE...AND WITH A LITTLE DRY
AIR IN THE MID LVLS THERE WILL BE A HIGHER THREAT OF DAMAGING
WIND/HAIL...MAINLY SAT AFTN-EVE. SPC HAS THE SE CWA IN AN AREA FOR
SLIGHT RISK OF SVR STORMS AND THIS LOOKS REASONABLE. TEMPS WILL
REMAIN ABOVE AVG THRU SAT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 2 PM FRIDAY...ANY CONVECTION THAT DEVELOPS ALONG LEE TROF/COLD
FRONT ACRS THE FTHLS/PIEDMONT SAT AFTN SHUD BE PUSHING EAST OF THE
AREA SAT EVE. THERE MAY BE A LULL IN PRECIP COVERAGE BEHIND THAT
BATCH OF CONVECTION OVERNIGHT BEFORE THE CENTER OF AN UPPER LOW
CROSSES THE AREA EARLY SUN MRNG. AS THE LOW PASSES...ANOTHER ROUND
OF SCATTERED SHWRS SHUD CROSS THE AREA. INSTBY WILL BE ELEV AND
WEAK. SO LTL IN WAY OF THUNDER CHCS EXPECTED. MIN TEMPS STILL ABOVE
NORMAL IN THE 40S MTNS AND LWR-MID 50S PIEDMONT.
SUNDAY...HEIGHT RISES IN WAKE OF UPPER LOW AND STRENGTHENING NWLY
LLVL SHUD PUT END TO PRECIP...SAVE FOR TN BORDER WHERE UPSLOPE WILL
CONTINUE. TEMPS STILL EXPECTED TO BE ABOVE NORMAL AS THICKNESSES
QUICKLY REBOUND BEHIND THE LOW AND ALSO DOWNSLOPE EAST OF THE MTNS
(HIGHS IN THE 60S MTNS AND LWR-MID 70S PIEDMONT).
SUNDAY NIGHT AND MONDAY...AN UPPER LEVEL RIDGE WILL AMPLIFY ACRS THE
CENTER OF THE CONUS...WHILE A TROF DIGS OVER THE NORTHEAST STATES.
THIS AMPLIFYING FLOW WILL ALLOW A STRONG CP AIR MASS TO PUSH INTO
THE EASTERN GREAT LAKES TO THE MID ATLANTIC WITH THE COLD FRONT
APPROACHING THE CWFA FROM THE NORTH. BOTH THE NAM AND GFS HAVE 850
MB TEMPS STILL IN THE 10-12C RANGE WITH DOWNSLOPE NNWLY FLOW. THE
BACKDOOR FRONT MAY PUSH IN MON AFTN...BUT FOR NOW EXPECTING IT TO
REMAIN NORTH OF THE AREA. SO I AM FORECASTING HIGHS IN THE MID-UPR
70S EAST OF THE MTNS (EXCEPT LWR 70S MTN VALLEYS AND 60S HIGH
TERRAIN).
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 230 PM FRIDAY...THE LATEST EXTENDED MODELS ARE IN GOOD
AGREEMENT WITH STRONG CANADIAN SURFACE HIGH PRESSURE OVER THE GREAT
LAKES PUSHING INTO OUR FORECAST AREA MONDAY AND LINGER INTO
WEDNESDAY. AS A RESULT...MOSTLY DRY CONDITIONS WITH COOLER
TEMPERATURES CAN BE EXPECTED ACROSS THE REGION THROUGH WEDNESDAY. A
WEAK COLD FRONT IS PROGGED TO CROSS THE CAROLINAS AND NE GEORGIA
WEDNESDAY NIGHT INTO THURSDAY MORNING. BOTH THE GFS AND THE ECMWF
INDICATE THAT THE LOWER PIEDMONT AREA WILL STAY MOSTLY DRY AS THE
UPPER LEVEL DYNAMICS WEAKENS AND THE AIRMASS REMAINS RELATIVELY DRY.
HOWEVER..DECENT LLVL NW FLOW LIFTING ALONG WITH WEAK DIURNAL
INSTABILITY OVER THE NC MOUNTAINS MAY SUPPORT FOR THE DEVELOPMENT OF
SCATTERED SHOWERS AND THUNDERSTORMS DURING THE PASSAGE OF THE FRONT.
HENCE...I MENTIONED 20-30 POPS THERE WITH MOSTLY DRY CONDITIONS
ELSEWHERE. FRIDAY AND SATURDAY...ANOTHER CANADIAN HIGH PRESSURE OVER
THE GREAT LAKES AND SE CANADA IS EXPECTED TO PUSH SOUTH ACROSS THE
REGION FOR MOSTLY DRY WEATHER AND MILD CONDITIONS THROUGH THE
PERIOD.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...A LINE OF TSTMS HAS LARGELY FIZZLED AS IT HAS MOVED ACROSS
THE AIRFIELD. AN UPDATE WILL PROBABLY BE NEEDED AT THE TOP OF THE
HOUR AS THE AIRFIELD HAS YET TO REPORT THUNDER. THERE WILL STILL BE
A SMALL CHANCE OF OF A SHRA/TSTM THE REST OF THE NIGHT. BETTER
CHANCES WILL DEVELOP BY TMRW AFTN AS AN UPPER LOW CROSSES THE
REGION. OTHERWISE...CIGS ARE EXPECTED TO LOWER IN THE MVFR AND
EVENTUALLY INTO THE LIFR RANGE WITH MOIST SOUTHERLY FLOW OVER THE
REGION. THIS DID NOT HAPPEN LAST NIGHT...BUT WITH MORE RAIN AROUND
THE AREA AND STRONGER LLVL FLOW...CHANCES FOR STRATUS LOOK BETTER
THAN LAST NIGHT.
ELSEWHERE...ISOLATED SHRA/TSTMS WILL LAST THROUGH THE NIGHT...BUT
COVERAGE IS NOT GREAT ENUF TO ADD ANY PREVAILING OR TEMPO
RESTRICTIONS IN RAIN. LATER TONIGHT WIDESPREAD STRATUS IS EXPECTED
TO DEVELOP AGAIN OVER THE REGION. WINDS WILL BE STRONGER IN THE
LLVLS OVERNIGHT...AND DEWPOINTS ARE STILL VERY HIGH. WHILE HIGH AND
MID CLOUDS WILL CURTAIN COOLING ABOVE THE BNDRY LAYER...LIFR STRATUS
IS STILL EXPECTED TO BE WIDESPREAD LATE TONIGHT. A BETTER COVERAGE
OF SHRA/TSTMS WILL DEVELOP BY TMRW AFTN.
OUTLOOK...SCATTERED TSTMS SHOULD CONTINUE SAT EVE AND SUN AS AN
UPPER LOW CENTER MOVES SLOWLY ACROSS THE REGION. EXPECT IFR
RESTRICTIONS SUN MRNG AND WITH HEAVIER SHWRS AND TSTMS. DRYING IS
EXPECTED EARLY NEXT WEEK.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...MCAVOY
SHORT TERM...ARK
LONG TERM...JOH
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
148 AM EDT THU MAR 22 2012
.SYNOPSIS...
WEAK HIGH PRESSURE WILL LINGER THROUGH THURSDAY BEFORE GIVING WAY TO
A COOL FRONTAL PASSAGE ON FRIDAY. A BROAD AREA OF LOW PRESSURE WILL
THEN SLOWLY MOVE ACROSS THE REGION THIS WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 145 AM...CANNOT RULE OUT AN ISOLATED SHOWER ALONG THE BLUE
RIDGE THE REST OF THE NIGHT...BUT ANY PRECIP WOULD BE LIGHT.
OTHERWISE...STILL EXPECT LOW CLOUDS TO BECOME WIDESPREAD IN THE SELY
LOW LEVEL FLOW AND INCREASING MOISTURE. MAIN CHANGES WERE FOR
CURRENT CONDITIONS.
AS OF 1030 PM EDT WED...ALL POPS HAVE BEEN REMOVED FOR THE OVERNIGHT
PERIOD EXCEPT FOR A SMALL STRIPE OF SLIGHT CHANCE ALONG THE EASTERN
ESCARPMENT OF THE BLUE RIDGE. THE 00 UTC FFC SOUNDING SHOWS A STRONG
TEMPERATURE INVERSION BETWEEN ABOUT 700-600 MB. THIS SHOWS UP WELL
ON THE RUC AND NAM 600 MB TEMPERATURES. THIS INVERSION STAYS PARKED
OVERNIGHT WITH ANY FORCING FROM THE MID-ATLANTIC SHORT WAVE STAYING
WELL TO OUR NE. THE LATEST NAM IS A LITTLE LESS BULLISH ON LOW CLOUD
CHANCES TONIGHT...BUT WITH THE DEWPOINT ALREADY 63 AT CAE...AND WITH
DEWPOINTS ACROSS THE BOARD RUNNING HIGHER THAT PREDICTED...AREAS OF
STRATUS STILL LOOK TO BE LIKELY OVERNIGHT. ALSO...ALTO-CU IS
SPREADING OUT UNDER THE STRONG INVERSION. THESE CLOUDS WILL
GRADUALLY ENCROACH FROM THE SOUTHWEST TONIGHT...WHICH SHOULD YIELD
MOSTLY CLOUDY SKIES WITHIN A FEW HOURS. THE NC PIEDMONT AND
FOOTHILLS WILL TAKE LONGER TO CLOUD UP. THESE AREAS ALSO HAVE
CONDENSATION PRESSURE DEFICITS NEAR ZERO. THEREFOR...THE I-77
CORRIDOR IS PROBABLY SETTING UP TO SEE AREAS OF DENSE FOG LATER ON.
FOG IS ALREADY IN THE GRIDS...AND CONFIDENCE ISN/T NEARLY HIGH
ENOUGH TO GO WITH AN ADVISORY...BUT IT WILL BE SOMETHING TO WATCH
OUT FOR AS THE NIGHT PROGRESSES.
AS OF 750 PM EDT WED...LOWERED POPS BACK INTO THE SLIGHT CHANCE
RANGE THROUGH MIDNIGHT ACROSS THE REGION AS SHRA ARE GENERALLY
WIDELY SCATTERED AND QUITE WEAK. A NICE OUTFLOW BNDRY MOVING INTO
THE REGION FROM THE SE ISN/T EVEN HELPING MATTERS. THE WORKSTATION
MODELS DON/T SHOW THIS BNDRY DOING MUCH AS IT MOVES TO THE
NE...WHICH IS HOW I/VE PLAYED THINGS. HOWEVER...AS IT INTERACTS WITH
THE MTNS...CONVECTION MAY BRIEFLY INTENSIFY PRIOR TO MIDNIGHT.
AS OF 500 PM EDT WED...TRIMMED POPS BACK AS MOST OF THE SHRA
ACTIVITY OVER THE FA REMAINS VERY LIGHT AND LOW TOPPED. STILL
LOOKING FOR COVERAGE TO INCREASE A LITTLE AS A SHORT WAVE APPROACHES
FROM THE NE THIS EVENING. OTHERWISE THE GRIDS ARE IN GOOD SHAPE.
AS OF 230 PM EDT...WATER VAPOR IMAGERY SHOWS A DEEP CLOSED LOW
MOVING NE THROUGH THE RED RIVER VALLEY THIS AFTN. A RIDGE AXIS
REMAINS IN PLACE ACROSS THE ERN THIRD OF THE NATION...BUT WITH A
WEAK LOW PRESSURE CENTER UNDER THE RIDGE IN SE VA. VORTICITY ASSOC
WITH THIS WEAK LOW IS MOVING SWD INTO CENTRAL NC. CONVECTION HAS
THUS FAR BEEN LIMITED TO LOW LEVEL FORCING IN THE HIGHER TERRAIN OF
THE FAR NRN MOUNTAINS...AND EAST OF THE AREA IN IMPROVING DPVA
ALOFT. THIS ACTIVITY WILL LIKELY CONVERGE ON THE NE QUARTER OF THE
FORECAST AREA TO WARRANT VERY SOLID CHANCE POPS THERE THROUGH THE
EVENING HOURS...WITH LESSER CHANCES FARTHER SW. MODEL AND LAPS
SOUNDINGS ARE FAIRLY WARM ALOFT...WITH SFC BASED CAPE VALUES STILL
LIMITED TO AROUND 1000 J/KG OR LESS DESPITE THE WARM SFC TEMPS. A
MARGINAL HAIL THREAT IS THE MAIN CONCERN WITH ANY TSTMS...IN
ADDITION TO LOCALLY HEAVY RAINFALL WITH THE SLOWLY MOVING CELLS.
IN ADDITION TO SCATTERED TO NUMEROUS CONVECTION APPROACHING FROM THE
NE WITH THE UPPER VORT LATE TODAY...SCATTERED COASTAL CONVECTION
COULD MAKE A RUN TOWARD THE PIEDMONT FROM THE SE THROUGH THIS
EVENING. ANY COVERAGE WITH THIS ACTIVITY SHOULD BE ISOLATED BY THE
TIME IT REACHES THE LOWER PIEDMONT. WILL PROBABLY NEED TO MAINTAIN
ISOLD SHRA CHANCES OVERNIGHT ALONG THE IMMEDIATE ESCARPMENT WITH
WEAK SE UPSLOPE FLOW...AND EAST OF INTERSTATE 77 WITH THE PASSING
UPPER VORT LOBE. OTHERWISE...LOW CLOUDS AND FOG WILL INCREASE IN THE
MOIST SE BOUNDARY LAYER FLOW...WITH PERSISTENCE A GOOD FORECAST ON
WARM OVERNIGHT MINS.
THE UPPER LOW WILL BEGIN TO SLOWLY LIFT ACROSS THE SRN PLAINS ON
THU. MORE OF A SHOTGUN APPROACH TO CHANCE POPS WILL BE WARRANTED ON
THURSDAY AS DEEPER LAYER SRLY FLOW DEVELOPS AHEAD OF THE LOW AND
PROFILES CONTINUE TO STEADILY MOISTEN. MINS WILL BE A TOUCH COOLER
GIVEN THE INCREASED CLOUD COVER FOR THE BULK OF THE DAY...AND ANY
SEVERE POTENTIAL SHOULD REMAIN LIMITED BY THE WARM PROFILES ALOFT.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
AT 230 PM EDT WEDNESDAY...AN UPPER RIDGE AXIS WILL BE OVER THE
SOUTHERN APPALACHIANS ON THURSDAY NIGHT...WHILE A CLOSED UPPER LOW
WILL BE OVER THE CENTRAL PLAINS. THE RIDGE AXIS PROGRESSES TO THE
EAST COAST BY SATURDAY...WHILE THE LOW MOVES OVER THE OH AND TN
VALLEYS. SURFACE HIGH PRESSURE WILL BE CENTERED IN THE VICINITY OF
BERMUDA THROUGH FRIDAY...WHILE A COLD FRONT SLOWLY CROSSES THE GULF
STATES AND REACHES THE MOUNTAINS. ON SATURDAY THE ATLANTIC HIGH
WEAKENS AND SHIFTS SOUTH WHILE THE COLD FRONT CROSSES OUR AREA.
MOIST SOUTHERLY FLOW AND INSTABILITY AHEAD OF THE FRONT WILL FAVOR
INCREASING POPS AHEAD OF THE FRONT...GREATEST OVER THE MOUNTAINS AND
FOOTHILLS ON FRIDAY...AND OVER THE PIEDMONT ON SATURDAY. HELICITY
VALUES DECREASE AS THE COLD FRONT REACHES THE MOUNTAINS ON FRIDAY
AND REMAIN LIMITED ON SATURDAY...BUT MODEL CAPE EXCEEDS 1500 J/KG IN
THE GFS AND 1000 J/KG IN THE NAM. QPF WILL BE GREATEST ALONG THE
SOUTH FACING BLUE RIDGE ESCARPMENT FRIDAY...WHERE THE BEST UPSLOPE
FLOW WILL OCCUR. TEMPERATURES WILL RUN OVER 10 DEGREE ABOVE NORMAL
ON FRIDAY UNDER THE UPPER RIDGE...WITH A SLIGHT COOLING SATURDAY AS
HEIGHTS FALL ALOFT AND THE COLD FRONT MOVES THROUGH.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 145 PM WEDNESDAY...UPPER LOW IS PROGGED TO CONTINUE WOBBLING
EASTWARD ATOP THE CWFA ON SUNDAY AND DESPITE BEING UNDER A LLVL
POST-FRONTAL AIRMASS...STEEPING LAPSE RATES ASSOCIATED WITH
COOLING MID-LVL TEMPS WILL GIVE RISE TO THE PROBABILITY OF THE
REDEVELOPMENT OF DEEPER CONVECTION. THE LOWERING OF FREEZING
LVLS...AS POCKET OF -20 DEG C 50H TEMPS ROTATE ACRS...COULD BE
ENUF TO PROMOTE HAIL PRODUCING TSTMS. OUTSIDE OF SHOWER/TSTM
CHANCES...SENSIBLE WX WILL FEATURE A MIX OF SUN AND CLOUDS...PERHAPS
BREEZY CONDS...AND MAX TEMPS 6-8 DEG F ABV CLIMO.
THE FIRST HALF OF NEXT WEEK IS SHAPING UP TO BE QUIET AND CONTINUED
MILD. WITH THE FLOW DEAMPLIFYING ON MONDAY AND RIDGING TRANSLATING
ATOP THE SE CONUS THEREAFTER...WILL PLAN ON KEEPING THE FCST DRY
WITH DAILY MAX TEMPS AVERAGING AROUND 10 DEG ABV NORMAL.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AT KCLT...AREAS OF IFR...OR LOWER...STRATUS DEVELOPED ACROSS THE
REGION LAST NIGHT. WITH THE PERSISTENT UPSLOPE FLOW...THE STRATUS
SHOULD BE MORE WIDESPREAD THAN LAST NIGHT. THIS IS ALSO SHOWN BY
MOST OF THE GUIDANCE...AND IS IN FACT DEVELOPING ALONG THE BLUE
RIDGE. THEREFORE...WILL CONTINUE IFR CIGS IN THE FORECAST FOR A FEW
HOURS AROUND SUNRISE...WITH CIGS SLOWLY LIFTING THROUGH THE MORNING
HOURS. FOR NOW I/M FAVORING STRATUS OVER FOG. HOWEVER... IF THE
BNDRY LAYER FLOW VERIFIES ANY WEAKER THAN IT LOOKS ON THE MODELS
RIGHT NOW...THEN CONDITIONS WOULD MORE STRONGLY FAVOR DENSE FOG.
EXPECT HIGH BASED CU TO CONTINUE THRU THE REST OF THE PERIOD.
CONVECTION IS AGAIN POSSIBLE...BUT TOO EARLY TO INCLUDE ATTM. LIGHT
SSE WIND BECOMES SLY DURING THE MORNING AND CONTINUES THRU THE DAY.
ELSEWHERE...STRATUS DEVELOPED ACROSS MUCH OF THE REGION LAST
NIGHT...AND WITH PERSISTENT UPSLOPE FLOW...IT IS EXPECTED TO BE EVEN
MORE WIDESPREAD TONIGHT. IN FACT...IT IS ALREADY DEVELOPING OVER THE
BLUE RIDGE. THE BNDRY LAYER FLOW WILL BE UP AROUND 10 KTS FROM THE
SW BY LATE TONIGHT. THIS MIGHT NOT BE ENOUGH TO KEEP THE SFC WINDS
FROM DECOUPLING. IF THIS OCCURS...THEN DENSE FOG MAY BE MORE
WIDESPREAD THAN WHAT IS IN THE TAFS NOW. CIGS WILL SLOWLY RISE THU
MORNING. EXPECT HIGH BASED CU TO CONTINUE THRU THE REST OF THE
PERIOD. CONVECTION IS AGAIN POSSIBLE...BUT TOO EARLY TO INCLUDE
ATTM. LIGHT SSE WIND BECOMES S TO SW DURING THE MORNING AND
CONTINUES THRU THE DAY.
OUTLOOK...CONVECTION THEN LIKELY BECOMING ORGANIZED ALONG AN
APPROACHING COLD FRONT FRI INTO SAT. TSTMS COULD CONTINUE INTO
SUNDAY AS A LOW CENTER MOVES BY OVERHEAD...BUT WITH DRYING EARLY
NEXT WEEK. IFR RESTRICTIONS WILL BE POSSIBLE THROUGHOUT EACH MORNING
THROUGH SUNDAY...AND ALSO WITH ANY HEAVIER SHOWERS AND TSTMS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...CSH
NEAR TERM...HG/MCAVOY/RWH
SHORT TERM...JAT
LONG TERM...CSH
AVIATION...RWH
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1252 PM CDT THU MAR 22 2012
.UPDATE...FRONTAL BOUNDARY TO OUR SW NOT ANTICIPATED TO ENTER SW QUAD OF CWA
UNTIL 18Z. LIKELY POPS STARTING AT 18Z IN FAR SW. NOT MUCH CHANGE OTHER
THEN THAT...LATEST HRRR RUN HAS A SIMILAR REFLECTIVITY FIELD POSITION
AS RADAR MOSAIC S-SW OF CWA. NOTABLY LAKE BREEZE BOUNDARY ON BASE SCAN
OF MKX RADAR...SHOULD KEEPS TEMPS SIGNIFICANT COOLER NEAR SHORE AND
INLAND...ESPECIALLY MILWAUKEE...OZAUKEE...SHEBOYGAN COUNTIES. THE WARM
START HAS TEMPS EXCEEDING FCST VALUES. VIS SAT TRENDS SHOW MORE
SUNSHINE IMPACTING THE TEMP FCST THAN PREVIOUSLY THOUGHT...THIS
COMBINED WITH LATEST MODEL RH FIELDS...GAVE REASON TO UPDATE SKY GRIDS.
GIVEN THE WARM START...PRESENT SKY CONDITIONS...AND SOUTHERLY
FLOW...TEMPS WERE INCREASED ACROSS THE CWA.
&&
.AVIATION/18Z TAFS/...SHOWERS WITH SOME ISOLATED THUNDER STILL
EXPECTED TO ARRIVE THIS AFTERNOON AND INTO THE EVENING. A LOT OF
LOW LEVEL DRY AIR TO OVERCOME UNTIL CIGS LOWER CONSIDERABLY. WILL
PROBABLY SEE CIGS HOLD ONTO VFR INTO THE EVENING...EVEN DURING THE
ONSET OF RAIN. SHOULD GET PRETTY SOUPY OVERNIGHT INTO FRIDAY
MORNING THOUGH AS SHOWERS CONTINUE...WITH IFR CONDITIONS POSSIBLE.
VFR LIKELY TO RETURN BY LATE FRIDAY MORNING AS THE RAIN MOVES OUT
AND A DRIER AIRMASS MOVES BACK IN.
&&
.PREV DISCUSSION... /ISSUED 330 AM CDT THU MAR 22 2012/
SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.
THE BIG UPPER LOW OVER THE SOUTHERN PLAINS WILL BEGIN TO SHIFT EAST
TODAY AND TONIGHT. HOWEVER...THE UPPER RIDGE ON ITS NORTHERN
PERIMETER REMAINS OVER OUR AREA THROUGH MUCH OF THE DAY...BEFORE
BREAKING DOWN BY TONIGHT...AND THIS SHOULD HELP TO HOLD OFF ANY
SERIOUS INTRUSION OF WET WEATHER UNTIL LATER THIS AFTERNOON AND
TONIGHT. SOME INITIAL 700MB WARM AIR ADVECTION AND ISENTROPIC LIFT
HAS RESULTED IN SHOWERS ACROSS THE WESTERN FORECAST AREA THIS
MORNING. THE MODELS MOVE THIS AREA NORTH BY MID MORNING...BRINGING A
LITTLE BREAK BEFORE MORE SHOWERS AND POSSIBLE THUNDERSTORMS ARRIVE
LATER THIS AFTERNOON. EXPECT THE EAST TO REMAIN DRY THROUGH THE
MORNING AND POSSIBLY INTO THE FIRST PART OF THE AFTERNOON.
BY MID AFTERNOON...THE ARRIVAL OF A SPOKE OF VORTICITY ROTATING
NORTH AHEAD OF THE UPPER LOW...ALONG WITH SOME DEEP FRONTOGENETIC
FORCING IN A GOOD MOIST CONVEYOR BELT...SHOULD RESULT IN A FAIRLY
SOLID BAND OF SHOWERS AND POSSIBLE STORMS INTO SOUTHWEST
WISCONSIN...SPREADING SLOWLY NORTHEAST TONIGHT. THINGS TAPER OFF
FROM SOUTH TO NORTH AFTER MIDNIGHT. LOOKS LIKE ENOUGH CAPE TO
SUPPORT ISOLATED THUNDER MENTION THROUGH THE EVENING HOURS.
ANOTHER MILD DAY EXPECTED TODAY...BUT COOLER THAN THE LAST FEW. AN
INCREASING NORTHEAST FLOW ACROSS THE NORTHEAST HALF OF THE FORECAST
AREA WILL BRING A LAKE COOLED AIRMASS TO THAT AREA...ESPECIALLY UP
AROUND SHEBOYGAN...FOND DU LAC AND PORT WASHINGTON. THERE COULD BE
SOME LAKE INDUCED FOG CLOSE TO THE SHORE...BUT CONFIDENCE NOT VERY
HIGH GIVEN THE LOWER DWPNTS ADVECTING IN...SO WILL LEAVE OUT FOR
NOW.
FRIDAY THROUGH SATURDAY...FORECAST CONFIDENCE...HIGH.
THE MAIN BAND OF SHOWERS ASSOCIATED WITH THE VORT MAX AND
FRONTOGENESIS ON THE NORTH EDGE OF THE UPPER LOW WILL CONTINUE TO
LIFT NORTHEAST OUT OF THE FORECAST AREA. SHOWERS ARE LIKELY IN THE
NORTHEAST PORTIONS FRIDAY MORNING. THEN POOLING MOISTURE AND
ADDITIONAL VORT MAXES ROTATING AROUND THE UPPER LOW WILL LEAD TO
SHOWERS DEVELOPING THROUGH THE REST OF FRIDAY AND WELL INTO
SATURDAY.
ELEVATED INSTABILITY WITH ABOUT 150 TO 200 J/KG OF CAPE WITH THE
STEEP MID LEVEL LAPSE RATES IN THE VICINITY OF THE SHORTWAVES
ROTATING AROUND THE UPPER LOW SUPPORT THE MENTION OF ISOLATED
THUNDER EMBEDDED WITHIN THE SCATTERED TO NUMEROUS SHOWERS ON FRIDAY.
NO MENTION OF THUNDER FOR FRI NIGHT/SAT.
TEMPERATURES WILL BE COOLER OVER THE WEEKEND WITH CLOUDS AND PRECIP
IN THE AREA. HIGHS EXPECTED IN THE 60S...WITH 50S NEAR THE LAKE ON
SAT.
SATURDAY NIGHT THROUGH SUNDAY...FORECAST CONFIDENCE...HIGH.
THE UPPER RIDGE WILL NOSE INTO THE CENTRAL U.S. AND DRIER AIR WILL
WORK INTO SOUTHERN WI. TEMPERATURES WILL BE COOLER THAN THIS PAST
WEEK...WITH HIGHS IN THE 60S AND UPPER 50S NEAR THE
LAKESHORE...WHICH IS STILL WELL ABOVE NORMAL FOR THIS TIME OF YEAR.
TEMPERATURES SHOULD WARM INTO THE UPPER 60S OR BACK INTO THE 70S
TOWARD WESTERN WI WITH THE BUILDING RIDGE. EASTERLY FLOW OFF LAKE
MICHIGAN WILL KEEP THE LAKESHORE COOL AND A TIGHT TEMP GRADIENT
ACROSS THE FORECAST AREA.
DRY WEATHER EXPECTED DURING THIS PERIOD...WITH DECREASING CLOUDS AS
THE UPPER LOW DRIFTS EASTWARD.
LONG TERM...
MONDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM.
THE 500MB RIDGE MAY BECOME THE FOCUS FOR VORT MAXES ROLLING ACROSS
THE TOP AND ALLOWING FOR AN MCS OR TWO TO DEVELOP ACROSS THE UPPER
MIDWEST. THIS WILL AFFECT TEMPERATURES AND THE PRECIP
CHANCES...ESPECIALLY FOR MONDAY.
WARM AIR ADVECTION THUNDERSTORMS WILL BE POSSIBLE MON NIGHT THROUGH
TUE AHEAD OF LOW PRESSURE APPROACHING FROM THE NORTHERN PLAINS.
WINDS ARE NOW LOOKING TO BE MORE SOUTHERLY RATHER THAN EASTERLY PER
CONSENSUS BETWEEN THE ECMWF AND GFS MODELS. THIS MEANS A POTENTIAL
GOOD WARM-UP INTO THE LOWER 70S FOR TUE INTO WED. WENT WITH
CONSENSUS FOR NOW WHICH GIVES HIGHS IN THE UPPER 60S. CLOUDS AND
PRECIP WOULD BE A LIMITING FACTOR FOR HIGH TEMPS. THE FRONT/SFC
TROUGH ASSOCIATED WITH THE WEAKENING LOW WILL CROSS WI TUE NIGHT AND
LINGERING THE CHANCE FOR THUNDERSTORMS.
LATEST ECMWF AND GFS MODELS BACKED OFF ON THEIR IDEA FOR COOLER
TEMPS FOR NEXT WEEKEND. RECORD WARM MARCH...
AVIATION/12Z TAFS/...
VFR CONDITIONS EXPECTED THROUGH ABOUT MID AFTERNOON. THEN A
FAIRLY SOLID BAND OF SHOWERS AND POSSIBLE THUNDERSTORMS WILL ROLL
NORTH THROUGH THE AREA FROM LATE AFTERNOON INTO TONIGHT...TAPERING
OFF FROM NORTH TO SOUTH AFTER MIDNIGHT. AS THE ATMOSPHERIC COLUMN
SATURATES...LOOK FOR CIGS AND VSBYS TO LOWER TO MVFR CONDITIONS
BEGINNING LATER THIS AFTERNOON. AREAS ALONG THE LAKE COULD ALSO
SEE SOME IFR CIGS/VSBYS DEVELOP DUE TO THE COLD ONSHORE FLOW. THIS
FLOW IS FAIRLY WEAK AND CONFIDENCE ISN/T VERY HIGH THIS WILL
OCCUR...BUT IT IS A POSSIBILITY.
MARINE...
ONLY MARINE CONCERN WILL BE THE POSSIBILITY OF FOG DEVELOPING AS
A MOIST AIRMASS INTERACTS WITH THE COLDER AIR OVER THE LAKE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...ET/DDV
TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
FRIDAY THROUGH WEDNESDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1140 AM CDT THU MAR 22 2012
.SHORT TERM...TODAY THROUGH SATURDAY
328 AM CDT THU MAR 22 2012
MAIN FORECAST CHALLENGE CONTINUES TO BE FOCUSED ON CLOSED LOW AND
RAIN CHANCES THROUGH SATURDAY ALONG WITH THUNDER CHANCES TODAY INTO
THIS EVENING.
CURRENT WATER VAPOR IMAGERY AND RUC ANALYSIS EARLY THIS MORNING
SHOWS A CLOSED MID-LEVEL LOW OVER OK WITH RIDGING ACROSS THE EASTERN
CONUS. EXTENSION OF THIS RIDGING AND IN ADVANCE OF THE CLOSED LOW
EXTENDED THROUGH THE GREAT LAKES REGION INTO OUR AREA. DRYING IN THE
LOWER LEVELS ACROSS OUR AREA IN THIS SUBSIDENCE WAS CAUSING MOST OF
THE SHOWERS MOVING IN AHEAD OF THE CLOSED LOW TOWARD THE AREA TO
EVAPORATE...THOUGH NOW A FEW MORE SURFACE OBS SHOWING RAIN MAKING IT
TO GROUND AS THEY BEGIN TO FEEL STRETCHING DEFORMATION/MID-LEVEL
FRONTOGENETIC FORCING WHICH IS PLACE FROM SOUTHWEST MN INTO NORTHERN
WI. RADAR MOSAIC/SURFACE OBS ALSO SHOWING A BAND OF SHOWER ACTIVITY
ASSOCIATED WITH THIS FORCING. OTHERWISE...TEMPERATURES ACROSS THE
AREA WERE VERY MILD ONCE AGAIN IN THE MID 50S TO MID 60S.
22.00Z MODELS IN GOOD AGREEMENT THROUGH THE PERIOD WITH HANDLING OF
THE MID-LEVEL LOW AND AFFECT ON THE AREA THROUGH SATURDAY.
THE CLOSED MID-LEVEL LOW OVER OK WILL MOVE INTO EASTERN KS LATER
THIS AFTERNOON. THIS WILL PUSH MOISTURE FETCH NORTHWARD TOWARD THE
AREA. AS A RESULT...LOOK FOR AN INCREASE IN SHOWER COVERAGE ACROSS
SOUTHERN PORTIONS OF THE FORECAST AREA TODAY...WITH ISOLATED TO
SCATTERED COVERAGE NORTHEAST OF I-94. CANNOT RULE OUT A CRACK OR TWO
OF THUNDER. WHILE 0-1KM MLCAPE IS MINIMAL...NAM ACTUALLY SHOWS 0-3KM
MUCAPE IN THE 500-1000J/KG RANGE BY THIS AFTERNOON. LEFT ISOLATED
MENTION OF THUNDER IN BASED ON THIS SIGNAL. TEMPERATURES WILL SUFFER
A BIT TODAY COMPARATIVELY TO LAST FEW DAYS DUE TO THE
CLOUDS/INCOMING SHOWERS...BUT STILL WELL ABOVE NORMAL IN THE
MID-UPPER 60S.
AS THE LOW CONTINUES TO LIFT NORTHEAST INTO MISSOURI TONIGHT...LOOK
FOR CONVEYOR OF SHOWERS TO CONTINUE ACROSS THE AREA. KEPT AN
ISOLATED THUNDER MENTION IN FOR EARLY THIS EVENING...BUT TOOK OUT
THE REST OF THE NIGHT AS ANY CAPE WANES QUICKLY. ANTICIPATING AROUND
1/2 INCH RAINFALL ON AVERAGE FOR TODAY THROUGH TONIGHT.
MODELS SHOW THE CONVEYOR BELT OF MOISTURE/BULK OF THE SHOWERS LIFTING
NORTHEAST OF I-94 ON FRIDAY AS THE LOW CONTINUES TO LIFT NORTHEAST
INTO SOUTHERN IL. LOOK FOR TEMPERATURES TO TOP OFF AGAIN IN THE
MID-UPPER 60S.
THE MID-LEVEL LOW WILL CONTINUE AFFECT THE AREA FRIDAY NIGHT THROUGH
SATURDAY WITH SCATTERED SHOWER ACTIVITY. SHOWERS ON SATURDAY SHOULD
BE CONFINED EAST OF THE MISSISSIPPI RIVER WHERE CYCLONIC FLOW
ALOFT/STEEPER LAPSE RATES WILL RESIDE. LOOKS LIKE CLOUDS WILL BE
MORE SCATTERED WEST OF THE MISSISSIPPI RIVER FOR A LITTLE MORE
HEATING. LOOK FOR HIGHS IN THE MIDDLE 60S ACROSS CENTRAL
WISCONSIN...TO SOME LOWER 70S ALONG AND WEST OF THE MISSISSIPPI
RIVER.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
328 AM CDT THU MAR 22 2012
22.00Z ECMWF/GFS DISPLAY SOME INTERESTING FEATURES IN THE EXTENDED
PERIOD.
FIRST FEATURE OF INTEREST WILL BE A COLD FRONT DROPPING SOUTH INTO
THE REGION ASSOCIATED WITH A LOW PASSING ACROSS SOUTHERN ONTARIO.
TIMING OF THIS FRONT WILL BE CRUCIAL TO HOW WARM WE GET. APPEARS THE
FRONT PUSHES THROUGH THE AREA DURING THE AFTERNOON. WILL GO WITH
MODEL CONSENSUS RIGHT NOW WHICH YIELDS HIGHS IN THE MIDDLE/UPPER
60S. IT APPEARS THIS FRONT WILL COME THROUGH DRY AS WELL. THEN FOR
SUNDAY NIGHT THROUGH MONDAY...CANADIAN HIGH PRESSURE OOZES SOUTH OUT
OF ONTARIO FOR COOLER/DRIER EASTERLY FLOW ACROSS THE AREA. ECMWF
DEFINITELY COOLER OF THE MODELS ON MONDAY...INDICATING 925MB AIR IN
THE 4-6C RANGE ACROSS THE AREA...WHILE THE GFS INDICATING 8-15C.
MODEL CONSENSUS GIVES US HIGHS ON MONDAY IN THE UPPER 50S-MIDDLE 60S
NORTHEAST OF I-94...TO THE UPPER 60S ALONG/WEST OF THE MISSISSIPPI
RIVER. IN ADDITION...THERE WILL BE A SMALL CHANCE OF ELEVATED
SHOWERS/THUNDER MONDAY WEST OF THE RIVER IN RESPONSE TO LIFT OVER A
WARM FRONT ACROSS THE NORTHERN PLAINS INTO IA. THEN FOR MONDAY NIGHT
THROUGH TUESDAY...PLAN ON INCREASING SHOWER/THUNDERSTORM CHANCES AS
A LOW TRACKS FROM THE NORTHERN PLAINS INTO CANADA...PULLING A COLD
FRONT INTO THE REGION. DEPENDING ON THE TIMING OF THE FRONT ON
TUESDAY...COULD SEE A BOUT OF SEVERE WEATHER. GFS INDICATING 0-1KM
MLCAPE AROUND 1200J/KG WITH PLENTY OF BULK SHEAR NOSING UP INTO
NORTHEAST IA/SOUTHEAST MN DURING THE AFTERNOON. TIMING OF THE
FRONTAL PASSAGE WILL BE OF THE ESSENCE HERE AND WILL HAVE TO BE
MONITORED CLOSELY. THE GFS AND TO A LESSER EXTENT THE ECMWF SHOW THE
AREA IN LINGERING DRY/BREEZY CYCLONIC FLOW ON WEDNESDAY. PLAN ON
HIGHS IN THE MIDDLE 50S TO MIDDLE 60S.
&&
.AVIATION...
1140 AM CDT THU MAR 22 2012
SOME CLEARING OF THE BKN MID LEVEL CLOUDS WILL ALLOW FOR
DESTABILIZATION THIS AFTERNOON. RUC13/HRRR/ARW MESO MODELS USE THE
INSTABILITY TO CONVECT SHRA/TS AROUND A SFC BOUNDARY THAT RUNS
WEST-EAST ACROSS THE REGION. MOST HOLD OFF UNTIL 20-21Z...AND WILL
USE THIS AS TIMING FOR THE TAFS. THE INSTABILITY IS WEAK AND DOESN/T
SUPPORT STRONG UPDRAFTS. HOWEVER...RUC SOUNDINGS POINT TO A NEAR SFC
DRY LAYER...WHICH WOULD ENHANCE GUSTY CONDITIONS AROUND ANY
SHRA/TS.
EXPECT MVFR CIGS TO ROTATE IN LATER TONIGHT ON THE NORTHSIDE OF AN
UPPER LEVEL LOW WOBBLING TOWARD THE MID MISSISSIPPI RIVER VALLEY.
KRST/KLSE COULD BE STUCK IN THESE LOW MVFR CIGS THROUGH FRIDAY
MORNING...WITH IMPROVEMENT DURING THE AFTERNOON.
THAT SAID...THERE IS SOME POTENTIAL THAT THIS LOW CLOUD COULD PUSH
FAR ENOUGH NORTH THAT KRST/KLSE COULD SLIDE UNDER A DRY SLOT. IT
WOULD BE LIKELY THAT LOW STRATUS AND/OR FOG WOULD FORM IN THIS DRY
SLOT OVERNIGHT...WITH SUB 1SM BR AND SUB 1KFT CIGS POSSIBLE.
CONFIDENCE ISN/T HIGH THAT THIS AREA WILL MAKE IT THAT FAR NORTH
TONIGHT...SO WILL STAY WITH THE MVFR STRATUS FOR NOW. CERTAINLY
THOUGH...THIS POTENTIAL WILL HAVE TO BE MONITORED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
328 AM CDT THU MAR 22 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
649 AM CDT THU MAR 22 2012
.SHORT TERM...TODAY THROUGH SATURDAY
328 AM CDT THU MAR 22 2012
MAIN FORECAST CHALLENGE CONTINUES TO BE FOCUSED ON CLOSED LOW AND
RAIN CHANCES THROUGH SATURDAY ALONG WITH THUNDER CHANCES TODAY INTO
THIS EVENING.
CURRENT WATER VAPOR IMAGERY AND RUC ANALYSIS EARLY THIS MORNING
SHOWS A CLOSED MID-LEVEL LOW OVER OK WITH RIDGING ACROSS THE EASTERN
CONUS. EXTENSION OF THIS RIDGING AND IN ADVANCE OF THE CLOSED LOW
EXTENDED THROUGH THE GREAT LAKES REGION INTO OUR AREA. DRYING IN THE
LOWER LEVELS ACROSS OUR AREA IN THIS SUBSIDENCE WAS CAUSING MOST OF
THE SHOWERS MOVING IN AHEAD OF THE CLOSED LOW TOWARD THE AREA TO
EVAPORATE...THOUGH NOW A FEW MORE SURFACE OBS SHOWING RAIN MAKING IT
TO GROUND AS THEY BEGIN TO FEEL STRETCHING DEFORMATION/MID-LEVEL
FRONTOGENETIC FORCING WHICH IS PLACE FROM SOUTHWEST MN INTO NORTHERN
WI. RADAR MOSAIC/SURFACE OBS ALSO SHOWING A BAND OF SHOWER ACTIVITY
ASSOCIATED WITH THIS FORCING. OTHERWISE...TEMPERATURES ACROSS THE
AREA WERE VERY MILD ONCE AGAIN IN THE MID 50S TO MID 60S.
22.00Z MODELS IN GOOD AGREEMENT THROUGH THE PERIOD WITH HANDLING OF
THE MID-LEVEL LOW AND AFFECT ON THE AREA THROUGH SATURDAY.
THE CLOSED MID-LEVEL LOW OVER OK WILL MOVE INTO EASTERN KS LATER
THIS AFTERNOON. THIS WILL PUSH MOISTURE FETCH NORTHWARD TOWARD THE
AREA. AS A RESULT...LOOK FOR AN INCREASE IN SHOWER COVERAGE ACROSS SOUTHERN
PORTIONS OF THE FORECAST AREA TODAY...WITH ISOLATED TO SCATTERED
COVERAGE NORTHEAST OF I-94. CANNOT RULE OUT A CRACK OR TWO OF
THUNDER. WHILE 0-1KM MLCAPE IS MINIMAL...NAM ACTUALLY SHOWS 0-3KM
MUCAPE IN THE 500-1000J/KG RANGE BY THIS AFTERNOON. LEFT ISOLATED
MENTION OF THUNDER IN BASED ON THIS SIGNAL. TEMPERATURES WILL SUFFER
A BIT TODAY COMPARATIVELY TO LAST FEW DAYS DUE TO THE
CLOUDS/INCOMING SHOWERS...BUT STILL WELL ABOVE NORMAL IN THE
MID-UPPER 60S.
AS THE LOW CONTINUES TO LIFT NORTHEAST INTO MISSOURI TONIGHT...LOOK
FOR CONVEYOR OF SHOWERS TO CONTINUE ACROSS THE AREA. KEPT AN
ISOLATED THUNDER MENTION IN FOR EARLY THIS EVENING...BUT TOOK OUT
THE REST OF THE NIGHT AS ANY CAPE WANES QUICKLY. ANTICIPATING AROUND
1/2 INCH RAINFALL ON AVERAGE FOR TODAY THROUGH TONIGHT.
MODELS SHOW THE CONVEYOR BELT OF MOISTURE/BULK OF THE SHOWERS LIFTING
NORTHEAST OF I-94 ON FRIDAY AS THE LOW CONTINUES TO LIFT NORTHEAST
INTO SOUTHERN IL. LOOK FOR TEMPERATURES TO TOP OFF AGAIN IN THE
MID-UPPER 60S.
THE MID-LEVEL LOW WILL CONTINUE AFFECT THE AREA FRIDAY NIGHT THROUGH
SATURDAY WITH SCATTERED SHOWER ACTIVITY. SHOWERS ON SATURDAY SHOULD
BE CONFINED EAST OF THE MISSISSIPPI RIVER WHERE CYCLONIC FLOW
ALOFT/STEEPER LAPSE RATES WILL RESIDE. LOOKS LIKE CLOUDS WILL BE
MORE SCATTERED WEST OF THE MISSISSIPPI RIVER FOR A LITTLE MORE
HEATING. LOOK FOR HIGHS IN THE MIDDLE 60S ACROSS CENTRAL
WISCONSIN...TO SOME LOWER 70S ALONG AND WEST OF THE MISSISSIPPI RIVER.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
328 AM CDT THU MAR 22 2012
22.00Z ECMWF/GFS DISPLAY SOME INTERESTING FEATURES IN THE EXTENDED
PERIOD.
FIRST FEATURE OF INTEREST WILL BE A COLD FRONT DROPPING SOUTH INTO
THE REGION ASSOCIATED WITH A LOW PASSING ACROSS SOUTHERN ONTARIO.
TIMING OF THIS FRONT WILL BE CRUCIAL TO HOW WARM WE GET. APPEARS THE
FRONT PUSHES THROUGH THE AREA DURING THE AFTERNOON. WILL GO WITH
MODEL CONSENSUS RIGHT NOW WHICH YIELDS HIGHS IN THE MIDDLE/UPPER
60S. IT APPEARS THIS FRONT WILL COME THROUGH DRY AS WELL. THEN FOR
SUNDAY NIGHT THROUGH MONDAY...CANADIAN HIGH PRESSURE OOZES SOUTH OUT
OF ONTARIO FOR COOLER/DRIER EASTERLY FLOW ACROSS THE AREA. ECMWF
DEFINITELY COOLER OF THE MODELS ON MONDAY...INDICATING 925MB AIR IN
THE 4-6C RANGE ACROSS THE AREA...WHILE THE GFS INDICATING 8-15C.
MODEL CONSENSUS GIVES US HIGHS ON MONDAY IN THE UPPER 50S-MIDDLE 60S
NORTHEAST OF I-94...TO THE UPPER 60S ALONG/WEST OF THE MISSISSIPPI
RIVER. IN ADDITION...THERE WILL BE A SMALL CHANCE OF ELEVATED
SHOWERS/THUNDER MONDAY WEST OF THE RIVER IN RESPONSE TO LIFT OVER A
WARM FRONT ACROSS THE NORTHERN PLAINS INTO IA. THEN FOR MONDAY NIGHT
THROUGH TUESDAY...PLAN ON INCREASING SHOWER/THUNDERSTORM CHANCES AS
A LOW TRACKS FROM THE NORTHERN PLAINS INTO CANADA...PULLING A COLD
FRONT INTO THE REGION. DEPENDING ON THE TIMING OF THE FRONT ON
TUESDAY...COULD SEE A BOUT OF SEVERE WEATHER. GFS INDICATING 0-1KM
MLCAPE AROUND 1200J/KG WITH PLENTY OF BULK SHEAR NOSING UP INTO
NORTHEAST IA/SOUTHEAST MN DURING THE AFTERNOON. TIMING OF THE
FRONTAL PASSAGE WILL BE OF THE ESSENCE HERE AND WILL HAVE TO BE
MONITORED CLOSELY. THE GFS AND TO A LESSER EXTENT THE ECMWF SHOW THE
AREA IN LINGERING DRY/BREEZY CYCLONIC FLOW ON WEDNESDAY. PLAN ON
HIGHS IN THE MIDDLE 50S TO MIDDLE 60S.
&&
.AVIATION...TODAY AND TONIGHT
648 AM CDT THU MAR 22 2012
AN AREA OF SHOWERS FROM IOWA INTO EASTERN MISSOURI WILL LIFT
NORTHEAST THROUGH THE TAF SITES THIS AFTERNOON AND EVENING. EASTERLY
LOW LEVEL LOOKS TO HOLD ENOUGH LOW LEVEL DRY AIR TO KEEP CEILINGS
AND VISIBILITIES VFR THROUGH AT LEAST MID AFTERNOON. ANTICIPATING
EVENTUALLY AT KRST THE CEILINGS WILL DROP TO MVFR SOMEWHERE AROUND
20Z. WITH KLSE BEING CLOSER TO THE DRIER AIR AND IN THE
VALLEY...PLANNING ON THE MVFR CEILING NOT TO DEVELOP UNTIL WELL
AFTER THE RAIN ENDS...AROUND 08Z. REGARDING LATE TONIGHT...CONCERN
EXISTS THAT A DRY SLOT/CLEARING WEDGE OVER SOUTHWEST MISSOURI WILL
LIFT INTO THE TAF SITES. SHOULD THIS OCCUR...A LOWER STRATUS
DEVELOPS WHICH IS INDICATED IN THE FORECAST...THOUGH POTENTIAL
EXISTS FOR EVEN LOWER. ANOTHER ALTERNATIVE IS SOME FOG WITH
VISIBILITIES AS LOW AS VLIFR. LASTLY...IT STAYS CLEAR IF THE DRY
AIR IS DEEP ENOUGH. THE FORECAST FOR LATE TONIGHT WILL NEED TO BE
REEVALUATED THROUGH TODAY AND INTO THIS EVENING...AS CONFIDENCE
ABOUT THE WEDGE OF DRY AIR AND CLEAR SKIES GROWS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
328 AM CDT THU MAR 22 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
328 AM CDT THU MAR 22 2012
.SHORT TERM...TODAY THROUGH SATURDAY
328 AM CDT THU MAR 22 2012
MAIN FORECAST CHALLENGE CONTINUES TO BE FOCUSED ON CLOSED LOW AND
RAIN CHANCES THROUGH SATURDAY ALONG WITH THUNDER CHANCES TODAY INTO
THIS EVENING.
CURRENT WATER VAPOR IMAGERY AND RUC ANALYSIS EARLY THIS MORNING
SHOWS A CLOSED MID-LEVEL LOW OVER OK WITH RIDGING ACROSS THE EASTERN
CONUS. EXTENSION OF THIS RIDGING AND IN ADVANCE OF THE CLOSED LOW
EXTENDED THROUGH THE GREAT LAKES REGION INTO OUR AREA. DRYING IN THE
LOWER LEVELS ACROSS OUR AREA IN THIS SUBSIDENCE WAS CAUSING MOST OF
THE SHOWERS MOVING IN AHEAD OF THE CLOSED LOW TOWARD THE AREA TO
EVAPORATE...THOUGH NOW A FEW MORE SURFACE OBS SHOWING RAIN MAKING IT
TO GROUND AS THEY BEGIN TO FEEL STRETCHING DEFORMATION/MID-LEVEL
FRONTOGENETIC FORCING WHICH IS PLACE FROM SOUTHWEST MN INTO NORTHERN
WI. RADAR MOSAIC/SURFACE OBS ALSO SHOWING A BAND OF SHOWER ACTIVITY
ASSOCIATED WITH THIS FORCING. OTHERWISE...TEMPERATURES ACROSS THE
AREA WERE VERY MILD ONCE AGAIN IN THE MID 50S TO MID 60S.
22.00Z MODELS IN GOOD AGREEMENT THROUGH THE PERIOD WITH HANDLING OF
THE MID-LEVEL LOW AND AFFECT ON THE AREA THROUGH SATURDAY.
THE CLOSED MID-LEVEL LOW OVER OK WILL MOVE INTO EASTERN KS LATER
THIS AFTERNOON. THIS WILL PUSH MOISTURE FETCH NORTHWARD TOWARD THE
AREA. AS A RESULT...LOOK FOR AN INCREASE IN SHOWER COVERAGE ACROSS SOUTHERN
PORTIONS OF THE FORECAST AREA TODAY...WITH ISOLATED TO SCATTERED
COVERAGE NORTHEAST OF I-94. CANNOT RULE OUT A CRACK OR TWO OF
THUNDER. WHILE 0-1KM MLCAPE IS MINIMAL...NAM ACTUALLY SHOWS 0-3KM
MUCAPE IN THE 500-1000J/KG RANGE BY THIS AFTERNOON. LEFT ISOLATED
MENTION OF THUNDER IN BASED ON THIS SIGNAL. TEMPERATURES WILL SUFFER
A BIT TODAY COMPARATIVELY TO LAST FEW DAYS DUE TO THE
CLOUDS/INCOMING SHOWERS...BUT STILL WELL ABOVE NORMAL IN THE
MID-UPPER 60S.
AS THE LOW CONTINUES TO LIFT NORTHEAST INTO MISSOURI TONIGHT...LOOK
FOR CONVEYOR OF SHOWERS TO CONTINUE ACROSS THE AREA. KEPT AN
ISOLATED THUNDER MENTION IN FOR EARLY THIS EVENING...BUT TOOK OUT
THE REST OF THE NIGHT AS ANY CAPE WANES QUICKLY. ANTICIPATING AROUND
1/2 INCH RAINFALL ON AVERAGE FOR TODAY THROUGH TONIGHT.
MODELS SHOW THE CONVEYOR BELT OF MOISTURE/BULK OF THE SHOWERS LIFTING
NORTHEAST OF I-94 ON FRIDAY AS THE LOW CONTINUES TO LIFT NORTHEAST
INTO SOUTHERN IL. LOOK FOR TEMPERATURES TO TOP OFF AGAIN IN THE
MID-UPPER 60S.
THE MID-LEVEL LOW WILL CONTINUE AFFECT THE AREA FRIDAY NIGHT THROUGH
SATURDAY WITH SCATTERED SHOWER ACTIVITY. SHOWERS ON SATURDAY SHOULD
BE CONFINED EAST OF THE MISSISSIPPI RIVER WHERE CYCLONIC FLOW
ALOFT/STEEPER LAPSE RATES WILL RESIDE. LOOKS LIKE CLOUDS WILL BE
MORE SCATTERED WEST OF THE MISSISSIPPI RIVER FOR A LITTLE MORE
HEATING. LOOK FOR HIGHS IN THE MIDDLE 60S ACROSS CENTRAL
WISCONSIN...TO SOME LOWER 70S ALONG AND WEST OF THE MISSISSIPPI RIVER.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
328 AM CDT THU MAR 22 2012
22.00Z ECMWF/GFS DISPLAY SOME INTERESTING FEATURES IN THE EXTENDED
PERIOD.
FIRST FEATURE OF INTEREST WILL BE A COLD FRONT DROPPING SOUTH INTO
THE REGION ASSOCIATED WITH A LOW PASSING ACROSS SOUTHERN ONTARIO.
TIMING OF THIS FRONT WILL BE CRUCIAL TO HOW WARM WE GET. APPEARS THE
FRONT PUSHES THROUGH THE AREA DURING THE AFTERNOON. WILL GO WITH
MODEL CONSENSUS RIGHT NOW WHICH YIELDS HIGHS IN THE MIDDLE/UPPER
60S. IT APPEARS THIS FRONT WILL COME THROUGH DRY AS WELL. THEN FOR
SUNDAY NIGHT THROUGH MONDAY...CANADIAN HIGH PRESSURE OOZES SOUTH OUT
OF ONTARIO FOR COOLER/DRIER EASTERLY FLOW ACROSS THE AREA. ECMWF
DEFINITELY COOLER OF THE MODELS ON MONDAY...INDICATING 925MB AIR IN
THE 4-6C RANGE ACROSS THE AREA...WHILE THE GFS INDICATING 8-15C.
MODEL CONSENSUS GIVES US HIGHS ON MONDAY IN THE UPPER 50S-MIDDLE 60S
NORTHEAST OF I-94...TO THE UPPER 60S ALONG/WEST OF THE MISSISSIPPI
RIVER. IN ADDITION...THERE WILL BE A SMALL CHANCE OF ELEVATED
SHOWERS/THUNDER MONDAY WEST OF THE RIVER IN RESPONSE TO LIFT OVER A
WARM FRONT ACROSS THE NORTHERN PLAINS INTO IA. THEN FOR MONDAY NIGHT
THROUGH TUESDAY...PLAN ON INCREASING SHOWER/THUNDERSTORM CHANCES AS
A LOW TRACKS FROM THE NORTHERN PLAINS INTO CANADA...PULLING A COLD
FRONT INTO THE REGION. DEPENDING ON THE TIMING OF THE FRONT ON
TUESDAY...COULD SEE A BOUT OF SEVERE WEATHER. GFS INDICATING 0-1KM
MLCAPE AROUND 1200J/KG WITH PLENTY OF BULK SHEAR NOSING UP INTO
NORTHEAST IA/SOUTHEAST MN DURING THE AFTERNOON. TIMING OF THE
FRONTAL PASSAGE WILL BE OF THE ESSENCE HERE AND WILL HAVE TO BE
MONITORED CLOSELY. THE GFS AND TO A LESSER EXTENT THE ECMWF SHOW THE
AREA IN LINGERING DRY/BREEZY CYCLONIC FLOW ON WEDNESDAY. PLAN ON
HIGHS IN THE MIDDLE 50S TO MIDDLE 60S.
&&
.AVIATION...THROUGH 06Z FRIDAY
1146 PM CDT WED MAR 21 2012
THE 22.00Z NAM HAS COME IN BETTER AGREEMENT WITH THE HRRR AND
HIRES EAST ARW SHOWING JUST THE POSSIBILITY OF SOME WIDELY
SCATTERED SHOWERS OR SPRINKLES ACROSS THE AREA FOR THE REMAINDER
OF THE NIGHT. REGIONAL RADARS SHOWING SOME OF THESE TRYING TO WORK
NORTH ACROSS IOWA WHERE SURFACE OBSERVATIONS INDICATE THESE ARE
JUST SPRINKLES FALLING OUT OF A MID LEVEL DECK. THE 22.01Z HRRR
SHOWS THE REMAINS OF THESE POSSIBLY REACHING THE I90 CORRIDOR
BETWEEN 12 AND 15Z AND WILL HAVE A VICINITY SHOWER AT BOTH SITES
TO REFLECT THIS. AFTER THAT...ANY SIGNIFICANT SHOWERS LOOK TO HOLD
OFF UNTIL THE LATE MORNING OR AFTERNOON. THE REMAINS OF THE LOW
LEVEL MOISTURE TRANSPORT BECOME FOCUSED ON THE AREA AT THAT TIME
AND THE NAM SUGGESTS THE POSSIBILITY OF A WEAK SHORT WAVE TROUGH
COMING ACROSS DURING THE AFTERNOON TO PRODUCE AROUND 4 PVU/S OF
VORTICITY ADVECTION IN THE 500-300 MB LAYER. THIS WILL BE
ACCOMPANIED BY SOME WEAK ISENTROPIC UP GLIDE ON THE 300K SURFACE
OF 1 TO 2 UBARS/S. WILL BRING IN SOME SHOWERS WITH THIS FORCING
BUT WITH NO VISIBILITY RESTRICTIONS AS CONFIDENCE ON HOW
WIDESPREAD OR HOW LONG THE SHOWERS WILL LAST IS STILL PRETTY LOW.
WILL KEEP THE FORECAST VFR UNTIL A COUPLE OF HOURS AFTER THE
SHOWERS BEGIN AND LOWER THE CEILING TO MVFR. WILL INDICATE THE
SHOWERS ENDING IN THE EVENING AS THE FORCING LIFTS TO THE NORTH
AND CONDITIONS RETURNING TO VFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
328 AM CDT THU MAR 22 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1146 PM CDT WED MAR 21 2012
.SHORT TERM...TONIGHT THROUGH SATURDAY
333 PM CDT WED MAR 21 2012
MAIN FORECAST CONCERNS ARE ON RAIN SHOWER CHANCES TONIGHT THROUGH
FRIDAY....ALONG WITH ISOLATED THUNDERSTORM POTENTIAL DURING THE
DAYTIME ON THURSDAY AND AGAIN ON FRIDAY.
CURRENT WATER VAPOR IMAGERY INDICATED AN UPPER LOW OVER CENTRAL
OKLAHOMA. ABUNDANT GULF OF MEXICO MOISTURE WAS STREAMING NORTHWARD
ALONG THE LOWER AND MIDDLE MISSISSIPPI RIVER VALLEY. SKIES THIS
AFTERNOON RANGED FROM PARTLY SUNNY ACROSS CENTRAL INTO FAR SOUTHWEST
WISCONSIN TO CLOUDY ACROSS SOUTHEAST MINNESOTA INTO NORTHEAST IOWA.
A NEARLY STATIONARY COLD COLD FRONT EXTENDED FROM THE ARROWHEAD OF
MINNESOTA...SOUTHWEST INTO CENTRAL NEBRASKA.
THE UPPER LOW IS EXPECTED TO DRIFT NORTH TONIGHT INTO THURSDAY WITH
RAIN SHOWERS SPREADING INTO THE FORECAST AREA LATE TONIGHT. 850 MB
MOISTURE TRANSPORT WILL INCREASE ALONG THE MIDDLE MISSISSIPPI RIVER
THIS EVENING AND ADVECT NORTH AND WEST INTO SOUTHERN/CENTRAL IOWA
LATE TONIGHT...FOCUSING INTO FORECAST AREA LATE TONIGHT INTO EARLY
THURSDAY MORNING. LOOK FOR SHOWERS TO SPREAD INTO NORTHEAST IOWA AND
FAR SOUTHWEST WISCONSIN BY EARLY THURSDAY MORNING...LIFTING
NORTHWARD INTO SOUTHEAST MINNESOTA AND MUCH OF WESTERN WISCONSIN
THROUGH THURSDAY AFTERNOON. MIXED LAYER CAPE WILL INCREASE INTO THE
200 TO 700 J/KG RANGE...WHICH COLD LEAD TO ISOLATED THUNDERSTORMS
THROUGH THE DAY ON THURSDAY. THE SHOWERS/ISOLATED THUNDERSTORMS WILL
PERSIST THROUGH THURSDAY AFTERNOON BEFORE GRADUALLY SHIFTING INTO
CENTRAL AND NORTH CENTRAL WISCONSIN LATE THURSDAY EVENING. DECIDED
TO INCREASE PRECIPITATION CHANCES ON THURSDAY. HAVE LOWERED HIGH
TEMPERATURES A FEW DEGREES WITH THE EXPECTED PRECIPITATION AND
ABUNDANT CLOUD COVER IN PLACE THROUGH THE DAY ON THURSDAY. LOOK FOR
HIGHS TO RANGE FROM THE LOWER 60S ACROSS NORTH CENTRAL WISCONSIN TO
THE THE UPPER 60S ACROSS NORTHEAST IOWA INTO SOUTHWEST WISCONSIN.
BY LATE TOMORROW NIGHT...MOST LOCATIONS SHOULD HAVE RECEIVED 1/4 TO
1/2 INCH OF RAINFALL. WITH PRECIPITABLE WATER VALUES RUNNING AROUND
350 PERCENT OF NORMAL...CANNOT RULE OUT A FEW 3/4 TO 1 INCH REPORTS
IF CONVECTION DEVELOPS.
THE UPPER LOW WILL MOVE INTO MISSOURI ON FRIDAY WITH MOISTURE
TRANSPORT FOCUSING INTO EASTERN WISCONSIN AND LOWER MICHIGAN. MODELS
GENERATE SOME WEAK ML CAPE ACROSS THE AREA ON FRIDAY WITH VALUES
AROUND 100 J/KG. IN ADDITION TO SCATTERED SHOWERS...AN ISOLATED
THUNDERSTORM OR TWO IS POSSIBLE MAINLY ACROSS CENTRAL INTO FAR
SOUTHWEST WISCONSIN. THE LATEST NAM SOLUTION TAKES THE UPPER LOW
MUCH FURTHER SOUTH VERSUS THE ECMWF/GFS/GEM. THE NAM SHOWS THE
UPPER LOW TRACKING ACROSS SOUTHERN MISSOURI DURING THE DAY ON
FRIDAY...AND MOVING OVER THE OHIO RIVER VALLEY FRIDAY NIGHT. THIS
SOLUTIONS APPEARS TO BE AN OUTLIER BUT WILL HAVE TO KEEP A CLOSE
WATCH ON THIS. IF THE LOW TRACK CLOSER TO THE NAM SOLUTION
PRECIPITATION CHANCES MAY BE A LITTLE HIGH ACROSS THE FORECAST AREA
FRIDAY INTO FRIDAY NIGHT. PLAN ON MOSTLY CLOUDY SKIES ON FRIDAY WITH
HIGHS IN THE 60S. THE LOW WILL FINALLY DRIFT SOUTH AND EAST OF THE
FORECAST AREA SATURDAY AFTERNOON AS A HIGH PRESSURE BUILDS INTO THE
UPPER MIDWEST. THERE IS A SLIGHT CHANCE OF A FEW LINGERING RAIN
SHOWERS MAINLY FRIDAY MORNING BEFORE THE HIGH BUILDS IN.
OTHERWISE...PLAN ON HIGHS RANGING FROM THE LOWER 60S ACROSS NORTH
CENTRAL WISCONSIN TO THE UPPER 60S ACROSS NORTHEAST IOWA. LOOK FOR
DECREASING CLOUDS SATURDAY NIGHT WITH LOWS FALLING INTO THE
40S.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
333 PM CDT WED MAR 21 2012
21.12 MEDIUM RANGE MODELS SHOWING SOME INTERESTING DIFFERENCES
REGARDING THE PLACEMENT OF COOL CANADIAN HIGH PRESSURE LATE SUNDAY
THROUGH MONDAY. THE GFS SHOWS 850 MB TEMPERATURES RANGING FROM 13 C
ACROSS NORTHEAST IOWA TO AROUND 8 C ACROSS NORTHERN WISCONSIN BY
MONDAY AFTERNOON. THE ECMWF AND GEM HAVE MUCH COOLER 850
TEMPERATURES...RANGING FROM 5 C ACROSS NORTHEAST IOWA TO -3 C ACROSS
CENTRAL INTO NORTHERN WISCONSIN. GIVEN THE UPPER LEVEL
PATTERN....WOULD EXPECT TO SEE SOME OF THESE COOLER TEMPERATURES
TRICKLE INTO NORTHERN AND CENTRAL WISCONSIN. GIVEN THE SPREAD IN
MODEL SOLUTIONS WILL SIDE WITH A MODELS CONSENSUS BLEND...WITH HIGHS
ON MONDAY RANGING FROM AROUND 60 ACROSS NORTH CENTRAL WISCONSIN TO
AROUND 70 ACROSS NORTHEAST IOWA. WILL HAVE TO KEEP A CLOSE WATCH ON
THE FRONTAL BOUNDARY MONDAY WITH THE POTENTIAL FOR THUNDERSTORM
DEVELOPMENT ALONG IT AS WEAK UPPER LEVEL IMPULSES MOVE ACROSS THE
FORECAST AREA. THE FRONT IS EXPECTED TO LIFT NORTH ACROSS THE
FORECAST AREA MONDAY NIGHT INTO TUESDAY BRINGING A CHANCE OF SHOWERS
AND THUNDERSTORM TO THE REGION. THE LOW LEVEL JET LOOKS TO SET UP
ACROSS THE CENTRAL PLAINS AND INTO SOUTHWEST MINNESOTA LATE MONDAY
NIGHT INTO EARLY TUESDAY MORNING...AND COULD SERVE AS A FOCUSING
MECHANISM FOR THUNDERSTORM DEVELOPMENT. FORECAST SOUNDINGS APPEAR A
LITTLE ON THE DRY SIDE FOR ELEVATED CONVECTION BUT WILL HAVE TO KEEP
A CLOSE WATCH ON THIS. THE WARM FRONT IS EXPECTED TO LIFT NORTH OF
THE REGION ON TUESDAY...LEAVING THE FORECAST AREA IN THE WARM SECTOR
AS A STRONG COLD FRONT APPROACHES FROM THE DAKOTAS. AFTERNOON 0-3 KM
MUCAPE VALUES ARE EXPECTED TO CLIMB TO AROUND 2100 J/KG BY LATE
TUESDAY AFTERNOON..WITH 0-6 KM BULK SHEAR VALUES OF 30 TO 35 KTS.
0-1 KM SHEAR VALUES ARE EXPECTED TO CLIMB TO AROUND 20 KTS. WILL
CONTINUE TO MONITOR FOR SEVERE THUNDERSTORM POTENTIAL WITH THIS
SYSTEM...ESPECIALLY IF MODEL TRENDS CONTINUE.
&&
.AVIATION...THROUGH 06Z FRIDAY
1146 PM CDT WED MAR 21 2012
THE 22.00Z NAM HAS COME IN BETTER AGREEMENT WITH THE HRRR AND
HIRES EAST ARW SHOWING JUST THE POSSIBILITY OF SOME WIDELY
SCATTERED SHOWERS OR SPRINKLES ACROSS THE AREA FOR THE REMAINDER
OF THE NIGHT. REGIONAL RADARS SHOWING SOME OF THESE TRYING TO WORK
NORTH ACROSS IOWA WHERE SURFACE OBSERVATIONS INDICATE THESE ARE
JUST SPRINKLES FALLING OUT OF A MID LEVEL DECK. THE 22.01Z HRRR
SHOWS THE REMAINS OF THESE POSSIBLY REACHING THE I90 CORRIDOR
BETWEEN 12 AND 15Z AND WILL HAVE A VICINITY SHOWER AT BOTH SITES
TO REFLECT THIS. AFTER THAT...ANY SIGNIFICANT SHOWERS LOOK TO HOLD
OFF UNTIL THE LATE MORNING OR AFTERNOON. THE REMAINS OF THE LOW
LEVEL MOISTURE TRANSPORT BECOME FOCUSED ON THE AREA AT THAT TIME
AND THE NAM SUGGESTS THE POSSIBILITY OF A WEAK SHORT WAVE TROUGH
COMING ACROSS DURING THE AFTERNOON TO PRODUCE AROUND 4 PVU/S OF
VORTICITY ADVECTION IN THE 500-300 MB LAYER. THIS WILL BE
ACCOMPANIED BY SOME WEAK ISENTROPIC UP GLIDE ON THE 300K SURFACE
OF 1 TO 2 UBARS/S. WILL BRING IN SOME SHOWERS WITH THIS FORCING
BUT WITH NO VISIBILITY RESTRICTIONS AS CONFIDENCE ON HOW
WIDESPREAD OR HOW LONG THE SHOWERS WILL LAST IS STILL PRETTY LOW.
WILL KEEP THE FORECAST VFR UNTIL A COUPLE OF HOURS AFTER THE
SHOWERS BEGIN AND LOWER THE CEILING TO MVFR. WILL INDICATE THE
SHOWERS ENDING IN THE EVENING AS THE FORCING LIFTS TO THE NORTH
AND CONDITIONS RETURNING TO VFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
333 PM CDT WED MAR 21 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
553 AM EDT SAT MAR 24 2012
.SYNOPSIS...
LOW PRESSURE LOCATED OVER THE OHIO RIVER VALLEY EARLY THIS
MORNING WILL PROGRESS EASTWARD AND IT SHOULD MOVE OFF THE MIDDLE
ATLANTIC COAST ON SUNDAY. A COLD FRONT FROM THE NORTHWEST IS
FORECAST TO PASS THROUGH OUR REGION EARLY ON MONDAY, FOLLOWED BY
HIGH PRESSURE FOR TUESDAY. A WARM FRONT APPROACHING FROM THE
SOUTHWEST IS EXPECTED TO ARRIVE ON WEDNESDAY, WITH A COLD FRONT
FROM THE WEST ANTICIPATED FOR WEDNESDAY NIGHT. HIGH PRESSURE
SHOULD BUILD INTO OUR REGION FROM THE NORTHWEST FOR THURSDAY AND
FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A FEW UPDATES WERE NEEDED TO ADJUST THE POPS UPWARD SOME ESPECIALLY
ACROSS THE SOUTHERN ZONES. THERE IS A BAND OF SHOWERS AND EVEN
SOME THUNDERSTORMS SLIDING THEIR WAY NORTHWARD. MOST OF THIS
APPEARS TO BE NORTH OF THE STALLED FRONTAL BOUNDARY, WITH THE
INITIATION MOSTLY DRIVEN BY INCREASING WAA ABOVE THE LOWER STABLE
LAYER ALONG WITH SOME PVA ARRIVING. A LAPS SOUNDING NEAR KSBY
INDICATED ABOUT 500 J/KG OF INSTABILITY, BUT THIS IS ALL
ELEVATED. THE RADAR IMAGERY SHOWS THAT THE CELLS ARE NOT ALL THAT
TALL, BUT ENOUGH VERTICAL EXTENT TO GENERATE SOME CHARGE
SEPARATION. THE HRRR PICKED UP ON THIS ACTIVITY ALTHOUGH THE
PLACEMENT IS OFF A BIT. THIS MODEL BRINGS THE ACTIVITY INTO
PORTIONS OF SOUTHEASTERN PENNSYLVANIA AND FAR SOUTHERN NEW JERSEY
BEFORE WEAKENING IT. THERE IS MOSTLY A BREAK BEHIND IT, THEN THE
MAIN BAND OF SHOWERS IS FARTHER TO THE SOUTHWEST. THE
AFOREMENTIONED LAPS SOUNDING ALSO HAD A STORM MOTION OF ONLY 10 MPH.
OTHERWISE, AFTER WIDESPREAD RECORD WARMTH YESTERDAY, UNSETTLED
WEATHER WILL BE MOVING INTO THE AREA AS WE GO THROUGH TODAY. OUR
REGION CAN ACTUALLY USE SOME RAIN. A SOMEWHAT CHALLENGING FORECAST
TODAY AS THE LARGE CLOSED LOW THAT HAS BEEN SITTING ACROSS THE
PLAINS TO THE OHIO VALLEY WILL BE SLOWLY ARRIVING IN OUR REGION.
THE FRONT THAT SLID SOUTHWARD YESTERDAY HAS STALLED ACROSS THE
DELMARVA. A PUSH OF DRIER AIR HAS BEEN TRYING TO GET INTO OUR FAR
SOUTHERN ZONES. HOWEVER WITH THE MOISTURE REMAINING DEEPER HERE,
AN ONSHORE FLOW, AND BOUNDARY LAYER COOLING HAS RESULTED IN AN
AREA OF STRATUS AND FOG. SOME OF THE FOG IS DENSE. THE FORECAST
SOUNDINGS, ESPECIALLY THE NAM/WRF SHOW A RATHER PRONOUNCED BUT
SHALLOW MOIST LAYER NEAR THE SURFACE WHICH IS HELPING TO TRAP THE
STRATUS. EVEN THIS IS FORECAST TO MIX OUT SOME THIS MORNING. IT
APPEARS THAT THIS MAY NOT TRULY EXPAND GIVEN DRIER AIR SITTING
ACROSS THE NORTHERN HALF OF THE CWA. WE ARE NOT CERTAIN THE DENSER
PORTIONS OF THE FOG LAST LONGER THIS MORNING, THEREFORE WE HELD OFF
ON ISSUING AN ADVISORY ATTM AND COVERED IT WITH A SPECIAL WEATHER
STATEMENT. THE CLOUDS WILL BE WINNING OUT OVERALL TODAY AS HIGHER
BASED CLOUDS LOWER THROUGH THE DAY.
THE SLOWNESS OF THIS SYSTEM CONTINUES GIVEN HOW CUT OFF IT
REMAINS TO BE. IN ADDITION, SOME DRIER AIR PUSHING SOUTHWESTWARD
ACROSS MOST OF OUR AREA MIGHT ALSO DEFLECT AND DELAY THE SHOWERS
MOSTLY TO OUR WEST FOR AWHILE. THEREFORE, WE TIGHTENED UP THE POPS
SOME MORE WITH A SLOWER INCREASE ACROSS THE NORTHERN AREAS.
IT APPEARS THAT INCREASING ASCENT AND ISENTROPIC LIFT AHEAD OF A
VORTICITY MAXIMUM ROTATING AROUND THE CLOSED LOW INITIATES A BAND
OF SHOWERS. THIS LOOKS TO BE THE INITIAL SPOKE OF SHOWERS THAT
ROTATES ACROSS OUR AREA THROUGH TODAY. THERE COULD BE SOME MORE
ISOLATED TO SCATTERED SHOWERS DEVELOPING AHEAD OF THIS. BASED ON
THE EASTERLY FLOW ACROSS OUR REGION, THE MODEL GUIDANCE INDICATES
THAT ANY DEVELOPING INSTABILITY WILL BE ELEVATED. THE BETTER
INSTABILITY LOOKS TO BE PLACED ACROSS THE SOUTHERN AND
SOUTHEASTERN ZONES WHERE A DEEPER MOISTURE PROFILE IS ACHIEVED
FIRST ALONG WITH THE START OF SOME COOLING ALOFT. THIS INSTABILITY
HOWEVER SHOULD NOT BE SURFACE BASED.
THE CONVECTION ACROSS CENTRAL PENNSYLVANIA LOOKS TO BE TIED TO
THE MAIN CONVEYOR BELT OF WAA. THIS IS FORECAST TO WEAKEN WITH AN
EASTWARD EXTENT, BUT THEN BECOME FOCUSED TO OUR SOUTH. THE ONSHORE
FLOW SHOULD PROTECT OUR REGION ALONG WITH THE MAIN WAA PUSH
SLIDING TO OUR SOUTH, THEREFORE ANY SEVERE WEATHER THREAT LOOKS TO
BE SOUTHWEST OF OUR REGION. WE CONTINUE TO CARRY A CHC OF
THUNDERSTORMS ACROSS THE SOUTHERN AND SOUTHWESTERN ZONES. THE FLOW
OVERALL IS FORECAST TO BE ON THE LIGHTER SIDE, THEREFORE CELL
MOTION MAY TEND TO BE SLOW. THIS COULD RESULT IN CONVECTIVE CELLS
PRODUCING LOCAL DOWNPOURS AS THE MOISTURE DEEPENS WITH THE PW
VALUES FORECAST TO INCREASE INTO THE 1.0 TO 1.5 INCH RANGE.
AS FOR TEMPERATURES, WE GENERALLY USED A MOS BLEND THEN MADE SOME
TWEAKS ESPECIALLY ALONG THE COAST GIVEN THE ONSHORE FLOW.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
THE CLOSED LOW WILL BE WORKING ITS WAY INTO THE MID ATLANTIC
REGION, AND THE MAJORITY OF THE SYNOPTIC SETUP WAS MENTIONED IN
THE NEAR TERM SECTION ABOVE. SHORT WAVE ENERGY ROTATING AROUND
THIS LARGE SYSTEM WILL ACT TO INITIATE BANDS OF SHOWERS. THE
COVERAGE MAY START TO DECREASE DURING THE OVERNIGHT AS THE
STRONGER LIFT SHIFTS TO OUR NORTHEAST. AS COOLING ALOFT TAKES
PLACE, SOME INSTABILITY WILL KEEP SHOWERS GOING THROUGH THE NIGHT
AND ANY THUNDER SHOULD MOSTLY BE CONFINED TO THE EVENING HOURS AND
ACROSS THE SOUTHERN ZONES. A SURFACE LOW IS FORECAST TO TRACK
CLOSE TO THE DELMARVA TOWARD MORNING, AND THIS WILL MAINTAIN AN
ONSHORE FLOW ACROSS THE ENTIRE REGION. AS A RESULT, A WEALTH OF
CLOUDS ARE EXPECTED TO CONTINUE. WHILE SOME FOG WILL BE AROUND, IT
MAY NOT REDUCE THE VISIBILITIES ENOUGH AND THEREFORE IT WAS NOT
INCLUDED IN THE PUBLIC FORECAST ATTM.
AS FOR TEMPERATURES, WE MOSTLY BLENDED THE GFS/NAM MOS. THE
TEMPERATURES MAY TAKE SOME TIME IN DROPPING ACROSS SOME AREAS FOR
AWHILE TONIGHT GIVEN LOTS OF CLOUDS AND THE ONSHORE FLOW.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
A MID LEVEL LOW IS FORECAST TO BE OVER SOUTH CAROLINA ON SUNDAY
MORNING. THE FEATURE IS EXPECTED TO PASS OFF THE COAST ON SUNDAY
AFTERNOON BEFORE MOVING OUT TO SEA AND BECOMING AN OPEN WAVE.
MEANWHILE, AT THE SURFACE BROAD LOW PRESSURE IS FORECAST TO EXTEND
FROM THE CHESAPEAKE BAY REGION TO EASTERN NORTH CAROLINA EARLY ON
SUNDAY. IT SHOULD SLOWLY PASS OFF THE COAST ON SUNDAY AFTERNOON
AND EVENING.
WE ARE EXPECTING TO BEGIN SUNDAY WITH THE LIKELIHOOD OF RAIN
SHOWERS THROUGHOUT OUR REGION. HOWEVER, AS THE SURFACE LOW BEGINS
TO MOVE OFF THE COAST DURING THE AFTERNOON SOME DRY AIR MAY BEGIN
TO BUILD INTO OUR NORTHERN COUNTIES.
ON SUNDAY, THE SURFACE FLOW SHOULD BE MAINLY FROM THE NORTHEAST,
KEEPING CONDITIONS RATHER STABLE NEAR THE SURFACE. HOWEVER, THERE
MAY BE ENOUGH INSTABILITY ALOFT TO RESULT IN SCATTERED
THUNDERSTORMS IN OUR SOUTHERN COUNTIES ON SUNDAY AFTERNOON AND
SUNDAY EVENING.
SUNDAY`S TEMPERATURE FORECAST IS RATHER TRICKY. DEPENDING UPON
WHERE MOST OF THE SHOWER ACTIVITY OCCURS AND DEPENDING UPON
WHETHER ANY SUBSTANTIAL BREAKS IN THE CLOUD COVER DEVELOP, THE LOW
NAM NUMBERS AND THE HIGH GFS NUMBERS ARE BOTH PLAUSIBLE. FOR NOW,
WE HAVE SIMPLY GONE WITH A COMPROMISE OF THE STATISTICAL GUIDANCE.
DRY AIR IS EXPECTED TO CONTINUE TO BUILD INTO OUR REGION FROM THE
NORTH ON SUNDAY NIGHT, BRINGING AN END TO THE THREAT OF
PRECIPITATION FROM NORTH TO SOUTH.
A MID LEVEL TROUGH FROM THE NORTHWEST SHOULD BEGIN TO DROP OVER
THE NORTHEASTERN STATES ON SUNDAY NIGHT, PUSHING A STRONG COLD
FRONT THROUGH OUR REGION EARLY ON MONDAY. THE AXIS OF THE MID
LEVEL TROUGH WILL LIKELY PASS OVER OUR REGION ON MONDAY AFTERNOON.
DRY AIR IS EXPECTED TO BUILD INTO OUR REGION FOR THE EARLY PART
OF THE WORK WEEK. TEMPERATURES SHOULD RETURN TO SEASONABLE LEVELS
FOR MONDAY NIGHT AND TUESDAY. AFTER THE RECENT STRETCH OF VERY
WARM WEATHER, IT MAY BE DIFFICULT TO BELIEVE THAT LOWS IN THE 30S
AND HIGHS IN THE 50S IS NORMAL.
ANOTHER MID LEVEL TROUGH SHOULD PASS OVER OUR REGION FROM
WEDNESDAY NIGHT INTO THURSDAY. AS IT APPROACHES, A WARM FRONT IS
FORECAST TO BE PULLED THROUGH OUR REGION ON WEDNESDAY, FOLLOWED BY
A COLD FRONT ON WEDNESDAY NIGHT. WE HAVE INDICATED A CHANCE OF
SHOWERS AT THAT TIME.
HIGH PRESSURE AND DRY WEATHER ARE EXPECTED TO RETURN FOR THE END
OF THE WEEK ALONG WITH SLIGHTLY ABOVE NORMAL TEMPERATURES.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE LOW-LEVEL MOISTURE HAS BEEN SOCKED IN AT KMIV AND KACY AS AN
AREA OF ENHANCED MOISTURE IS TRAPPED UNDER A RATHER STRONG BUT
SHALLOW INVERSION. NOT TO FAR TO THE NORTH, DRIER AIR HAS BEEN
SEEPING SOUTHWESTWARD WITH THE SURFACE DEW POINTS DROPPING SOME.
IT IS NOT ALL THAT CLEAR IF THIS IS ABLE TO GET TO KMIV AND KACY
AND UNDERCUT THE FOG. WE FAVORED MORE FOG FOR AWHILE THIS MORNING
THEN INDICATED SOME IMPROVEMENTS BEFORE CONDITIONS LOWER ONCE
AGAIN. OTHERWISE, THE AIR IS A BIT DRIER AT KILG AND THE KPHL
METRO THEREFORE NOT REALLY ANY FOG HOWEVER THE STRATUS HAS BEEN
SLIDING WESTWARD AND HAS MADE IT TO THESE TERMINALS. OUR
CONFIDENCE IS LOW REGARDING HOW LONG THIS LINGERS, HOWEVER WE ARE
LEANING TOWARD SOME IMPROVEMENT TAKING PLACE THIS MORNING BEFORE
CONDITIONS LOWER ONCE AGAIN. SOME SHOWERS AND EVEN A FEW
THUNDERSTORMS ARE MOVING SLOWLY NORTHWARD ACROSS MARYLAND AND
PARTS OF DELAWARE. THIS MAY TEND TO HOLD SOUTH AND WEST OF OUR
TERMINALS FOR AWHILE, THEREFORE WILL MONITOR RADAR TRENDS AND
ISSUE AMENDMENTS IF THESE LOOK TO IMPACT A TERMINAL EARLIER THAN
ANTICIPATED.
A SLOW MOVING STORM SYSTEM WILL BE APPROACHING TODAY, AND THIS
WILL ALLOW THE CLOUDS OVERALL TO INCREASE AND LOWER THROUGH THE
DAY. IT APPEARS THE MAIN PUSH OF SHOWERS WILL BE SLOWER AS SOME OF
THE DRIER AIR FROM THE NORTHEAST MAY ALSO HELP WITH THE DELAY. THE
BULK OF THE SHOWERS LOOK TO OCCUR STARTING FROM ABOUT MIDDAY
ONWARD. THERE IS THE POTENTIAL FOR A THUNDERSTORM OR TWO, ALTHOUGH
THIS MAINLY LOOKS TO BE SOUTH AND WEST OF A KRDG TO KMIV LINE. OUR
CONFIDENCE IS LOW ON THE COVERAGE, THEREFORE NO THUNDER WAS
INCLUDED AT THIS TIME. THE SHOWERS SHOULD TEND TO ARRIVE IN A BAND
FROM SOUTHWEST TO NORTHEAST. THE FLOW IS FAIRLY WEAK, THEREFORE
THESE COULD BE SLOW MOVERS AND PRODUCE LOCAL DOWNPOURS. WE
CONTINUED TO INDICATE LOWERING VISIBILITIES THROUGH THE DAY
/OUTSIDE OF ANY EARLY MORNING FOG/. AN EASTERLY WIND WILL INCREASE
TO AROUND 10 KNOTS, AND THERE COULD BE A LITTLE GUSTINESS FOR A
TIME MAINLY FROM THE KPHL METRO SOUTH AND EAST.
THE CONDITIONS ARE EXPECTED TO BE WIDESPREAD SUB-VFR TONIGHT AS
SOME SHOWERS CONTINUE. GIVEN THE DEEPENING MOISTURE, SOME FOG
SHOULD ALSO BE AROUND HOWEVER THIS IS NOT EXPECTED TO BE DENSE AT
THIS TIME. THE EAST TO SOUTHEAST WINDS MAY TEND TO SHIFT MORE TO
THE NORTHEAST TONIGHT BUT GENERALLY BE UNDER 10 KNOTS.
OUTLOOK...
SUNDAY...POSSIBLE MVFR/IFR CONDITIONS IN SHOWERS AND SCATTERED
THUNDERSTORMS.
SUNDAY NIGHT...VFR.
MONDAY...VFR WITH A GUSTY NORTHWEST WIND.
MONDAY NIGHT THROUGH TUESDAY NIGHT...VFR.
WEDNESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
AN AREA OF ENHANCED LOW-LEVEL MOISTURE TRAPPED UNDER A RATHER LOW
INVERSION IS RESULTING IN SOME LOW CLOUDS AND FOG EARLY THIS
MORNING, MAINLY SOUTH OF ATLANTIC CITY AND INTO DELAWARE BAY. SOME
DRIER AIR IS TRYING TO UNDERCUT THIS, HOWEVER IT IS NOT REAL
CERTAIN HOW THIS BEHAVES THROUGH THE MORNING. THE OVERALL FOG
SHOULD IMPROVE THIS MORNING, THEREFORE NO HEADLINE BUT A MENTION
WILL BE CARRIED IN THE FORECAST THROUGH ABOUT 12Z. A CLOSED LOW
WILL GRADUALLY MOVE INTO OUR AREA THROUGH TONIGHT. AS LOW PRESSURE
TRACKS ACROSS THE MID ATLANTIC REGION AND HIGH PRESSURE SETTLES
OFF THE NEW ENGLAND COAST, A TIGHTENED PRESSURE GRADIENT WILL
RESULT. THIS IS MAINLY THE GREATEST ACROSS THE NORTHERN WATERS,
ALTHOUGH THE FORECAST SOUNDINGS SUGGEST THE SURFACE WINDS REMAIN
BELOW ADVISORY CRITERIA. THE ONSHORE FLOW HOWEVER MAY ALLOW THE
SEAS TO BUILD TO 5 FEET MAINLY ACROSS THE NORTHERN ZONES. THIS MAY
END UP BEING MARGINAL AND DUE TO LOWER THAN AVERAGE CONFIDENCE, WE
OPTED TO HOLD OFF ON ANY SMALL CRAFT ADVISORY ISSUANCE ATTM.
OUTLOOK...
BROAD LOW PRESSURE IS FORECAST TO PASS OFF THE MIDDLE ATLANTIC
COAST ON SUNDAY. A STRONG COLD FRONT FROM THE NORTHWEST IS
EXPECTED TO REACH THE COASTAL WATERS OF NEW JERSEY AND DELAWARE
EARLY ON MONDAY, FOLLOWED BY HIGH PRESSURE. A WARM FRONT IS
ANTICIPATED TO APPROACH FROM THE SOUTHWEST AND IT MAY ARRIVE ON
WEDNESDAY.
A SMALL CRAFT ADVISORY MAY BE NEEDED FROM LATE SUNDAY NIGHT INTO
TUESDAY MORNING FOR THE GUSTY NORTHWEST WINDS IN THE COLD
ADVECTION. ISOLATED GALE FORCE GUSTS MAY OCCUR FROM LATE MONDAY
INTO MONDAY NIGHT.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...IOVINO
NEAR TERM...GORSE
SHORT TERM...GORSE
LONG TERM...IOVINO
AVIATION...GORSE/IOVINO
MARINE...GORSE/IOVINO
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
432 AM EDT SAT MAR 24 2012
.SYNOPSIS...
A SLIGHT CHANCE OF SEVERE THUNDERSTORMS TODAY AS A WARM AND MOIST
AIR MASS BLANKETS THE REGION. A COLD FRONT WILL MOVE THROUGH THE AREA
TONIGHT WITH HIGH PRESSURE SLOWLY BUILDING IN FROM THE NORTHWEST
SUNDAY THROUGH MONDAY. A FRONT WILL DROP THROUGH ON TUESDAY...THEN
ANOTHER COLD FRONT WILL MOVE IN LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
PRE-DAWN...OVERNIGHT MSAS AND RUC MESOANALYSIS DATA SHOWS MUCH OF
OUR FORECAST AREA REMAINED STABILIZED BY THE EARLIER CONVECTION WITH
INSTABILITY GRADIENTS RUNNING ALONG THE CSRA AND ALTAMAHA RIVER
REGIONS BORDERING OUR FORECAST AREA. THIS WILL BE QUICK TO CHANGE
LATER THIS MORNING BUT UNTIL THEN WE ARE MONITORING FOR SOME
PATCHY FOG AND STRATUS AND WITH SPOTTY CONVECTIVE RAINS POSSIBLE
UNTIL DAYBREAK.
FORECAST TODAY BLENDED BETWEEN PERSISTENCE AND CONSENSUS SYNOPTIC
SCALE TRENDS FROM THE 00Z MODEL RUN. OUR REGION CONTINUES TO BE
HIGHLIGHTED UNDER A SLIGHT RISK FOR SEVERE CONVECTION TODAY AND
ONGOING TRENDS GIVE NO INDICATION TO SWAY FROM THAT THINKING. TO
BEGIN TODAY...OVERNIGHT SATELLITE TRENDS SUGGEST THAT THERE LIKELY
WILL BE AREAS OF INSOLATION ACROSS GEORGIA AND SOUTH CAROLINA
WHICH WILL RAPIDLY ENHANCE DESTABILIZATION. CUTTING THROUGH OUR
INLAND ZONES IS AN IMPRESSIVE DEEP MOISTURE GRADIENT TODAY WITH
PWATS E OF I-95 AT OR SLIGHTLY ABOVE 1.5 INCHES AND INLAND FROM
THERE FALLING WELL BELOW 1 INCH THIS AFTERNOON. CONVECTION IS
EXPECTED TO FLOURISH ALONG AND SE OF THIS GRADIENT FROM LATE
MORNING THROUGH THE AFTERNOON. BY 18Z...THE GEM/GFS/ECMWF ALL SHOW
HAIL CAPES EXCEEDING 600 J/KG OVER S GEORGIA AND ANOTHER MORE
MORE IMPRESSIVE MAXIMA OVER THE EASTERN SOUTH CAROLINA MIDLANDS
EXTENDING INTO OUR INLAND SOUTH CAROLINA ZONES.
THE MID LEVEL ENVIRONMENT WILL REMAIN FAIRLY UNIFORM THROUGH MID
AFTERNOON WITH LATE DAY HEIGHT FALLS NOTED FROM THE ESE MOVEMENT
OF THE DEEP UPPER LOW OVER THE TENNESSEE/KENTUCKY REGION. THE
ENVIRONMENT IS HIGHLIGHTED BY FAIR LAPSE RATES NEAR -6C AND
FAVORABLE HAIL PARAMETERS PROVIDED CONVECTIVE INITIATION IS NOT
TOO FAST TODAY. 0-6KM BULK SHEAR IS FORECAST TO INCREASE STEADILY
TO AROUND 40 KT BY LATE DAY...INCREASING POTENTIAL FOR ENHANCED
ORGANIZATION AND MIXED-MODE CONVECTION.
MODELS SUGGEST THE FIRST ROUND TODAY WILL DEVELOP IN SE GEORGIA
AND DEVELOP OR PROPAGATE ALONG BOUNDARIES NE THROUGH THE COASTAL
HALF OF THE FORECAST AREA THIS AFTERNOON WITH ISOLATED SEVERE
TSTMS POSSIBLE. TSTMS WITH MORE ROBUST HAIL AND WIND POTENTIAL
WILL LIKELY BEGIN TO TAKE SHAPE IN A N-S CONVERGENCE ZONE TO THE
S OF WEAK SURFACE LOW IN UPSTATE SOUTH CAROLINA. THESE STORMS
WILL POSE A LATE DAY THREAT TO OUR INLAND ZONES WITH FAIR
CHANCES FOR CONVECTIVE WATCHES BY MID AFTERNOON FOR PARTS OF
OUR FORECAST AREA.
WE RAISED MAX TEMPS A COUPLE OF DEGREES TODAY IN ADVANCE OF
CONVECTION. DEEPER MIXED LAYER INLAND SUGGEST SW SURFACE WINDS
COULD BECOME A BIT GUSTY AT TIMES THIS AFTERNOON.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
THE NAM SUGGESTS STRONG TO SEVERE CONVECTION WILL SHIFT TOWARD
THE COAST THIS EVENING AS STRONG UPPER HEIGHT FALLS KICK IN AND
OUR REGION COMES UNDER A FAIRLY IMPRESSIVE RIGHT ENTRANCE REGION
IN A 250 MB JET SEGMENT. OTHER MODELS SHIFT DEEPER MOISTURE AND
INSTABILITY OFFSHORE A BIT QUICKER BUT WILL HIGHLIGHT A SEVERE
RISK CONTINUING UNTIL MIDNIGHT IN RESPECT TO THE AIR MASS IN
PLACE TODAY AND THE STRENGTH OF THE SYNOPTIC SCALE SYSTEM.
THE DEEP 500 MB LOW WILL ROTATE THROUGH SOUTHERN SC SUNDAY AFTERNOON
WITH THE CENTER PASSING NEAR OR JUST NORTH OF CHARLESTON AROUND 18Z.
MOST OF THE MODELS PROG 500 MB TEMPS OF -22C AT 18Z SUNDAY WITH A
FREEZING LEVEL BELOW 7500 FT. A FAIRLY DEEP WESTERLY FLOW WILL DRY
THE LOWER ATMOSPHERE AND DOWNSLOPE FLOW WILL RESULT IN SUBSIDENCE.
HOWEVER THERE LOOKS TO BE ENOUGH LOW-LEVEL MOISTURE WRAPPING AROUND
THE SURFACE LOW ALONG THE NC COAST TO SPUR A FEW SHOWERS OR ISOLATED
THUNDERSTORMS DURING THE HOURS OF PEAK HEATING ON SUNDAY...MAINLY
ACROSS SOUTHERN SC. DUE TO SUCH COLD TEMPERATURES ALOFT...SOME SMALL
HAIL CANNOT BE RULED OUT WITH ANY CONVECTIVE ELEMENTS. DESPITE THE
COLD ADVECTION...DOWNSLOPING WILL PUSH HIGH TEMPS INTO THE UPPER
70S.
CLOUDS WILL CLEAR OUT FROM SW TO NE SUNDAY NIGHT AND WEAK COLD
ADVECTION WILL DROP OVERNIGHT LOWS INTO THE LOWER 50S. THE UPPER
LEVEL RIDGE AXIS WILL BUILD TOWARD THE SOUTHEAST UNITED STATES
MONDAY INTO TUESDAY. BUILDING LOW-LEVEL THICKNESSES ON MONDAY WITH
SUNNY SKIES WILL PUSH HIGH TEMPS BACK INTO THE LOWER 80S.
A BACKDOOR COLD FRONT WILL DROP THROUGH LATE MONDAY NIGHT INTO
TUESDAY WITH COOLER AIR FILTERING IN FROM THE NORTH. A RATHER SHARP
TEMPERATURE GRADIENT IS EXPECTED FOR TUESDAY WITH NEAR 80 TO THE FAR
SW AND LOWER 70S OVER THE TRI-COUNTY. ISOLATED SHOWERS CANNOT BE
ENTIRELY RULED OUT ON TUESDAY...ESPECIALLY SOUTHERN SECTIONS WHERE A
WEAK COASTAL TROUGH MAY DEVELOP. BUT DUE TO A RELATIVE LACK OF
MOISTURE WE KEPT DRY CONDITIONS FOR NOW.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
HIGH PRESSURE WILL STRENGTHEN OVER THE WESTERN ATLANTIC TUESDAY
NIGHT THROUGH THURSDAY AS THE UPPER RIDGE HOLDS STRONG TO OUR WEST.
DRY CONDITIONS AND WARM TEMPERATURES EXPECTED WITH HIGHS BUILDS INTO
THE UPPER 70S WEDNESDAY AND LOWER 80S THURSDAY. ANOTHER BACKDOOR
FRONT MAY DROP THROUGH THURSDAY NIGHT OR FRIDAY WITH INCREASING
CLOUDINESS AND COOLER TEMPERATURES. WE HAVE NOT ADDED ANY
PRECIPITATION IN THE EXTENDED DUE TO LIMITED MOISTURE WITH THE LATE
WEEK FRONT.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
ADDITIONAL SHOWERS BREAKING OUT TO THE W OF I-95 AND WILL LIKELY
SKIRT W OF BOTH TERMINALS OVERNIGHT BUT CANNOT RULE OUT SPOTTY
CONVECTIVE RAINS OVERNIGHT IN THE COASTAL CORRIDOR. VFR CONDITIONS
ARE LIKELY BUT WITH POCKETS OF MVFR/IFR CIGS ON CURRENT REGIONAL
OBSERVATIONS...LOWER CONDITIONS ALSO CANNOT BE RULED OUT.
SCATTERED BOUTS OF CONVECTION ARE LIKELY TODAY...AS EARLY AS MID
TO LATE MORNING AND THEN PERHAPS STRONGER CONVECTION LATE TODAY
AND THIS EVENING AHEAD OF A COLD FRONT AND THE SE SAGGING MID
LEVEL CUT-OFF LOW UPSTREAM. CONFIDENCE ON TIMING THESE ROUNDS
OF SHOWERS AND TSTMS IS QUESTIONABLE GIVEN SUBTLETIES IN MODEL
OUTPUT DIFFERENCES. WE HAVE BROAD-BRUSHED VCSH WITH CB MENTIONS
THIS AFTERNOON AND EVENING UNTIL RADAR TRENDS DICTATE TEMPO OR
PREVAILING GROUPS OF CONVECTION. WE INTRODUCED SOME SURFACE
WIND GUSTS NEARING 20 KT AT KCHS AND AT LEAST TEMPO GUSTS AT
TIMES AT KSAV AS WELL THIS AFTERNOON.
EXTENDED AVIATION OUTLOOK...BRIEF MVFR VSBY POSSIBLE AT CHS ON
SUNDAY IN ISO/SCT SHOWERS/TSTMS. OTHERWISE VFR.
&&
.MARINE...
NO SIGNIFICANT CHANGES WITH SW FLOW SHIFTING W IN THE WAKE OF
THE COLD FRONT TONIGHT. SPEEDS WILL MAINLY BE 15 KT OR LESS WITH
SOME GUSTS TO 20 KT AT TIMES BEYOND 20 NM OFF THE COAST. SEAS
THROUGH TONIGHT 2-4 NEAR SHORE AND 3 TO 5 FT OVER OUTER GEORGIA
WATERS.
OFFSHORE FLOW BEHIND THE COLD FRONT ON SUNDAY WILL ALLOW SEAS TO
GRADUALLY SUBSIDE. A BRIEF NORTHEAST WIND SURGE WILL DEVELOP TUESDAY
MORNING BEHIND A BACKDOOR COLD FRONT BUT IT SHOULD BE OF SHORT
DURATION AS THE PARENT HIGH SHIFTS QUICKLY OFFSHORE. THE NEXT SURGE
WILL COME WEDNESDAY NIGHT INTO THURSDAY AHEAD OF THE NEXT COLD
FRONT. IN GENERAL WE KEEP WINDS/SEAS BELOW ADVISORY THRESHOLDS
DURING THE MEDIUM RANGE PERIOD.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JRL
NEAR TERM...
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...
MARINE...JRL
AREA FORECAST DISCUSSION
NWS JACKSON KY
434 AM EDT SAT MAR 24 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 434 AM EDT SAT MAR 24 2012
SURFACE ANALYSIS ACROSS THE AREA AS OF 08Z HAS THE LINE OF SHOWERS
AND THUNDERSTORMS WITH A SURFACE FRONT AND ASSOCIATED 500MB WAVE
ROTATING AROUND A CLOSED CUT OFF LOW MOVING OFF TO THE EAST. LOOKING
AT CURRENT RADAR TRENDS AND OBS...LOOKING LIKE ALL THE INSTABILITY
HAS BEEN TAPPED OUT EAST AS ONLY A FEW CELLS SEEM TO BE LEFT. A FEW
SHOWERS HAVE BEGUN TO DEVELOP BEHIND THE LINE OVER THE SOUTHWEST
COUNTIES SO HAVE LEFT SOME ISOLATED SHOWERS MENTIONED IN THE ZONES
DURING THE MORNING HOURS. THIS IS SUPPORTED BY THE HRRR AND RUC AS
THE UPPER LEVEL SUPPORT WILL BE AVAILABLE ALL DAY TODAY AS THE LOW
WILL SLOWLY MOVE SOUTH AND EAST.
THINKING SHOWERS AND THUNDERSTORMS WILL REDEVELOP AGAIN TODAY WITH
THE HEATING OF THE DAY AS ANOTHER 500MB WAVE ROTATES AROUND THE LOW
AGAIN AND THROUGH EAST KENTUCKY AND AS SUCH...RAMPED UP POPS TO GOOD
CHANCES AND ALSO WENT WITH COVERAGE RATHER THAN PROBABILITY. ALSO THE
RAPID STABILIZATION DURING THE EVENING HOURS LEADS TO FOG DEVELOPING
IN THE VALLEYS AND SO PUT FOG INTO THE ZONES TO ACCOUNT FOR THIS.
BY SUNDAY NIGHT...THE SHORT TERM MODELS SEEM TO BE IN AGREEMENT THAT
THE CLOSED LOW FINALLY DRIFTS OFF TO THE SOUTH AND EAST. SO WILL RAMP
DOWN THE POPS FOR THIS TIME PERIOD. CONCERNING TEMPERATURES...THE
MERIDIONAL PATTERN WITH A TROUGH MOVING THROUGH THE EASTERN US...WILL
KEEP TEMPERATURES NEAR NORMAL FOR THE SHORT TERM PERIOD.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 434 AM EDT SAT MAR 24 2012
A RATHER PROGRESSIVE PATTERN IS EXPECTED DURING THE PERIOD. INITIALLY
ON MONDAY...RECENT GFS AND ECMWF RUNS INDICATE THAT UPPER LEVEL
RIDGING WILL BE BUILDING INTO THE REGION FROM THE PLAINS AND MS
VALLEY WHILE THE SOUTHERN END OF A RIDGE OF SFC HIGH PRESSURE WILL BE
NOSING INTO THE OH VALLEY AND APPALACHIAN REGION. THE UPPER LEVEL
RIDGE IS EXPECTED TO CONTINUE TO BUILD INTO THE REGION ON MON NIGHT
AND INTO TUE....WHILE THE AXIS OF THE SFC HIGH WILL SHIFT ON OFF TO
THE EAST ON TUE. AS THE SFC HIGH SHIFTS EAST OF THE AREA...A WARM
FRONT OR SFC TROUGH IS PROGGED TO SHIFT TO THE EASTERN PORTIONS OF
THE CWA.
AT THE SAME TIME...AN UPPER LEVEL TROUGH AND ASSOCIATED SYSTEM WILL
TRACK FROM THE CENTRAL AND NORTHERN ROCKIES AND INTO THE NORTHERN
PLAINS/WESTERN GREAT LAKES REGION BY TUE EVENING AND NIGHT WITH THIS
UPPER LEVEL SYSTEM THEN TRACKING NEARLY DUE EAST INTO THE
NORTHEASTERN STATES ON WED INTO WED NIGHT. UPPER LEVEL RIDGING IS
THEN EXPECTED TO BUILD BACK INTO THE GREAT LAKES AND OH VALLEY AND
APPALACHIAN REGION AND LIKELY REMAIN DOMINANT THROUGH THE END OF THE
PERIOD. THE GREATEST UNCERTAINTY COMES AT THE END OF THE PERIOD AS
THE GFS TRACKS A COUPLE OF SHORTWAVES EAST A BIT QUICKER AND IS
WEAKER WITH THE LATE WEEK RIDGING. DURING THIS PERIOD OF GREATER
UNCERTAINTY...GENERALLY FOLLOWED A BLEND OF THE MODEL CONSENSUS AND
THE USUALLY RELIABLE ECMWF.
A SFC LOW SHOULD FOLLOW A SIMILAR PATH AS THE UPPER LEVEL SYSTEM
FROM MON TO TUE...REACHING THE GREAT LAKES REGION TUE NIGHT INTO WED
AND THEN TRACKING OFF THE NORTHEASTERN US COAST WED NIGHT INTO THU.
THIS SYSTEM WILL SEND A COLD FRONT INTO THE LOCAL AREA ON WED WITH
THE MODEL CONSENSUS SHIFTING THIS FRONT SOUTH OF THE AREA ON WED
NIGHT. ALTHOUGH I HAVE ALLOWED FOR SOME 10 POPS WHICH ARE PART OF
THE MODEL CONSENSUS ON TUE AFTERNOON AS THE PAST COUPLE OF ECMWF
RUNS DEVELOP SOME CONVECTION OVER THE NORTHEASTERN OR EASTERN PART
OF THE CWA IN THE VICINITY OF THE SFC TROUGH/WARM FRONT FEATURE ON
TUE...THE BEST CHANCE DURING THE PERIOD FOR MEASURABLE PRECIP WILL
COME ON WED INTO WED EVENING.
AS FOR TEMPERATURES...MAX TEMPERATURES SHOULD GENERALLY AVERAGE
SLIGHTLY ABOVE NORMAL EARLY IN THE PERIOD AND AT THE END OF THE
PERIOD TO AS MUCH AS 10 DEGREES OR MORE ABOVE NORMAL ON WED JUST
AHEAD OF THE COLD FRONT. LOW THROUGH THE PERIOD SHOULD GENERALLY BE
IN THE 40S OR EVEN THE 50S...WITH ONE EXCEPTION...MONDAY NIGHT. SFC
HIGH PRESSURE SHOULD ALLOW FOR SOME OF THE NORMALLY COLDER VALLEY
LOCATIONS IN THE FAR NORTH AND EAST TO REACH THE UPPER 30S ON MON
NIGHT. THIS WOULD LEAD TO AT LEAST A SLIGHT CONCERN FOR SOME PATCHY
FROST AT LEAST IF THESE MIN TEMPS WERE TO TREND SLIGHTLY COLDER AS
RECENT WARM WEATHER HAS ALLOWED VEGETATION TO BE RUNNING A COUPLE OF
WEEKS OR SO AHEAD OF AVERAGE. HOWEVER...ATTM...EVEN IT ONE WERE TO
OCCUR IT APPEARS AS IF IT WOULD BE VERY PATCHY TO ISOLATED AND WOULD
OCCUR IN THE COLDEST OF THE NORMALLY COLD SPOTS. THIS POTENTIAL
SCENARIO WILL CONTINUE TO BE MONITORED...HOWEVER CONFIDENCE IN EVEN
ISOLATED TO PATCHY VALLEY FROST IS TOO LOW AT THIS POINT TO INCLUDE
IN THE HWO.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 145 AM EDT SAT MAR 24 2012
CONCERNING AVIATION TONIGHT...THE MAIN THREAT IS WITH THE LINE OF SHOWERS
AND THUNDERSTORMS MOVING THROUGH EASTERN KENTUCKY. IFR TO MVFR FLIGHT
CONDITIONS WILL BE ASSOCIATED WITH THE LINE AS IT MOVES THROUGH.
GOING BY TIMING...THE LINE IS EXPECTED TO MOVE THROUGH THE AREA BY
12Z. CONCERNING THE CLEARING BEHIND THE LINE...SOME FOG IS EXPECTED
TO DEVELOP IN THE VALLEYS ESPECIALLY WHERE THE HEAVIEST RAIN HAS
FALLEN SO PUT IFR CONDITIONS IN THE TAF SITES LATER TONIGHT AS THE
SURFACE TEMPS DROP A BIT. WITH ANOTHER VORT LOBE ROTATING AROUND THE
LOW LATER IN THE DAY...AND WITH THE DAYTIME HEATING...THE THREAT OF
SHOWERS AND THUNDERSTORMS WILL DEVELOP LATER IN THE DAY SO THIS WAS
PUT INTO THE TAFS AS WELL.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SHALLENBERGER
LONG TERM....JP
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS JACKSON KY
145 AM EDT SAT MAR 24 2012
.UPDATE...
ISSUED AT 145 AM EDT SAT MAR 24 2012
A LINE OF SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE THROUGH EASTERN
KENTUCKY AT THIS HOUR. HAVE UPDATED THE POPS TO MIRROR THIS LINE AND
THE TIMING AS IT MOVES THROUGH THE AREA. THE ACTIVITY AS OF 0535Z
SEEM TO BE WEAKENING AS THE AMOUNT OF INSTABILITY EAST OF THE I-75
CORRIDOR DROPS OFF SIGNIFICANTLY AS SHOWN BY SURFACE ANALYSIS. WILL
STILL KEEP THE THREAT OF HEAVY DOWNPOURS IN THE FORECAST AS STILL
ALOT OF UPPER LEVEL DYNAMICS AND MOISTURE WILL BE AVAILABLE THROUGH
THE NIGHT. WILL MONITOR THE PROGRESSION OF THIS ACTIVITY AND PROVIDE
ANOTHER UPDATE BY 0830Z.
UPDATE ISSUED AT 1043 PM EDT FRI MAR 23 2012
NDFD AND ASSOCIATED PRODUCTS HAVE BEEN UPDATED FOR LATEST
OBSERVATIONAL TRENDS. PREVIOUS TIMING ON CONVECTION FOR THE REMAINDER
OF THE NIGHT STILL LOOKS GOOD BASED ON LATEST RADAR TRENDS AND SHORT
RANGE MODEL DATA. CONVECTION IS NEARING THE SOUTHWEST PART OF THE
FORECAST AREA AT THIS TIME. LATEST HRRR SEEMS TO HAVE A PRETTY GOOD
HANDLE ON THE CONVECTION...AND EXPECT INTENSITY OF SHOWERS AND
THUNDERSTORMS TO DECREASE OVERNIGHT PER THE 23Z HRRR. HAVE CONTINUE
WITH THE IDEA OF SCATTERED SHOWERS AND THUNDERSTORMS. SOME REPORTS OF
FOG IN LOCAL VALLEY AREAS AND WILL ADD THIS TO THE HWO.
UPDATE ISSUED AT 747 PM EDT FRI MAR 23 2012
SCATTERED SHOWERS CURRENTLY EAST OF A LINE FROM MOREHEAD TO
WHITESBURG CONTINUE TO DIMINISH IN COVERAGE AND INTENSITY AS THEY
MOVE NORTHEAST AT 40 MPH. ALSO AN SHOWER MOVING INTO WAYNE COUNTY AT
THIS TIME. FOR THE MOST PART EXPECT DRY WEATHER TO PREVAIL FOR THE
REST OF THE EVENING WITH ONLY ISOLATED SHOWERS AND THUNDERSTORMS
POSSIBLE. SHOWERS AND THUNDERSTORMS CURRENTLY INCREASING FROM NORTH
OF BOWLING GREEN INTO CENTRAL INDIANA. AS LOW AND SURFACE FRONT MOVE
EAST TONIGHT EXPECT SHOWERS AND THUNDERSTORMS TO ONCE AGAIN BECOME
MORE NUMEROUS IN EASTERN KY...GENERALLY AFTER MIDNIGHT. THIS IS IN
AGREEMENT WITH CURRENT TRENDS AND THE LATEST HRRR AND NAM. FOR NOW
WILL KEEP PRECIPITATION SCATTERED IN NATURE LATER TONIGHT WITH 50
PERCENT PROBABILITIES. HAVE ALSO MADE SOME MINOR UPDATES TO NDFD FOR
LATEST SURFACE OBSERVATIONAL TRENDS.
UPDATE ISSUED AT 441 PM EDT FRI MAR 23 2012
HAVE UPDATED NDFD OUT THROUGH THE NEXT SEVERAL HOURS FOR LATEST
OBSERVATIONAL TRENDS. LATEST SHORT RANGE GUIDANCE STILL POINTS
TOWARDS A DECREASING CHANCE OF SHOWERS AND THUNDERSTORMS AFTER 00Z AS
THE CURRENT ACTIVITY NOW AFFECTING EASTERN KY MOVES NORTHEAST OF THE
AREA. THE CHANCE WILL THEN RAMP UP AGAIN LATER TONIGHT AS THE CLOSED
UPPER LOW MOVES EAST.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 306 PM EDT FRI MAR 23 2012
SAT IMAGERY AND SFC ANALYSIS AS OF 18Z SHOWS THE CENTER OF A BROAD
STACKED LOW NOW MOVING FROM MO INTO IL. CONVECTION OVER ERN KY HAS
BEEN RATHER ANEMIC THUS FAR LARGELY DUE TO THE EXTENSIVE CLOUD COVER
INHIBITING INSTABILITY. HOWEVER...BLENDED PWAT PRODUCT SHOWS THE AXIS
OF AMPLE MOISTURE TRANSPORT FROM THE GOMEX STILL ALIGNED FROM SRN AL
UP THRU MIDDLE TN AND INTO CENTRAL KY....FUELING WIDESPREAD SHOWERS
OVER ERN KY WITH LIGHTNING JUST NOW STARTING TO PICK UP OVER OUR
AREA...ALONG WITH A HINT OF ROTATION IN A CELL MOVING INTO LESLIE
COUNTY SUGGESTING AT LEAST A POTENTIAL FOR HAIL MAY STILL EXIST
THROUGH THE REMAINDER OF THE FIRST PERIOD AS WELL.
CURRENT RADAR TRENDS OVER WRN KY WHERE CONVECTION HAS BEEN NOTABLY
DEEPER SUGGEST 12Z MODELS MAY NOT BE TOO FAR OFF THE MARK WITH THE
IDEA OF A SOLID LULL IN ACTIVITY OVERNIGHT. HOWEVER...STILL WOULD NOT
RULE OUT A STRONG TSTM OR TWO THRU THIS EVENING WITH IR INDICATING
SOME ENHANCEMENT IN THE CONVECTION MOVING UP FROM ERN TN. GUIDANCE
REMAINS IN GOOD AGREEMENT FOR SATURDAY BRINGING LOWERING HEIGHTS
ALOFT AS THE BROAD LOW APPROACHES WITH STEEPENING LAPSE RATES THROUGH
THE AFTERNOON IN RESPONSE...WARRANTING ANOTHER ROUND OF CHANCE TSTMS
THRU THE MORNING AND INTO THE AFTERNOON...THOUGH WITH SIGNIFICANTLY
LESS SEVERE POTENTIAL THAN TODAY.
BY SATURDAY NIGHT...MODELS BEGIN TO DIVERGE WITH THE TRACK OF THE
UPPER LOW AND THIS WILL UNDOUBTEDLY HAVE AN INFLUENCE ON THE SFC
TRACK AND POPS AS WELL. HAVE LEANED MORE TOWARDS THE ECMWF AFTER 00Z
SUNDAY FOR THE SYNOPTIC PICTURE AS IT APPEARS TO HAVE THE MORE
CONSISTENT SOLUTION. THIS WOULD MOVE THE CORE OF THE UPPER LOW INTO
SERN KY BY SUNDAY MORNING BEFORE EXITING THE COMMONWEALTH...LEAVING A
DEEP NW FLOW OVERHEAD WITH A POTENTIAL FOR A GOOD FETCH OF MOISTURE
OFF THE GREAT LAKES AND POSSIBLY JUST ENOUGH RESIDUAL MID LEVEL
ENERGY ON THE BACKSIDE OF THE DEPARTING SYSTEM TO AFFECT A FEW
SHOWERS ACROSS THE CWA ON SUNDAY. BUFR SOUNDINGS ATTM INDICATE
MINIMAL INSTABILITY THROUGH THE DAY AND HAVE KEPT SLIGHT CHANCE
WORDING FOR TSTMS FOR THE MOMENT...THOUGH IF MODEL TRENDS CONTINUE
THEN THE NEXT ISSUANCE COULD PROBABLY PULL THUNDER FROM SUNDAY AND
JUST LEAVE ISOLATED SHOWERS.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 306 PM EDT FRI MAR 23 2012
PATTERN IS QUITE PROGRESSIVE THROUGH THE EXTENDED PERIOD. ALSO...
MODELS ARE IN GOOD AGREEMENT UNTIL DY7 WHEN SOLUTIONS DISPLAY A
SIGNIFICANT DEPARTURE...ESPECIALLY THE GFS. HOWEVER...TREND HAS BEEN
TOWARDS THE ECMWF SOLUTION. A FAST MOVING SHORT WAVE RIDGE TRANSITS
OUR AREA AT THE START OF THE EXTENDED BEHIND EXITING LOW OFF THE
ATLANTIC COAST. BUT SHORT WAVE ENERGY DIGGING SOUTHEASTWARD ACROSS
THE GREAT LAKES LATE MONDAY NIGHT INTO TUESDAY MORNING WILL SEND A
BACK DOOR SFC FRONT INTO THE CWA. BUT THIS FEATURE STALLS OUT ACROSS
OUR AREA TUESDAY BEFORE SHOOTING BACK TO OUR NORTH AS OUR NEXT
WEATHER MAKER ROLLS OUT OF THE NORTHERN PLAINS...PULLING A COLD
FRONT THROUGH EASTERN KENTUCKY MID WEEK...PROBABLY WEDNESDAY. DRY
WEATHER TAKES OVER AS CANADIAN HIGH PRESSURE NOSES ITS WAY INTO THE
OHIO VALLEY REGION TO CLOSE OUT THE WEEK.
IN GENERAL TEMPERATURES WILL COOL THROUGH THE PERIOD AS COMPARED TO
OUR RECENT RECORD HIGHS...BUT STILL REMAIN ABOVE NORMAL. LOOK FOR
HIGHS AROUND 70...EXCEPT MID 70S ON WEDNESDAY AND LOWS IN THE UPPER
40S TO LOWER 50S THROUGH THE FORECAST PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 145 AM EDT SAT MAR 24 2012
CONCERNING AVIATION TONIGHT...THE MAIN THREAT IS WITH THE LINE OF SHOWERS
AND THUNDERSTORMS MOVING THROUGH EASTERN KENTUCKY. IFR TO MVFR FLIGHT
CONDITIONS WILL BE ASSOCIATED WITH THE LINE AS IT MOVES THROUGH.
GOING BY TIMING...THE LINE IS EXPECTED TO MOVE THROUGH THE AREA BY
12Z. CONCERNING THE CLEARING BEHIND THE LINE...SOME FOG IS EXPECTED
TO DEVELOP IN THE VALLEYS ESPECIALLY WHERE THE HEAVIEST RAIN HAS
FALLEN SO PUT IFR CONDITIONS IN THE TAF SITES LATER TONIGHT AS THE
SURFACE TEMPS DROP A BIT. WITH ANOTHER VORT LOBE ROTATING AROUND THE
LOW LATER IN THE DAY...AND WITH THE DAYTIME HEATING...THE THREAT OF
SHOWERS AND THUNDERSTORMS WILL DEVELOP LATER IN THE DAY SO THIS WAS
PUT INTO THE TAFS AS WELL.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHALLENBERGER
SHORT TERM...MB
LONG TERM....RAY
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
414 AM EDT SAT MAR 24 2012
.SYNOPSIS...
LOW PRESSURE, MOVING EAST FROM KENTUCKY, WILL PROVIDE SHOWERS INTO
SUNDAY AS TEMPERATURES COOL TO VALUES COMMON FOR MAY. CANADIAN HIGH
PRESSURE WILL FOLLOW WITH DRY SEASONABLE CONDITIONS MONDAY, WHICH
MEANS THERE CAN BE A FROST MONDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BAND OF SHOWERS CONTINUES TO SLOWLY DRIFT EASTWARD, AS THE RAIN IN
THE BAND IS MOVING NORTHWARD. AREAS OF FOG HAVE ALSO DEVELOPED IN
THE MOIST ATMOSPHERE, SO WILL NEED TO MENTION PATCHY FOG THROUGH
DAWN.
HI-RES MODEL OUTPUT SHOWS THERE MAY BE A DRY BREAK SATURDAY MORNING,
FOLLOWED BY A BAND OF SHOWERS SATURDAY AFTERNOON THAT MAY INCLUDE
THUNDERSTORMS. SPC HAS MENTIONED SEVERE POTENTIAL WILL BE LIMITED AS
SREF MODEL OUTPUT SHOWS WEAK INSTABILITY AND VERTICAL SHEAR.
INSTABILITY WILL HAVE TO MONITORED TODAY IF THE DRY BREAK PRODUCES A
PERIOD OF SUNSHINE WHICH CAUSE AN UPWARD SPIKE IN SURFACE
TEMPERATURES.
CONSENSUS OF GFS AND NAM MOS MAINTAIN MAINLY CLOUDY SKIES TODAY, AND
SO THE STRING OF RECORD WARM TEMPERATURES SHOULD END. PITTSBURGH HAS
HAD ELEVEN CONSECUTIVE MARCH DAYS OF 70 PLUS, BUT MAY STRUGGLE TO
REACH 70 TODAY TO RUN THE STRING TO TWELVE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
RECENT SREF MODEL OUTPUT CONTINUES TO SHOW POST-SYSTEM SHOWERS MAY
LINGER ACROSS THE UPPER OHIO VALLEY INTO LATE SUNDAY AS THE LOW
PRESSURE SYSTEM EXITS EAST THROUGH VIRGINIA.
ENSUING CANADIAN HIGH PRESSURE WILL PROVIDE DRYING BY MONDAY. NORTH
WINDS AHEAD OF THE HIGH PRESSURE WILL FUNNEL SEASONABLE COLD
TEMPERATURES INTO THE UPPER OHIO VALLEY.
CLEAR SKIES AND LIGHT WINDS MONDAY NIGHT CAN CAUSE FROST TO DEVELOP
IN MANY AREAS. SUCH A FROST OCCURRENCE IS TYPICAL FOR LATE MARCH,
BUT THIS ONE MAY HAVE HIGH IMPACT ON THE HEELS OF THE RECENT WARM
SPELL THAT HAS SPURRED AN EARLY START TO THE GROWING SEASON. THIS
THREAT HAS BEEN HIGHLIGHTED IN THE HAZARDOUS WEATHER OUTLOOK/HWO/.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
BLEND OF RECENT ECMWF AND NAEFS MODEL OUTPUT SHOW DRY SEASONABLE
CONDITIONS CONTINUING ACROSS THE UPPER OHIO VALLEY TUESDAY AS THE
CANADIAN HIGH PRESSURE EXITS EAST.
A MORE ZONAL UPPER LEVEL JETSTREAM WILL STEER A WYOMING-BRED LOW
PRESSURE SYSTEM EASTBOUND TO BRING SHOWERS WEDNESDAY. HIGH PRESSURE
WILL FOLLOW WITH DRY CONDITIONS THURSDAY AND FRIDAY.
AS MENTIONED, TEMPERATURES WILL BE CLOSER TO NORMAL THIS PERIOD,
ALTHOUGH THERE MAY BE A WARM UP TO 10 DEGREES WARMER THAN NORMAL
WEDNESDAY IF THE LOW PRESSURE SYSTEM MOVES SLOWER THAN CURRENTLY
FORECASTED.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
AN AREA OF IFR CIGS/VIS IS QUICKLY DEVELOPING ACROSS PORTIONS OF W
PA IN THE MOISTURE LL ATMOSPHERE. WILL KEEP THESE LOW CONDITIONS
THROUGH DAWN. WILL NEED TO WATCH ZZV, AS CIGS AND VIS THERE ARE
ALSO DROPPING. OBS TO THE SOUTH OF ZZV, ARE SHOWING IFR
CONDITIONS, SO WILL INCLUDE TEMPO GROUP FOR NOW.
BLEND OF RECENT SURFACE AND RADAR DATA COUPLED WITH HRRR MODEL
OUTPUT SHOW A BAND OF MVFR SHOWERS WILL PASS NORTHEASTWARD THROUGH
THE UPPER OHIO VALLEY THROUGH 12Z. EVAPORATION OF THE RAIN MAY
MAINTAIN MVFR CONDITIONS INTO 15Z. A SECOND BAND OF SHOWERS, PERHAPS
EMBEDDED WITH SCATTERED THUNDERSTORMS, WILL PASS THROUGH THIS
AFTERNOON, AND PROLONG MVFR RESTRICTIONS.
SPC HAS MENTIONED WEAK SEVERE POTENTIAL WITH THE THUNDERSTORMS. FOR
AVIATION, THE MAIN CONCERN WOULD BE HAIL ALOFT.
POST SYSTEM COOLING MAY MAINTAIN A NEAR SATURATED SURFACE LAYER INTO
TONIGHT AND SUNDAY WHICH COULD RESULT IN LINGERING MVFR RESTRICTIONS.
OUTLOOK...SUNDAY NIGHT THROUGH TUESDAY...
CANADIAN HIGH PRESSURE SHOULD PROVIDE VFR MONDAY INTO TUESDAY. COLD
FRONTAL SHOWERS MAY CAUSE RESTRICTIONS LATE TUESDAY INTO WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
400 AM EDT SAT MAR 24 2012
.SYNOPSIS...
LOW PRESSURE OVER THE OHIO VALLEY WILL APPROACH TODAY...AND WILL
MOVE ACROSS THE SOUTHERN MID-ATLANTIC REGION TONIGHT INTO
SUNDAY. A DRY COLD FRONT MOVES THROUGH ON MONDAY...THEN HIGH
PRESSURE BUILDS IN FOR TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
BACKDOOR FRONT WILL CONTINUE TO SINK SOUTH AND LIKELY STALL ACROSS
THE SOUTHERN PORTION OF THE CWA EARLY THIS MORNING.
MEANWHILE...THERE/S ALREADY SOME PVA/WAA MAKING ITS WAY INTO THE CWA
WELL AHEAD OF LOW PRESSURE OVER THE OHIO VALLEY. RESULT IS SHOWERS
ACROSS THE WESTERN PORTIONS OF THE CWA WHICH WILL GRADUALLY SPREAD
TO THE EAST/EXPAND THROUGH THE MORNING HOURS...POSSIBLY EXITING
DURING THE EARLY AFTERNOON. FAST ON ITS HEELS WITH LIKELY BE ANOTHER
ROUND OF SHOWERS AS LOW PRESSURE/COLD FRONT MOVE INTO THE
APPALACHIANS. THERE MAY NOT BE A HUGE TIME LULL IN BETWEEN
ROUNDS...SO AM UNCERTAIN HOW MUCH IF ANY BREAKS IN THE CLOUD COVER
MAY DEVELOP FOR THE AFTERNOON. THE BEST AREA FOR THIS MAY BE ACROSS
CENTRAL VIRGINIA SOUTH OF THE AFOREMENTIONED STALLED BOUNDARY. EVEN
WITHOUT BREAKS...WITH HIGH DEWPOINTS AND PW/S AND ALSO SOME COOLING
ALOFT...THERE MAY BE THUNDERSTORMS THAT ACCOMPANY THE SHOWERS LATER
IN THE AFTERNOON/EVENING. MAIN CONCERN GIVEN HIGH MOISTURE CONTENT
WILL BE HEAVY RAINFALL AND LOCALIZED FLASH FLOODING...ALTHOUGH FLASH
FLOOD GUIDANCE IS FAIRLY HIGH. ALSO CAN/T RULE OUT ISOLATED STRONG
TO MARGINALLY SEVERE STORMS /HAIL/ ESPECIALLY CENTRAL VIRGINIA WHICH
IS WHERE SREFS HAS MAINTAINED CONSISTENCY IN A CHANCE OF MUCAPE GTE
1000 J/KG AND 0-6 KM SHEAR 30 KT. BUT AGAIN...INSTABILITY MAGNITUDE
IS SOMEWHAT CONTINGENT ON WHETHER THERE CAN BE BREAKS OR NOT.
LEANED MORE TOWARD THE COOLER MET MOS ESPECIALLY NORTH OF THE
BOUNDARY IN AN EASTERLY FLOW. BUT GIVEN CLOUDS/SHOWERS...EVEN AREA
FURTHER SOUTH INTO CENTRAL VIRGINIA SHOULD FAVOR THE COOLER GUIDANCE.
LOW PRESSURE MOVES ACROSS THE THE SOUTHERN PORTIONS OF THE CWA
OVERNIGHT. EXPECT MORE SHOWERS TO CONTINUE...AND ITS POSSIBLE THAT
A BAND OF LOCALLY HEAVY SHOWERS MAY OCCUR ON THE NORTH SIDE OF
THE LOW.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
THE CLOSED LOW IS FCST TO REACH THE LEE SIDE OF THE SOUTHERN/CENTRAL
APPALACHIANS BY SUN MRNG BEFORE SLOWLY REACHING THE CAROLINA COAST
SUN AFTN. THE BEST SYNOPTIC LIFT AND ACCORDINGLY THE STEADIEST/
HEAVIEST PRECIP WILL SHIFT WELL SOUTH AND EAST OF THE AREA SUN. THE
CWA WILL BE LOCATED ON NRN PERIPHERY OF THE LOW...WHERE LGT PRECIP
IS EXPECTED NEAR MID-LVL DEFORMATION AXIS. SHOWER ACTIVITY WILL BE
AIDED BY WEAK INSTABILITY DURING THE AFTN FROM THE COLD POOL ALOFT
AND LIMITED BOUNDARY LAYER HEATING. HAVE ADDED SLIGHT CHANCE FOR
TSTMS SUN AFTN AS FAR NORTH AS WOO-IAD-DMH. SHEAR-INSTABILITY
PROFILES DO NOT INDICATE A SEVERE WEATHER THREAT. QPF AMOUNTS ARE
AROUND A QUARTER INCH ON SUN.
MAX TEMP FCST A BIT TRICKY DUE TO VARIABLE CLOUD COVER OVER THE
REGION. ATTM...MAX TEMPS RANGE FROM THE MID 60S OVER THE MTS AND
NEAR THE MASON-DIXON LINE TO THE LOW 70S IN CENTRAL VA AND SRN MD.
THE LOW WILL FINALLY MOVE OFF THE COAST. SHOWER ACTIVITY SHOULD
DIMINISH DURING THE EVE WITH THE LOSS OF DAYTIME HEATING AND AS
DRIER AIR MOVES IN ALOFT. SKIES MAY EVEN GO PARTLY CLOUDY BY DAWN
MON MRNG.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
COOL CANADIAN AIR WILL FINALLY PUSH FAR ENOUGH SOUTH TO IMPACT THE
MID-ATLANTIC STATES FOR THE FIRST TIME IN OVER TWO WEEKS. NRN-STREAM
ENERGY IS EXPECTED TO DIG SEWD INTO THE NE STATES ON MON. NW FLOW
BEHIND THE LOW WILL DRIVE COLDER AIR SWD INTO THE AREA THRUOUT THE
DAY. STRONG CAA SHOULD OFFSET DAYTIME HEATING SOMEWHAT. TEMPS ARE
STILL EXPECTED TO REACH THE 60S AND EVEN 70F ACROSS CENTRAL VA/SRN
WITH THE AIDE OF THE INCREASING SUN ANGLE OF ERY SPRING.
HIPRES BUILDS INTO THE AREA MON NGT. THE COLDEST NGT SINCE THE FIRST
WEEK OF MARCH IS EXPECTED MON NGT. AS PREVIOUS FORECASTER
IMPLIED...CAA PATTERN AND DECENT PRESSURE GRADIENT FROM HIPRES
BUILDING SWD SHOULD PREVENT WINDS FROM DECOUPLING AND WIDESPREAD
FROST. SHELTERED VLYS WITHIN THE POTOMAC HIGHLANDS MAY FLIRT WITH
THE FREEZING MARK.
HIPRES/UPPER RIDGE OVER THE AREA TUE WILL GRADUALLY SHIFT OFF THE
COAST WED. AFTER MAX TEMPS FINALLY RETURN TOWARD NORMAL LVLS FOR
LATE MARCH ON TUE /UPPER 50S AND LOW 60S/...WAA PATTERN WILL YIELD
HIGHS IN THE UPPER 60S AND LOW 70S BY WED.
THE NEXT CHANCE OF PRECIP WILL BE WED AS A COLD FRONT MOVES THRU THE
REGION LATE WED INTO ERY THU. TEMPS RETURN TOWARD SEASONABLE LVLS
LATE IN THE WORK WEEK.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
BACKDOOR BOUNDARY SINKING SOUTH WILL REINFORCE EASTERLY FLOW TODAY.
ALREADY HAVE IFR CIGS CREEPING INTO MTN/BWI AT 07Z. HRRR SUGGESTS
IFR CIGS MAKE IT TO IAD TOWARD DAYBREAK...AND FORECAST REFLECTS THIS
ALTHOUGH HAVE SOME UNCERTAINTY REGARDING WESTWARD EXTENT AND TIMING
OF STRATUS THIS MORNING. AT THE SAME TIME...THERE/S SHOWERS MOVING
IN FROM THE WEST WELL OF AHEAD OF LOW PRESSURE OVER THE OHIO VALLEY.
THESE SHOWERS WILL ALSO AFFECT THE TERMINALS FIRST CHO/MRB THEN
SPREADING EAST AFTER DAYBREAK AT THE HUBS. EXPECT OCCASIONAL SHOWERS
TODAY/TONIGHT...WITH THUNDERSTORMS ALSO POSSIBLE MAINLY THIS
AFTERNOON/EVENING. AT LEAST MVFR FLIGHT RESTRICTIONS WILL ACCOMPANY
SHOWERS TODAY...BUT GIVEN EASTERLY FLOW ON THE NORTH SIDE OF THE
BOUNDARY THERE IS THE CHANCE THAT IFR CONDITIONS BECOME ENTRENCHED.
IF THEY DO...THEY ARE LIKELY TO REMAIN THROUGH THE NIGHT AND
LIKELY DROP TO LIFR OVERNIGHT. ON THE OTHER HAND...IF MVFR WINDS
UP PREVAILING THE BULK OF THE DAY...THEN IFR/LIFR SHOULD RETURN
THIS EVENING.
IFR CIGS SUN MRNG MAY IMPROVE TO MVFR LVLS BY THE AFTN. EXACT
EVOLUTION OF CIGS AND EVEN VSBYS WILL DEPEND ON SHRA COVERAGE DURING
THIS TIME. CANNOT RULE OUT AN ISO TSTM SUN AFTN...ESPECIALLY SOUTH
OF MRB-BWI-MTN.
IMPROVING CONDITIONS LATE SUN NGT AS DRIER AIR WORKS IN FROM THE
NORTH. DRY CONDITIONS EXPECTED MON AND TUE. NW WINDS WILL BE BREEZY
ON MON...15-20 KT GUSTING TO 30 KT.
&&
.MARINE...
HIGH PRESSURE MOVES FURTHER AWAY FROM THE EASTERN SEABOARD AS LOW
PRESSURE APPROACHES FROM THE WEST. RESULT WILL BE EASTERLY
FLOW...THAT MAY INCREASE INTO THE 10 TO 15 KT RANGE TODAY.
OCCASIONAL SHOWERS AND POSSIBLE THUNDERSTORMS WILL BRING VIS
RESTRICTIONS OF 1 TO 3 NM FROM TIME TO TIME THROUGH TONIGHT. LOW
PRESSURE LOOKS TO PASS OVER THE SOUTHERN WATER LATE TONIGHT.
AN ISO TSTM POSSIBLE OVER THE WATERS SUN AFTN. N-NW FLOW WILL
INCREASE SUN NGT AND MON BEHIND A COLD FRONT. SCA CONDITIONS
POSSIBLE LATE SUN NGT AND LIKELY MON THRU A PORTION OF TUE.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BPP/JRK
NEAR TERM...BPP
SHORT TERM...JRK
LONG TERM...JRK
AVIATION...BPP/JRK
MARINE...BPP/JRK
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
242 AM EDT SAT MAR 24 2012
.SYNOPSIS...
LOW PRESSURE, MOVING EAST FROM KENTUCKY, WILL PROVIDE SHOWERS INTO
SUNDAY AS TEMPERATURES COOL TO VALUES COMMON FOR MAY. CANADIAN HIGH
PRESSURE WILL FOLLOW WITH DRY SEASONABLE CONDITIONS MONDAY, WHICH
MEANS THERE CAN BE A FROST MONDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
BLEND OF RECENT RADAR DATA AND HRRR MODEL OUTPUT SHOW A BAND OF
SHOWERS, ASSOCIATED WITH THE CIRCULATION AROUND THE LOW PRESSURE
CENTER MOVING EAST FROM KENTUCKY, WILL PASS NORTHEASTWARD THROUGH
THE UPPER OHIO VALLEY UNTIL MORNING. TEMPERATURES WILL AT MOST ONLY
DROP 2 OR 3 DEGREES FOR OVERNIGHT LOWS.
HI-RES MODEL OUTPUT SHOWS THERE MAY BE A DRY BREAK SATURDAY MORNING,
FOLLOWED BY A BAND OF SHOWERS SATURDAY AFTERNOON THAT MAY INCLUDE
THUNDERSTORMS. SPC HAS MENTIONED SEVERE POTENTIAL WILL BE LIMITED AS
SREF MODEL OUTPUT SHOWS WEAK INSTABILITY AND VERTICAL SHEAR.
INSTABILITY WILL HAVE TO MONITORED TODAY IF THE DRY BREAK PRODUCES A
PERIOD OF SUNSHINE WHICH CAUSE AN UPWARD SPIKE IN SURFACE
TEMPERATURES.
CONSENSUS OF GFS AND NAM MOS MAINTAIN MAINLY CLOUDY SKIES TODAY, AND
SO THE STRING OF RECORD WARM TEMPERATURES SHOULD END. PITTSBURGH HAS
HAD ELEVEN CONSECUTIVE MARCH DAYS OF 70 PLUS, BUT MAY STRUGGLE TO
REACH 70 TODAY TO RUN THE STRING TO TWELVE.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
RECENT SREF MODEL OUTPUT CONTINUES TO SHOW POST-SYSTEM SHOWERS MAY
LINGER ACROSS THE UPPER OHIO VALLEY INTO LATE SUNDAY AS THE LOW
PRESSURE SYSTEM EXITS EAST THROUGH VIRGINIA.
ENSUING CANADIAN HIGH PRESSURE WILL PROVIDE DRYING BY MONDAY. NORTH
WINDS AHEAD OF THE HIGH PRESSURE WILL FUNNEL SEASONABLE COLD
TEMPERATURES INTO THE UPPER OHIO VALLEY.
CLEAR SKIES AND LIGHT WINDS MONDAY NIGHT CAN CAUSE FROST TO DEVELOP
IN MANY AREAS. SUCH A FROST OCCURRENCE IS TYPICAL FOR LATE MARCH,
BUT THIS ONE MAY HAVE HIGH IMPACT ON THE HEELS OF THE RECENT WARM
SPELL THAT HAS SPURRED AN EARLY START TO THE GROWING SEASON. THIS
THREAT HAS BEEN HIGHLIGHTED IN THE HAZARDOUS WEATHER OUTLOOK/HWO/.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
BLEND OF RECENT ECMWF AND NAEFS MODEL OUTPUT SHOW DRY SEASONABLE
CONDITIONS CONTINUING ACROSS THE UPPER OHIO VALLEY TUESDAY AS THE
CANADIAN HIGH PRESSURE EXITS EAST.
A MORE ZONAL UPPER LEVEL JETSTREAM WILL STEER A WYOMING-BRED LOW
PRESSURE SYSTEM EASTBOUND TO BRING SHOWERS WEDNESDAY. HIGH PRESSURE
WILL FOLLOW WITH DRY CONDITIONS THURSDAY AND FRIDAY.
AS MENTIONED, TEMPERATURES WILL BE CLOSER TO NORMAL THIS PERIOD,
ALTHOUGH THERE MAY BE A WARM UP TO 10 DEGREES WARMER THAN NORMAL
WEDNESDAY IF THE LOW PRESSURE SYSTEM MOVES SLOWER THAN CURRENTLY
FORECASTED.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
BLEND OF RECENT SURFACE AND RADAR DATA COUPLED WITH HRRR MODEL
OUTPUT SHOW A BAND OF MVFR SHOWERS WILL PASS NORTHEASTWARD THROUGH
THE UPPER OHIO VALLEY THROUGH 12Z. EVAPORATION OF THE RAIN MAY
MAINTAIN MVFR CONDITIONS INTO 15Z. A SECOND BAND OF SHOWERS, PERHAPS
EMBEDDED WITH SCATTERED THUNDERSTORMS, WILL PASS THROUGH THIS
AFTERNOON, AND PROLONG MVFR RESTRICTIONS.
SPC HAS MENTIONED WEAK SEVERE POTENTIAL WITH THE THUNDERSTORMS. FOR
AVIATION, THE MAIN CONCERN WOULD BE HAIL ALOFT.
POST SYSTEM COOLING MAY MAINTAIN A NEAR SATURATED SURFACE LAYER INTO
TONIGHT AND SUNDAY WHICH COULD RESULT IN LINGERING MVFR RESTRICTIONS.
OUTLOOK...SUNDAY NIGHT THROUGH TUESDAY...
CANADIAN HIGH PRESSURE SHOULD PROVIDE VFR MONDAY INTO TUESDAY. COLD
FRONTAL SHOWERS MAY CAUSE RESTRICTIONS LATE TUESDAY INTO WEDNESDAY.
&&
.CLIMATE...
AS OF FRIDAY, PITTSBURGH HAS HAD 11 CONSECUTIVE MARCH DAYS WITH
HIGHS OF 70 PLUS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1224 AM CDT SAT MAR 24 2012
.AVIATION...06Z KGRI TAF. AS AN UPPER LEVEL RIDGE BUILDS INTO THE
PLAINS THIS EVENING...WEATHER CONDITIONS WILL REMAIN FAIRLY CALM
THROUGH THE TAF PERIOD. WINDS WILL REMAIN LIGHT OUT OF THE
SOUTHWEST THROUGH THE DAY BECOMING LIGHT AND VARIABLE SATURDAY
EVENING. A FEW HIGH CLOUDS WILL LIKELY STICK AROUND THIS EVENING
BEFORE BECOMING MOSTLY CLEAR.
&&
PREV DISCUSSION... /ISSUED 354 PM CDT FRI MAR 23 2012/
SHORT TERM...THROUGH SATURDAY AFTERNOON. NEEDLESS TO SAY...THE
NEXT 24 HOURS CONTINUE THE RETURN TO INCREDIBLY NICE LATE MARCH
WEATHER...WITH HIGH TEMPS ON SATURDAY FORECAST TO BE RIGHT AROUND
CLIMATOLOGICAL NORMALS FOR LATE MAY/EARLY JUNE.
STARTING OFF AT 20Z THIS AFTERNOON...A LIGHT AND SOMEWHAT VARIABLE
WIND REGIME IS IN PLACE ACROSS THE CWA...THANKS TO A BROAD DIFFUSE
RIDGE AXIS. THE COMBINATION OF MODEST BOUNDARY LAYER
MOISTURE...ALONG WITH SOME COOLER MID LEVEL AIR ON THE BACK SIDE
OF THE DEPARTING CLOSED LOW OVER SOUTH CENTRAL MISSOURI...HAS
RESULTED IN A LEGITIMATE SCATTERED FAIR WEATHER CUMULUS FIELD
ESPECIALLY ACROSS THE EASTERN HALF OF THE CWA. ALTHOUGH THIS
SCATTERED TO LOCALLY BROKEN DECK WAS A BIT MORE CLOUD COVER THAN
EARLIER EXPECTED...TEMPS HAVE HAD STILL HAD NO PROBLEMS MAKING IT
INTO AT LEAST THE MID-UPPER 60S AT THIS HOUR...WITH SOME PLACES
POSSIBLY TOUCHING 70 BY DAYS END. AS MENTIONED...WATER VAPOR
IMAGERY AND SHORT TERM MODEL DATA CLEARLY REVEAL THE DEPARTING
CLOSED LOW AS THE MAIN MID/UPPER FEATURE OF INTEREST...WITH
SHORTWAVE RIDGING NOW BUILDING ALONG AN AXIS FROM THE SOUTHERN
ROCKIES TO NORTHERN PLAINS...AND THE NEXT LOW PRESSURE SYSTEM OF
INTEREST STILL WELL OFF THE PACIFIC COAST.
FOR LATE THIS AFTERNOON...HAVE KEPT THE FORECAST DRY...ALTHOUGH
THE HRRR CONTINUES TO INSIST THAT A FEW SPRINKLES COULD FLIRT WITH
FAR SOUTHEAST EDGES OF THE CWA. BASED ON LATEST VIS SATELLITE
TRENDS...ANY SLIGHTLY ENHANCED CUMULUS GROWTH POTENTIALLY
CONDUCIVE TO SPRINKLES/LIGHT RAIN SHOULD REMAIN JUST EAST OF THESE
COUNTIES.
THIS EVENING/TONIGHT...BOUNDARY LAYER CUMULUS DEVELOPMENT SHOULD
QUICKLY FADE AWAY...RESULTING IN ESSENTIALLY CLEAR SKIES AS
SHORTWAVE RIDGING CONTINUES TO NOSE OVERHEAD IN THE WAKE OF THE
DEPARTING LOW...WHICH WILL BE NEAR THE IL/IN/KY BORDER AREA BY
12Z. BREEZES WILL REMAIN LIGHT OVERNIGHT...BUT THE DIRECTION WILL
PREVAIL FROM THE WEST/SOUTHWEST. ONLY POTENTIAL ISSUE IS FOG
DEVELOPMENT OVERNIGHT. VARIOUS MODEL BOUNDARY LAYER RELATIVE
HUMIDITY PROGS...ALONG WITH MET/MAV VISIBILITY GUIDANCE...SUGGEST
THAT THIS LIGHT WESTERLY LOW LEVEL FLOW WILL NOT BE VERY CONDUCIVE
TO FOG DEVELOPMENT. THAT BEING SAID...AT LEAST LIGHT FOG HAS
DEVELOPED HERE AND THERE ACROSS THE CWA THE PAST FEW NIGHTS
LARGELY DUE TO MOIST GROUND IN THE WAKE OF RECENT RAINFALL. GIVEN
THAT PATCHY FOG WORDING HAS ALREADY BEEN IN THE FORECAST FOR OVER
24 HOURS NOW IN SOME AREAS...WILL LET IT RIDE...BUT WOULD BE VERY
SURPRISED TO SEE MORE THAN PATCHY LIGHT VISIBILITY RESTRICTIONS.
FOR LOW TEMPS...KEPT SIMILAR TO PREVIOUS FORECAST IN EASTERN
ZONES...BUT BUMPED DOWNWARD A FEW DEGREES IN THE WEST...RESULTING
IN A RANGE FROM MID-UPPER 30S WEST...LOW 40S CENTRAL...MID 40S
SOUTHEAST. BASED ON WHAT HAPPENED THIS MORNING WITH LOWS TUMBLING
INTO THE LOW 30S WEST...WOULD NOT BE SURPRISED IF TONIGHTS LOWS
END UP A BIT LOWER THAN FORECAST. HOWEVER...THE LIGHT WESTERLY
BREEZES SHOULD HELP HOLD THINGS UP A BIT VERSUS LAST NIGHT.
SATURDAY...THE MID/UPPER PATTERN REMAINS QUITE TRANQUIL...AS THE
HEART OF THE 700-500MB RIDGE BUILDS OVER THE PLAINS...WELL TO THE
EAST OF THE DEEP TROUGH AXIS OFF THE PACIFIC COAST...AND THE
PRIMARY 300MB JET AXIS SNAKING FROM NORTHERN CA THEN EASTWARD
ACROSS SOUTHERN CANADA. AS A SURFACE HIGH PRESSURE SYSTEM WORKS
INTO SOUTHERN CANADA INTO THE DAKOTAS...A VERY WEAK COLD FRONT
WILL PUSH SOUTHWARD TOWARD/INTO THE NORTHWEST CWA DURING THE
AFTERNOON. OTHERWISE...LIGHT SOUTHWEST BREEZES WILL PREVAIL ACROSS
MOST OF THE CWA FOR THE MAJORITY OF THE DAY. WITH FORECAST
SOUNDINGS A BIT DRIER IN THE BOUNDARY LAYER COMPARED TO
TODAY...NOT ANTICIPATING MUCH CUMULUS DEVELOPMENT...AND IN FACT
VERY LITTLE CLOUD COVER. TEMP WISE...GIVEN THE WIDESPREAD SUN AND
850MB TEMPS CLIMBING WELL INTO THE 14-17C RANGE...A NOTABLE JUMP
IN AFTERNOON HIGHS IN LIKELY. DIDN/T GET TOO CARRIED AWAY...BUT
NUDGED UP PREVIOUS FORECAST TOWARD HIGHER END OF MET/MAV GUIDANCE
CONSENSUS...WITH MOST OF THE CWA INTO THE 78-80 RANGE.
LONG TERM...SATURDAY NIGHT THROUGH FRIDAY. WE KICK THINGS OFF
SATURDAY NIGHT WITH A PROMINENT UPPER RIDGE OVER THE PLAINS AND A
HIGHLY AMPLIFIED TROUGH ON ENTERING THE WEST COAST OF THE UNITED
STATES. WEATHER SHOULD REMAIN DRY INTO SUNDAY THANKS TO BEING
UNDER THE INFLUENCE OF NOT ONLY THE UPPER LEVEL RIDGE BUT A
SURFACE RIDGE AS WELL. THERE WILL BE A SURFACE TROUGH DEVELOPING
IN THE LEE OF THE ROCKIES BY SUNDAY NIGHT WITH A HEALTHY FAIRLY
STRONG LOW-LEVEL JET INCREASING OVER PARTS OF WESTERN AND CENTRAL
KANSAS...WITH THE NOSE OF THE JET MAKING ITS WAY INTO SOUTHERN AND
CENTRAL PARTS OF THE CWA BY LATE SUNDAY NIGHT...WITH THE NAM A BIT
STRONGER HERE...INDICATING A 50 KT JET...AS OPPOSED TO NEAR 40 KTS
FOR THE GFS AND ECMWF. AT THIS POINT...THERE DOES NOT APPEAR TO BE
ENOUGH MOISTURE TO GET ANY CONVECTION GOING...BUT IF THERE
WERE...STRONG TO SEVERE THUNDERSTORMS WOULD CERTAINLY NOT BE OUT
OF THE QUESTION. CONFIDENCE IS NOT HIGH ENOUGH TO INTRODUCE
CHANCES OF RAIN AT THIS POINT.
A POTENT NEGATIVELY TILTED SHORTWAVE TROUGH WILL EJECT NORTHEAST OUT
OF THE CENTRAL ROCKIES MONDAY NIGHT AND HAS BEEN PROJECTED TO DO SO
FOR SOME TIME. THERE ARE SOME STRENGTH AND TIMING DIFFERENCES
BETWEEN MEDIUM TO LONG RANGE MODELS...BUT THE GENERAL SCENARIO IS
SIMILAR. THE ECMWF CONTINUES TO PROJECT A STRONGER WAVE THAT EJECTS
INTO THE PLAINS SOONER THAN THE GFS SOLUTION. SURFACE PRESSURE
GRADIENTS WILL INCREASE ALONG WITH INCREASED MIXING AND WE COULD BE
GETTING CLOSE TO WIND ADVISORY WITH HEALTHY WIND FROM THE
SOUTH...ESPECIALLY IN THE WESTERN CWA. MODELS GENERALLY PRODUCE THE
NOSE OF THE LOW-LEVEL JET WELL NORTH OF THE CWA...ALONG WITH THE
BEST MID TO UPPER LEVEL FORCING TO THE NORTH AS WELL. AT THE
SURFACE...BY MONDAY EVENING...THE DRY LINE SHOULD STILL BE WELL TO
THE WEST OF THE CWA...WHILE A WARM FRONT IS EXPECTED TO HAVE PASSED
TO THE NORTHEAST OF THE CWA BY THEN. SEVERE PARAMETERS SUGGEST
POSSIBLE SEVERE WEATHER NEAR THESE BOUNDARIES...BUT WE MAY WIGGLE
OUT OF MOST OF THE SEVERE WEATHER BY BEING BETWEEN THESE BOUNDARIES
WHILE SEVERE WEATHER INITIATES TOWARD EVENING...GIVEN THAT SOUNDINGS
SUGGEST WE WILL BE TOO CAPPED TO PRODUCED MUCH OF ANYTHING IN THE
REGION UNTIL LATE AFTERNOON AND QUITE LIKELY IN THE EVENING...AND
FOR THIS REASON...I HAVE ALL BUT PULLED CHANCES OF PRECIPITATION
FROM MONDAY AFTERNOON...SAVE PERHAPS THE FAR NORTHEASTERN CORNER OF
THE CWA IF THE WARM FRONT DOES NOT GET OUT OF THE CWA FAST
ENOUGH...AND HAVE LIMITED THAT SMALL AREA TO LATE
AFTERNOON...DESPITE THE FACT THAT THE LATEST ECMWF PAINTS SOME QPF
OVER THE NORTHWEST. THIS DOES NOT LOOK PROBABLE AS IT APPEARS THAT
THE WARM FRONT SHOULD CLEAR THE CWA BEFORE CONVECTION BEGINS AND
THERE IS NO OTHER FOCUS FOR CONVECTION IN THE AFTERNOON TO REALLY
GET THINGS GOING FROM WHAT IT LOOKS LIKE FOR NOW. THIS LOOKS LIKE A
SCENARIO WHERE WE MAY WIND UP GETTING SOME NOCTURNAL HIGH PLAINS
CONVECTION AS THE THETA E AXIS WILL MOVE FROM WEST TO EAST ACROSS
THE CWA BETWEEN 03Z AND 08Z TUESDAY (MONDAY EVENING)...BUT THIS MAY
BE MORE OF A WEAKER LEFTOVER EVENT...GIVING US ELEVATED
STRONGER/HEAVY RAINER STORMS...BUT PERHAPS NO LONGER SEVERE. I AM
NOT CONFIDENT ENOUGH TO PULL SEVERE POTENTIAL OUT OF THE HWO...AS
TIMING DIFFERENCES COULD MAKE A HUGE DIFFERENCE...AND BEING SO FAR
OUT IN THE FORECAST...IT WOULD BE PRUDENT TO KEEP SEVERE POTENTIAL
MENTIONED IN THE HWO.
AFTER THE WAVE PASSES MONDAY NIGHT...THERE WILL BE LITTLE MORE
CHANCE OF PRECIPITATION FOR A COUPLE OF DAYS WITH RIDGING TAKING
PLACE. TUESDAY COULD BE GETTING CLOSE TO RED FLAG POTENTIAL IN THE
FAR WESTERN CWA WITH RELATIVE HUMIDITY POSSIBLY GETTING NEAR 20
PERCENT AND WEST WINDS APPROACHING SUSTAINED 20 MPH. THE ECMWF
INDICATES A SMALL PERTURBATION RIDING THE RIDGE BY WEDNESDAY NIGHT
ALONG OUR SOUTHERN FRINGE WITH PERHAPS THE AID OF SOME CONVERGENCE
AT 850 MB...BUT EVEN WITH QPF ADVERTISED BY THE ECMWF...PROBABILITY
OF PRECIPITATION FOR RUSSEL AND CONCORDIA ARE AROUND 20
PERCENT...AND LOWER THAN THIS IN OUR CWA TO THE NORTH. FOR THE REST
OF THE EXTENDED...I LEFT LOW CHANCES OF PRECIPITATION AS FLOW COULD
CONTAIN POTENTIAL SMALL WAVES OF ENERGY...ALTHOUGH TEMPERATURES WILL
REMAIN WELL ABOVE NORMAL.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
125 AM EDT SAT MAR 24 2012
.SYNOPSIS...
AN UPPER LEVEL LOW OVER MISSOURI WILL MOVE SLOWLY EASTWARD TO
WESTERN KENTUCKY BY SATURDAY AFTERNOON. THIS LOW WILL WEAKEN AND
MOVE OFF THE MIDDLE ATLANTIC COAST BY SUNDAY EVENING. HIGH
PRESSURE WILL BUILD SOUTHEAST INTO THE AREA BY LATE MONDAY THEN
SHIFT OFF TO THE EAST BY LATE TUESDAY. ANOTHER AREA OF LOW PRESSURE
WILL MOVE INTO THE CENTRAL GREAT LAKES FOR THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
DID A QUICK UPDATE TO FRESHEN UP THE WORDING AND KEEP THE POPS
CHANCE OVER NORTHWEST OHIO. WATCHING CONVECTION OVER EASTERN
INDIANA. THE HRRR MODELS IS FORECASTING ALL THAT CONVECTION WILL
DECREASE BY AROUND 08Z....WILL CONTINUE TO MONITOR THIS. ADJUSTED
MINS UP BASED ON THE CLOUDS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
THE UPPER LOW WILL BE OVER KY BY SATURDAY AFTERNOON WITH SOME
COOLER AIR EXPECTED ALOFT. THIS WILL AT LEAST ALLOW FOR SOME
SHOWERS AND THUNDERSTORMS TO PERSIST THROUGH AT LEAST THE MORNING.
THE COOLER AIR ALOFT MAY ALLOW FOR ADDITIONAL DEVELOPMENT DURING
THE AFTERNOON. THE LOW STILL MAY PROVIDE A FEW SHOWERS/THUNDER
INTO SUNDAY BUT SHOULD BE SCATTERED IN NATURE. BY SUNDAY NIGHT
HIGH PRESSURE WILL RIDGE INTO THE AREA HELPING TO CLEAR SKIES AND
COOLER TEMPERATURES INTO MONDAY. PATCHY FROST MAY BE POSSIBLE AS
EARLY AS MONDAY MORNING...ESPECIALLY ACROSS INLAND NW PA.
LIGHT WINDS AND CLEAR SKIES MONDAY NIGHT MAY ALLOW FOR AREAS OF
FROST AND MAYBE EVEN A HARD FREEZE BY TUESDAY MORNING. THIS
POTENTIAL HAS BEEN MENTIONED IN THE HWO.
HIGHS SATURDAY WILL REMAIN IN THE 60S BUT IT WILL BE COOLER ON
SUNDAY AS ANOTHER FRONT PASSES. HIGHS SUNDAY WILL GENERALLY BE NEAR
AROUND 60 DEGREES. IN THE WAKE OF THE FRONT ON MONDAY HIGHS WILL
REMAIN IN THE 50S...MAYBE UPPER 40S ACROSS NW PA.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
STRONG SFC HIGH PRES WILL KEEP CONDITIONS DRY TUE...BUT PLENTY OF
SUNSHINE SHOULD ALLOW TEMPS TO ABOVE NORMAL (LOWER 50S) DESPITE A COLD
START. A WARM FRONT AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM WILL
PUSH THROUGH THE REGION LATE TUESDAY RESULTING IN LOWS IN THE 40S
OVERNIGHT. RAIN AND STORMS WILL BE POSSIBLE WED WITH THE LOW PASSAGE
BUT WILL BROAD BRUSH THE TIMING GIVEN POST WARM FRONT SCT
SHOWERS...COLD FROPA...AND UPPER LVL LOW TIMING ISSUES. BY THU THE
LOW WILL BE EAST OF THE AREA AND NE FLOW WILL SET UP ACROSS THE
LAKE. THIS WILL KEEP CLOUDS AND LIGHT RAIN POSSIBLE WITH TEMPS IN
THE LOWER 50S. GENERALLY STAYED WITH A MODEL CONSENSUS FOR MUCH OF
THE PERIOD RELYING MORE ON RAW DATA THAN GUIDANCE.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
WIDESPREAD SHRA AND TSRA WILL AFFECT THE AREA THROUGH THE TAF
PERIOD. CONDITIONS SHOULD LOWER TO MOSTLY MVFR WITH POCKETS OF IFR
THE REST OF TONIGHT AS LOW LEVEL MOISTURE INCREASES AND THE AIRMASS
COOLS. DAYTIME HEATING SAT SHOULD LIFT CONDITIONS TO MOSTLY VFR BY
LATE MORNING AND HOLD THAT WAY INTO EARLY SAT EVENING THEN DAYTIME
COOLING WILL AGAIN ALLOW CONDITIONS TO LOWER BACK TO MVFR BY THE END
OF THE TAF PERIOD. THE COOLING AND HEATING OF THE AIRMASS SHOULD
ALSO LEAD TO SOME DECREASE IN OVERALL CONVECTIVE ACTIVITY BY SAT
MORNING THEN SHRA/TSRA SHOULD AGAIN BECOME MORE NUMEROUS SAT
AFTERNOON AS NEW ACTIVITY DEVELOPS FROM DAYTIME HEATING.
.OUTLOOK...NON VFR POSSIBLE LATE SATURDAY NIGHT AND SUNDAY.
&&
.MARINE...
WINDS ARE EXPECTED TO DIMINISH OVERNIGHT OUT OF THE EAST AND BECOME
VARIABLE BY SATURDAY MORNING. GENERALLY LIGHT AND VARIABLE FLOW WILL
CONTINUE THROUGH THE REST OF THE WEEKEND. WINDS DO INCREASE
CONSIDERABLY SUNDAY NIGHT INTO MONDAY FROM THE NORTH AND WE WILL
LIKELY NEED TO HOIST SMALL CRAFT ADVISORIES DURING THAT PERIOD. I
ANTICIPATE SMALL CRAFT ADVISORIES WILL NEED TO REMAIN IN EFFECT
THROUGH TUESDAY.
LARGE AREA OF SHOWERS AND THUNDERSTORMS CONTINUE TO SLOWLY ADVANCE
EAST TOWARD THE LAKE. IT WILL TAKE SOME TIME TO GET INTO THE REGION.
ONCE THEY ARRIVE...THEY WILL SLOWLY DECREASE FROM WEST TO EAST
SATURDAY NIGHT INTO SUNDAY. FAIR WEATHER WILL RETURN ACROSS THE
ENTIRE LAKE SUNDAY NIGHT.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MULLEN
NEAR TERM...KIELTYKA
SHORT TERM...MULLEN
LONG TERM...JAMISON
AVIATION...ADAMS
MARINE...LOMBARDY
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
427 AM EDT SAT MAR 24 2012
.SYNOPSIS...
LOW PRESSURE OVER THE OHIO VALLEY WILL MOVE EAST THEN SOUTHEAST
TODAY AND TONIGHT. BY SUNDAY NIGHT THE LOW WILL BE OFF THE CAROLINA
COAST. HIGH PRESSURE WILL BUILD OVER THE REGION MONDAY AND
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 410 AM EDT SATURDAY...
EXPECTING SEVERAL BANDS OF SHOWERS AND THUNDERSTORMS TODAY AND
TONIGHT. FIRST AREA WAS OVER THE CENTRAL AND EASTERN COUNTY
WARNING AREA EARLY THIS MORNING AND WAS MOVING NORTHEAST AROUND 20
MPH. THE NEXT BAND EXTENDS FROM OHIO INTO EASTERN TENNESSEE. LOCAL
WRF AND HRRR BRING THIS BAND INTO THE WESTERN COUNTY WARNING AREA
BY 8AM.
AS THE UPPER LOW MOVES EAST THIS MOVING SO WILL THE SHOWERS AND
THUNDERSTORMS. ADDITIONAL SHOWERS AND THUNDERSTORMS WILL DEVELOP
OVER THE FORECAST AREA THIS AFTERNOON. COLDER AIR ALOFT
ASSOCIATED WITH THE UPPER LOW WILL REACH THE FORECAST AREA
TODAY...CREATING LARGE LAPSE RATES AND LOWERING THE FREEZING
LEVEL. GUSTY WINDS AND LARGE HAIL WILL BE A THREAT WITH ANY
STRONGER STORMS...ESPECIALLY THIS AFTERNOON AND EVENING.
THE UPPER LOW MOVES SOUTHEAST INTO SOUTH CAROLINA BY SUNDAY
MORNING. EXPECT COVERAGE AND PROBABILITY OF PRECIPITATION TO
DECREASE LATE TONIGHT.
THERE WAS A BREAK IN THE CLOUD COVER AHEAD OF THE SHOWERS AND
THUNDERSTORMS APPROACHING FROM THE WEST. FOG MAY DEVELOP EARLY
THIS MORNING AS THE CLOUDS BRIEFLY CLEAR. WITH ALL THE
PRECIPITATION EXPECTED TODAY...HAVE GONE ON THE COOL SIDE OF
GUIDANCE. STAYED CLOSE TO A BLEND OF BIAS CORRECTED MAV/MET
GUIDANCE FOR LOWS TONIGHT.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 330 AM EST SATURDAY...
SUNDAY MORNING WILL START OUT WITH THE UPPER LEVEL LOW PASSING JUST
TO THE SOUTH OF OUR AREA...POSSIBLY CLIPPING OUR NORTH CAROLINA
COUNTIES. IN ANY EVENT...EXPECT TO SEE GREATER COVERAGE OF SHOWER
ACTIVITY NORTH OF INTERSTATE 81...AS A SLOT OF DRIER AIR WORKS ITS
WAY IN SOUTH CLOSER TO THE LOW. COVERAGE WILL INCREASE FURTHER
DURING THE AFTERNOON AS DAYTIME HEATING HELPS DESTABILIZE THE
ATMOSPHERE...AND WILL NOT BE SURPRISED TO SEE A FEW THUNDERSTORMS
DEVELOP BY LATE MORNING. WITH THE UPPER LOW PASSING SO CLOSE TO OUR
AREA...BELIEVE THAT HAIL WILL BE A CONCERN IN THE STRONGER SHOWER
AND THUNDERSTORM ACTIVITY...BUT EXPECT MOST HAIL TO BE IN THE PEA TO
DIME SIZE RANGE WHERE IT OCCURS. SHOWER AND THUNDERSTORM ACTIVITY
WILL DECREASE FROM WEST TO EAST BY LATE AFTERNOON AS THE UPPER LOW
CONTINUES TO PUSH OFF THE ATLANTIC COAST...AND SHOWER ACTIVITY IS
EXPECTED TO BE CONFINED TO THE MOUNTAINS...MAINLY IN SOUTHEAST WEST
VIRGINIA BY LATE SUNDAY EVENING. DESPITE THE PASSAGE OF THE UPPER
LOW...SUNDAY NIGHT TEMPERATURES WILL REMAIN MILD ACROSS OUR
AREA...WITH OVERNIGHT LOWS RANGING FROM THE LOW TO MID 50S EAST...TO
THE UPPER 40S WEST.
IT WILL BE MONDAY MORNING WHEN WE SEE A CHANGE IN OUR WEATHER
PATTERN AS ANOTHER COLD FRONT BRINGS A SHOT OF COOLER CANADIAN AIR
INTO OUR AREA. MONDAY AFTERNOON TEMPERATURES ARE EXPECTED TO REMAIN
MILD ACROSS OUR AREA...ALBEIT A LITTLE COOLER...HOWEVER IT WILL BE
MONDAY NIGHT/TUESDAY MORNING TEMPERATURES THAT WILL BE OF CONCERN AS
LOWS FALL INTO THE 30S ACROSS THE MOUNTAINS. BELIEVE THAT NEAR
FREEZING TEMPERATURES WILL BE CONFINED TO GREENBRIER COUNTY IN
SOUTHEAST WEST VIRGINIA...AS WELL AS THE ALLEGHANY HIGHLANDS IN
VIRGINIA...LOCATIONS THAT HAVE NOT EXPERIENCED A START TO THE
GROWING SEASON TO THE SAME EXTENT THAT HAS OCCURRED IN LOWER
ELEVATIONS. THAT STATED...IT WOULD BE A GOOD IDEA TO CONSIDER
PRECAUTIONS AGAINST THE COLD FOR ANY SENSITIVE VEGETATION WHICH HAS
STARTED TO GROW IN YOUR AREA.
HIGH PRESSURE WILL SLIDE EAST ON TUESDAY AFTERNOON...ALLOWING WINDS
TO BECOME SOUTHERLY ACROSS OUR AREA. WITH A RIDGE OF UPPER LEVEL
HIGH PRESSURE BUILDING IN FROM THE WEST LATE TUESDAY EVENING...
OVERNIGHT TEMPERATURES WILL BE CONSIDERABLY WARMER...WITH LOWS
EXPECTED TO RANGE FROM THE MID 40S IN THE WEST...TO THE UPPER 30S IN
THE EAST.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 330 AM EDT SATURDAY...
ON WEDNESDAY...A HIGH PRESSURE RIDGE WILL SLIDE EAST OFF THE COAST.
SOUTHERLY FLOW RETURNS WITH MODERATING TEMPERATURES FOR THE
REMAINDER OF THE WORK WEEK. LIGHT RAIN SHOWERS ARE POSSIBLE
WEDNESDAY INTO THURSDAY AS A WEAK COOL FRONT PASSES OVER THE REGION.
THIS RAIN WILL NOT BE ANY WHERE CLOSE IN INTENSITY TO THIS WEEKENDS
RAIN EVENT.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
AS OF 230 AM EDT SATURDAY...
EXPECT SEVERAL PERIODS OF SHOWERS AND THUNDERSTORMS ACROSS
THE FORECAST AREA THROUGH 06Z SUNDAY. CEILINGS AND VISIBILITIES
WILL LOWER TO MVFR IN ASSOCIATION WITH THE SHOWERS AND STORMS.
SOME OF THE STRONGER STORMS TODAY MAY PRODUCE GUSTY WINDS AND
LARGE HAIL. MODERATE CONFIDENCE...SUPPORTED BY THE LOCAL WRF AND
THE 04Z HRRR RUN...THAT THUNDERSTORMS IN EASTERN KENTUCKY WILL
REACH BLF AND LWB BETWEEN 10Z-12Z THIS MORNING.
SHRA WILL CONTINUE TO DEVELOP ACROSS THE AREA SUN...BUT WITH
CONSIDERABLE LESS INSTABILITY INDICATED AND A COLDER/MORE STABLE SFC
ENVIRONMENT...DO NOT ANTICIPATE MUCH TSRA ACTIVITY SUN...JUST SHRA.
DRIER WEATHER AND VFR CONDITIONS ARE EXPECTED BEHIND THIS WEATHER
SYSTEM SUNDAY NIGHT THROUGH TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...NF
LONG TERM...RCS/NF
AVIATION...AMS/KK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
236 AM EDT SAT MAR 24 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL TRACK EAST OUT OF THE MID MISSISSIPPI
VALLEY TONIGHT...THEN SOUTHEAST ACROSS THE TENNESSEE VALLEY ON
SATURDAY. BY MONDAY...THE SYSTEM WILL BE OFF THE EAST COAST.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1030 PM EDT FRIDAY...
CONTINUED WITH CATEGORICAL/DEFINITE POPS THROUGH 06Z ACROSS THE
CWA...THEN DECREASED TO CHC POPS AFT 06Z AS FIRST WAVE OF PVA
ASSOCIATED WITH LEADING CIRCULATION FROM APPROACHING CLOSED LOW
MOVES ACROSS THE CWA FROM WEST TO EAST. INTENSITY OF ACTIVITY HAS
CONTINUED TO DECREASE SINCE SUNSET AND THE ONLY AREA NOW EXHIBITING
ANY LIGHTNING IS NEAR DAN. CONFINED TSRA THREAT TO EC/SE PARTS OF
THE CWA...THEN ENDED BY 06Z. THUNDERSTORMS EXPECTED TO DEVELOP SAT
AFTERNOON WITH DRY SLOT DURING THE FIRST HALF OF THE DAY EXPECTED TO
PROVIDE AMPLE INSOLATION...WHICH COMBINED WITH COLDER TEMPS ALOFT
SPREADING ACROSS THE AREA WILL RESULT IN STEEP LAPSE RATES. WET BULB
ZERO HEIGHTS WILL ALSO LOWER. MAIN THREAT WILL BE QUARTER-SIZED
HAIL. STORMS COULD ALSO BE EFFICIENT LIGHTNING PRODUCERS. SPC
CURRENTLY HAS MUCH OF THE SE PART OF THE CWA IN A SLIGHT RISK FOR
SAT AFTERNOON. TEMP AND SKY GRIDS APPEAR TO BE ON TRACK AT THIS TIME.
AS OF 300 PM EDT FRIDAY...
WSR-88D KFCX SHOWED ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING IN THE WARM UNSTABLE AIR THIS AFTERNOON ESPECIALLY WEST
OF I77. SHOWERS AND THUNDERSTORMS WILL INCREASE IN NUMBERS AND
COVERAGE THIS EVENING INTO TONIGHT...AS THE DEEP CLOSED LOW ALOFT
AND TRAILING FRONTAL BOUNDARY APPROACHES. ANY TRAINING OF SHOWERS
AND THUNDERSTORMS WITH PRECIPITABLE WATER VALUES BETWEEN 1.25 AND
1.50 INCHES COULD PRODUCE LOCAL FLOODING CONCERNS. TRIED TO INSERT
MORE OF A DIURNAL TREND FOR THE THUNDERSTORM POTENTIAL AND TRIMMED
THUNDER MENTION OVERNIGHT WITH THE LOSS OF THE HEATING. PLAYED LOW
TEMPERATURES OVERNIGHT CLOSE TO THE MILD ADJMET VALUES WITH READINGS
FROM THE MID 50S TO AROUND 60 DEGREES IN THE SOUTHEAST.
ON SATURDAY...THE UPPER-LEVEL LOW WILL MOVE EASTWARD ACROSS
THE OHIO VALLEY IN OUR REGION. AS SFC TEMPERATURES WARM BENEATH THE
UPPER-LEVEL LOW...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
WILL DEVELOP. SPC HAS PLACED EASTERN PORTIONS OF OUR CWA UNDER A
SLIGHT RISK FOR SEVERE THUNDERSTORMS ON SATURDAY. DUE TO COLD AIR
ALOFT...STEEP MID-LEVEL LAPSE RATES AND LARGE-SCALE ASCENT
ASSOCIATED WITH THE UPPER-LEVEL LOW...SOME OF THE CONVECTION COULD
CONTAIN HAIL DURING THE AFTERNOON. HEAVY RAINFALL IS ALSO POSSIBLE
ON SATURDAY WITH THE THUNDERSTORMS. HIGHS ON SATURDAY WILL RANGE
FROM THE LOWER 60S IN THE MOUNTAINS TO THE MID 70S IN THE
PIEDMONT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
AS OF 222 PM EDT FRIDAY...
THE UPPER LEVEL LOW THAT HAS BEEN SPINNING ACROSS THE USA MOST OF
THIS WEEK WILL PLAGUE THE EAST COAST OVER THE WEEKEND. SATURDAY
NIGHT...THE LOW WILL BE CENTERED IN THE TENNESSEE VALLEY THEN CROSS
THE SOUTHERN APPALACHIANS AND OVER THE CAROLINAS BY SUNDAY MORNING.
MODELS DISPLAYING A SURFACE LOW DEVELOPING ALONG THE FRONT IN THE
VA/NC COASTAL PIEDMONT SATURDAY NIGHT. EVENTUALLY...THIS TWO SYSTEMS
WILL BECOME AN OCCLUDED LOW OVER THE OUTER BANKS SUNDAY...SLOWING
DOWN THE EXIT OF SHOWERS UNTIL SUNDAY EVENING. RAIN SHOWERS WILL NOT
BE CONTINUOUS SATURDAY NIGHT. BANDS OF SHOWERS WILL PASS OVER THE
AREA THEN A BRIEF DRY PERIOD BEFORE THE NEXT BAND COMES IN. EACH
BAND OF SHOWERS COULD PRODUCE UP TO A QUARTER OF AN INCH OF RAIN.
THE DRYING TIME BETWEEN BANDS AND INCREASE VEGETATION SHOULD TAKE
CARE OF MOST OF THE RUNOFF. HOWEVER...IF CONVECTION IS STRONGER AND
RAINFALL RATES ARE HIGHER...LOCALIZED FLASH FLOODING IS POSSIBLE
SATURDAY NIGHT.
AREAL FLOODING BECOMES AN ISSUE ON SUNDAY AS THE LOW TRACKS OVER THE
OUTER BANKS AND OUT TO SEA. THE DEFORMATION ZONE WILL PIVOT OVER THE
AREA...CROSSING THE MOUNTAINS IN THE MORNING...THEN EAST OF THE BLUE
RIDGE SUNDAY AFTERNOON/EVENING. RAIN FROM THIS DEFORMATION ZONE WILL
BE CONTINUOUS WITH AMOUNTS FROM A QUARTER TO A HALF OF AN INCH.
RAIN FINALLY MOVES EAST OF THE AREA SUNDAY EVENING. BRIEF UPSLOPE
SHOWERS/DRIZZLE ON WESTERN SLOPES SUNDAY NIGHT...THEN AN EXTENDED
DRY PERIOD PERSIST INTO MID WEEK.
RAIN WILL HELP COOL TEMPERATURES CLOSER TO SEASONAL LEVELS
SUNDAY...HOWEVER....THEY WILL STILL BE ABOVE NORMAL. UNDERCUT THE
COLDEST GUIDANCE (METMOS) WITH RAIN AND THE UPPER LEVEL LOW TO OUR
SOUTH SUNDAY. COOLER AIR ARRIVES MONDAY...BUT TEMPERATURES WILL
STILL RUN ABOUT 10F ABOVE NORMAL. OVERNIGHTS WILL REMAIN MUGGY UNTIL
THE SYSTEM MOVES OUT TO SEA EARLY MONDAY MORNING.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 232 PM EDT FRIDAY...
SURFACE HIGH PRESSURE WILL MOVE FROM NEW ENGLAND TO THE MID
ATLANTIC REGION TUESDAY. THIS RIDGE WILL KNOCK TEMPERATURES DOWN
TO NEAR NORMAL. ON WEDNESDAY...THE RIDGE SLIDES OFF THE COAST.
SOUTHERLY FLOW RETURNS WITH MODERATING TEMPERATURES FOR THE
REMAINDER OF THE WORK WEEK. LIGHT RAIN SHOWERS ARE POSSIBLE
WEDNESDAY INTO THURSDAY AS A WEAK COOL FRONT PASSES OVER THE
REGION. THIS RAIN WILL NOT BE ANY WHERE CLOSE TO THIS WEEKENDS
RAIN EVENT.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
AS OF 230 AM EDT SATURDAY...
EXPECT SEVERAL PERIODS OF SHOWERS AND THUNDERSTORMS ACROSS
THE FORECAST AREA THROUGH 06Z SUNDAY. CEILINGS AND VISIBILITIES
WILL LOWER TO MVFR IN ASSOCIATION WITH THE SHOWERS AND STORMS.
SOME OF THE STRONGER STORMS TODAY MAY PRODUCE GUSTY WINDS AND
LARGE HAIL. MODERATE CONFIDENCE...SUPPORTED BY THE LOCAL WRF AND
THE 04Z HRRR RUN...THAT THUNDERSTORMS IN EASTERN KENTUCKY WILL
REACH BLF AND LWB BETWEEN 10Z-12Z THIS MORNING.
SHRA WILL CONTINUE TO DEVELOP ACROSS THE AREA SUN...BUT WITH
CONSIDERABLE LESS INSTABILITY INDICATED AND A COLDER/MORE STABLE SFC
ENVIRONMENT...DO NOT ANTICIPATE MUCH TSRA ACTIVITY SUN...JUST SHRA.
DRIER WEATHER AND VFR CONDITIONS ARE EXPECTED BEHIND THIS WEATHER
SYSTEM SUNDAY NIGHT THROUGH TUESDAY.
&&
.CLIMATE...
RECORD HIGH TEMPS FOR FRIDAY...
3/23
ROANOKE 82 IN 2007
LYNCHBURG 91 IN 2007
DANVILLE 86 IN 1966
BLUEFIELD 77 IN 2007
BLACKSBURG 80 IN 1966
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...KK
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...AMS/KK
CLIMATE...AMS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
302 AM CDT SAT MAR 24 2012
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
302 AM CDT SAT MAR 24 2012
THE MAIN FOCUS THROUGH EARLY NEXT WEEK IS WITH THE DWINDLING RAIN
CHANCES THIS MORNING FOLLOWED BY THE RETURN OF PRECIPITATION
SUNDAY NIGHT INTO MONDAY NIGHT.
THE CUT OFF LOW TO THE SOUTH WILL CONTINUE TO MAKE SOME HEADWAY
EAST TODAY AS IT TAKES AIM AT THE OHIO RIVER VALLEY. A FEW SHOWERS
AND POCKETS OF DRIZZLE WILL REMAIN POSSIBLE THIS MORNING ACROSS
SOUTHERN WISCONSIN AND NORTHEAST IOWA ALONG THE WEAKENING
850-925MB MOISTURE TRANSPORT THAT WILL ALSO BE PULLING EAST ALONG
WITH THE LOW. WITH LIGHT WINDS...MOIST LOW LEVELS AND RECENT
RAINFALL...SOME FOG HAS DEVELOPED ACROSS THE REGION. SOME LOCALLY
DENSE FOG WILL BE POSSIBLE AT TIMES THIS MORNING...THOUGH NOT
WIDESPREAD ENOUGH TO BE CONSIDERED FOR AN ADVISORY AT THIS POINT
WITH VISIBILITY IN THE 1-3SM RANGE THROUGHOUT THE REGION WITH
JUST A LOW LEVEL STRATUS DECK IN SOME LOCATIONS.
AS THE LOW CONTINUES TO PROPAGATE EAST THIS MORNING AND RIDGING
MOVES IN FROM THE WEST...DRIER AIR SHOULD SLOWLY MAKE ITS WAY INTO
THE REGION. THE 24.00Z NAM/ECMWF DO PRODUCE SOME QPF THIS
AFTERNOON ACROSS WESTERN WISCONSIN...LIKELY DUE TO THE FEW HUNDRED
J/KG OF MUCAPE THEY DEVELOP. THERE DOES NOT APPEAR TO BE MUCH OF A
TRIGGER IN THE WAY OF A FORCING MECHANISM...SO WILL CONTINUE THE
DRY FORECAST AFTER 18Z TODAY.
AFTER THE RIDGE MOVES THROUGH TONIGHT...A COLD FRONT WILL QUICKLY
DROP DOWN INTO THE REGION AND BRING SOME COOLER AIR DOWN WITH IT.
THE 24.00Z NAM DOES PRODUCE SOME PRECIPITATION ALONG THE FRONT
SUNDAY AFTERNOON...WHILE THE REST OF THE GUIDANCE EITHER HAS THE
FRONT SOUTH OF THE FORECAST AREA BY 18Z OR DO NOT PRODUCE ANY
SHOWERS. THE 24.00Z NAM FORECAST SOUNDINGS SHOW AN UNCAPPED
ATMOSPHERE WITH THE FRONT ACTING AS THE INITIATOR. AGAIN...HAVE
OPTED TO KEEP SUNDAY DRY GIVEN THAT THE NAM APPEARS TO BE THE
OUTLIER WITH OTHER GUIDANCE KEEPING THE INSTABILITY MUCH LOWER.
COOLER 850MB AIR WILL MAKE IT DOWN ACROSS WISCONSIN TO THE
MISSISSIPPI RIVER VALLEY SUNDAY NIGHT INTO MONDAY AND WILL LIMIT
HOW MUCH TEMPERATURES ARE ABLE TO WARM.
THIS FRONT WILL STALL OUT ACROSS THE PLAINS WITH A FAIRLY TIGHT
TEMPERATURE GRADIENT IN PLACE TO THE NORTHEAST OF THE FRONT. THIS
SETUP WILL PRODUCE A STRONG FRONTOGENESIS CIRCULATION THROUGH THE
REGION STARTING SUNDAY NIGHT AND LASTING INTO MONDAY NIGHT. WHILE
THE PRECIPITATION TYPE WILL LIKELY BE ALL RAIN THROUGHOUT...THERE
ARE SOME INDICATIONS THAT THIS COLD...SHALLOW AIR MASS COULD COME
CLOSE TO BEING COLD ENOUGH TO CAUSE THE LIQUID TO FREEZE INTO
ICE/SLEET. SURFACE TEMPERATURES ARE FORECAST TO DROP INTO THE 30S
MONDAY MORNING ALONG AND EAST OF THE MISSISSIPPI...BUT SHOULD STAY
ABOVE FREEZING AS THE PRECIPITATION FALLS. TEMPERATURES IN THE
SHALLOW COLD LAYER DROP TO AROUND -5C JUST BELOW 900MB OFF OF THE
24.00Z NAM IN WESTERN WISCONSIN. THAT SHOULD NOT BE COLD ENOUGH TO
REFREEZE INTO ICE...BUT ITS CLOSE ENOUGH...ALONG WITH SURFACE
TEMPERATURES...TO THE CRITICAL THRESHOLDS THAT IT MERITS WATCHING.
AS THE NEXT UPPER LEVEL TROUGH EJECTS OUT OF THE ROCKIES MONDAY
INTO MONDAY NIGHT...THE FRONTOGENETIC CIRCULATION WILL STRENGTHEN
AND LIFT NORTH AND BRING SOME BETTER CHANCES FOR PRECIPITATION TO
DEVELOP.
.LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
302 AM CDT SAT MAR 24 2012
THE BIG QUESTION TO START OFF THE EXTENDED PERIOD IS WITH THE
SYSTEM THAT TRACKS THROUGH THE REGION ON TUESDAY AND WHETHER THE
TIMING WILL WORK OUT FOR THE DEVELOPMENT OF ORGANIZED CONVECTION.
THE 24.00Z GFS/ECMWF/GEM ALL FORM A BAND OF PRECIPITATION TUESDAY
MORNING ALONG AND NORTHEAST OF THE WARM FRONT DUE TO ISENTROPIC
LIFT/FRONTOGENESIS WITH THIS BAND LIFTING NORTH TOWARD LAKE
SUPERIOR BY 18Z TUESDAY. GIVEN A BRIEF PERIOD OF WARMING BETWEEN
THIS FRONT AND THE COLD FRONT...WHICH APPEARS TO COME THROUGH
TUESDAY AFTERNOON...THERE SHOULD BE A SMALL WINDOW WHERE SOME
WEAK INSTABILITY DEVELOPS AHEAD OF THE COLD FRONT. MID LEVEL
LAPSE RATES ARE NOT VERY STEEP DUE TO THE CORE OF THE MID LEVEL
LOW GOING THROUGH THE DAKOTAS...SO IT WILL BE TOUGH TO DEVELOP ANY
STRONG INSTABILITY. GIVEN THE TIMING OF THE MID LEVEL TROUGH
COMING THROUGH...IT APPEARS THAT THE FORCING FROM IT MAY GO MORE
TO THE NORTH AND BE THROUGH BEFORE ANY INSTABILITY CAN FORM IN THE
AFTERNOON.
AFTER THE COLD FRONT COMES THROUGH...VERY DRY AIR GETS ADVECTED
INTO THE REGION IN THE DRY SLOT OF THE SYSTEM. FORECAST SOUNDINGS
FROM THE 24.00Z GFS SHOW MIXING UP TO 800MB WITH WIND GUSTS IN THE
30-40KT RANGE POSSIBLE BASED ON MOMENTUM TRANSFER. HIGH PRESSURE
WILL THEN SETUP FROM SOUTHERN CANADA INTO THE UPPER MISSISSIPPI
RIVER VALLEY WEDNESDAY INTO THURSDAY BEFORE LOW LEVEL MOISTURE
RETURN BRINGS SHOWERS AND STORMS BACK INTO THE REGION THURSDAY
NIGHT INTO NEXT WEEKEND.
&&
.AVIATION...THROUGH 06Z SUNDAY
1135 PM CDT FRI MAR 23 2012
THE CLOUDS HAVE BEEN SLOWLY DISSIPATING ACROSS SOUTHEAST MINNESOTA
THROUGH THE EVENING. BASED ON IR SATELLITE...KRST IS NOW VERY
CLOSE TO THE EDGE OF THE CLOUDS WITH A VERY SLOW SOUTHWARD DRIFT
OCCURRING. THIS SHOULD ALLOW THE CLOUDS TO BRIEFLY CLEAR LONG
ENOUGH TO ALLOW DENSE FOG AND IFR CEILINGS TO QUICKLY FORM. THE
24.01Z HRRR SUGGESTS THAT DENSE FOG WILL FORM OVER SOUTH CENTRAL
MINNESOTA AND NORTH CENTRAL IOWA JUST TO THE WEST OF KRST. PLENTY
OF LOW LEVEL MOISTURE STILL RESIDES OVER THE AREA ALONG WITH LIGHT
WINDS...SO IF THE CLOUDS CAN CLEAR OUT...WOULD EXPECT THE FOG TO
FORM. KLSE IS DEEPER INTO THE CLOUDS...BUT WITH THE SOUTHWARD
DRIFT...STILL HAS A CHANCE OF CLEARING OUT LATE ALLOWING THE FOG
TO FORM. HAVE CONTINUED THE IFR CONDITIONS FOR BOTH SITES
UNCHANGED FROM THE PREVIOUS FORECAST. EXPECTING THE FOG TO BEGIN
LIFTING BY MID MORNING WITH MVFR CONDITIONS THEN PREVAILING INTO
THE MID TO LATE AFTERNOON BEFORE THE CLOUDS SCATTER OUT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
302 AM CDT SAT MAR 24 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1135 PM CDT FRI MAR 23 2012
.SHORT TERM...TONIGHT THROUGH MONDAY
332 PM CDT FRI MAR 23 2012
MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES AND FOG TONIGHT
THROUGH EARLY SATURDAY MORNING. FOCUS THEN TURNS TO TEMPERATURES AND
PRECIPITATION CHANCES ON MONDAY.
LATEST WATER VAPOR IMAGERY SHOWED A BROAD LOW PRESSURE SYSTEM
CENTERED OVER SOUTHERN MISSOURI. GULF OF MEXICO MOISTURE CONTINUES
TO STREAM NORTH AND WEST OF THE LOW INTO THE UPPER MISSISSIPPI
RIVER VALLEY.
THE LOW IS EXPECTED TO MOVE EAST INTO THE OHIO RIVER VALLEY
TONIGHT. CLEARING NOTED ON VISIBLE SATELLITE THIS AFTERNOON ACROSS
SOUTHWEST MINNESOTA INTO NORTHWEST IOWA...AS HIGH PRESSURE EDGED IN
FROM THE DAKOTAS. WILL HAVE TO KEEP A CLOSE WATCH ON CLOUD TRENDS
AND THE PRESSURE GRADIENT TONIGHT. IF THE WINDS GO CALM OR ANY
CLEARING OCCURS...DENSE FOG WOULD QUICKLY DEVELOP GIVEN THE NEARLY
SATURATED AIRMASS IN PLACE OVER THE FORECAST AREA. HAVE ADDED AREAS
OF FOG TO THE FORECAST FOR PORTIONS OF SOUTHEAST MINNESOTA INTO
NORTHEAST IOWA...AND PATCHY FOG ACROSS ALL OF THE WISCONSIN COUNTIES
FROM MIDNIGHT INTO MID SATURDAY MORNING. SCATTERED RAIN SHOWERS WILL
PERSIST THROUGH THIS EVENING AS THE MOISTURE CONTINUES TO STREAM
INTO THE FORECAST AREA FROM THE SOUTHEAST. PLAN ON DECREASING SHOWER
ACTIVITY EARLY SATURDAY MORNING AS THE LOW STARTS TO SHIFT EAST.
LOOK FOR LOW TEMPERATURES TONIGHT TO FALL INTO THE LOWER
50S...POSSIBLY THE UPPER 40S IF ANY CLEARING OCCURS.
HIGH PRESSURE WILL BUILD INTO THE AREA TOMORROW WITH SHOWER CHANCES
ENDING ACROSS WISCONSIN BY SATURDAY AFTERNOON. PLAN ON DECREASING
CLOUDS AS THE HIGH MOVES IN. HIGH TEMPERATURES WILL RANGE FROM THE
MID TO LOWER 60S ACROSS NORTH CENTRAL WISCONSIN TO AROUND 70 ACROSS
NORTHEAST IOWA. COOLER AIR WILL SETTLE INTO THE AREA SUNDAY THROUGH
SUNDAY NIGHT AS CANADIAN HIGH PRESSURE BUILDS IN FROM THE NORTHEAST.
850 MB TEMPERATURES WILL RANGE FROM 6C ACROSS NORTHERN WISCONSIN TO
AROUND 10 C ACROSS NORTHEAST IOWA EARLY IN THE DAY ON SUNDAY. THE
COOLER AIR WILL THEN FILTER IN THROUGH THE DAY SUNDAY INTO SUNDAY
NIGHT WITH 850 MB TEMPS FALLING INTO THE SINGLE DIGITS BELOW ZERO
ACROSS NORTHERN WISCONSIN TO AROUND 6 C ACROSS NORTHEAST IOWA. PLAN
ON HIGHS ON SUNDAY RANGING FROM AROUND 60 ACROSS NORTH CENTRAL
WISCONSIN TO THE UPPER 60S ACROSS NORTHEAST IOWA. LOOK FOR LOWS TO
FALL INTO THE LOWER 30S ACROSS NORTH CENTRAL WISCONSIN TO THE MIDDLE
40S ACROSS NORTHEAST IOWA...RATHER CHILLY COMPARED TO WHAT WE HAVE
SEEN OVER THE PAST FEW WEEKS BUT STILL ABOVE NORMAL FOR THIS TIME OF
YEAR. A BAROCLINIC ZONE IS EXPECTED TO STRETCH FROM NORTH CENTRAL
NORTH DAKOTA SOUTHEAST THROUGH NORTHERN ILLINOIS...AND WILL BE THE
FOCUS FOR SHOWER AND ISOLATED THUNDERSTORM DEVELOPMENT ON MONDAY
ACROSS SOUTHEAST MINNESOTA...NORTHEAST IOWA AND PORTIONS OF
SOUTHWEST WISCONSIN. HAVE LOWERED DEWPOINTS INTO THE LOWER TEENS
ACROSS NORTH CENTRAL AND CENTRAL WISCONSIN MONDAY AFTERNOON...THIS
PRODUCES RELATIVE HUMIDITY VALUES IN THE MID TO LOWER 20S. THE
BAROCLINIC ZONE WILL LIFT NORTHEAST AS A WARM FRONT SETS UP
ACROSS THE DAKOTAS AND LIFTS NORTHEAST. SHOWERS AND THUNDERSTORMS
ARE EXPECTED TO DEVELOP ALONG THE FRONT...SOME POSSIBLY SEVERE
ACROSS FAR SOUTHWEST MINNESOTA THROUGH THE DAKOTAS...AS A STRONG
LOW PRESSURE SYSTEM DEVELOPS. LOOK FOR MORE SEASONABLE HIGHS
ACROSS THE AREA ON MONDAY WITH HIGHS RANGING FROM THE UPPER 40S
ACROSS NORTH CENTRAL WISCONSIN TO THE LOWER 50S ACROSS NORTHEAST
IOWA. EAST WINDS WILL INCREASE ACROSS THE FORECAST AREA ON MONDAY
AS THE LOW DEEPENS ACROSS SOUTH DAKOTA. LOOK FOR WINDS TO INCREASE
INTO THE 10 TO 20 MPH RANGE MONDAY AFTERNOON WITH GUSTS TO AROUND
25 MPH POSSIBLE. THE WARM FRONT IS EXPECTED TO LIFT INTO THE
FORECAST AREA MONDAY NIGHT INTO TUESDAY MORNING BRINGING A CHANCE
OF SHOWERS AND THUNDERSTORMS TO THE FORECAST AREA. PLAN ON LOWS
FALLING INTO THE UPPER 30S TO LOWER 40S.
.LONG TERM...TUESDAY THROUGH FRIDAY
332 PM CDT FRI MAR 23 2012
23.12 MEDIUM RANGE FORECAST MODELS CONTINUE TO INDICATE THE POTENTIAL
FOR STRONG TO SEVERE THUNDERSTORMS TUESDAY AFTERNOON INTO TUESDAY
EVENING AS A STRONG LOW PRESSURE SYSTEM MOVES EAST INTO THE REGION
FROM THE DAKOTAS. THE MAJOR LIMITING FACTOR IS INSTABILITY. MODELS
ARE STRUGGLING TO GENERATE HIGH CAPE VALUES...WITH CAPE RANGING
FORM 200 TO 800 J/KG IN A VERY NARROW CORRIDOR RIGHT ALONG THE
COLD FRONT. SHEAR IS RATHER STRONG WITH THIS SYSTEM WITH 0-6 KM
BULK SHEAR OF 45 TO 55 KT. 0-1 KM BULK SHEAR VALUES ARE VERY
STRONG...WITH VALUES OF 30 TO 50 KTS. GIVEN THE STRENGTH OF THE
SOUTHERLY FLOW...HIGHER DEWPOINTS AND WARMER AIR SHOULDNT HAVE ANY
PROBLEMS ADVECTING NORTHWARD INTO THE FORECAST AREA AHEAD OF THE
LOW. IF ANY SUNSHINE IS SEEN TUESDAY AFTERNOON...INSTABILITY
SHOULD INCREASE LEADING TO RAPID THUNDERSTORM DEVELOPMENT ALONG
AND AHEAD OF THE COLD FRONT TUESDAY AFTERNOON ACROSS SOUTHEAST
MINNESOTA AND NORTHEAST IOWA. THESE STORMS SHOULD THEN PUSH INTO
WESTERN WISCONSIN LATE TUESDAY AFTERNOON INTO TUESDAY EVENING.
WILL HAVE TO CONTINUE TO CLOSELY MONITOR SEVERE THUNDERSTORM
POTENTIAL THE NEXT FEW MODEL RUNS. IF THE THUNDERSTORMS CAN
DEVELOP...STRONG WINDS AND ISOLATED TORNADOES WOULD BE THE PRIMARY
CONCERNS. HIGH PRESSURE WILL BUILD IN BEHIND THE LOW TUESDAY NIGHT
INTO WEDNESDAY AND REMAIN OVER THE REGION THROUGH THURSDAY. PLAN
ON QUIET WEATHER WITH HIGHS IN THE 50S TO LOWER 60S WITH LOWS IN
THE MIDDLE 30S TO LOWER 40S. ANOTHER TROUGH LOOKS TO TAKE AIM ON
THE REGION THURSDAY NIGHT INTO FRIDAY BRINGING CHANCES FOR SHOWERS
AND THUNDERSTORM TO THE AREA.
&&
.AVIATION...THROUGH 06Z SUNDAY
1135 PM CDT FRI MAR 23 2012
THE CLOUDS HAVE BEEN SLOWLY DISSIPATING ACROSS SOUTHEAST MINNESOTA
THROUGH THE EVENING. BASED ON IR SATELLITE...KRST IS NOW VERY
CLOSE TO THE EDGE OF THE CLOUDS WITH A VERY SLOW SOUTHWARD DRIFT
OCCURRING. THIS SHOULD ALLOW THE CLOUDS TO BRIEFLY CLEAR LONG
ENOUGH TO ALLOW DENSE FOG AND IFR CEILINGS TO QUICKLY FORM. THE
24.01Z HRRR SUGGESTS THAT DENSE FOG WILL FORM OVER SOUTH CENTRAL
MINNESOTA AND NORTH CENTRAL IOWA JUST TO THE WEST OF KRST. PLENTY
OF LOW LEVEL MOISTURE STILL RESIDES OVER THE AREA ALONG WITH LIGHT
WINDS...SO IF THE CLOUDS CAN CLEAR OUT...WOULD EXPECT THE FOG TO
FORM. KLSE IS DEEPER INTO THE CLOUDS...BUT WITH THE SOUTHWARD
DRIFT...STILL HAS A CHANCE OF CLEARING OUT LATE ALLOWING THE FOG
TO FORM. HAVE CONTINUED THE IFR CONDITIONS FOR BOTH SITES
UNCHANGED FROM THE PREVIOUS FORECAST. EXPECTING THE FOG TO BEGIN
LIFTING BY MID MORNING WITH MVFR CONDITIONS THEN PREVAILING INTO
THE MID TO LATE AFTERNOON BEFORE THE CLOUDS SCATTER OUT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
332 PM CDT FRI MAR 23 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
750 AM EDT SAT MAR 24 2012
.SYNOPSIS...
A SLIGHT CHANCE OF SEVERE THUNDERSTORMS TODAY AS A WARM AND MOIST
AIR MASS BLANKETS THE REGION. A COLD FRONT WILL MOVE THROUGH THE AREA
TONIGHT WITH HIGH PRESSURE SLOWLY BUILDING IN FROM THE NORTHWEST
SUNDAY THROUGH MONDAY. A FRONT WILL DROP THROUGH ON TUESDAY...THEN
ANOTHER COLD FRONT WILL MOVE IN LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
NEARING-DAWN...OVERNIGHT MSAS AND RUC MESOANALYSIS DATA SHOWS
ATMOSPHERIC DESTABILIZATION AS 850 MB THETA-E ADVECTION SURGES
IN FROM SW GEORGIA AND THE FLORIDA PANHANDLE. REGIONAL RADARS
INDICATED SHOWERS WERE BREAKING OUT IN THE AXIS OF LOW LEVEL
MOISTURE TRANSPORT...A FEW WERE ALREADY NOTED ACROSS INLAND SE
GEORGIA. MSAS AND RUC MESOANALYSIS BOTH SHOW THAT THE AIR MASS
HAS DESTABILIZED AND TSTMS WILL BE POSSIBLE ANYTIME AFTER
SUNRISE.
FORECAST TODAY BLENDED BETWEEN PERSISTENCE AND CONSENSUS SYNOPTIC
SCALE TRENDS FROM THE 00Z MODEL RUN. OUR REGION CONTINUES TO BE
HIGHLIGHTED UNDER A SLIGHT RISK FOR SEVERE CONVECTION TODAY AND
ONGOING TRENDS GIVE NO INDICATION TO SWAY FROM THAT THINKING. TO
BEGIN TODAY...OVERNIGHT SATELLITE TRENDS SUGGEST THAT THERE LIKELY
WILL BE AREAS OF INSOLATION ACROSS GEORGIA AND SOUTH CAROLINA
WHICH WILL RAPIDLY ENHANCE DESTABILIZATION. CUTTING THROUGH OUR
INLAND ZONES IS AN IMPRESSIVE DEEP MOISTURE GRADIENT TODAY WITH
PWATS E OF I-95 AT OR SLIGHTLY ABOVE 1.5 INCHES AND INLAND FROM
THERE FALLING WELL BELOW 1 INCH THIS AFTERNOON. CONVECTION IS
EXPECTED TO FLOURISH ALONG AND SE OF THIS GRADIENT FROM LATE
MORNING THROUGH THE AFTERNOON. BY 18Z...THE GEM/GFS/ECMWF ALL SHOW
HAIL CAPES EXCEEDING 600 J/KG OVER S GEORGIA AND ANOTHER MORE
MORE IMPRESSIVE MAXIMA OVER THE EASTERN SOUTH CAROLINA MIDLANDS
EXTENDING INTO OUR INLAND SOUTH CAROLINA ZONES.
THE MID LEVEL ENVIRONMENT WILL REMAIN FAIRLY UNIFORM THROUGH MID
AFTERNOON WITH LATE DAY HEIGHT FALLS NOTED FROM THE ESE MOVEMENT
OF THE DEEP UPPER LOW OVER THE TENNESSEE/KENTUCKY REGION. THE
ENVIRONMENT IS HIGHLIGHTED BY FAIR LAPSE RATES NEAR -6C AND
FAVORABLE HAIL PARAMETERS PROVIDED CONVECTIVE INITIATION IS NOT
TOO FAST TODAY. 0-6KM BULK SHEAR IS FORECAST TO INCREASE STEADILY
TO AROUND 40 KT BY LATE DAY...INCREASING POTENTIAL FOR ENHANCED
ORGANIZATION AND MIXED-MODE CONVECTION.
MODELS SUGGEST THE FIRST ROUND TODAY WILL DEVELOP IN SE GEORGIA
AND DEVELOP OR PROPAGATE ALONG BOUNDARIES NE THROUGH THE COASTAL
HALF OF THE FORECAST AREA THIS AFTERNOON WITH ISOLATED SEVERE
TSTMS POSSIBLE. TSTMS WITH MORE ROBUST HAIL AND WIND POTENTIAL
WILL LIKELY BEGIN TO TAKE SHAPE IN A N-S CONVERGENCE ZONE TO THE
S OF WEAK SURFACE LOW IN UPSTATE SOUTH CAROLINA. THESE STORMS
WILL POSE A LATE DAY THREAT TO OUR INLAND ZONES WITH FAIR
CHANCES FOR CONVECTIVE WATCHES BY MID AFTERNOON FOR PARTS OF
OUR FORECAST AREA.
WE RAISED MAX TEMPS A COUPLE OF DEGREES TODAY IN ADVANCE OF
CONVECTION. DEEPER MIXED LAYER INLAND SUGGEST SW SURFACE WINDS
COULD BECOME A BIT GUSTY AT TIMES THIS AFTERNOON.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
THE NAM SUGGESTS STRONG TO SEVERE CONVECTION WILL SHIFT TOWARD
THE COAST THIS EVENING AS STRONG UPPER HEIGHT FALLS KICK IN AND
OUR REGION COMES UNDER A FAIRLY IMPRESSIVE RIGHT ENTRANCE REGION
IN A 250 MB JET SEGMENT. OTHER MODELS SHIFT DEEPER MOISTURE AND
INSTABILITY OFFSHORE A BIT QUICKER BUT WILL HIGHLIGHT A SEVERE
RISK CONTINUING UNTIL MIDNIGHT IN RESPECT TO THE AIR MASS IN
PLACE TODAY AND THE STRENGTH OF THE SYNOPTIC SCALE SYSTEM.
THE DEEP 500 MB LOW WILL ROTATE THROUGH SOUTHERN SC SUNDAY AFTERNOON
WITH THE CENTER PASSING NEAR OR JUST NORTH OF CHARLESTON AROUND 18Z.
MOST OF THE MODELS PROG 500 MB TEMPS OF -22C AT 18Z SUNDAY WITH A
FREEZING LEVEL BELOW 7500 FT. A FAIRLY DEEP WESTERLY FLOW WILL DRY
THE LOWER ATMOSPHERE AND DOWNSLOPE FLOW WILL RESULT IN SUBSIDENCE.
HOWEVER THERE LOOKS TO BE ENOUGH LOW-LEVEL MOISTURE WRAPPING AROUND
THE SURFACE LOW ALONG THE NC COAST TO SPUR A FEW SHOWERS OR ISOLATED
THUNDERSTORMS DURING THE HOURS OF PEAK HEATING ON SUNDAY...MAINLY
ACROSS SOUTHERN SC. DUE TO SUCH COLD TEMPERATURES ALOFT...SOME SMALL
HAIL CANNOT BE RULED OUT WITH ANY CONVECTIVE ELEMENTS. DESPITE THE
COLD ADVECTION...DOWNSLOPING WILL PUSH HIGH TEMPS INTO THE UPPER
70S.
CLOUDS WILL CLEAR OUT FROM SW TO NE SUNDAY NIGHT AND WEAK COLD
ADVECTION WILL DROP OVERNIGHT LOWS INTO THE LOWER 50S. THE UPPER
LEVEL RIDGE AXIS WILL BUILD TOWARD THE SOUTHEAST UNITED STATES
MONDAY INTO TUESDAY. BUILDING LOW-LEVEL THICKNESSES ON MONDAY WITH
SUNNY SKIES WILL PUSH HIGH TEMPS BACK INTO THE LOWER 80S.
A BACKDOOR COLD FRONT WILL DROP THROUGH LATE MONDAY NIGHT INTO
TUESDAY WITH COOLER AIR FILTERING IN FROM THE NORTH. A RATHER SHARP
TEMPERATURE GRADIENT IS EXPECTED FOR TUESDAY WITH NEAR 80 TO THE FAR
SW AND LOWER 70S OVER THE TRI-COUNTY. ISOLATED SHOWERS CANNOT BE
ENTIRELY RULED OUT ON TUESDAY...ESPECIALLY SOUTHERN SECTIONS WHERE A
WEAK COASTAL TROUGH MAY DEVELOP. BUT DUE TO A RELATIVE LACK OF
MOISTURE WE KEPT DRY CONDITIONS FOR NOW.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
HIGH PRESSURE WILL STRENGTHEN OVER THE WESTERN ATLANTIC TUESDAY
NIGHT THROUGH THURSDAY AS THE UPPER RIDGE HOLDS STRONG TO OUR WEST.
DRY CONDITIONS AND WARM TEMPERATURES EXPECTED WITH HIGHS BUILDS INTO
THE UPPER 70S WEDNESDAY AND LOWER 80S THURSDAY. ANOTHER BACKDOOR
FRONT MAY DROP THROUGH THURSDAY NIGHT OR FRIDAY WITH INCREASING
CLOUDINESS AND COOLER TEMPERATURES. WE HAVE NOT ADDED ANY
PRECIPITATION IN THE EXTENDED DUE TO LIMITED MOISTURE WITH THE LATE
WEEK FRONT.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
CONVECTION TIMING AND INTENSITY VERY TRICKY ALONG THE COASTAL
CORRIDOR TODAY AND EVEN THROUGH THIS EVENING. SHOWERS AND TSTMS
WILL BRUSH THE REGION FROM MID MORNING INTO THIS AFTERNOON.
BRIEF MVFR CIGS/VSBYS POSSIBLE IN DOWNPOURS. THIS EVENING IT
APPEARS THE BEST BET FOR CONVECTIVE RAINS WILL IMPACT THE
CHARLESTON TRI-COUNTY AREA NORTH GIVE INSTABILITY AND LIFT
PROGS. THE COLD FRONT WILL MOVE THROUGH AFTER MIDNIGHT...
A WIND SHIFT TO LIGHT W AND SOME LATE NIGHT CLEARING EXPECTED.
WE MAINTAINED SOME SURFACE WIND GUSTS NEARING 20 KT AT KCHS AND AT
LEAST TEMPO GUSTS AT TIMES AT KSAV AS WELL THIS AFTERNOON.
EXTENDED AVIATION OUTLOOK...BRIEF MVFR VSBY POSSIBLE AT CHS ON
SUNDAY IN ISO/SCT SHOWERS/TSTMS. OTHERWISE VFR.
&&
.MARINE...
NO SIGNIFICANT CHANGES WITH SW FLOW SHIFTING W IN THE WAKE OF
THE COLD FRONT TONIGHT. SPEEDS WILL MAINLY BE 15 KT OR LESS WITH
SOME GUSTS TO 20 KT AT TIMES BEYOND 20 NM OFF THE COAST. SEAS
THROUGH TONIGHT 2-4 NEAR SHORE AND 3 TO 5 FT OVER OUTER GEORGIA
WATERS.
OFFSHORE FLOW BEHIND THE COLD FRONT ON SUNDAY WILL ALLOW SEAS TO
GRADUALLY SUBSIDE. A BRIEF NORTHEAST WIND SURGE WILL DEVELOP TUESDAY
MORNING BEHIND A BACKDOOR COLD FRONT BUT IT SHOULD BE OF SHORT
DURATION AS THE PARENT HIGH SHIFTS QUICKLY OFFSHORE. THE NEXT SURGE
WILL COME WEDNESDAY NIGHT INTO THURSDAY AHEAD OF THE NEXT COLD
FRONT. IN GENERAL WE KEEP WINDS/SEAS BELOW ADVISORY THRESHOLDS
DURING THE MEDIUM RANGE PERIOD.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JRL
NEAR TERM...
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...
MARINE...JRL
AREA FORECAST DISCUSSION
NWS JACKSON KY
1054 AM EDT SAT MAR 24 2012
.UPDATE...
ISSUED AT 1054 AM EDT SAT MAR 24 2012
LULL IN SHOWER AND THUNDERSTORM ACTIVITY THIS MORNING WILL PICK BACK
UP AGAIN THIS AFTERNOON WITH DIURNAL HEATING AND AS UPPER LEVEL LOW
CURRENTLY OVER SOUTHERN IL AND WESTERN KY TRACKS ACROSS THE
COMMONWEALTH THROUGH THE AFTERNOON TIME FRAME. REGIONAL SAT ALSO
SHOWS SOME BREAKS IN THE CLOUD COVER. THIS WILL HELP STEEPEN UP THOSE
BOUNDARY LAYER LAPSE RATES AS MID LEVELS COOL. SO A FEW STRONG
STORMS CAN NOT BE RULED OUT THIS AFTERNOON. UPDATED POPS AND SKY
COVER FOR LATEST TRENDS. TEMPS WERE NOT TOO BAD SO ONLY SOME MINOR
TWEAKS THERE. EXPECT DIURNAL CU FIELD WILL FILL BACK IN BREAKS WITH
TIME. WITH FCST SOUNDINGS SHOWING ONLY MARGINAL INSTABILITY THROUGH
THE OVERNIGHT PERIODS...DID ADJUST WEATHER GRIDS TO INTRODUCE A MORE
DIURNAL FLAVOR TO ANY THUNDERSTORM ACTIVITY.
UPDATE ISSUED AT 745 AM EDT SAT MAR 24 2012
HOURLY POPS WERE UPDATED TO ACCOUNT FOR NEAR CATEGORICAL COVERAGE
ONGOING AND OVER THE NEXT HOUR OR SO IN THE KY/WV AND VA TRI STATE
AREA. OTHERWISE...HELD ONTO SOME SLIGHT CHANCE POPS AS FAR WEST AS A
MIDDLESBORO TO JKL TO ELLIOTT COUNTY LINE OR SO OVER THE NEXT HOUR OR
TWO...BEFORE BLENDING INTO POPS FROM THE PREVIOUS FORECAST THAT
REFLECT AN INCREASE IN COVERAGE OF SHRA AND ISOLATED TO SCATTERED
TSRA AS THE UPPER LEVEL LOW NEARS THE REGION AND THIS COMBINED WITH
SOME SOLAR INSOLATION SHOULD LEAD TO AN INCREASE IN COVERAGE AND
INTENSITY OF CONVECTION DURING THE AFTERNOON.
HOURLY TEMP AND DEW POINT CURVES WERE ALSO FRESHENED UP BASED ON
RECENT OBS. UPDATED GRIDS HAVE BEEN SENT ALONG WITH A FRESHENED UP
ZFP.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 434 AM EDT SAT MAR 24 2012
SURFACE ANALYSIS ACROSS THE AREA AS OF 08Z HAS THE LINE OF SHOWERS
AND THUNDERSTORMS WITH A SURFACE FRONT AND ASSOCIATED 500MB WAVE
ROTATING AROUND A CLOSED CUT OFF LOW MOVING OFF TO THE EAST. LOOKING
AT CURRENT RADAR TRENDS AND OBS...LOOKING LIKE ALL THE INSTABILITY
HAS BEEN TAPPED OUT EAST AS ONLY A FEW CELLS SEEM TO BE LEFT. A FEW
SHOWERS HAVE BEGUN TO DEVELOP BEHIND THE LINE OVER THE SOUTHWEST
COUNTIES SO HAVE LEFT SOME ISOLATED SHOWERS MENTIONED IN THE ZONES
DURING THE MORNING HOURS. THIS IS SUPPORTED BY THE HRRR AND RUC AS
THE UPPER LEVEL SUPPORT WILL BE AVAILABLE ALL DAY TODAY AS THE LOW
WILL SLOWLY MOVE SOUTH AND EAST.
THINKING SHOWERS AND THUNDERSTORMS WILL REDEVELOP AGAIN TODAY WITH
THE HEATING OF THE DAY AS ANOTHER 500MB WAVE ROTATES AROUND THE LOW
AGAIN AND THROUGH EAST KENTUCKY AND AS SUCH...RAMPED UP POPS TO GOOD
CHANCES AND ALSO WENT WITH COVERAGE RATHER THAN PROBABILITY. ALSO THE
RAPID STABILIZATION DURING THE EVENING HOURS LEADS TO FOG DEVELOPING
IN THE VALLEYS AND SO PUT FOG INTO THE ZONES TO ACCOUNT FOR THIS.
BY SUNDAY NIGHT...THE SHORT TERM MODELS SEEM TO BE IN AGREEMENT THAT
THE CLOSED LOW FINALLY DRIFTS OFF TO THE SOUTH AND EAST. SO WILL RAMP
DOWN THE POPS FOR THIS TIME PERIOD. CONCERNING TEMPERATURES...THE
MERIDIONAL PATTERN WITH A TROUGH MOVING THROUGH THE EASTERN US...WILL
KEEP TEMPERATURES NEAR NORMAL FOR THE SHORT TERM PERIOD.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 434 AM EDT SAT MAR 24 2012
A RATHER PROGRESSIVE PATTERN IS EXPECTED DURING THE PERIOD. INITIALLY
ON MONDAY...RECENT GFS AND ECMWF RUNS INDICATE THAT UPPER LEVEL
RIDGING WILL BE BUILDING INTO THE REGION FROM THE PLAINS AND MS
VALLEY WHILE THE SOUTHERN END OF A RIDGE OF SFC HIGH PRESSURE WILL BE
NOSING INTO THE OH VALLEY AND APPALACHIAN REGION. THE UPPER LEVEL
RIDGE IS EXPECTED TO CONTINUE TO BUILD INTO THE REGION ON MON NIGHT
AND INTO TUE....WHILE THE AXIS OF THE SFC HIGH WILL SHIFT ON OFF TO
THE EAST ON TUE. AS THE SFC HIGH SHIFTS EAST OF THE AREA...A WARM
FRONT OR SFC TROUGH IS PROGGED TO SHIFT TO THE EASTERN PORTIONS OF
THE CWA.
AT THE SAME TIME...AN UPPER LEVEL TROUGH AND ASSOCIATED SYSTEM WILL
TRACK FROM THE CENTRAL AND NORTHERN ROCKIES AND INTO THE NORTHERN
PLAINS/WESTERN GREAT LAKES REGION BY TUE EVENING AND NIGHT WITH THIS
UPPER LEVEL SYSTEM THEN TRACKING NEARLY DUE EAST INTO THE
NORTHEASTERN STATES ON WED INTO WED NIGHT. UPPER LEVEL RIDGING IS
THEN EXPECTED TO BUILD BACK INTO THE GREAT LAKES AND OH VALLEY AND
APPALACHIAN REGION AND LIKELY REMAIN DOMINANT THROUGH THE END OF THE
PERIOD. THE GREATEST UNCERTAINTY COMES AT THE END OF THE PERIOD AS
THE GFS TRACKS A COUPLE OF SHORTWAVES EAST A BIT QUICKER AND IS
WEAKER WITH THE LATE WEEK RIDGING. DURING THIS PERIOD OF GREATER
UNCERTAINTY...GENERALLY FOLLOWED A BLEND OF THE MODEL CONSENSUS AND
THE USUALLY RELIABLE ECMWF.
A SFC LOW SHOULD FOLLOW A SIMILAR PATH AS THE UPPER LEVEL SYSTEM
FROM MON TO TUE...REACHING THE GREAT LAKES REGION TUE NIGHT INTO WED
AND THEN TRACKING OFF THE NORTHEASTERN US COAST WED NIGHT INTO THU.
THIS SYSTEM WILL SEND A COLD FRONT INTO THE LOCAL AREA ON WED WITH
THE MODEL CONSENSUS SHIFTING THIS FRONT SOUTH OF THE AREA ON WED
NIGHT. ALTHOUGH I HAVE ALLOWED FOR SOME 10 POPS WHICH ARE PART OF
THE MODEL CONSENSUS ON TUE AFTERNOON AS THE PAST COUPLE OF ECMWF
RUNS DEVELOP SOME CONVECTION OVER THE NORTHEASTERN OR EASTERN PART
OF THE CWA IN THE VICINITY OF THE SFC TROUGH/WARM FRONT FEATURE ON
TUE...THE BEST CHANCE DURING THE PERIOD FOR MEASURABLE PRECIP WILL
COME ON WED INTO WED EVENING.
AS FOR TEMPERATURES...MAX TEMPERATURES SHOULD GENERALLY AVERAGE
SLIGHTLY ABOVE NORMAL EARLY IN THE PERIOD AND AT THE END OF THE
PERIOD TO AS MUCH AS 10 DEGREES OR MORE ABOVE NORMAL ON WED JUST
AHEAD OF THE COLD FRONT. LOW THROUGH THE PERIOD SHOULD GENERALLY BE
IN THE 40S OR EVEN THE 50S...WITH ONE EXCEPTION...MONDAY NIGHT. SFC
HIGH PRESSURE SHOULD ALLOW FOR SOME OF THE NORMALLY COLDER VALLEY
LOCATIONS IN THE FAR NORTH AND EAST TO REACH THE UPPER 30S ON MON
NIGHT. THIS WOULD LEAD TO AT LEAST A SLIGHT CONCERN FOR SOME PATCHY
FROST AT LEAST IF THESE MIN TEMPS WERE TO TREND SLIGHTLY COLDER AS
RECENT WARM WEATHER HAS ALLOWED VEGETATION TO BE RUNNING A COUPLE OF
WEEKS OR SO AHEAD OF AVERAGE. HOWEVER...ATTM...EVEN IT ONE WERE TO
OCCUR IT APPEARS AS IF IT WOULD BE VERY PATCHY TO ISOLATED AND WOULD
OCCUR IN THE COLDEST OF THE NORMALLY COLD SPOTS. THIS POTENTIAL
SCENARIO WILL CONTINUE TO BE MONITORED...HOWEVER CONFIDENCE IN EVEN
ISOLATED TO PATCHY VALLEY FROST IS TOO LOW AT THIS POINT TO INCLUDE
IN THE HWO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 656 AM EDT SAT MAR 24 2012
CURRENT CONDITIONS ACROSS EASTERN KENTUCKY AS OF 11Z HAS SOME SHOWERS
MOVING OFF TO THE EAST. SOME OF THE PRECIP OVERNIGHT HAS MOISTEN THE
BL AND SOME FOG HAS DEVELOPED IN THE VALLEYS. MOST OF THE AREA THOUGH
IS DEALING WITH SOME LOW LEVEL STRATUS AND THIS IS SEEN ON THE RIDGES
AS JKL HAS SOME FOG ON THE RIDGES. THE FOG/STRATUS SHOULD BURN OFF BY
15Z TODAY. WITH ANOTHER WAVE MOVING THROUGH TODAY WITH THE UPPER
LEVEL LOW AND THE HEATING OF THE DAY...EXPECT TO SEE SOME SHOWERS AND
THUNDERSTORMS DEVELOPING AGAIN TODAY. THE RAINFALL AGAIN WILL SET THE
STAGE FOR MORE FOG AND LOW LEVEL STRATUS AGAIN TONIGHT AND HAVE PUT
IFR CONDITIONS AT THE TAF SITES BY 08Z TONIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...RAY
SHORT TERM...SHALLENBERGER
LONG TERM....JP
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
746 AM EDT SAT MAR 24 2012
.UPDATE...
ISSUED AT 745 AM EDT SAT MAR 24 2012
HOURLY POPS WERE UPDATED TO ACCOUNT FOR NEAR CATEGORICAL COVERAGE
ONGOING AND OVER THE NEXT HOUR OR SO IN THE KY/WV AND VA TRI STATE
AREA. OTHERWISE...HELD ONTO SOME SLIGHT CHANCE POPS AS FAR WEST AS A
MIDDLESBORO TO JKL TO ELLIOTT COUNTY LINE OR SO OVER THE NEXT HOUR OR
TWO...BEFORE BLENDING INTO POPS FROM THE PREVIOUS FORECAST THAT
REFLECT AN INCREASE IN COVERAGE OF SHRA AND ISOLATED TO SCATTERED
TSRA AS THE UPPER LEVEL LOW NEARS THE REGION AND THIS COMBINED WITH
SOME SOLAR INSOLATION SHOULD LEAD TO AN INCREASE IN COVERAGE AND
INTENSITY OF CONVECTION DURING THE AFTERNOON.
HOURLY TEMP AND DEWPOINT CURVES WERE ALSO FRESHENED UP BASED ON
RECENT OBS. UPDATED GRIDS HAVE BEEN SENT ALONG WITH A FRESHENED UP
ZFP.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 434 AM EDT SAT MAR 24 2012
SURFACE ANALYSIS ACROSS THE AREA AS OF 08Z HAS THE LINE OF SHOWERS
AND THUNDERSTORMS WITH A SURFACE FRONT AND ASSOCIATED 500MB WAVE
ROTATING AROUND A CLOSED CUT OFF LOW MOVING OFF TO THE EAST. LOOKING
AT CURRENT RADAR TRENDS AND OBS...LOOKING LIKE ALL THE INSTABILITY
HAS BEEN TAPPED OUT EAST AS ONLY A FEW CELLS SEEM TO BE LEFT. A FEW
SHOWERS HAVE BEGUN TO DEVELOP BEHIND THE LINE OVER THE SOUTHWEST
COUNTIES SO HAVE LEFT SOME ISOLATED SHOWERS MENTIONED IN THE ZONES
DURING THE MORNING HOURS. THIS IS SUPPORTED BY THE HRRR AND RUC AS
THE UPPER LEVEL SUPPORT WILL BE AVAILABLE ALL DAY TODAY AS THE LOW
WILL SLOWLY MOVE SOUTH AND EAST.
THINKING SHOWERS AND THUNDERSTORMS WILL REDEVELOP AGAIN TODAY WITH
THE HEATING OF THE DAY AS ANOTHER 500MB WAVE ROTATES AROUND THE LOW
AGAIN AND THROUGH EAST KENTUCKY AND AS SUCH...RAMPED UP POPS TO GOOD
CHANCES AND ALSO WENT WITH COVERAGE RATHER THAN PROBABILITY. ALSO THE
RAPID STABILIZATION DURING THE EVENING HOURS LEADS TO FOG DEVELOPING
IN THE VALLEYS AND SO PUT FOG INTO THE ZONES TO ACCOUNT FOR THIS.
BY SUNDAY NIGHT...THE SHORT TERM MODELS SEEM TO BE IN AGREEMENT THAT
THE CLOSED LOW FINALLY DRIFTS OFF TO THE SOUTH AND EAST. SO WILL RAMP
DOWN THE POPS FOR THIS TIME PERIOD. CONCERNING TEMPERATURES...THE
MERIDIONAL PATTERN WITH A TROUGH MOVING THROUGH THE EASTERN US...WILL
KEEP TEMPERATURES NEAR NORMAL FOR THE SHORT TERM PERIOD.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 434 AM EDT SAT MAR 24 2012
A RATHER PROGRESSIVE PATTERN IS EXPECTED DURING THE PERIOD. INITIALLY
ON MONDAY...RECENT GFS AND ECMWF RUNS INDICATE THAT UPPER LEVEL
RIDGING WILL BE BUILDING INTO THE REGION FROM THE PLAINS AND MS
VALLEY WHILE THE SOUTHERN END OF A RIDGE OF SFC HIGH PRESSURE WILL BE
NOSING INTO THE OH VALLEY AND APPALACHIAN REGION. THE UPPER LEVEL
RIDGE IS EXPECTED TO CONTINUE TO BUILD INTO THE REGION ON MON NIGHT
AND INTO TUE....WHILE THE AXIS OF THE SFC HIGH WILL SHIFT ON OFF TO
THE EAST ON TUE. AS THE SFC HIGH SHIFTS EAST OF THE AREA...A WARM
FRONT OR SFC TROUGH IS PROGGED TO SHIFT TO THE EASTERN PORTIONS OF
THE CWA.
AT THE SAME TIME...AN UPPER LEVEL TROUGH AND ASSOCIATED SYSTEM WILL
TRACK FROM THE CENTRAL AND NORTHERN ROCKIES AND INTO THE NORTHERN
PLAINS/WESTERN GREAT LAKES REGION BY TUE EVENING AND NIGHT WITH THIS
UPPER LEVEL SYSTEM THEN TRACKING NEARLY DUE EAST INTO THE
NORTHEASTERN STATES ON WED INTO WED NIGHT. UPPER LEVEL RIDGING IS
THEN EXPECTED TO BUILD BACK INTO THE GREAT LAKES AND OH VALLEY AND
APPALACHIAN REGION AND LIKELY REMAIN DOMINANT THROUGH THE END OF THE
PERIOD. THE GREATEST UNCERTAINTY COMES AT THE END OF THE PERIOD AS
THE GFS TRACKS A COUPLE OF SHORTWAVES EAST A BIT QUICKER AND IS
WEAKER WITH THE LATE WEEK RIDGING. DURING THIS PERIOD OF GREATER
UNCERTAINTY...GENERALLY FOLLOWED A BLEND OF THE MODEL CONSENSUS AND
THE USUALLY RELIABLE ECMWF.
A SFC LOW SHOULD FOLLOW A SIMILAR PATH AS THE UPPER LEVEL SYSTEM
FROM MON TO TUE...REACHING THE GREAT LAKES REGION TUE NIGHT INTO WED
AND THEN TRACKING OFF THE NORTHEASTERN US COAST WED NIGHT INTO THU.
THIS SYSTEM WILL SEND A COLD FRONT INTO THE LOCAL AREA ON WED WITH
THE MODEL CONSENSUS SHIFTING THIS FRONT SOUTH OF THE AREA ON WED
NIGHT. ALTHOUGH I HAVE ALLOWED FOR SOME 10 POPS WHICH ARE PART OF
THE MODEL CONSENSUS ON TUE AFTERNOON AS THE PAST COUPLE OF ECMWF
RUNS DEVELOP SOME CONVECTION OVER THE NORTHEASTERN OR EASTERN PART
OF THE CWA IN THE VICINITY OF THE SFC TROUGH/WARM FRONT FEATURE ON
TUE...THE BEST CHANCE DURING THE PERIOD FOR MEASURABLE PRECIP WILL
COME ON WED INTO WED EVENING.
AS FOR TEMPERATURES...MAX TEMPERATURES SHOULD GENERALLY AVERAGE
SLIGHTLY ABOVE NORMAL EARLY IN THE PERIOD AND AT THE END OF THE
PERIOD TO AS MUCH AS 10 DEGREES OR MORE ABOVE NORMAL ON WED JUST
AHEAD OF THE COLD FRONT. LOW THROUGH THE PERIOD SHOULD GENERALLY BE
IN THE 40S OR EVEN THE 50S...WITH ONE EXCEPTION...MONDAY NIGHT. SFC
HIGH PRESSURE SHOULD ALLOW FOR SOME OF THE NORMALLY COLDER VALLEY
LOCATIONS IN THE FAR NORTH AND EAST TO REACH THE UPPER 30S ON MON
NIGHT. THIS WOULD LEAD TO AT LEAST A SLIGHT CONCERN FOR SOME PATCHY
FROST AT LEAST IF THESE MIN TEMPS WERE TO TREND SLIGHTLY COLDER AS
RECENT WARM WEATHER HAS ALLOWED VEGETATION TO BE RUNNING A COUPLE OF
WEEKS OR SO AHEAD OF AVERAGE. HOWEVER...ATTM...EVEN IT ONE WERE TO
OCCUR IT APPEARS AS IF IT WOULD BE VERY PATCHY TO ISOLATED AND WOULD
OCCUR IN THE COLDEST OF THE NORMALLY COLD SPOTS. THIS POTENTIAL
SCENARIO WILL CONTINUE TO BE MONITORED...HOWEVER CONFIDENCE IN EVEN
ISOLATED TO PATCHY VALLEY FROST IS TOO LOW AT THIS POINT TO INCLUDE
IN THE HWO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 656 AM EDT SAT MAR 24 2012
CURRENT CONDITIONS ACROSS EASTERN KENTUCKY AS OF 11Z HAS SOME SHOWERS
MOVING OFF TO THE EAST. SOME OF THE PRECIP OVERNIGHT HAS MOISTEN THE
BL AND SOME FOG HAS DEVELOPED IN THE VALLEYS. MOST OF THE AREA THOUGH
IS DEALING WITH SOME LOW LEVEL STRATUS AND THIS IS SEEN ON THE RIDGES
AS JKL HAS SOME FOG ON THE RIDGES. THE FOG/STRATUS SHOULD BURN OFF BY
15Z TODAY. WITH ANOTHER WAVE MOVING THROUGH TODAY WITH THE UPPER
LEVEL LOW AND THE HEATING OF THE DAY...EXPECT TO SEE SOME SHOWERS AND
THUNDERSTORMS DEVELOPING AGAIN TODAY. THE RAINFALL AGAIN WILL SET THE
STAGE FOR MORE FOG AND LOW LEVEL STRATUS AGAIN TONIGHT AND HAVE PUT
IFR CONDITIONS AT THE TAF SITES BY 08Z TONIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...SHALLENBERGER
LONG TERM....JP
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS JACKSON KY
655 AM EDT SAT MAR 24 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 434 AM EDT SAT MAR 24 2012
SURFACE ANALYSIS ACROSS THE AREA AS OF 08Z HAS THE LINE OF SHOWERS
AND THUNDERSTORMS WITH A SURFACE FRONT AND ASSOCIATED 500MB WAVE
ROTATING AROUND A CLOSED CUT OFF LOW MOVING OFF TO THE EAST. LOOKING
AT CURRENT RADAR TRENDS AND OBS...LOOKING LIKE ALL THE INSTABILITY
HAS BEEN TAPPED OUT EAST AS ONLY A FEW CELLS SEEM TO BE LEFT. A FEW
SHOWERS HAVE BEGUN TO DEVELOP BEHIND THE LINE OVER THE SOUTHWEST
COUNTIES SO HAVE LEFT SOME ISOLATED SHOWERS MENTIONED IN THE ZONES
DURING THE MORNING HOURS. THIS IS SUPPORTED BY THE HRRR AND RUC AS
THE UPPER LEVEL SUPPORT WILL BE AVAILABLE ALL DAY TODAY AS THE LOW
WILL SLOWLY MOVE SOUTH AND EAST.
THINKING SHOWERS AND THUNDERSTORMS WILL REDEVELOP AGAIN TODAY WITH
THE HEATING OF THE DAY AS ANOTHER 500MB WAVE ROTATES AROUND THE LOW
AGAIN AND THROUGH EAST KENTUCKY AND AS SUCH...RAMPED UP POPS TO GOOD
CHANCES AND ALSO WENT WITH COVERAGE RATHER THAN PROBABILITY. ALSO THE
RAPID STABILIZATION DURING THE EVENING HOURS LEADS TO FOG DEVELOPING
IN THE VALLEYS AND SO PUT FOG INTO THE ZONES TO ACCOUNT FOR THIS.
BY SUNDAY NIGHT...THE SHORT TERM MODELS SEEM TO BE IN AGREEMENT THAT
THE CLOSED LOW FINALLY DRIFTS OFF TO THE SOUTH AND EAST. SO WILL RAMP
DOWN THE POPS FOR THIS TIME PERIOD. CONCERNING TEMPERATURES...THE
MERIDIONAL PATTERN WITH A TROUGH MOVING THROUGH THE EASTERN US...WILL
KEEP TEMPERATURES NEAR NORMAL FOR THE SHORT TERM PERIOD.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 434 AM EDT SAT MAR 24 2012
A RATHER PROGRESSIVE PATTERN IS EXPECTED DURING THE PERIOD. INITIALLY
ON MONDAY...RECENT GFS AND ECMWF RUNS INDICATE THAT UPPER LEVEL
RIDGING WILL BE BUILDING INTO THE REGION FROM THE PLAINS AND MS
VALLEY WHILE THE SOUTHERN END OF A RIDGE OF SFC HIGH PRESSURE WILL BE
NOSING INTO THE OH VALLEY AND APPALACHIAN REGION. THE UPPER LEVEL
RIDGE IS EXPECTED TO CONTINUE TO BUILD INTO THE REGION ON MON NIGHT
AND INTO TUE....WHILE THE AXIS OF THE SFC HIGH WILL SHIFT ON OFF TO
THE EAST ON TUE. AS THE SFC HIGH SHIFTS EAST OF THE AREA...A WARM
FRONT OR SFC TROUGH IS PROGGED TO SHIFT TO THE EASTERN PORTIONS OF
THE CWA.
AT THE SAME TIME...AN UPPER LEVEL TROUGH AND ASSOCIATED SYSTEM WILL
TRACK FROM THE CENTRAL AND NORTHERN ROCKIES AND INTO THE NORTHERN
PLAINS/WESTERN GREAT LAKES REGION BY TUE EVENING AND NIGHT WITH THIS
UPPER LEVEL SYSTEM THEN TRACKING NEARLY DUE EAST INTO THE
NORTHEASTERN STATES ON WED INTO WED NIGHT. UPPER LEVEL RIDGING IS
THEN EXPECTED TO BUILD BACK INTO THE GREAT LAKES AND OH VALLEY AND
APPALACHIAN REGION AND LIKELY REMAIN DOMINANT THROUGH THE END OF THE
PERIOD. THE GREATEST UNCERTAINTY COMES AT THE END OF THE PERIOD AS
THE GFS TRACKS A COUPLE OF SHORTWAVES EAST A BIT QUICKER AND IS
WEAKER WITH THE LATE WEEK RIDGING. DURING THIS PERIOD OF GREATER
UNCERTAINTY...GENERALLY FOLLOWED A BLEND OF THE MODEL CONSENSUS AND
THE USUALLY RELIABLE ECMWF.
A SFC LOW SHOULD FOLLOW A SIMILAR PATH AS THE UPPER LEVEL SYSTEM
FROM MON TO TUE...REACHING THE GREAT LAKES REGION TUE NIGHT INTO WED
AND THEN TRACKING OFF THE NORTHEASTERN US COAST WED NIGHT INTO THU.
THIS SYSTEM WILL SEND A COLD FRONT INTO THE LOCAL AREA ON WED WITH
THE MODEL CONSENSUS SHIFTING THIS FRONT SOUTH OF THE AREA ON WED
NIGHT. ALTHOUGH I HAVE ALLOWED FOR SOME 10 POPS WHICH ARE PART OF
THE MODEL CONSENSUS ON TUE AFTERNOON AS THE PAST COUPLE OF ECMWF
RUNS DEVELOP SOME CONVECTION OVER THE NORTHEASTERN OR EASTERN PART
OF THE CWA IN THE VICINITY OF THE SFC TROUGH/WARM FRONT FEATURE ON
TUE...THE BEST CHANCE DURING THE PERIOD FOR MEASURABLE PRECIP WILL
COME ON WED INTO WED EVENING.
AS FOR TEMPERATURES...MAX TEMPERATURES SHOULD GENERALLY AVERAGE
SLIGHTLY ABOVE NORMAL EARLY IN THE PERIOD AND AT THE END OF THE
PERIOD TO AS MUCH AS 10 DEGREES OR MORE ABOVE NORMAL ON WED JUST
AHEAD OF THE COLD FRONT. LOW THROUGH THE PERIOD SHOULD GENERALLY BE
IN THE 40S OR EVEN THE 50S...WITH ONE EXCEPTION...MONDAY NIGHT. SFC
HIGH PRESSURE SHOULD ALLOW FOR SOME OF THE NORMALLY COLDER VALLEY
LOCATIONS IN THE FAR NORTH AND EAST TO REACH THE UPPER 30S ON MON
NIGHT. THIS WOULD LEAD TO AT LEAST A SLIGHT CONCERN FOR SOME PATCHY
FROST AT LEAST IF THESE MIN TEMPS WERE TO TREND SLIGHTLY COLDER AS
RECENT WARM WEATHER HAS ALLOWED VEGETATION TO BE RUNNING A COUPLE OF
WEEKS OR SO AHEAD OF AVERAGE. HOWEVER...ATTM...EVEN IT ONE WERE TO
OCCUR IT APPEARS AS IF IT WOULD BE VERY PATCHY TO ISOLATED AND WOULD
OCCUR IN THE COLDEST OF THE NORMALLY COLD SPOTS. THIS POTENTIAL
SCENARIO WILL CONTINUE TO BE MONITORED...HOWEVER CONFIDENCE IN EVEN
ISOLATED TO PATCHY VALLEY FROST IS TOO LOW AT THIS POINT TO INCLUDE
IN THE HWO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 656 AM EDT SAT MAR 24 2012
CURRENT CONDITIONS ACROSS EASTERN KENTUCKY AS OF 11Z HAS SOME SHOWERS
MOVING OFF TO THE EAST. SOME OF THE PRECIP OVERNIGHT HAS MOISTEN THE
BL AND SOME FOG HAS DEVELOPED IN THE VALLEYS. MOST OF THE AREA THOUGH
IS DEALING WITH SOME LOW LEVEL STRATUS AND THIS IS SEEN ON THE RIDGES
AS JKL HAS SOME FOG ON THE RIDGES. THE FOG/STRATUS SHOULD BURN OFF BY
15Z TODAY. WITH ANOTHER WAVE MOVING THROUGH TODAY WITH THE UPPER
LEVEL LOW AND THE HEATING OF THE DAY...EXPECT TO SEE SOME SHOWERS AND
THUNDERSTORMS DEVELOPING AGAIN TODAY. THE RAINFALL AGAIN WILL SET THE
STAGE FOR MORE FOG AND LOW LEVEL STRATUS AGAIN TONIGHT AND HAVE PUT
IFR CONDITIONS AT THE TAF SITES BY 08Z TONIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SHALLENBERGER
LONG TERM....JP
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
719 AM EDT SAT MAR 24 2012
.SYNOPSIS...
LOW PRESSURE WILL PROVIDE SHOWERS INTO SUNDAY AS TEMPERATURES COOL
TO VALUES COMMON FOR MAY. CANADIAN HIGH PRESSURE WILL FOLLOW WITH
DRY SEASONABLE CONDITIONS MONDAY, WHICH MEANS THERE CAN BE A FROST
MONDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS ARE STREAMING INTO SOUTHERN OHIO AS 850 MB LOW MOVES SLOWLY
EAST ACROSS THE OHIO VALLEY. SHOWERS WILL BE LIKELY ACROSS THE FORECAST
AREA TODAY WITH AN INCREASING CHANCE OF THUNDER WITH THE HEATING OF
THE DAY. SPC HAS MENTIONED SEVERE POTENTIAL WILL BE LIMITED AS
SREF MODEL OUTPUT SHOWS WEAK INSTABILITY AND VERTICAL SHEAR.
CONSENSUS OF GFS AND NAM MOS MAINTAIN MAINLY CLOUDY SKIES TODAY,
AND SO THE STRING OF RECORD WARM TEMPERATURES SHOULD END.
PITTSBURGH HAS HAD ELEVEN CONSECUTIVE MARCH DAYS OF 70 PLUS, BUT
MAY STRUGGLE TO REACH 70 TODAY TO RUN THE STRING TO TWELVE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
RECENT SREF MODEL OUTPUT CONTINUES TO SHOW POST-SYSTEM SHOWERS MAY
LINGER ACROSS THE UPPER OHIO VALLEY INTO LATE SUNDAY AS THE LOW
PRESSURE SYSTEM EXITS EAST THROUGH VIRGINIA.
ENSUING CANADIAN HIGH PRESSURE WILL PROVIDE DRYING BY MONDAY. NORTH
WINDS AHEAD OF THE HIGH PRESSURE WILL FUNNEL SEASONABLE COLD
TEMPERATURES INTO THE UPPER OHIO VALLEY.
CLEAR SKIES AND LIGHT WINDS MONDAY NIGHT CAN CAUSE FROST TO DEVELOP
IN MANY AREAS. SUCH A FROST OCCURRENCE IS TYPICAL FOR LATE MARCH,
BUT THIS ONE MAY HAVE HIGH IMPACT ON THE HEELS OF THE RECENT WARM
SPELL THAT HAS SPURRED AN EARLY START TO THE GROWING SEASON. THIS
THREAT HAS BEEN HIGHLIGHTED IN THE HAZARDOUS WEATHER OUTLOOK/HWO/.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
BLEND OF RECENT ECMWF AND NAEFS MODEL OUTPUT SHOW DRY SEASONABLE
CONDITIONS CONTINUING ACROSS THE UPPER OHIO VALLEY TUESDAY AS THE
CANADIAN HIGH PRESSURE EXITS EAST.
A MORE ZONAL UPPER LEVEL JETSTREAM WILL STEER A WYOMING-BRED LOW
PRESSURE SYSTEM EASTBOUND TO BRING SHOWERS WEDNESDAY. HIGH PRESSURE
WILL FOLLOW WITH DRY CONDITIONS THURSDAY AND FRIDAY.
AS MENTIONED, TEMPERATURES WILL BE CLOSER TO NORMAL THIS PERIOD,
ALTHOUGH THERE MAY BE A WARM UP TO 10 DEGREES WARMER THAN NORMAL
WEDNESDAY IF THE LOW PRESSURE SYSTEM MOVES SLOWER THAN CURRENTLY
FORECASTED.
&&
.AVIATION /11Z SATURDAY THROUGH WEDNESDAY/...
AN AREA OF IFR CIGS/VIS IS QUICKLY DEVELOPING ACROSS PORTIONS OF W
PA IN THE MOISTURE LL ATMOSPHERE. WILL KEEP THESE LOW CONDITIONS
THROUGH DAWN. WILL NEED TO WATCH ZZV, AS CIGS AND VIS THERE ARE
ALSO DROPPING. OBS TO THE SOUTH OF ZZV, ARE SHOWING IFR
CONDITIONS, SO WILL INCLUDE TEMPO GROUP FOR NOW.
BLEND OF RECENT SURFACE AND RADAR DATA COUPLED WITH HRRR MODEL
OUTPUT SHOW A BAND OF MVFR SHOWERS WILL PASS NORTHEASTWARD THROUGH
THE UPPER OHIO VALLEY THROUGH 12Z. EVAPORATION OF THE RAIN MAY
MAINTAIN MVFR CONDITIONS INTO 15Z. A SECOND BAND OF SHOWERS, PERHAPS
EMBEDDED WITH SCATTERED THUNDERSTORMS, WILL PASS THROUGH THIS
AFTERNOON, AND PROLONG MVFR RESTRICTIONS.
SPC HAS MENTIONED WEAK SEVERE POTENTIAL WITH THE THUNDERSTORMS. FOR
AVIATION, THE MAIN CONCERN WOULD BE HAIL ALOFT.
POST SYSTEM COOLING MAY MAINTAIN A NEAR SATURATED SURFACE LAYER INTO
TONIGHT AND SUNDAY WHICH COULD RESULT IN LINGERING MVFR RESTRICTIONS.
OUTLOOK...SUNDAY NIGHT THROUGH TUESDAY...
CANADIAN HIGH PRESSURE SHOULD PROVIDE VFR MONDAY INTO TUESDAY. COLD
FRONTAL SHOWERS MAY CAUSE RESTRICTIONS LATE TUESDAY INTO WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
917 AM EDT SAT MAR 24 2012
.SYNOPSIS...
LOW PRESSURE OVER THE OHIO VALLEY WILL MOVE EAST THEN SOUTHEAST
TODAY AND TONIGHT. BY SUNDAY NIGHT THE LOW WILL BE OFF THE CAROLINA
COAST. HIGH PRESSURE WILL BUILD OVER THE REGION MONDAY AND
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
ADJUSTED TEMPERATURES AND POPS ACCORDING TO LATEST OBS AND RADAR
TRENDS. EXPANDED THE MENTION OF GUSTY WINDS AND HAIL FURTHER
NORTH TO MATCH SPC LATEST DAY1 OUTLOOK. HWO WAS UPDATED. PNS
OUT FOR HIGH MIN TEMPERATURES. ALSO ANOTHER PNS COMING OUT FOR
RAINFALL AMOUNTS. THE UPPER LOW IS MOVING EAST WITH COLD POOL
WHICH WILL RESULT IN NUMEROUS SHOWERS AND THUNDERSTORMS THIS
AFTERNOON INTO TONIGHT. LOOK FOR SEVERAL ISC UPDATES TODAY WITH
THE ACTIVE WEATHER EXPECTED.
AS OF 410 AM EDT SATURDAY...
EXPECTING SEVERAL BANDS OF SHOWERS AND THUNDERSTORMS TODAY AND
TONIGHT. FIRST AREA WAS OVER THE CENTRAL AND EASTERN COUNTY
WARNING AREA EARLY THIS MORNING AND WAS MOVING NORTHEAST AROUND 20
MPH. THE NEXT BAND EXTENDS FROM OHIO INTO EASTERN TENNESSEE. LOCAL
WRF AND HRRR BRING THIS BAND INTO THE WESTERN COUNTY WARNING AREA
BY 8AM.
AS THE UPPER LOW MOVES EAST THIS MOVING SO WILL THE SHOWERS AND
THUNDERSTORMS. ADDITIONAL SHOWERS AND THUNDERSTORMS WILL DEVELOP
OVER THE FORECAST AREA THIS AFTERNOON. COLDER AIR ALOFT
ASSOCIATED WITH THE UPPER LOW WILL REACH THE FORECAST AREA
TODAY...CREATING LARGE LAPSE RATES AND LOWERING THE FREEZING
LEVEL. GUSTY WINDS AND LARGE HAIL WILL BE A THREAT WITH ANY
STRONGER STORMS...ESPECIALLY THIS AFTERNOON AND EVENING.
THE UPPER LOW MOVES SOUTHEAST INTO SOUTH CAROLINA BY SUNDAY
MORNING. EXPECT COVERAGE AND PROBABILITY OF PRECIPITATION TO
DECREASE LATE TONIGHT.
THERE WAS A BREAK IN THE CLOUD COVER AHEAD OF THE SHOWERS AND
THUNDERSTORMS APPROACHING FROM THE WEST. FOG MAY DEVELOP EARLY
THIS MORNING AS THE CLOUDS BRIEFLY CLEAR. WITH ALL THE
PRECIPITATION EXPECTED TODAY...HAVE GONE ON THE COOL SIDE OF
GUIDANCE. STAYED CLOSE TO A BLEND OF BIAS CORRECTED MAV/MET
GUIDANCE FOR LOWS TONIGHT.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 330 AM EST SATURDAY...
SUNDAY MORNING WILL START OUT WITH THE UPPER LEVEL LOW PASSING JUST
TO THE SOUTH OF OUR AREA...POSSIBLY CLIPPING OUR NORTH CAROLINA
COUNTIES. IN ANY EVENT...EXPECT TO SEE GREATER COVERAGE OF SHOWER
ACTIVITY NORTH OF INTERSTATE 81...AS A SLOT OF DRIER AIR WORKS ITS
WAY IN SOUTH CLOSER TO THE LOW. COVERAGE WILL INCREASE FURTHER
DURING THE AFTERNOON AS DAYTIME HEATING HELPS DESTABILIZE THE
ATMOSPHERE...AND WILL NOT BE SURPRISED TO SEE A FEW THUNDERSTORMS
DEVELOP BY LATE MORNING. WITH THE UPPER LOW PASSING SO CLOSE TO OUR
AREA...BELIEVE THAT HAIL WILL BE A CONCERN IN THE STRONGER SHOWER
AND THUNDERSTORM ACTIVITY...BUT EXPECT MOST HAIL TO BE IN THE PEA TO
DIME SIZE RANGE WHERE IT OCCURS. SHOWER AND THUNDERSTORM ACTIVITY
WILL DECREASE FROM WEST TO EAST BY LATE AFTERNOON AS THE UPPER LOW
CONTINUES TO PUSH OFF THE ATLANTIC COAST...AND SHOWER ACTIVITY IS
EXPECTED TO BE CONFINED TO THE MOUNTAINS...MAINLY IN SOUTHEAST WEST
VIRGINIA BY LATE SUNDAY EVENING. DESPITE THE PASSAGE OF THE UPPER
LOW...SUNDAY NIGHT TEMPERATURES WILL REMAIN MILD ACROSS OUR
AREA...WITH OVERNIGHT LOWS RANGING FROM THE LOW TO MID 50S EAST...TO
THE UPPER 40S WEST.
IT WILL BE MONDAY MORNING WHEN WE SEE A CHANGE IN OUR WEATHER
PATTERN AS ANOTHER COLD FRONT BRINGS A SHOT OF COOLER CANADIAN AIR
INTO OUR AREA. MONDAY AFTERNOON TEMPERATURES ARE EXPECTED TO REMAIN
MILD ACROSS OUR AREA...ALBEIT A LITTLE COOLER...HOWEVER IT WILL BE
MONDAY NIGHT/TUESDAY MORNING TEMPERATURES THAT WILL BE OF CONCERN AS
LOWS FALL INTO THE 30S ACROSS THE MOUNTAINS. BELIEVE THAT NEAR
FREEZING TEMPERATURES WILL BE CONFINED TO GREENBRIER COUNTY IN
SOUTHEAST WEST VIRGINIA...AS WELL AS THE ALLEGHANY HIGHLANDS IN
VIRGINIA...LOCATIONS THAT HAVE NOT EXPERIENCED A START TO THE
GROWING SEASON TO THE SAME EXTENT THAT HAS OCCURRED IN LOWER
ELEVATIONS. THAT STATED...IT WOULD BE A GOOD IDEA TO CONSIDER
PRECAUTIONS AGAINST THE COLD FOR ANY SENSITIVE VEGETATION WHICH HAS
STARTED TO GROW IN YOUR AREA.
HIGH PRESSURE WILL SLIDE EAST ON TUESDAY AFTERNOON...ALLOWING WINDS
TO BECOME SOUTHERLY ACROSS OUR AREA. WITH A RIDGE OF UPPER LEVEL
HIGH PRESSURE BUILDING IN FROM THE WEST LATE TUESDAY EVENING...
OVERNIGHT TEMPERATURES WILL BE CONSIDERABLY WARMER...WITH LOWS
EXPECTED TO RANGE FROM THE MID 40S IN THE WEST...TO THE UPPER 30S IN
THE EAST.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 330 AM EDT SATURDAY...
ON WEDNESDAY...A HIGH PRESSURE RIDGE WILL SLIDE EAST OFF THE COAST.
SOUTHERLY FLOW RETURNS WITH MODERATING TEMPERATURES FOR THE
REMAINDER OF THE WORK WEEK. LIGHT RAIN SHOWERS ARE POSSIBLE
WEDNESDAY INTO THURSDAY AS A WEAK COOL FRONT PASSES OVER THE REGION.
THIS RAIN WILL NOT BE ANY WHERE CLOSE IN INTENSITY TO THIS WEEKENDS
RAIN EVENT.
&&
.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
AS OF 230 AM EDT SATURDAY...
EXPECT SEVERAL PERIODS OF SHOWERS AND THUNDERSTORMS ACROSS
THE FORECAST AREA THROUGH 06Z SUNDAY. CEILINGS AND VISIBILITIES
WILL LOWER TO MVFR IN ASSOCIATION WITH THE SHOWERS AND STORMS.
SOME OF THE STRONGER STORMS TODAY MAY PRODUCE GUSTY WINDS AND
LARGE HAIL...MAINLY THIS AFTERNOON.
COVERAGE OF PRECIPITATION WILL DIMINISH TONIGHT. LOW CLOUDS AND
FOG WILL FILL IN OVERNIGHT WITH CEILINGS LOWERING TO IFR/MVFR
LEVELS. HAVE LOWERED VISIBILITY TO LIFR AT LYH WITH MEDIUM
CONFIDENCE. IF NORTHWEST SURFACE AND LOW LEVEL WINDS ARE A LITTLE
STRONGER THAN EXPECTED THEN PROBABILITY OF LIFR OR IFR FOG WILL BE
LOWER.
SHRA WILL DEVELOP AGAIN ACROSS THE AREA SUN...BUT WITH
CONSIDERABLE LESS INSTABILITY INDICATED AND A COLDER/MORE STABLE
SFC ENVIRONMENT...DO NOT ANTICIPATE MUCH TSRA ACTIVITY SUN...JUST
SHOWERS.
DRIER WEATHER AND VFR CONDITIONS ARE EXPECTED BEHIND THIS WEATHER
SYSTEM SUNDAY NIGHT THROUGH TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...NF
LONG TERM...RCS
AVIATION...AMS/KK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
742 AM EDT SAT MAR 24 2012
.SYNOPSIS...
LOW PRESSURE OVER THE OHIO VALLEY WILL MOVE EAST THEN SOUTHEAST
TODAY AND TONIGHT. BY SUNDAY NIGHT THE LOW WILL BE OFF THE CAROLINA
COAST. HIGH PRESSURE WILL BUILD OVER THE REGION MONDAY AND
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 410 AM EDT SATURDAY...
EXPECTING SEVERAL BANDS OF SHOWERS AND THUNDERSTORMS TODAY AND
TONIGHT. FIRST AREA WAS OVER THE CENTRAL AND EASTERN COUNTY
WARNING AREA EARLY THIS MORNING AND WAS MOVING NORTHEAST AROUND 20
MPH. THE NEXT BAND EXTENDS FROM OHIO INTO EASTERN TENNESSEE. LOCAL
WRF AND HRRR BRING THIS BAND INTO THE WESTERN COUNTY WARNING AREA
BY 8AM.
AS THE UPPER LOW MOVES EAST THIS MOVING SO WILL THE SHOWERS AND
THUNDERSTORMS. ADDITIONAL SHOWERS AND THUNDERSTORMS WILL DEVELOP
OVER THE FORECAST AREA THIS AFTERNOON. COLDER AIR ALOFT
ASSOCIATED WITH THE UPPER LOW WILL REACH THE FORECAST AREA
TODAY...CREATING LARGE LAPSE RATES AND LOWERING THE FREEZING
LEVEL. GUSTY WINDS AND LARGE HAIL WILL BE A THREAT WITH ANY
STRONGER STORMS...ESPECIALLY THIS AFTERNOON AND EVENING.
THE UPPER LOW MOVES SOUTHEAST INTO SOUTH CAROLINA BY SUNDAY
MORNING. EXPECT COVERAGE AND PROBABILITY OF PRECIPITATION TO
DECREASE LATE TONIGHT.
THERE WAS A BREAK IN THE CLOUD COVER AHEAD OF THE SHOWERS AND
THUNDERSTORMS APPROACHING FROM THE WEST. FOG MAY DEVELOP EARLY
THIS MORNING AS THE CLOUDS BRIEFLY CLEAR. WITH ALL THE
PRECIPITATION EXPECTED TODAY...HAVE GONE ON THE COOL SIDE OF
GUIDANCE. STAYED CLOSE TO A BLEND OF BIAS CORRECTED MAV/MET
GUIDANCE FOR LOWS TONIGHT.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 330 AM EST SATURDAY...
SUNDAY MORNING WILL START OUT WITH THE UPPER LEVEL LOW PASSING JUST
TO THE SOUTH OF OUR AREA...POSSIBLY CLIPPING OUR NORTH CAROLINA
COUNTIES. IN ANY EVENT...EXPECT TO SEE GREATER COVERAGE OF SHOWER
ACTIVITY NORTH OF INTERSTATE 81...AS A SLOT OF DRIER AIR WORKS ITS
WAY IN SOUTH CLOSER TO THE LOW. COVERAGE WILL INCREASE FURTHER
DURING THE AFTERNOON AS DAYTIME HEATING HELPS DESTABILIZE THE
ATMOSPHERE...AND WILL NOT BE SURPRISED TO SEE A FEW THUNDERSTORMS
DEVELOP BY LATE MORNING. WITH THE UPPER LOW PASSING SO CLOSE TO OUR
AREA...BELIEVE THAT HAIL WILL BE A CONCERN IN THE STRONGER SHOWER
AND THUNDERSTORM ACTIVITY...BUT EXPECT MOST HAIL TO BE IN THE PEA TO
DIME SIZE RANGE WHERE IT OCCURS. SHOWER AND THUNDERSTORM ACTIVITY
WILL DECREASE FROM WEST TO EAST BY LATE AFTERNOON AS THE UPPER LOW
CONTINUES TO PUSH OFF THE ATLANTIC COAST...AND SHOWER ACTIVITY IS
EXPECTED TO BE CONFINED TO THE MOUNTAINS...MAINLY IN SOUTHEAST WEST
VIRGINIA BY LATE SUNDAY EVENING. DESPITE THE PASSAGE OF THE UPPER
LOW...SUNDAY NIGHT TEMPERATURES WILL REMAIN MILD ACROSS OUR
AREA...WITH OVERNIGHT LOWS RANGING FROM THE LOW TO MID 50S EAST...TO
THE UPPER 40S WEST.
IT WILL BE MONDAY MORNING WHEN WE SEE A CHANGE IN OUR WEATHER
PATTERN AS ANOTHER COLD FRONT BRINGS A SHOT OF COOLER CANADIAN AIR
INTO OUR AREA. MONDAY AFTERNOON TEMPERATURES ARE EXPECTED TO REMAIN
MILD ACROSS OUR AREA...ALBEIT A LITTLE COOLER...HOWEVER IT WILL BE
MONDAY NIGHT/TUESDAY MORNING TEMPERATURES THAT WILL BE OF CONCERN AS
LOWS FALL INTO THE 30S ACROSS THE MOUNTAINS. BELIEVE THAT NEAR
FREEZING TEMPERATURES WILL BE CONFINED TO GREENBRIER COUNTY IN
SOUTHEAST WEST VIRGINIA...AS WELL AS THE ALLEGHANY HIGHLANDS IN
VIRGINIA...LOCATIONS THAT HAVE NOT EXPERIENCED A START TO THE
GROWING SEASON TO THE SAME EXTENT THAT HAS OCCURRED IN LOWER
ELEVATIONS. THAT STATED...IT WOULD BE A GOOD IDEA TO CONSIDER
PRECAUTIONS AGAINST THE COLD FOR ANY SENSITIVE VEGETATION WHICH HAS
STARTED TO GROW IN YOUR AREA.
HIGH PRESSURE WILL SLIDE EAST ON TUESDAY AFTERNOON...ALLOWING WINDS
TO BECOME SOUTHERLY ACROSS OUR AREA. WITH A RIDGE OF UPPER LEVEL
HIGH PRESSURE BUILDING IN FROM THE WEST LATE TUESDAY EVENING...
OVERNIGHT TEMPERATURES WILL BE CONSIDERABLY WARMER...WITH LOWS
EXPECTED TO RANGE FROM THE MID 40S IN THE WEST...TO THE UPPER 30S IN
THE EAST.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 330 AM EDT SATURDAY...
ON WEDNESDAY...A HIGH PRESSURE RIDGE WILL SLIDE EAST OFF THE COAST.
SOUTHERLY FLOW RETURNS WITH MODERATING TEMPERATURES FOR THE
REMAINDER OF THE WORK WEEK. LIGHT RAIN SHOWERS ARE POSSIBLE
WEDNESDAY INTO THURSDAY AS A WEAK COOL FRONT PASSES OVER THE REGION.
THIS RAIN WILL NOT BE ANY WHERE CLOSE IN INTENSITY TO THIS WEEKENDS
RAIN EVENT.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 230 AM EDT SATURDAY...
EXPECT SEVERAL PERIODS OF SHOWERS AND THUNDERSTORMS ACROSS
THE FORECAST AREA THROUGH 06Z SUNDAY. CEILINGS AND VISIBILITIES
WILL LOWER TO MVFR IN ASSOCIATION WITH THE SHOWERS AND STORMS.
SOME OF THE STRONGER STORMS TODAY MAY PRODUCE GUSTY WINDS AND
LARGE HAIL...MAINLY THIS AFTERNOON.
COVERAGE OF PRECIPITATION WILL DIMINISH TONIGHT. LOW CLOUDS AND
FOG WILL FILL IN OVERNIGHT WITH CEILINGS LOWERING TO IFR/MVFR
LEVELS. HAVE LOWERED VISIBILITY TO LIFR AT LYH WITH MEDIUM
CONFIDENCE. IF NORTHWEST SURFACE AND LOW LEVEL WINDS ARE A LITTLE
STRONGER THAN EXPECTED THEN PROBABILITY OF LIFR OR IFR FOG WILL BE
LOWER.
SHRA WILL DEVELOP AGAIN ACROSS THE AREA SUN...BUT WITH
CONSIDERABLE LESS INSTABILITY INDICATED AND A COLDER/MORE STABLE
SFC ENVIRONMENT...DO NOT ANTICIPATE MUCH TSRA ACTIVITY SUN...JUST
SHOWERS.
DRIER WEATHER AND VFR CONDITIONS ARE EXPECTED BEHIND THIS WEATHER
SYSTEM SUNDAY NIGHT THROUGH TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...NF
LONG TERM...RCS
AVIATION...AMS/KK
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
1040 AM PDT SAT MAR 24 2012
...UPDATED AVIATION DISCUSSION...
.SYNOPSIS...
A COLD LOW WILL MOVE SOUTH OVER THE REGION TONIGHT THROUGH SUNDAY
NIGHT AND FURTHER COOL TEMPERATURES. PRECIPITATION WILL BEGIN IN
SAN LUIS OBISPO AND SANTA BARBARA COUNTIES BY TONIGHT. ON
SUNDAY...RAIN...HEAVY AT TIMES...WITH A SLIGHT CHANCE OF
THUNDERSTORMS WILL AFFECT THE ENTIRE AREA. THE LOW WILL MOVE EAST ON
MONDAY FOR FAIR WEATHER. ANOTHER LOW WILL APPROACH BY MIDWEEK FOR
POSSIBLE PRECIPITATION IN SAN LUIS OBISPO AND SANTA BARBARA
COUNTIES. THE TEMPERATURES WILL BE BACK TO SEASONAL NORMALS ON
THURSDAY.
&&
.SHORT TERM (TODAY-MON)...HAVE ISSUED AN UPDATE THIS MORNING TO
INCLUDE A SLIGHT CHANCE OF LIGHT RAIN ALONG THE NORTHERN HALF OF THE
CENTRAL COAST AND ADJUSTED POPS UP IN THE EVENING OVER THE ENTIRE
AREA. COMPLEX LOW OVER THE EASTERN PACIFIC AND TROUGH AXIS WAS
INITIALIZED APPROXIMATELY 400 MILES WEST OF NORTHERN CALIFORNIA THIS
MORNING. AND PICTURES FROM SPACE HAD INDICATED 180 MILE WIDE CLOUD
BAND WITHIN THE FRONTAL BOUNDARY WITH THE LEADING EDGE OVER THE
MONTEREY/SAN LUIS OBISPO COUNTY BORDER. LATEST RUC INDICATED
DECREASING MID LEVEL STABILITY AND INCREASING UPPER LEVEL
DEFORMATION AND MID LEVEL ASCENDING FLOW OVER THE CENTRAL COAST THIS
AFTERNOON AND THERE IS A SLIGHT CHANCE LIGHT RAIN WILL BEGIN IN THE
AFTERNOON. THE AREA OF INSTABILITY AND DEFORMATION WILL NUDGE
SOUTHEAST AND RAIN WILL LIKELY BEGIN AS FAR SOUTH AS THE WESTERN
HALF OF VENTURA COUNTY LATE IN THE EVENING.
THE FOLLOWING IS AN EXCERPT FROM THE PREVIOUS DISCUSSION
CLOSER TO HOME...A 2100 FOOT MARINE LAYER HAS ALLOWED LOW CLOUDS TO
FORM. THE CLOUDS HAVE BEEN EXPANDING OVERNIGHT AND NOW COVER MOST OF
THE COAST SOUTH OF POINT CONCEPTION AND WILL LIKELY COVER THE L.A.
VLYS BY DAWN. SOME LOW CLOUDS ARE FORMING NORTH OF POINT CONCEPTION
DUE TO SOME WEAK LIFT PROVIDED BY A LITTLE ATMOSPHERIC RIPPLE MOVING
ACROSS THE AREA.
THE LOW CLOUDS WILL SLOWLY BURN OFF THIS MORNING AND BY AFTERNOON
THEY SHOULD BE MOSTLY GONE BUT SKIES WILL THEN BE PARTLY CLOUDY AS
CLOUDS AHEAD OF SUNDAYS STORM STREAM IN. THERE IS A CHANCE THAT SOME
LIGHT RAIN WILL ARRIVE NORTH OF MORRO BAY LATER THIS AFTERNOON BUT
MORE LIKELY THAN NOT THE RAIN WILL HOLD OFF UNTIL THIS EVENING.
TEMPS WILL BE SIMILAR TO FRIDAYS...IN THE MID TO UPPER 60S ACROSS
MOST NON MOUNTAIN AREAS.
SUNDAY WILL BE WET. RAIN WILL OVERSPREAD THE AREA DURING THE
MORNING. RAINFALL WILL BE HEAVY AT TIMES (EARLY IN THE MORNING SLO
AND SBA COUNTIES...MID MORNING TO EARLY AFTERNOON VTA COUNTY...AND
DURING THE AFTERNOON L.A. COUNTY) RAIN WILL TURN TO SHOWERS BEHIND
THE FRONT STARTING OVER SLO COUNTY LATE IN THE MORNING ACROSS SLO
COUNTY WORKING ITS WAY DOWN TO L.A. COUNTY BY LATE AFTERNOON.
GOOD JET DYNAMICS...MID LEVEL POSITIVE VORTICITY ADVECTION...AND
FALLING 500 MB TEMPS WILL COMBINE TO PRODUCE A SLIGHT CHC OF TSTMS
ACROSS THE AREA. THERE IS A GENEROUS AMOUNT OF HELICITY WITH THIS
SYSTEM AND THERE WILL MORE THAN LIKELY BE A NUMBER OF WATERSPOUTS
DURING THE AFTERNOON. THE NAM HAS THE COLD CORE OF THE LOW MOVING
DIRECTLY OVER SBA COUNTY LATE IN THE AFTERNOON AND THIS IF CORRECT
COULD BE THE BEST CHC FOR TSTMS.
SNOW LEVELS WILL START OFF BETWEEN 6500 AND 7500 FEET THIS EVENING
WILL THEN FALL TO BETWEEN 5000 AND 5500 FEET BY EARLY SUNDAY
MORNING. THE SNOW LEVEL WILL LOWER LOCALLY TO 4500 FEET BY SUNDAY
NIGHT.
EXPECTED RAINFALL AMOUNTS RANGE FROM .75 TO 1.5 INCHES FOR COAST AND
VALLEYS...WHILE FOOTHILL AND MOUNTAIN AREAS SHOULD SEE 2-4 INCHES.
SNOW ACCUMULATIONS BETWEEN 8 AND 14 INCHES ARE LIKELY ABOVE 5500
FEET...WITH LOCAL AMOUNTS UP TO 16 INCHES IN FAVORABLE LOCATIONS
ABOVE 7000 FEET. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THE VTA
AND LA MTNS WITH THE VTA WARNING STARTING LATE TONIGHT AND THE LA
WARNING STARTING MID MORNING SUNDAY.
THE 06Z NAM THROWS A FLY INTO THE OINTMENT. IT DEVELOPS A BROAD
EASTERLY FLOW ACROSS THE AREA. THIS DRYING OFFSHORE FLOW WILL...IF
TRUE...WILL SEVERELY LIMIT THE RAINFALL. THIS IS THE OUTLIER
FORECAST BUT IT HAS HAPPENED BEFORE AND NEEDS TO WATCHED.
THIS STORM WILL NOT BE A COLD NOR A WINDY AS LAST WEEKS. HIGHS WILL
BE IN THE UPPER 50S FOR MOST AREAS AS OPPOSED TO LOW 50S LAST WEEK.
WIND ADVISORIES MAY BE NEEDED FOR THE MTNS OF SLO AND SBA COUNTY BUT
THE LOWER ELEVATIONS SHOULD ONLY SEE NON ADVISORY WINDS 15 TO 25 MPH.
THE STORM WILL MOVE OUT LATE SUNDAY NIGHT AND WHILE THERE WILL BE A
CHANCE OF SOME MORNING SHOWERS MONDAY MORNING ACROSS L.A. COUNTY THE
DAY WILL MOSTLY BE DRY AND COOL.
.LONG TERM (TUE-FRI)...
UN-EXCITING WEATHER RETURNS FOR THE EXTENDED PERIOD. FLAT SOUTHWEST
FLOW WILL BRING PARTLY CLOUDY SKIES TO THE AREA TUESDAY TEMPS WILL
RISE A DEGREE OR TWO BUT WILL REMAIN BELOW NORMAL.
THE TAIL END OF A WEAK COLD FRONT WILL MOVE OVER THE CENTRAL COAST
WEDNESDAY. IT WILL BE GOOD FOR A CHANCE OF RAIN. IT WILL BRING
CLOUDS TO THE ENTIRE AREA AND A DEGREE OR SO OF COOLING. RAINFALL IF
ANY WILL BE UNDER A QUARTER INCH.
SOUTHWEST FLOW AND RISING HGTS WILL MAKE THURSDAY THE NICEST OF THE
NEXT 7 WITH NEAR NORMAL TEMPS AND MOSTLY CLEAT SKIES.
THE FLOW TURNS WESTERLY FRIDAY AS A GULF OF ALASKA STORM MOVES
SLIGHTLY SOUTHWARD. SKIES WILL TURN PARTLY CLOUDY AND MAX TEMPS WILL
DROP A COUPLE OF DEGREES.
&&
.AVIATION...24/1740Z...
MVFR CIGS GRADUALLY DISSIPATING SOUTH OF POINT CONCEPTION THIS
MORNING...WITH VFR CONDS EXPECTED THIS AFTERNOON AND EVENING. NORTH
OF POINT CONCEPTION...SKIES ARE CURRENTLY CLEAR...BUT CLOUDS WILL BE
ON THE INCREASE THIS AFTERNOON AS FRONT APPROACHES.
OVERNIGHT AND SUNDAY MORNING...COLD FRONT WILL BEGIN TO MOVE ACROSS
THE AREA...BRINGING MVFR/IFR CONDS TO ALL TAF SITES WITH MODERATE
RAINFALL. CONFIDENCE IN TIMING OF STEADY RAINFALL IS LOW WITH THE
18Z TAF PACKAGE.
KLAX...MODERATE CONFIDENCE IN 18Z TAF. HIGH CONFIDENCE IN VFR CONDS
THIS AFTERNOON AND EVENING. LOW CONFIDENCE IN TIMING OF THE ARRIVAL
OF MVFR DECK AND ASSOCIATED RAINFALL TONIGHT.
KBUR...MODERATE CONFIDENCE IN 18Z TAF. HIGH CONFIDENCE IN VFR CONDS
THIS AFTERNOON AND EVENING. LOW CONFIDENCE IN TIMING OF THE ARRIVAL
OF MVFR DECK AND ASSOCIATED RAINFALL TONIGHT.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING (SEE LAXWSWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
SPECIAL WEATHER STATEMENT (SEE LAXSPSLOX).
&&
$$
PUBLIC...RORKE
AVIATION...RAT
SYNOPSIS...B
WWW.WEATHER.GOV/LOSANGELES
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
945 AM PDT SAT MAR 24 2012
.SYNOPSIS...
A COLD LOW WILL MOVE SOUTH OVER THE REGION TONIGHT THROUGH SUNDAY
NIGHT AND FURTHER COOL TEMPERATURES. PRECIPITATION WILL BEGIN IN
SAN LUIS OBISPO AND SANTA BARBARA COUNTIES BY TONIGHT. ON
SUNDAY...RAIN...HEAVY AT TIMES...WITH A SLIGHT CHANCE OF
THUNDERSTORMS WILL AFFECT THE ENTIRE AREA. THE LOW WILL MOVE EAST ON
MONDAY FOR FAIR WEATHER. ANOTHER LOW WILL APPROACH BY MIDWEEK FOR
POSSIBLE PRECIPITATION IN SAN LUIS OBISPO AND SANTA BARBARA
COUNTIES. THE TEMPERATURES WILL BE BACK TO SEASONAL NORMALS ON
THURSDAY.
&&
.SHORT TERM (TODAY-MON)...HAVE ISSUED AN UPDATE THIS MORNING TO
INCLUDE A SLIGHT CHANCE OF LIGHT RAIN ALONG THE NORTHERN HALF OF THE
CENTRAL COAST AND ADJUSTED POPS UP IN THE EVENING OVER THE ENTIRE
AREA. COMPLEX LOW OVER THE EASTERN PACIFIC AND TROUGH AXIS WAS
INITIALIZED APPROXIMATELY 400 MILES WEST OF NORTHERN CALIFORNIA THIS
MORNING. AND PICTURES FROM SPACE HAD INDICATED 180 MILE WIDE CLOUD
BAND WITHIN THE FRONTAL BOUNDAY WITH THE LEADING EDGE OVER THE
MONTEREY/SAN LUIS OBISPO COUNTY BORDER. LATEST RUC INDICATED
DECREASING MID LEVEL STABILITY AND INCREASING UPPER LEVEL
DEFORMATION AND MID LEVEL ASCENDING FLOW OVER THE CENTRAL COAST THIS
AFTERNOON AND THERE IS A SLIGHT CHANCE LIGHT RAIN WILL BEGIN IN THE
AFTEROON. THE AREA OF INSTABILITY AND DEFORMATION WILL NUDGE
SOUTHEAST AND RAIN WILL LIKELY BEGIN AS FAR SOUTH AS THE WESTERN
HALF OF VENTURA COUNTY LATE IN THE EVENING.
THE FOLLOWING IS AN EXCERPT FROM THE PREVIOUS DISCUSSION
CLOSER TO HOME...A 2100 FOOT MARINE LAYER HAS ALLOWED LOW CLOUDS TO
FORM. THE CLOUDS HAVE BEEN EXPANDING OVERNIGHT AND NOW COVER MOST OF
THE COAST SOUTH OF POINT CONCEPTION AND WILL LIKELY COVER THE L.A.
VLYS BY DAWN. SOME LOW CLOUDS ARE FORMING NORTH OF POINT CONCEPTION
DUE TO SOME WEAK LIFT PROVIDED BY A LITTLE ATMOSPHERIC RIPPLE MOVING
ACROSS THE AREA.
THE LOW CLOUDS WILL SLOWLY BURN OFF THIS MORNING AND BY AFTERNOON
THEY SHOULD BE MOSTLY GONE BUT SKIES WILL THEN BE PARTLY CLOUDY AS
CLOUDS AHEAD OF SUNDAYS STORM STREAM IN. THERE IS A CHANCE THAT SOME
LIGHT RAIN WILL ARRIVE NORTH OF MORRO BAY LATER THIS AFTERNOON BUT
MORE LIKELY THAN NOT THE RAIN WILL HOLD OFF UNTIL THIS EVENING.
TEMPS WILL BE SIMILAR TO FRIDAYS...IN THE MID TO UPPER 60S ACROSS
MOST NON MOUNTAIN AREAS.
SUNDAY WILL BE WET. RAIN WILL OVERSPREAD THE AREA DURING THE
MORNING. RAINFALL WILL BE HEAVY AT TIMES (EARLY IN THE MORNING SLO
AND SBA COUNTIES...MID MORNING TO EARLY AFTERNOON VTA COUNTY...AND
DURING THE AFTERNOON L.A. COUNTY) RAIN WILL TURN TO SHOWERS BEHIND
THE FRONT STARTING OVER SLO COUNTY LATE IN THE MORNING ACROSS SLO
COUNTY WORKING ITS WAY DOWN TO L.A. COUNTY BY LATE AFTERNOON.
GOOD JET DYNAMICS...MID LEVEL POSITIVE VORTICITY ADVECTION...AND
FALLING 500 MB TEMPS WILL COMBINE TO PRODUCE A SLIGHT CHC OF TSTMS
ACROSS THE AREA. THERE IS A GENEROUS AMOUNT OF HELICITY WITH THIS
SYSTEM AND THERE WILL MORE THAN LIKELY BE A NUMBER OF WATERSPOUTS
DURING THE AFTERNOON. THE NAM HAS THE COLD CORE OF THE LOW MOVING
DIRECTLY OVER SBA COUNTY LATE IN THE AFTERNOON AND THIS IF CORRECT
COULD BE THE BEST CHC FOR TSTMS.
SNOW LEVELS WILL START OFF BETWEEN 6500 AND 7500 FEET THIS EVENING
WILL THEN FALL TO BETWEEN 5000 AND 5500 FEET BY EARLY SUNDAY
MORNING. THE SNOW LEVEL WILL LOWER LOCALLY TO 4500 FEET BY SUNDAY
NIGHT.
EXPECTED RAINFALL AMOUNTS RANGE FROM .75 TO 1.5 INCHES FOR COAST AND
VALLEYS...WHILE FOOTHILL AND MOUNTAIN AREAS SHOULD SEE 2-4 INCHES.
SNOW ACCUMULATIONS BETWEEN 8 AND 14 INCHES ARE LIKELY ABOVE 5500
FEET...WITH LOCAL AMOUNTS UP TO 16 INCHES IN FAVORABLE LOCATIONS
ABOVE 7000 FEET. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THE VTA
AND LA MTNS WITH THE VTA WARNING STARTING LATE TONIGHT AND THE LA
WARNING STARTING MID MORNING SUNDAY.
THE 06Z NAM THROWS A FLY INTO THE OINTMENT. IT DEVELOPS A BROAD
EASTERLY FLOW ACROSS THE AREA. THIS DRYING OFFSHORE FLOW WILL...IF
TRUE...WILL SEVERELY LIMIT THE RAINFALL. THIS IS THE OUTLIER
FORECAST BUT IT HAS HAPPENED BEFORE AND NEEDS TO WATCHED.
THIS STORM WILL NOT BE A COLD NOR A WINDY AS LAST WEEKS. HIGHS WILL
BE IN THE UPPER 50S FOR MOST AREAS AS OPPOSED TO LOW 50S LAST WEEK.
WIND ADVISORIES MAY BE NEEDED FOR THE MTNS OF SLO AND SBA COUNTY BUT
THE LOWER ELEVATIONS SHOULD ONLY SEE NON ADVISORY WINDS 15 TO 25 MPH.
THE STORM WILL MOVE OUT LATE SUNDAY NIGHT AND WHILE THERE WILL BE A
CHANCE OF SOME MORNING SHOWERS MONDAY MORNING ACROSS L.A. COUNTY THE
DAY WILL MOSTLY BE DRY AND COOL.
.LONG TERM (TUE-FRI)...
UN-EXCITING WEATHER RETURNS FOR THE EXTENDED PERIOD. FLAT SOUTHWEST
FLOW WILL BRING PARTLY CLOUDY SKIES TO THE AREA TUESDAY TEMPS WILL
RISE A DEGREE OR TWO BUT WILL REMAIN BELOW NORMAL.
THE TAIL END OF A WEAK COLD FRONT WILL MOVE OVER THE CENTRAL COAST
WEDNESDAY. IT WILL BE GOOD FOR A CHANCE OF RAIN. IT WILL BRING
CLOUDS TO THE ENTIRE AREA AND A DEGREE OR SO OF COOLING. RAINFALL IF
ANY WILL BE UNDER A QUARTER INCH.
SOUTHWEST FLOW AND RISING HGTS WILL MAKE THURSDAY THE NICEST OF THE
NEXT 7 WITH NEAR NORMAL TEMPS AND MOSTLY CLEAT SKIES.
THE FLOW TURNS WESTERLY FRIDAY AS A GULF OF ALASKA STORM MOVES
SLIGHTLY SOUTHWARD. SKIES WILL TURN PARTLY CLOUDY AND MAX TEMPS WILL
DROP A COUPLE OF DEGREES.
&&
.AVIATION...24/1140Z
N OF POINT CONCEPTION...LOW CONFIDENCE WITH STRATUS IN RESPECT TO
BURNOFF TIME. HIGHER CONFIDENCE WITH TIMING OF PRECIPITATION
OVERNIGHT. RAIN SHOULD DEVELOP AROUND 08Z-10Z TONIGHT INTO EARLY
SUNDAY MORNING. GUSTY SOUTHERLY WINDS AHEAD OF THE FRONT. SLIGHT
CHANCE OF THUNDERSTORMS BY SUNDAY MORNING.
S OF POINT CONCEPTION...MODERATE CONFIDENCE WITH 12Z TAF. MVFR CIGS
WILL GIVE WAY T VFR CIGS BY THIS AFTERNOON. 30 PERCENT CHANCE FOR
MVFR CIGS TO STICK AROUND UNTIL NOON. INCREASING HIGH CLOUDS WILL
PREVAIL LATER THIS AFTERNOON. NO RAIN EXPECTED FOR AREAS S OF POINT
CONCEPTION UNTIL AROUND 12Z SUNDAY THROUGH 18Z. THEN RAIN SHOULD
SPREAD EVERYWHERE BY SUNDAY AFTERNOON. GUSTY SOUTHERLY WINDS ARE
EXPECTED THROUGH MUCH OF THE DAY. Z LEVEL SHOULD BE AROUND 5.6KFT BY
SUNDAY AFTERNOON.
KLAX...MODERATE CONFIDENCE WITH 12Z TAF. MVFR CIGS SHOULD GIVE WAY
TO VFR CIGS BY 18-21Z TODAY. WITH INCREASING HIGH CLOUDS LATER IN
THE DAY. SEA BREEZE WILL KICK IN BY 19-21Z. CLOUDS WILL BE
INCREASING BY SUNDAY MORNING...AND RAIN SHOULD BEGIN BY SUNDAY
18-20Z AND PERSIST THROUGH MUCH OF SUNDAY EVENING INTO THE OVERNIGHT
HOURS. WINDS SHOULD STAY OF THE SE ON SUNDAY MORNING...AND PERSIST
IN THAT DIRECTION THROUGH MUCH OF THE DAY. WINDS SHIFTING BY SUNDAY
EVENING TO SW.
KBUR...MODERATE CONFIDENCE WITH 12Z TAF. LOW MVFR CIGS WILL CONTINUE
THROUGH 18Z THEN VFR CIGS WITH HIGH CLOUDS INCREASING THROUGH THE
DAY. SIMILAR TIMING OF SHOWERS AS KLAX BY SUNDAY LATE MORNING INTO
EARLY AFTERNOON. WINDS SHOULD REMAIN E TO SE MOST OF SUNDAY.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING (SEE LAXWSWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
SPECIAL WEATHER STATEMENT (SEE LAXSPSLOX).
&&
$$
PUBLIC...RORKE
AVIATION...KAPLAN
SYNOPSIS...B
WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
659 PM EDT SAT MAR 24 2012
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF US AND MOVE OFF THE COAST SUNDAY
EVENING. A COLD FRONT WILL MOVE THROUGH THE AREA DURING THE DAY ON
MONDAY. HIGH PRESSURE WILL THEN ARRIVE FOR TUESDAY AND PERSIST
THROUGH EARLY WEDNESDAY. A WARM FRONT IS FORECAST TO LIFT
NORTHEASTWARD TOWARD THE REGION LATE ON WEDNESDAY. ANOTHER COLD
FRONT, MOVING IN FROM THE WEST, SHOULD WORK ITS WAY THROUGH THE
AREA ON WEDNESDAY NIGHT. MORE HIGH PRESSURE IS FORECAST FOR
THURSDAY, FRIDAY, AND POSSIBLY SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
THE UPPER LOW ACROSS THE OHIO VALLEY WILL MOVE EWRD TONIGHT INTO
THE CAROLINAS. A SFC LOW WILL MOVE A LITTLE AHEAD OF THE UPPER LOW
AND CAUSE A FRONTAL SYSTEM TO APPROACH THE AREA TONIGHT. THE
REGIONAL RADARS ARE SHOWING SHOWERS APPROACHING FROM THE SW ATTM.
THESE SHOWERS WILL BE ACROSS THE AREA EARLY TONIGHT ALONG WITH
AREAS OF FOG WHICH SHOULD DEVELOP TOO. THE FOG WILL PROBABLY BE
MORE ABUNDANT NEAR THE SHORE...BUT WAS INCLUDED IN ALL AREAS WITH
THIS FCST. RAINFALL TOTALS WILL BE AROUND A TENTH TO ONE QUARTER
INCH. LOW TEMPERATURES WILL RANGE FROM THE LOW OR MID 50S ACROSS
THE DELMARVA TO THE LOW/MID 40S ACROSS THE NRN AREAS. WINDS WILL
BE ERLY AT 5 TO 10 MPH. BASED ON LATEST RADAR TRENDS, HAVE LOWERED
POPS FOR NEXT FEW HOURS. HRRR DATA INDICATES AN INCREASE IN PRECIP
AGAIN AFTER 02 OR 03Z, SO DIDN`T MAKE CHANGES AFTER THAT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
SLOW IMPROVEMENT IN THE WEATHER FOR SUNDAY. THE LOW PRESSURE SYSTEM
WILL BE OFFSHORE AND MOVING TO THE NORTHEAST. IT WILL SLOWLY
STRENGTHEN AND BRING MORE OF A NERLY THEN NRLY WINDS ACROSS THE
AREA. WHILE CLOUDS ARE EXPECTED MUCH OF THE DAY...A GRADUAL
IMPROVEMENT SHOULD OCCUR LATE. A FEW LINGERING SHOWERS ARE POSSIBLE
SOUTH AND EAST MOSTLY DURING THE MORNING. HIGHS ON SUN WILL BE
SOMEWHAT DEPENDENT ON HOW MUCH SUN BREAK OUT LATE IN THE DAY...I
HAVE GONE MOSTLY MID TO UPPER 60S ATTM WITH UPPER 50S ACROSS THE SRN
POCONOS...THIS IS A FEW DEGREES LOWER THAN WHAT THE GUIDANCE TEMPS
HAVE. WINDS WILL BE MOSTLY LIGHT ON SUNDAY...MOSTLY NE OR N AT 5 TO
10 MPH.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
THE MID-LEVEL LOW AXIS IS FORECAST TO SHIFT OFF THE COAST SUNDAY
NIGHT BRINGING AN END TO THE SHOWER THREAT. WHILE A DRY COLD FRONT
ON MONDAY WON`T BRING ANY RAIN TO THE REGION, IT WILL PROVIDE A
CHANGE IN AIRMASS. WITH IT`S STRONG CAA AND GUSTY WINDS, MARCH
26TH WILL ACTUALLY FEEL LIKE MARCH 26TH, NOT APRIL OR MAY 26TH. A
SURFACE HIGH, CENTERED ACROSS ONTARIO, MONDAY NIGHT WILL BEGIN TO
SAG INTO THE REGION BRINGING WITH IT A LITTLE LESS GRADIENT. THE
HIGH WILL BE ON TOP OF US ON TUESDAY AND WILL MOVE TO THE COAST ON
TUESDAY NIGHT. LOOKS LIKE A WARM FRONT IS GOING TO APPROACH US
FROM THE SOUTH ON WEDNESDAY, BUT STRUGGLE TO MOVE THROUGH. WHAT`S
MORE CERTAIN IS THE COLD FRONT, COMING IN FROM THE WEST, THAT WILL
CROSS THE REGION ON WEDNESDAY NIGHT. HIGH PRESSURE IS FORECAST TO
BUILD IN BEHIND THIS FRONT AND PERSIST INTO FRIDAY AND MAYBE EVEN
SATURDAY.
NO HEAVY PRECIPITATION IS EXPECTED THROUGH THIS PERIOD. SHOWERS WILL
BE CARRIED SUNDAY NIGHT, AT LEAST EARLY, AND AGAIN ON WEDNESDAY
INTO THURSDAY WITH THE MIDWEEK COLD FRONT.
AS FOR TEMPERATURES, NOT MUCH CHANGE FROM YESTERDAY. WE`LL SEE MORE
CHANGEABLE CONDITIONS, SYNONYMOUS OF SPRING. MONDAY SHOULD BE ABOVE
NORMAL (ALTHOUGH THE NAM MOS SAYS OTHERWISE), TUESDAY AROUND NORMAL,
WEDNESDAY/THURSDAY ABOVE NORMAL, AND BACK TO NEAR NORMAL
FRIDAY/SATURDAY.
THE REGION WILL SEE SOME 30S NEXT WEEK IN THE MORNING. THE COLDEST
MORNING STILL LOOKS TO BE TUESDAY WHERE WE SHOULD SEE SUB-FREEZING
TEMPERATURES. NOT A GOOD THING FOR SENSITIVE VEGETATION/TREES THAT
HAVE GOTTEN OFF TO A TWO TO FOUR WEEK HEAD START THANKS TO WHAT
COULD AMOUNT TO A TOP 3 MARCH TEMP-WISE.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
CONDITIONS WERE MAINLY VFR AND MVFR ERLY THIS EVENING. LATEST
GUIDANCE CONTINUED TO INDICATE DETERIORATION WILL BEGIN LATER THIS
EVENING AS ANOTHER AREA OF SHOWERS AND DEEPER MOISTURE
ARRIVE...WITH FLYING CONDITIONS EXPECTED TO GO IFR IN MOST AREAS
BY MIDNIGHT. HOWEVER, LATEST TRENDS IMPLY THAT THE DETERIORATION
MAY START A BIT LATER THAN EARLIER FCST. ONLY SLOW IMPROVEMENT
WILL OCCUR SUNDAY MORNING...SINCE THE SFC/UPPER LOW MOVING ACROSS
THE AREA WILL NOT BE MOVING THAT FAST. BETTER CONDITIONS WILL
ARRIVE LATER SUNDAY...ONCE THE SYSTEM MOVES AWAY AND SFC WINDS
TURN MORE TOWARD THE N OR NW.
OUTLOOK...
SUNDAY NIGHT...VFR.
MONDAY...VFR WITH A GUSTY NORTHWEST WIND.
MONDAY NIGHT THROUGH TUESDAY NIGHT...VFR.
WEDNESDAY...MAINLY VFR. BUT A CHANCE OF SHOWERS WITH THE COLD FRONT.
THURSDAY...MAINLY VFR WITH SOME REMNANT POST FRONT SHOWERS POSSIBLE.
&&
.MARINE...
EAST WINDS HAVE REMAINED AROUND 10 TO 15 KTS ON THE WATERS
TODAY...THE DEVELOPING SFC LOW TO THE SOUTH SHOULD KEEP WINDS
MOSTLY ERLY TONIGHT. A SCA FLAG WILL PROBABLY NOT BE NEEDED
TONIGHT...BUT SEAS MAY GET CLOSE TO 5 FT...WE MAY HAVE TO ISSUE
SCA IF THE SEAS GET OVER 5 FT. LOW CONFID IN THIS ATTM. WINDS WILL
SLACKEN SUN MORNING AS THE SFC PRESSURE TROUGH CROSSES THE WATERS.
WINDS WILL SLOWLY VEER NERLY THEN NRLY ON SUNDAY. AREAS OF SHOWERS
AND FOG WILL BE ON THE WATERS TONIGHT AND SUN MORNING.
OUTLOOK...
A STRONG COLD FRONT, FROM THE NORTHWEST, IS EXPECTED TO CROSS THE
COASTAL WATERS OF NEW JERSEY AND DELAWARE ON MONDAY. HIGH PRESSURE
WILL FOLLOW AND PERSIST THROUGH LATE TUESDAY. A WARM FRONT IS
ANTICIPATED TO APPROACH FROM THE SOUTHWEST ON WEDNESDAY FOLLOWED BY
A COLD FRONT ON WEDNESDAY NIGHT.
A SMALL CRAFT ADVISORY MAY BE NEEDED FROM MONDAY INTO TUESDAY
MORNING FOR THE GUSTY NORTHWEST WINDS IN THE COLD ADVECTION.
ISOLATED GALE FORCE GUSTS MAY OCCUR FROM LATE MONDAY INTO MONDAY
NIGHT.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KRUZDLO
NEAR TERM...NIERENBERG/O`HARA
SHORT TERM...O`HARA
LONG TERM...KRUZDLO
AVIATION...KRUZDLO/NIERENBERG/O`HARA
MARINE...KRUZDLO/O`HARA
AREA FORECAST DISCUSSION...UPDATED
NWS TALLAHASSEE FL
628 PM EDT Sat Mar 24 2012
.MESOSCALE UPDATE...
An interesting mesoscale setup across our area early this evening
that suggests the thunderstorm threat is not completely over for
our land areas. The important feature that we have been tracking
appears to be a surge of low-level moisture that is slowly
propagating to the NNW, and currently arcs from near Lakeland, GA
or Moody AFB, to the northwest side of Tallahassee, to near
Carrabelle in Franklin County. The dewpoint at the TLH airport and
the NWS office have increased about 10-12 degrees in the past hour
and now sit around 66F. The push of low-level moisture has created
a sharp thetae gradient and the boundary is even evident on the
latest TLH radar reflectivity as well as on visible satellite
(with a line of towering cumulus). Winds in the moist air mass
have backed to a S-SSE direction, whereas winds in the drier air
mass are almost due west. This should act to increase low-level
convergence in the next several hours and could provide the
necessary focus for additional thunderstorm development. The RUC
and NAM have been handling this mesoscale feature rather well, and
both indicate QPF in the 00-06z timeframe in our SE areas.
Modifying a 01z RUC forecast sounding for VLD with 77/66 surface
conditions yields about 1500-2000 j/kg of CAPE with very little
CINH for a parcel lifted from near the surface. The other thing to
consider is that deep layer shear will be on the increase in the
next few hours, so any storm that can tap this environment may be
a little more organized than what we saw earlier.
The main message is that thunderstorm potential is not necessarily
over, and we cannot rule out a severe thunderstorm or two prior to
midnight in our southeastern areas.
&&
.PREV DISCUSSION (issued at 237 PM EDT Sat Mar 24 2012)...
SHORT TERM (Tonight through Monday night)...Cold front associated
with the deep upper low will finally exit the forecast area this
evening. Showers and thunderstorms will likely linger into the
mid-evening hours over the eastern big bend before ending by
midnight. With the latest VWP data showing winds veering
substantially at KVLD, severe threat should be rather low.
A drier airmass will arrive in the wake of the front. This will
allow overnight lows to fall back into the lower to mid 50s for
the next few nights. However, highs will continue to reach the
lower to mid 80s each afternoon. After this evening, no rain is
expected throug Monday night.
LONG TERM (Tuesday through next Saturday)...There is good
consensus between the models that the long term period will remain
rather calm, with a benign weather pattern in place. The northern
stream flow will remain across the northern half of the country
through the period, with a chain of shortwaves forecast to pass
through it. Across the southern part of the country, a mix of
ridging and a zonal flow regime will dominate. As each of the
aforementioned shortwaves pass well north of the local area, they
will have little effect on the local weather, with the exception
of dampening any ridging that is occurring over the southeastern
part of the country. The result of this pattern will be dry and
warm afternoons, with mild evenings. Temperatures are forecast to
climb into the lower to middle 80s each afternoon, with low
temperatures bottoming out in the middle to upper 50s. No
mentionable rain chances exist through the period.
AVIATION (through 18Z Sunday)... A weak cold front was pushing
slowly southeastward across eastern portions of the Tri-State Area
this afternoon. Along and ahead of the front, bands of showers and
isolated thunderstorms continued to develop over southern and
eastern portions of the Big Bend and adjacent coastal waters,
accompanied by MVFR ceilings. The showers and storms will clear
the southeast Big Bend by late tonight as the front pushes south
of the area, and VFR conditions will prevail through the remainder
of the forecast period and beyond. Winds Sunday will be generally
northwest 8 to 12 knots with occasional gusts to around 15 knots.
MARINE...Winds will turn from the west to the northwest overnight
in the wake of a cold front. Wind speeds are expected to remain
just below headline criteria. A very weak pressure gradient for
Monday into Tuesday will keep winds and seas minimal. Easterly
flow will increase by mid-week as high pressure builds along the
eastern seaboard.
FIRE WEATHER...Drier air will be spreading across the Tri-State
Area tonight and Sunday, on the heels of a cold front that will
push south and east of the area later tonight. Relative humidities
are forecast to fall to critical levels across all but the
immediate coastal areas of the eastern Florida Panhandle and Big
Bend, as well as southeast Alabama on Sunday afternoon. Durations
across southeast Alabama are not expected to be met. However,
dispersions across Florida zones are expected to exceed 75, and a
Red Flag Warning will be issued for all but the coastal zones of
Florida. On Monday and Tuesday, relative humidities are expected
to approach or briefly drop below red flag criteria, however
durations are not expected to be met.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 54 81 52 84 53 / 10 0 0 0 0
Panama City 59 79 60 79 61 / 10 0 0 0 0
Dothan 54 80 55 84 56 / 0 0 0 0 0
Albany 53 79 53 82 55 / 10 0 0 0 0
Valdosta 54 79 53 82 54 / 20 0 0 0 0
Cross City 58 81 52 83 53 / 50 10 0 0 0
Apalachicola 59 76 57 77 60 / 10 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...Red Flag Warning from 2 PM EDT /1 PM CDT/ to 7 PM EDT /6 PM CDT/
Sunday for Calhoun-Central Walton-Gadsden-Holmes-Inland Bay-
Inland Dixie-Inland Franklin-Inland Gulf-Inland Jefferson-
Inland Taylor-Inland Wakulla-Inland Walton-Jackson-
Lafayette-Leon-Liberty-Madison-Washington.
GM...None.
&&
$$
Update...08-Lamers
AREA FORECAST DISCUSSION
NWS JACKSON KY
210 PM EDT SAT MAR 24 2012
.UPDATE...
ISSUED AT 210 PM EDT SAT MAR 24 2012
SHOWERS AND THUNDERSTORMS HAVE BEGUN TO DEVELOP ACROSS PORTIONS OF
THE AREA...PARTICULARLY SOUTHERN PORTIONS OF THE CWA IN RESPONSE TO
DIURNAL HEATING AND APPROACH OF UPPER LEVEL LOW CURRENTLY OVER
WESTERN KY. SHOWER ACTIVITY SHOULD BEGIN TO DIE DOWN AFTER SUNSET
AND AS THE LOW PUSHES PAST OUR AREA TOWARDS THE ATLANTIC COAST. FIRST
BAND OR ROUND OF SHOWERS CONTINUES TO MOVE NORTHEASTWARD. ADDITIONAL
SHOWERS WILL FORM ALONG CONVERGENT ZONES ROTATING IN PINWHEEL FASHION
AROUND THE PARENT LOW. INCREASED POPS SLIGHTLY FOR LOCATIONS THAT
SHOWERS ARE CURRENTLY TAKING AIM FOR AND SHOULD AFFECT DURING THE
NEXT FEW HOURS. SCATTERED THUNDER IS STILL A DECENT BET AS GOOD SFC
HEATING CONTINUES TO DESTABILIZE THE BOUNDARY LAYER. BUMPED TEMPS UP
SLIGHTLY IN THE EAST WHERE AMPLE SUNSHINE HAS ALREADY ALLOWED TEMPS
TO SHOOT UP CLOSE TO FORECASTED HIGHS.
UPDATE ISSUED AT 1054 AM EDT SAT MAR 24 2012
LULL IN SHOWER AND THUNDERSTORM ACTIVITY THIS MORNING WILL PICK BACK
UP AGAIN THIS AFTERNOON WITH DIURNAL HEATING AND AS UPPER LEVEL LOW
CURRENTLY OVER SOUTHERN IL AND WESTERN KY TRACKS ACROSS THE
COMMONWEALTH THROUGH THE AFTERNOON TIME FRAME. REGIONAL SAT ALSO
SHOWS SOME BREAKS IN THE CLOUD COVER. THIS WILL HELP STEEPEN UP THOSE
BOUNDARY LAYER LAPSE RATES AS MID LEVELS COOL. SO A FEW STRONG
STORMS CAN NOT BE RULED OUT THIS AFTERNOON. UPDATED POPS AND SKY
COVER FOR LATEST TRENDS. TEMPS WERE NOT TOO BAD SO ONLY SOME MINOR
TWEAKS THERE. EXPECT DIURNAL CU FIELD WILL FILL BACK IN BREAKS WITH
TIME. WITH FCST SOUNDINGS SHOWING ONLY MARGINAL INSTABILITY THROUGH
THE OVERNIGHT PERIODS...DID ADJUST WEATHER GRIDS TO INTRODUCE A MORE
DIURNAL FLAVOR TO ANY THUNDERSTORM ACTIVITY.
UPDATE ISSUED AT 745 AM EDT SAT MAR 24 2012
HOURLY POPS WERE UPDATED TO ACCOUNT FOR NEAR CATEGORICAL COVERAGE
ONGOING AND OVER THE NEXT HOUR OR SO IN THE KY/WV AND VA TRI STATE
AREA. OTHERWISE...HELD ONTO SOME SLIGHT CHANCE POPS AS FAR WEST AS A
MIDDLESBORO TO JKL TO ELLIOTT COUNTY LINE OR SO OVER THE NEXT HOUR OR
TWO...BEFORE BLENDING INTO POPS FROM THE PREVIOUS FORECAST THAT
REFLECT AN INCREASE IN COVERAGE OF SHRA AND ISOLATED TO SCATTERED
TSRA AS THE UPPER LEVEL LOW NEARS THE REGION AND THIS COMBINED WITH
SOME SOLAR INSOLATION SHOULD LEAD TO AN INCREASE IN COVERAGE AND
INTENSITY OF CONVECTION DURING THE AFTERNOON.
HOURLY TEMP AND DEW POINT CURVES WERE ALSO FRESHENED UP BASED ON
RECENT OBS. UPDATED GRIDS HAVE BEEN SENT ALONG WITH A FRESHENED UP
ZFP.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 434 AM EDT SAT MAR 24 2012
SURFACE ANALYSIS ACROSS THE AREA AS OF 08Z HAS THE LINE OF SHOWERS
AND THUNDERSTORMS WITH A SURFACE FRONT AND ASSOCIATED 500MB WAVE
ROTATING AROUND A CLOSED CUT OFF LOW MOVING OFF TO THE EAST. LOOKING
AT CURRENT RADAR TRENDS AND OBS...LOOKING LIKE ALL THE INSTABILITY
HAS BEEN TAPPED OUT EAST AS ONLY A FEW CELLS SEEM TO BE LEFT. A FEW
SHOWERS HAVE BEGUN TO DEVELOP BEHIND THE LINE OVER THE SOUTHWEST
COUNTIES SO HAVE LEFT SOME ISOLATED SHOWERS MENTIONED IN THE ZONES
DURING THE MORNING HOURS. THIS IS SUPPORTED BY THE HRRR AND RUC AS
THE UPPER LEVEL SUPPORT WILL BE AVAILABLE ALL DAY TODAY AS THE LOW
WILL SLOWLY MOVE SOUTH AND EAST.
THINKING SHOWERS AND THUNDERSTORMS WILL REDEVELOP AGAIN TODAY WITH
THE HEATING OF THE DAY AS ANOTHER 500MB WAVE ROTATES AROUND THE LOW
AGAIN AND THROUGH EAST KENTUCKY AND AS SUCH...RAMPED UP POPS TO GOOD
CHANCES AND ALSO WENT WITH COVERAGE RATHER THAN PROBABILITY. ALSO THE
RAPID STABILIZATION DURING THE EVENING HOURS LEADS TO FOG DEVELOPING
IN THE VALLEYS AND SO PUT FOG INTO THE ZONES TO ACCOUNT FOR THIS.
BY SUNDAY NIGHT...THE SHORT TERM MODELS SEEM TO BE IN AGREEMENT THAT
THE CLOSED LOW FINALLY DRIFTS OFF TO THE SOUTH AND EAST. SO WILL RAMP
DOWN THE POPS FOR THIS TIME PERIOD. CONCERNING TEMPERATURES...THE
MERIDIONAL PATTERN WITH A TROUGH MOVING THROUGH THE EASTERN US...WILL
KEEP TEMPERATURES NEAR NORMAL FOR THE SHORT TERM PERIOD.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 434 AM EDT SAT MAR 24 2012
A RATHER PROGRESSIVE PATTERN IS EXPECTED DURING THE PERIOD. INITIALLY
ON MONDAY...RECENT GFS AND ECMWF RUNS INDICATE THAT UPPER LEVEL
RIDGING WILL BE BUILDING INTO THE REGION FROM THE PLAINS AND MS
VALLEY WHILE THE SOUTHERN END OF A RIDGE OF SFC HIGH PRESSURE WILL BE
NOSING INTO THE OH VALLEY AND APPALACHIAN REGION. THE UPPER LEVEL
RIDGE IS EXPECTED TO CONTINUE TO BUILD INTO THE REGION ON MON NIGHT
AND INTO TUE....WHILE THE AXIS OF THE SFC HIGH WILL SHIFT ON OFF TO
THE EAST ON TUE. AS THE SFC HIGH SHIFTS EAST OF THE AREA...A WARM
FRONT OR SFC TROUGH IS PROGGED TO SHIFT TO THE EASTERN PORTIONS OF
THE CWA.
AT THE SAME TIME...AN UPPER LEVEL TROUGH AND ASSOCIATED SYSTEM WILL
TRACK FROM THE CENTRAL AND NORTHERN ROCKIES AND INTO THE NORTHERN
PLAINS/WESTERN GREAT LAKES REGION BY TUE EVENING AND NIGHT WITH THIS
UPPER LEVEL SYSTEM THEN TRACKING NEARLY DUE EAST INTO THE
NORTHEASTERN STATES ON WED INTO WED NIGHT. UPPER LEVEL RIDGING IS
THEN EXPECTED TO BUILD BACK INTO THE GREAT LAKES AND OH VALLEY AND
APPALACHIAN REGION AND LIKELY REMAIN DOMINANT THROUGH THE END OF THE
PERIOD. THE GREATEST UNCERTAINTY COMES AT THE END OF THE PERIOD AS
THE GFS TRACKS A COUPLE OF SHORTWAVES EAST A BIT QUICKER AND IS
WEAKER WITH THE LATE WEEK RIDGING. DURING THIS PERIOD OF GREATER
UNCERTAINTY...GENERALLY FOLLOWED A BLEND OF THE MODEL CONSENSUS AND
THE USUALLY RELIABLE ECMWF.
A SFC LOW SHOULD FOLLOW A SIMILAR PATH AS THE UPPER LEVEL SYSTEM
FROM MON TO TUE...REACHING THE GREAT LAKES REGION TUE NIGHT INTO WED
AND THEN TRACKING OFF THE NORTHEASTERN US COAST WED NIGHT INTO THU.
THIS SYSTEM WILL SEND A COLD FRONT INTO THE LOCAL AREA ON WED WITH
THE MODEL CONSENSUS SHIFTING THIS FRONT SOUTH OF THE AREA ON WED
NIGHT. ALTHOUGH I HAVE ALLOWED FOR SOME 10 POPS WHICH ARE PART OF
THE MODEL CONSENSUS ON TUE AFTERNOON AS THE PAST COUPLE OF ECMWF
RUNS DEVELOP SOME CONVECTION OVER THE NORTHEASTERN OR EASTERN PART
OF THE CWA IN THE VICINITY OF THE SFC TROUGH/WARM FRONT FEATURE ON
TUE...THE BEST CHANCE DURING THE PERIOD FOR MEASURABLE PRECIP WILL
COME ON WED INTO WED EVENING.
AS FOR TEMPERATURES...MAX TEMPERATURES SHOULD GENERALLY AVERAGE
SLIGHTLY ABOVE NORMAL EARLY IN THE PERIOD AND AT THE END OF THE
PERIOD TO AS MUCH AS 10 DEGREES OR MORE ABOVE NORMAL ON WED JUST
AHEAD OF THE COLD FRONT. LOW THROUGH THE PERIOD SHOULD GENERALLY BE
IN THE 40S OR EVEN THE 50S...WITH ONE EXCEPTION...MONDAY NIGHT. SFC
HIGH PRESSURE SHOULD ALLOW FOR SOME OF THE NORMALLY COLDER VALLEY
LOCATIONS IN THE FAR NORTH AND EAST TO REACH THE UPPER 30S ON MON
NIGHT. THIS WOULD LEAD TO AT LEAST A SLIGHT CONCERN FOR SOME PATCHY
FROST AT LEAST IF THESE MIN TEMPS WERE TO TREND SLIGHTLY COLDER AS
RECENT WARM WEATHER HAS ALLOWED VEGETATION TO BE RUNNING A COUPLE OF
WEEKS OR SO AHEAD OF AVERAGE. HOWEVER...ATTM...EVEN IT ONE WERE TO
OCCUR IT APPEARS AS IF IT WOULD BE VERY PATCHY TO ISOLATED AND WOULD
OCCUR IN THE COLDEST OF THE NORMALLY COLD SPOTS. THIS POTENTIAL
SCENARIO WILL CONTINUE TO BE MONITORED...HOWEVER CONFIDENCE IN EVEN
ISOLATED TO PATCHY VALLEY FROST IS TOO LOW AT THIS POINT TO INCLUDE
IN THE HWO.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 210 PM EDT SAT MAR 24 2012
SHOWERS AND THUNDERSTORMS HAVE BEGUN TO DEVELOP ACROSS PORTIONS OF
THE AREA...PARTICULARLY SOUTH PORTIONS OF THE CWA IN RESPONSE TO
DIURNAL HEATING AND APPROACH OF UPPER LEVEL LOW CURRENTLY OVER
WESTERN KY. THE MAIN THREAT OF RAIN WILL CONTINUE THROUGH THE FIRST
SEVERAL HOURS OF THE TAF FORECAST...UNTIL AND JUST AFTER SUNSET.
ACTIVITY SHOULD BEGIN TO DIE OUT THEREAFTER AS THE LOW PUSHES PAST
OUR AREA TOWARDS THE ATLANTIC COAST. FIRST BAND OR ROUND OF SHOWERS
WILL MOVE INTO VCTY OF JACKSON WITHIN AN HOUR. ONLY CONCERN WAS
POTENTIAL FOR MIST...FOG TONIGHT. ATTM GUIDANCE SUGGEST THERE SHOULD
BE ENOUGH CLOUD COVER AND WIND...MIXING TO MAINTAIN VFR OR HIGH END
MVFR AS A WORSE CASE. WENT MORE OPTIMISTIC AND ONLY INCLUDED MVFR
VSBYS AT KJKL FOR THE TYPICAL MIST THAT TENDS TO DEVELOP DURING THE
PRE DAWN HORUS AND/OR THAT MOVES UP THE FROM THE VALLEY FLOOR AS DAWN
BREAKS.
WINDS HAVE INCREASED AND VEERED OUT OF THE WEST AT 5 TO 10 KTS BUT
WILL DIE OFF AGAIN AS THE MAIN LOW CLOSES IN. WINDS WILL INCREASE
AGAIN ON SUNDAY OUT OF THE NW AROUND 10KTS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RAY
SHORT TERM...SHALLENBERGER
LONG TERM....JP
AVIATION...RAY
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
322 PM CDT SAT MAR 24 2012
.DISCUSSION...
SEVERAL FEATURES OF INTEREST WILL IMPACT THE REGION OVER THE
COMING WEEK... ALTHOUGH AT THIS POINT NO PARTICULARLY SIGNIFICANT
WEATHER APPEARS LIKELY. IN THE BIG PICTURE... THE LARGE SCALE
UPPER FLOW WILL BECOME LESS AMPLIFIED AND HENCE MORE
PROGRESSIVE AND SLIGHTLY MORE SEASONABLE IN OUR NECK OF THE WOODS.
THIS MEANS THAT INSTEAD OF SEEING TEMPERATURES OF 20-30 DEGREES
ABOVE NORMAL... THEY MAY BE MORE ON THE ORDER OF 10-15 DEGREES
ABOVE NORMAL FOR A GOOD PART OF THE UPCOMING WEEK. ONE MAJOR
CONCERN COULD BE THE POTENTIAL FOR FREEZING TEMPERATURES IN THE
UPCOMING WEEK... SINCE SOME OF THE CALENDAR-DEFICIENT PLANTS HAVE
DECIDED IT/S ALREADY TIME TO START GROWING. IT DOESN/T APPEAR AS
THOUGH ANY WIDESPREAD FREEZING TEMPERATURES WILL OCCUR THROUGH THE
UPCOMING WEEK... BUT PORTIONS OF THE AREA COULD SEE READINGS DIP
NEAR OR BELOW FREEZING ON A COUPLE OF MORNINGS. THE GFS AND ECMWF
ARE IN DECENT AGREEMENT THROUGH MOST OF THE WEEK... SO GENERALLY
FOLLOWED A BLEND OF THEIR GUIDANCE... INCREASINGLY BLENDING IT
WITH THE PREVIOUS FORECAST IN THE LATER PERIODS.
VISIBILE IMAGERY SHOWS THIS MORNING/S LOW CLOUDS AND FOG HAVE
FINALLY BURNED OFF OVER MOST OF THE AREA. TEMPERATURES ARE
RESPONDING QUICKLY TO THE SUNSHINE... WITH READINGS CLIMBING
THROUGH THE 60S TO AROUND 70. SHOULD CONTINUE TO SEE READINGS WORK
UPWARD THE NEXT COUPLE OF HOURS... THEN THINGS WILL COOL OFF BOTH
IN RESPONSE TO DARKNESS AND THE COLD FRONT MARCHING SOUTHEAST
THROUGH THE AREA. THE FRONT CURRENTLY STRETCHES FROM NEAR
INTERNATIONAL FALLS SOUTHWEST INTO EASTERN SOUTH DAKOTA.
TEMPERATURES DROP OFF BEHIND THE FRONT... WITH A BIG DROP IN
DEWPOINTS NOTED AS WELL. A FEW SHRA COULD DEVELOP IN NORTHEAST
MINNESOTA AND NORTHWEST WISCONSIN AS THE FRONT MOVES THROUGH THIS
AFTERNOON AND EVENING... BUT AT THIS POINT IT LOOKS LIKE ANY OF
THAT ACTIVITY SHOULD STAY NORTH OF OUR AREA. THE HRRR AND LOCAL
4KM WRF-ARW DO MANAGE TO PRODUCE SOME LIGHT SHRA INTO THE
NORTHEAST PART OF OUR AREA... BUT AT THIS POINT WOULD RATHER SEE
MORE GOING ON IN THE REAL WORLD TO INCLUDE A MENTION. AS
MENTIONED... THE FRONT WILL SLIDE THROUGH TONIGHT... WITH RIDGING
AND COOLER/DRIER AIR ARRIVING FOR OVERNIGHT THROUGH THE DAY ON
SUNDAY. BUT... GIVEN THE MORE PROGRESSIVE FLOW... THIS CHANGE WILL
BE SHORT-LIVED... WITH RETURN FLOW SETTING UP QUICKLY SUNDAY
NIGHT. ISENTROPIC LIFT SUNDAY NIGHT INTO MONDAY IS IMPRESSIVE AS
THE ELEVATED WARM FRONT LIFTS BACK NORTHEAST ACROSS THE AREA. IN
ADDITION TO THE ISENTROPIC LIFT... FAIRLY SUBSTANTIAL LOW-MID
LEVEL FRONTOGENESIS IS PROGGED FROM LATE SUNDAY NIGHT THROUGH THE
DAY ON MONDAY AS THE BOUNDARY SLOWLY LIFTS NORTHEAST ACROSS THE
AREA. A LOOK AT ELEVATED INSTABILITY... PER 850-500MB DIFFERENTIAL
THETA-E VALUES... SHOWS SOME POTENTIAL FOR THUNDER CREEPING IN
FROM WEST TO EAST LATE SUNDAY NIGHT INTO MONDAY NIGHT... WITH A
CHANCE FOR SOME THUNDER ACROSS THE ENTIRE AREA BY LATER MONDAY
NIGHT AS THE WARM SECTOR FULLY ESTABLISHES ITSELF OVER SOUTHERN
MINNESOTA INTO WEST CENTRAL WISCONSIN. EXPECT AN INITIAL ARC OF
PCPN ASSOCIATED WITH ELEVATED WARM ADVECTION TO LIFT INTO THE AREA
LATE SUNDAY NIGHT INTO MONDAY MORNING... THEN A SECONDARY
DEVELOPMENT OF PCPN BEHIND THAT OWING TO INCREASING ISENTROPIC
LIFT ALONG WITH FRONTOGENESIS AND THE ARRIVAL OF ELEVATED
INSTABILTY. IN ADDITION... SOME POTENT STORMS MAY DEVELOP TO OUR
WEST MONDAY AFTERNOON INTO MONDAY EVENING... AND WHAT IS LEFT OF
THOSE COULD WORK INTO THE AREA MONDAY NIGHT.
LOW PRESSURE IS EXPECTED TO LIFT NORTHEAST INTO NORTHWEST
MINNESOTA BY TUESDAY AFTERNOON... WORKING TO DRAG A COLD FRONT
EAST THROUGH OUR AREA SOMEWHAT EARLY IN THE DAY. THE FRONT LOOKS
TO GET ACROSS MOST OF THE MINNESOTA CWFA BY 18Z... AND THROUGH THE
WISCONSIN PORTION OF THE AREA BY MID AFTERNOON. ALTHOUGH DEEP
LAYER SHEAR SHOULD STILL BE QUITE STRONG ON TUESDAY... LOW LEVEL
SHEAR DOES NOT LOOK TO BE AS IMPRESSIVE AS IT DID YESTERDAY...
MAINLY DUE TO THE EARLIER PROGGED ARRIVAL OF THE FRONT. THE
EARLIER FROPA WOULD ALSO LIMIT INSTABILITY INTO THE AREA... WHICH
IS A NEGATIVE TOWARD THE SEVERE WEATHER POSSIBILITIES. SO... AT
THIS POINT... THE OVERALL SEVERE WEATHER CHANCES FROM MONDAY NIGHT
THROUGH TUESDAY DO NOT APPEAR PARTICULARLY HIGH ACROSS THE AREA.
BUT... IT IS STILL A FEW DAYS AWAY... SO ANY CHANGES IN THE TIMING
AND POSITION OF FEATURES COULD STILL CHANGE THINGS A BIT... SO IT
IS WORTH KEEPING AN EYE ON THE SITUATION. STRONG WESTERLY WINDS
WILL USHER IN DRIER AIR BEHIND THE FRONT LATE TUESDAY AFTERNOON
INTO TUESDAY NIGHT... WITH 850MB TEMPERATURES OF BELOW ZERO
ACTUALLY MAKING IT INTO THE AREA FOR A TIME ON WEDNESDAY INTO
WEDNESDAY NIGHT. HOWEVER... THIS CHANGE WILL BE SHORTLIVED ONCE
AGAIN... WITH RETURN FLOW AND WARMER AIR WORKING BACK INTO THE
REGION BY LATER THURSDAY AND INTO FRIDAY. CHANCES FOR SHOWERS AND
A FEW THUNDERSTORMS WILL ACCOMPANY THE RETURN OF WARMER
TEMPERATURES THURSDAY INTO FRIDAY WITH PERHAPS SOME SHOWER CHANCES
LINGERING INTO SATURDAY AS A SHORTWAVE MOVES BY TO OUR NORTH.
&&
.AVIATION... /18Z TAF ISSUANCE/
/ISSUED 1246 PM CDT SAT MAR 24 2012/
CONTINUED IMPROVEMENT THIS AFTERNOON WITH CEILINGS BECOMING VFR
FROM KSTC AND KMSP ON EASTWARD DURING THE MID TO LATE AFTERNOON
HOURS. HOLES ARE DEVELOPING QUICKLY IN THE VISIBLE IMAGERY
BETWEEN KMSP AND KDLH. KAXN AND KRWF ARE IN THE CLEAR BUT THE
CONCERN FOR THESE TWO SITES...ESPECIALLY KAXN IS THE EXTENSIVE
STRATUS BEHIND THE COLD FRONT OVER PORTIONS OF ND/SD. HAVE TIMED
SOME BKN010 INTO KAXN THIS EVENING AS WELL AS KSTC DURING THE LATE
EVENING. BOTH THE NAM AND GFS LOW LEVEL RH FIELDS WOULD SUPPORT A
BAND OF LOW MVFR CEILINGS. IN FACT...IF THIS DOES OCCUR...THE
CEILINGS WILL LIKELY RIDE ALL THE WAY THROUGH THE TWIN CITIES
DURING THE LATE NIGHT HOURS AND ACROSS WEST CENTRAL WI EARLY
SUNDAY MORNING. CONFIDENCE IS NOT HIGH AND ONLY SCT CONDITIONS USED
AT THIS POINT. LIGHT WINDS THIS AFTERNOON BECOMING NORTHWEST WITH
FROPA WITH SPEEDS OF 8-10 KNOTS A FEW HOURS AFTER THE FRONT GOES
THROUGH.
KMSP...IMPROVEMENT TO A VFR CEILING OR PERHAPS JUST SCT CONDITIONS
STILL EXPECTED BY 21Z. WINDS THIS AFTERNOON WILL BE LIGHT AND FROM
THE NORTHWEST. A DRY COLD FRONT WILL MOVE ACROSS THE AIRFIELD
AROUND 03Z TONIGHT. WINDS WILL BECOME MORE NORTHERLY (330-350)
WITH SPEEDS UP TO 10 KNOTS FOR THE OVERNIGHT HOURS. ONE CONCERN
TONIGHT IS THE POSSIBILITY OF BKN-OVC010-015 DURING THE LATE NIGHT
HOURS. THIS WOULD PRIMARILY BE AFTER 06Z AND LAST UNTIL NEAR 12Z.
CONFIDENCE IS NOT HIGH ON OCCURRENCE WITH SCT CONDITIONS INDICATED
FOR NOW.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
.../RAH
AREA FORECAST DISCUSSION
NWS DULUTH MN
1242 PM CDT SAT MAR 24 2012
.AVIATION...18Z TAFS
IFR CONDITIONS COVERED MUCH OF THE NORTHLAND...BUT SATELLITE AND
OBSERVATIONS BOTH REVEAL RISING AND THINNING CEILINGS. VFR
CONDITIONS WILL DEVELOP IN SPOTS FOR A FEW HOURS...THEN MVFR/HIGH
IFR CEILINGS WILL MOVE BACK IN BEHIND A COLD FRONT. CEILINGS WILL
LIFT AND SCATTER OUT LATER TONIGHT BEHIND THE COLD FRONT.
THE FRONT MAY BRING A FEW SHOWERS AHEAD OF IT AND SOME GUSTY WINDS
UPON PASSAGE. SUNDAY WILL FEATURE VFR CONDITIONS.
&&
.PREV DISCUSSION... /ISSUED 1153 AM CDT SAT MAR 24 2012/
UPDATE...DENSE FOG HAS LESSENED CONSIDERABLY ACROSS THE REGION AS
OF LATE MORNING. LATEST RUC13 SHOWS MID LVL FLOW IS INCREASING AND
ASSOCIATED SFC FRONT HAS PASSED THROUGH A KBDE/KFGN TO KGWR LINE.
TEMPS IN 30S/40S BEHIND FRONT ACROSS NE NDAK. 88D HS BEEN SHOWING
CONVECTIVE APPEARING ECHOES QUICKLY PASSING ACROSS NWRN CWA AHEAD
OF FRONT. MAINLY MID LVL AT THIS POINT. ZFP/PFM PRODUCTS UPDATED.
PREV DISCUSSION... /ISSUED 946 AM CDT SAT MAR 24 2012/
UPDATE...EXTENDED DFA THRU 18Z OVER WRN CWA AND 21Z FOR ERN
ZONES. ALSO ADDED IRON COUNTY. WEDGE OF HIGH PRESSURE STILL
LODGED ACROSS LAKE SUPERIOR...RIDGING SOUTHWEST TOWARD KAIT.
VISIBILITIES HAVE BEEN AROUND 1/4SM-1/2SM. MSAS SHOWS SFC LOW HAS
DEVELOPED WITHIN INVERTED TROUGH OVER SWRN CORNER OF ONT. TRAILING
COLD FRONT THROUGH KGFK INTO NCTRL SD. LATEST NWP SHOWS POTENTIAL
FOR PRE-FRONTAL THETAE AXIS TO INITIATE CONVECTION ONCE BDRY LYR
MIXING/WARMING DEVELOPS LATER TODAY. OZ SPC WRF SHOWS THIN LINE OF
RW DEVELOPING AFTER 21Z OVER NWRN CWA AND MOVING SE INTO WISC THIS
EVENING. MAY NEED TO ADD LOW POPS OVER NWRN WISC IN LATER FCST IF
PRECIP DOES MATERIALIZE. FCST MAX TEMPS VERY TRICKY. AS LONG AS
STRATUS/FOG LAYER RESIDES OVERHEAD DIURNAL CURVE IS RESTRICTED.
HOWEVER EXISTING FCST IS BASED ON EVENTUAL WARM ADVECTION INCREASE
JUST AHEAD OF APPROACHING FRONT. MOST IMPORTANTLY...ENOUGH
DECREASE IN CLOUD LAYER WILL NEED TO OCCUR TO ALLOW ABOUT A 3HR
WINDOW OF PARTIAL SUNSHINE.
PREV DISCUSSION... /ISSUED 700 AM CDT SAT MAR 24 2012/
AVIATION.../12Z TAF ISSUANCE/
LIFR TO IFR CONDITIONS ARE WIDESPREAD ACROSS THE AREA THIS EARLY
MORNING. AS THE MORNING WEARS ON...CONDITIONS WILL LARGELY IMPROVE
TO MVFR OR EVEN VFR...AS DRIER LOW LEVEL AIR SPREADS IN. A COLD
FRONT WILL MOVE ACROSS THE NORTHLAND LATER TODAY OR DURING THE
EVENING. IN THE VICINITY OF THE FRONT...SOME ADDITIONAL MVFR
CONDITIONS WILL BE POSSIBLE.
PREV DISCUSSION... /ISSUED 415 AM CDT SAT MAR 24 2012/
SHORT TERM...LATEST SURFACE ANALYSIS SHOWS A TROUGH OF LOW
PRESSURE OVER THE DAKOTAS...WITH A COLD FRONT EXTENDING SOUTH OF
THE TROUGH ACROSS WRN NEBRASKA AND ERN COLORADO. THERE IS ALSO A
WARM FRONT SHOWING UP ON THE SURFACE ANALYSIS...GENERALLY FROM
ERN SODAK ACROSS IOWA AND CNTL ILLINOIS. NORTH OF THE WARM FRONT
ACROSS MUCH OF THE UPPER MIDWEST...INCLUDING THE NORTHLAND...THE LOW-
LEVELS HAVE BECOME SATURATED...RESULTING IN WIDESPREAD FOG.
ACROSS OUR CWA...THE FOG HAS BECOME DENSE IN MANY AREAS...AND
ESPECIALLY AROUND LAKE SUPERIOR. AS A RESULT...WE HAVE EXPANDED
THE DENSE FOG ADVISORY TO INCLUDE THE BRAINERD LAKES REGION...IRON
RANGE...ARROWHEAD AND SOUTHSHORE. THE FOG SHOULD GRADUALLY
DISSIPATE AFTER SUNRISE...AND LIFT BY MIDDAY.
THE AFOREMENTIONED WARM FRONT IS THEN PROGGED TO LIFT NEWD ACROSS
THE UPPER MIDWEST TODAY...BRIEFLY BRINGING THE WARM SECTOR ACROSS
THE REGION...RESULTING IN HIGHS IN THE 60S FOR MOST LOCATIONS THIS
AFTERNOON. THE COLD FRONT WILL TRACK EWD ACROSS THE CWA THIS
AFTERNOON AND EVENING...BRINGING COOLER AND MUCH DRIER AIR TO THE
NORTHLAND LATER TONIGHT INTO SUNDAY. THE COLD FRONT MAY ALSO
TRIGGER A FEW SHOWERS AND STORMS ACROSS OUR MN ZONES THIS
AFTERNOON AS IT MOVES THROUGH.
LONG TERM...SUNDAY NIGHT THROUGH FRIDAY.
UPPER LEVEL RIDGING WILL MOVE INTO THE REGION SUNDAY NIGHT AND
MONDAY...AS STRONG LOW LEVEL WAA INITIATES DURING THE FIRST PART
OF THE WORK WEEK. A 50 KNOT LLJ WILL BE IN PLACE BY MONDAY EVENING
ACROSS THE UPPER MIDWEST...AS A SURFACE LOW PRESSURE SYSTEM MOVES
INTO THE DAKOTAS. HEIGHTS WILL DROP CONSIDERABLY AS A CLOSED LOW
DEVELOPS OVER MINNESOTA BY LATE TUESDAY. THE ECMWF APPEARS TO
OFFER A COMPROMISE SOLUTION BETWEEN THE FURTHER NORTH GFS AND THE
STRONGER AND FURTHER WEST GEM SOLUTION. BASED ON THE ECMWF
SOLUTION...SHOWERS AND THUNDERSTORMS WILL BE LIKELY FOR THE EARLY
TO MID PART OF THE WEEK. H5 HEIGHTS WILL BEGIN TO BUILD ONCE AGAIN
BY THURSDAY...AHEAD OF THE NEXT SYSTEM TO MOVE INTO THE REGION
THURSDAY AND FRIDAY. FOR THE LATE WEEK SYSTEM...IT APPEARS THERE
WILL BE AN AMPLE SUPPLY OF MOISTURE FROM THE GULF OF
MEXICO...RESULTING IN MORE SHOWERS AND THUNDERSTORMS FOR THE LAST
PART OF THE WEEK. TEMPERATURES ARE STILL EXPECTED TO BE ABOVE
NORMAL THROUGHOUT THE ENTIRE EXTENDED TIME PERIOD...ALTHOUGH
COOLER THAN WHAT IT HAS BEEN AWAY FROM THE LAKE RECENTLY.
&&
.POINT TEMPS/POPS...
DLH 34 50 29 40 / 10 10 10 10
INL 26 45 25 45 / 10 10 0 20
BRD 33 53 35 47 / 10 10 20 40
HYR 38 56 31 50 / 10 10 10 20
ASX 38 50 30 44 / 10 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...DENSE FOG ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ121-
140>148.
&&
$$
SHORT TERM...CANNON
LONG TERM....DAP
AVIATION...MELDE
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1153 AM CDT SAT MAR 24 2012
.UPDATE...DENSE FOG HAS LESSENED CONSIDERABLY ACROSS THE REGION AS
OF LATE MORNING. LATEST RUC13 SHOWS MID LVL FLOW IS INCREASING AND
ASSOCIATED SFC FRONT HAS PASSED THROUGH A KBDE/KFGN TO KGWR LINE.
TEMPS IN 30S/40S BEHIND FRONT ACROSS NE NDAK. 88D HS BEEN SHOWING
CONVECTIVE APPEARING ECHOES QUICKLY PASSING ACROSS NWRN CWA AHEAD
OF FRONT. MAINLY MID LVL AT THIS POINT. ZFP/PFM PRODUCTS UPDATED.
&&
.PREV DISCUSSION... /ISSUED 946 AM CDT SAT MAR 24 2012/
UPDATE...EXTENDED DFA THRU 18Z OVER WRN CWA AND 21Z FOR ERN
ZONES. ALSO ADDED IRON COUNTY. WEDGE OF HIGH PRESSURE STILL
LODGED ACROSS LAKE SUPERIOR...RIDGING SOUTHWEST TOWARD KAIT.
VISIBILITIES HAVE BEEN AROUND 1/4SM-1/2SM. MSAS SHOWS SFC LOW HAS
DEVELOPED WITHIN INVERTED TROUGH OVER SWRN CORNER OF ONT. TRAILING
COLD FRONT THROUGH KGFK INTO NCTRL SD. LATEST NWP SHOWS POTENTIAL
FOR PRE-FRONTAL THETAE AXIS TO INITIATE CONVECTION ONCE BDRY LYR
MIXING/WARMING DEVELOPS LATER TODAY. OZ SPC WRF SHOWS THIN LINE OF
RW DEVELOPING AFTER 21Z OVER NWRN CWA AND MOVING SE INTO WISC THIS
EVENING. MAY NEED TO ADD LOW POPS OVER NWRN WISC IN LATER FCST IF
PRECIP DOES MATERIALIZE. FCST MAX TEMPS VERY TRICKY. AS LONG AS
STRATUS/FOG LAYER RESIDES OVERHEAD DIURNAL CURVE IS RESTRICTED.
HOWEVER EXISTING FCST IS BASED ON EVENTUAL WARM ADVECTION INCREASE
JUST AHEAD OF APPROACHING FRONT. MOST IMPORTANTLY...ENOUGH
DECREASE IN CLOUD LAYER WILL NEED TO OCCUR TO ALLOW ABOUT A 3HR
WINDOW OF PARTIAL SUNSHINE.
PREV DISCUSSION... /ISSUED 700 AM CDT SAT MAR 24 2012/
AVIATION.../12Z TAF ISSUANCE/
LIFR TO IFR CONDITIONS ARE WIDESPREAD ACROSS THE AREA THIS EARLY
MORNING. AS THE MORNING WEARS ON...CONDITIONS WILL LARGELY IMPROVE
TO MVFR OR EVEN VFR...AS DRIER LOW LEVEL AIR SPREADS IN. A COLD
FRONT WILL MOVE ACROSS THE NORTHLAND LATER TODAY OR DURING THE
EVENING. IN THE VICINITY OF THE FRONT...SOME ADDITIONAL MVFR
CONDITIONS WILL BE POSSIBLE.
PREV DISCUSSION... /ISSUED 415 AM CDT SAT MAR 24 2012/
SHORT TERM...LATEST SURFACE ANALYSIS SHOWS A TROUGH OF LOW
PRESSURE OVER THE DAKOTAS...WITH A COLD FRONT EXTENDING SOUTH OF
THE TROUGH ACROSS WRN NEBRASKA AND ERN COLORADO. THERE IS ALSO A
WARM FRONT SHOWING UP ON THE SURFACE ANALYSIS...GENERALLY FROM
ERN SODAK ACROSS IOWA AND CNTL ILLINOIS. NORTH OF THE WARM FRONT
ACROSS MUCH OF THE UPPER MIDWEST...INCLUDING THE NORTHLAND...THE LOW-
LEVELS HAVE BECOME SATURATED...RESULTING IN WIDESPREAD FOG.
ACROSS OUR CWA...THE FOG HAS BECOME DENSE IN MANY AREAS...AND
ESPECIALLY AROUND LAKE SUPERIOR. AS A RESULT...WE HAVE EXPANDED
THE DENSE FOG ADVISORY TO INCLUDE THE BRAINERD LAKES REGION...IRON
RANGE...ARROWHEAD AND SOUTHSHORE. THE FOG SHOULD GRADUALLY
DISSIPATE AFTER SUNRISE...AND LIFT BY MIDDAY.
THE AFOREMENTIONED WARM FRONT IS THEN PROGGED TO LIFT NEWD ACROSS
THE UPPER MIDWEST TODAY...BRIEFLY BRINGING THE WARM SECTOR ACROSS
THE REGION...RESULTING IN HIGHS IN THE 60S FOR MOST LOCATIONS THIS
AFTERNOON. THE COLD FRONT WILL TRACK EWD ACROSS THE CWA THIS
AFTERNOON AND EVENING...BRINGING COOLER AND MUCH DRIER AIR TO THE
NORTHLAND LATER TONIGHT INTO SUNDAY. THE COLD FRONT MAY ALSO
TRIGGER A FEW SHOWERS AND STORMS ACROSS OUR MN ZONES THIS
AFTERNOON AS IT MOVES THROUGH.
LONG TERM...SUNDAY NIGHT THROUGH FRIDAY.
UPPER LEVEL RIDGING WILL MOVE INTO THE REGION SUNDAY NIGHT AND
MONDAY...AS STRONG LOW LEVEL WAA INITIATES DURING THE FIRST PART
OF THE WORK WEEK. A 50 KNOT LLJ WILL BE IN PLACE BY MONDAY EVENING
ACROSS THE UPPER MIDWEST...AS A SURFACE LOW PRESSURE SYSTEM MOVES
INTO THE DAKOTAS. HEIGHTS WILL DROP CONSIDERABLY AS A CLOSED LOW
DEVELOPS OVER MINNESOTA BY LATE TUESDAY. THE ECMWF APPEARS TO
OFFER A COMPROMISE SOLUTION BETWEEN THE FURTHER NORTH GFS AND THE
STRONGER AND FURTHER WEST GEM SOLUTION. BASED ON THE ECMWF
SOLUTION...SHOWERS AND THUNDERSTORMS WILL BE LIKELY FOR THE EARLY
TO MID PART OF THE WEEK. H5 HEIGHTS WILL BEGIN TO BUILD ONCE AGAIN
BY THURSDAY...AHEAD OF THE NEXT SYSTEM TO MOVE INTO THE REGION
THURSDAY AND FRIDAY. FOR THE LATE WEEK SYSTEM...IT APPEARS THERE
WILL BE AN AMPLE SUPPLY OF MOISTURE FROM THE GULF OF
MEXICO...RESULTING IN MORE SHOWERS AND THUNDERSTORMS FOR THE LAST
PART OF THE WEEK. TEMPERATURES ARE STILL EXPECTED TO BE ABOVE
NORMAL THROUGHOUT THE ENTIRE EXTENDED TIME PERIOD...ALTHOUGH
COOLER THAN WHAT IT HAS BEEN AWAY FROM THE LAKE RECENTLY.
AVIATION.../06Z TAF ISSUANCE/
ALONG THE LAKE SUPERIOR SHORE AND AROUND THE WESTERN NOSE
INCLUDING DLH...DYT...SUW...COQ...AND TWM...LIFR IN DENSE FOG WILL
LIFT TO MVFR IN CLOUDS ABOUT MID MORNING SATURDAY. ELSEWHERE...IFR
OR LOW-END VFR IN CLOUDS AND PATCHY FOG WILL LIFT TO MVFR IN
CLOUDS EARLY SATURDAY MORNING. CONDITIONS WILL THEN LIFT TO VFR IN
SCATTERED CLOUDS LATE SATURDAY.
&&
.POINT TEMPS/POPS...
DLH 61 34 50 29 / 10 10 10 10
INL 56 26 45 25 / 30 10 10 0
BRD 63 33 53 35 / 10 10 10 20
HYR 62 38 56 31 / 10 10 10 10
ASX 56 38 50 30 / 10 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...DENSE FOG ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ121-
140>148.
&&
$$
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
339 PM EDT SAT MAR 24 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL GRADUALLY MOVE OFFSHORE LATE SUNDAY
AND SUNDAY NIGHT. A SECONDARY COLD FRONT WILL CROSS THE AREA ON
MONDAY FOLLOWED BY STRONG COOL HIGH PRESSURE THROUGH MID WEEK.
&&
.NEAR TERM /TONIGHT/...
AS OF 330 PM SATURDAY...SHOWERS AND TSTMS HAVE BECOME WIDESPREAD
ACROSS EASTERN NORTH CAROLINA OVER THE PAST HOUR OR TWO. A REPORT
OF DIME-SIZED HAIL WAS RECEIVED FROM JONES COUNTY. THE STORMS
CROSSING THE AREA WILL HAVE THE POTENTIAL TO PRODUCE GUSTY
WINDS...SMALL HAIL AND FREQUENT LIGHTNING OVER THE NEXT 2 TO 3
HOURS. ADDITIONAL CONVECTION ASSOCIATED WITH THE ACTUAL COLD FRONT
WILL BE MORE SCATTERED PER LATEST 4 KM WRF AND RUC MODELS...BUT
COULD BE STRONG TO SEVERE LATER IN THE EVENING GIVEN BETTER
INSTABILITY OVER THE CENTRAL PORTION OF THE STATE WORKING ITS WAY
EASTWARD. HAVE LIKELY POPS TAPERING TO HIGH CHANCE AFTER 23Z. POPS
GRADUALLY DROP OVERNIGHT WITH THE SEVERE THREAT LESSENING AFTER
ABOUT 03Z OR SO. MINIMUM TEMPERATURES TONIGHT SHOULD BE IN THE 57
TO 62 DEGREE RANGE.
&&
.SHORT TERM /SUNDAY/...
AS OF 335 PM SAT...AS UPPER LOW MOVES NEAR OR JUST SOUTH OF THE
AREA DURING THE DAY ON SUNDAY WITH SURFACE LOW JUST TO OUR
NORTH...THERE WILL SUFFICIENTLY STRONG LAPSE RATES AND INSTABILITY
TO PRODUCE SCATTERED SHOWERS AND TSTMS. DUE TO THE COLD AIR
ALOFT...SOME OF THE STRONGER STORMS COULD BECOME HAIL PRODUCERS.
COVERAGE OF PRECIPITATION IS TOUGH FOR TOMORROW BUT BEST GUESS IN
TAPERING THE POPS FROM SLIGHT CHANCE FAR SOUTH TO HIGH CHANCE TO
LOW LIKELY FAR NORTH...IN CLOSER PROXIMITY TO THE SURFACE LOW.
TEMPERATURES SHOULD RANGE FROM ABOUT 73 TO 77 DEGREES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
AS OF 315 PM SAT...UPR LOW WILL MOVE THROUGH E NC SUN
NIGHT...WITH DEFORMATION AXIS PIVOTING THROUGH DURING THE EVENING.
SUFFICIENT DEEP LAYER MOISTURE WILL EXIST WITH SCT SHOWER CHANCES
AS ENOUGH LIFT WILL ACCOMPANY THE UPR LOW PASSAGE. MUCH DRIER AIR
INFILTRATES THE REGION ON NW FLOW. DESPITE THE FRONTAL PASSAGE...
TEMPS WILL BE QUITE WARM MON AFTERNOON COMPLIMENTS OF DOWNSLOPING
FLOW OFF APPALACHIANS. THE STEEP LAPSE RATES WILL LEND TO GUSTY
WINDS FOR MON UNDER SUNNY SKIES.
HIGH PRES WILL NOSE INTO THE AREA MON NIGHT WITH WINDS BECOMING
LIGHT. THERE MAY BE SOME SCT FROST FOR AREAS AWAY FROM THE COAST
WITH MINS DROPPING INTO THE MID 30S. ATTM NOT EXPECTING FREEZING
TEMPS THOUGH WITH TD`S NEAR 30...COMPLETE DECOUPLING WOULD ALLOW
FOR SOME FAVORED LOCATIONS INLAND TO DIP DOWN NEAR FREEZING.
REINFORCING SURGE OF NORTHERLY FLOW OCCURS TUE WITH LOW LEVEL
THICKNESSES FALLING A BIT...AND MAX TEMPS WILL GENERALLY BE IN THE
LOW TO MID 60S. ANOTHER COOL NIGHT EXPECTED TUE NIGHT AS SFC HIGH
PRES WILL BE CENTERED OVERHEAD.
RETURN FLOW COMMENCES ON WED WITH WSW FLOW ALLOWING FOR MAX TEMPS
TO REBOUND INTO THE MID 70S. A SHORTWAVE TROUGH WILL SWING THROUGH
NORTH OF THE AREA WED EVENING BRINGING A SMALL CHANCE OF TRW FOR
NORTHERN PORTIONS OF THE CWA...THOUGH THIS FRONTAL PASSAGE WILL BE
MOISTURE STARVED SO NOT EXPECTING MUCH IN THE WAY OF QPF.
THUR AND FRI WILL FEATURE SEASONABLY MILD TEMPERATURES AND DRY
CONDITIONS WITH ZONAL FLOW ALOFT AND SFC HIGH PRES IN THE AREA.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH SUNDAY/
AS OF 1235 PM SATURDAY...CEILINGS ARE VFR AT PGV AND OAJ AND HAVE
IMPROVED TO MVFR AT EWN AND ISO AS MIXING INCREASES. SCATTERED
SHOWERS AND TSTMS ARE POSSIBLE THRU THE AFTERNOON HOURS INTO THIS
EVENING WITH PERIODS OF LOWER CEILINGS AND VSBYS LIKELY. FOR
TONIGHT AND SUNDAY...AFTER SOME LIKELY DRY-SLOTTING EARLY IN THE
EVENING...MOST ALL GUIDANCE INDICATES IFR AND POSSIBLE LIFR
CEILINGS AS LOW LEVEL MOISTURE LINGERS THROUGH LATE TONIGHT AND
SUNDAY MORNING...BEFORE CONDITIONS IMPROVE MONDAY.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 315PM SAT...COULD BE SOME MVFR CIGS SUN NIGHT AS UPR LOW
SWINGS THROUGH THE AREA WITH SCT SHOWERS. MOISTURE WILL ERODE
QUICKLY ON MON AS DRY AIR FILTERS IN WITH MOSTLY SUNNY SKIES.
WINDS WILL BECOME NW AND BECOME A BIT GUSTY ON MON. DRY CONDITIONS
EXPECTED THROUGH MIDWEEK AS HIGH PRES WILL BE IN THE AREA.
&&
.MARINE...
SHORT TERM /THROUGH SUNDAY/
AS OF 335 PM SATURDAY...HAVE ADJUSTED START TIME OF SCA TO SUNDAY
MORNING AS WINDS/SEAS WILL BE A BIT SLOWER TO RAMP UP PER LATEST
MODELS. WINDS STILL BELOW 15 KNOTS AND SEAS GENERALLY 2 TO 3 FEET
CURRENTLY. GUSTY SOUTHWEST WINDS AND SOUTHWEST WAVE ENERGY DUE TO
THE COMBINATION OF APPROACHING COLD FRONT AND HIGH PARKED NEAR
BERMUDA WILL LEAD TO SOME 6 FOOT SEAS...ESPECIALLY OVER THE OUTER
WATERS THROUGH THE DAY SUNDAY.
LONG TERM SUNDAY THROUGH WEDNESDAY/...
AS OF 3 PM SAT...IT APPEARS THERE WILL BE A BRIEF WINDOW OF SEAS
AND WINDS TO BE BELOW SCA CONDITIONS FOR SUN EVENING. BY 12Z
MON...WINDS AND SEAS WILL INCREASE DRASTICALLY AS COLD FRONT MOVES
THROUGH THE WATERS WITH STRONG CAA OCCURRING. SCA WILL BE LIKELY
FOR THE WATERS AND SOUNDS BY MON MORNING. A REINFORCING SHOT OF
NORTHERLY WINDS MON NIGHT INTO TUE WILL KEEP SCA CONDITIONS FOR
MOST OF THE WATERS. WINDS AND SEAS WILL BE HIGHEST FOR THE
NORTHERN/CENTRAL WATERS WITH SEAS OF 7 TO 9 FEET EXPECTED HERE.
WINDS AND SEAS SHOULD DIMINISH BELOW SCA BY TUE EVENING.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 8 PM EDT SUNDAY
FOR AMZ152-154-156-158.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...TL
AVIATION...CTC/TL
MARINE...CTC/TL
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
323 PM EDT SAT MAR 24 2012
.SYNOPSIS...
LOW PRESSURE OVER THE OHIO VALLEY WILL MOVE EAST THEN SOUTHEAST
TODAY AND TONIGHT. BY SUNDAY NIGHT THE LOW WILL BE OFF THE CAROLINA
COAST. HIGH PRESSURE WILL BUILD OVER THE REGION MONDAY AND
TUESDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 300 PM EDT SATURDAY...
UPDATED ISC GRIDS FOR SEVERE THUNDERSTORM WATCH 107 IN EFFECT
UNTIL 10 PM TONIGHT.
AS OF 1250 PM SATURDAY...
UPDATED ISC GRIDS FOR SEVERE THUNDERSTORM WATCH 105 IN EFFECT
UNTIL 8 PM EDT THIS EVENING.
AS OF 1150 AM EDT SATURDAY...
CONVECTION WHICH TAPERED OFF THIS MORNING ALLOWING SOME SUNSHINE TO
RETURN FOR THE WEST...WILL REDEVELOP THIS AFTERNOON INTO TONIGHT.
SOME OF THE STORMS WILL BE STRONG TO SEVERE WITH THE POTENTIAL
FOR LOCALLY HEAVY RAINS. THE UPPER LOW TO OUR WEST WILL STEADILY
APPROACH THIS AFTERNOON AND MOVE ACROSS THE SRN APPALACHIANS
TONIGHT. LIKE THE HRRR FOR EARLY THIS AFTERNOON AND SHAPE POPS
CLOSE TO SOLUTION.
AS OF 915 AM EDT SATURDAY...
ADJUSTED TEMPERATURES AND POPS ACCORDING TO LATEST OBS AND RADAR
TRENDS. EXPANDED THE MENTION OF GUSTY WINDS AND HAIL FURTHER NORTH
TO MATCH SPC LATEST DAY1 OUTLOOK. HWO WAS UPDATED. PNS OUT FOR
HIGH MIN TEMPERATURES. ALSO ANOTHER PNS COMING OUT FOR RAINFALL
AMOUNTS. THE UPPER LOW IS MOVING EAST WITH COLD POOL WHICH WILL
RESULT IN NUMEROUS SHOWERS AND THUNDERSTORMS THIS AFTERNOON INTO
TONIGHT. LOOK FOR SEVERAL ISC UPDATES TODAY WITH THE ACTIVE
WEATHER EXPECTED.
AS OF 410 AM EDT SATURDAY...
EXPECTING SEVERAL BANDS OF SHOWERS AND THUNDERSTORMS TODAY AND
TONIGHT. FIRST AREA WAS OVER THE CENTRAL AND EASTERN COUNTY
WARNING AREA EARLY THIS MORNING AND WAS MOVING NORTHEAST AROUND 20
MPH. THE NEXT BAND EXTENDS FROM OHIO INTO EASTERN TENNESSEE. LOCAL
WRF AND HRRR BRING THIS BAND INTO THE WESTERN COUNTY WARNING AREA
BY 8AM.
AS THE UPPER LOW MOVES EAST THIS MOVING SO WILL THE SHOWERS AND
THUNDERSTORMS. ADDITIONAL SHOWERS AND THUNDERSTORMS WILL DEVELOP
OVER THE FORECAST AREA THIS AFTERNOON. COLDER AIR ALOFT
ASSOCIATED WITH THE UPPER LOW WILL REACH THE FORECAST AREA
TODAY...CREATING LARGE LAPSE RATES AND LOWERING THE FREEZING
LEVEL. GUSTY WINDS AND LARGE HAIL WILL BE A THREAT WITH ANY
STRONGER STORMS...ESPECIALLY THIS AFTERNOON AND EVENING.
THE UPPER LOW MOVES SOUTHEAST INTO SOUTH CAROLINA BY SUNDAY
MORNING. EXPECT COVERAGE AND PROBABILITY OF PRECIPITATION TO
DECREASE LATE TONIGHT.
THERE WAS A BREAK IN THE CLOUD COVER AHEAD OF THE SHOWERS AND
THUNDERSTORMS APPROACHING FROM THE WEST. FOG MAY DEVELOP EARLY
THIS MORNING AS THE CLOUDS BRIEFLY CLEAR. WITH ALL THE
PRECIPITATION EXPECTED TODAY...HAVE GONE ON THE COOL SIDE OF
GUIDANCE. STAYED CLOSE TO A BLEND OF BIAS CORRECTED MAV/MET
GUIDANCE FOR LOWS TONIGHT.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
AS OF 330 AM EST SATURDAY...
SUNDAY MORNING WILL START OUT WITH THE UPPER LEVEL LOW PASSING JUST
TO THE SOUTH OF OUR AREA...POSSIBLY CLIPPING OUR NORTH CAROLINA
COUNTIES. IN ANY EVENT...EXPECT TO SEE GREATER COVERAGE OF SHOWER
ACTIVITY NORTH OF INTERSTATE 81...AS A SLOT OF DRIER AIR WORKS ITS
WAY IN SOUTH CLOSER TO THE LOW. COVERAGE WILL INCREASE FURTHER
DURING THE AFTERNOON AS DAYTIME HEATING HELPS DESTABILIZE THE
ATMOSPHERE...AND WILL NOT BE SURPRISED TO SEE A FEW THUNDERSTORMS
DEVELOP BY LATE MORNING. WITH THE UPPER LOW PASSING SO CLOSE TO OUR
AREA...BELIEVE THAT HAIL WILL BE A CONCERN IN THE STRONGER SHOWER
AND THUNDERSTORM ACTIVITY...BUT EXPECT MOST HAIL TO BE IN THE PEA TO
DIME SIZE RANGE WHERE IT OCCURS. SHOWER AND THUNDERSTORM ACTIVITY
WILL DECREASE FROM WEST TO EAST BY LATE AFTERNOON AS THE UPPER LOW
CONTINUES TO PUSH OFF THE ATLANTIC COAST...AND SHOWER ACTIVITY IS
EXPECTED TO BE CONFINED TO THE MOUNTAINS...MAINLY IN SOUTHEAST WEST
VIRGINIA BY LATE SUNDAY EVENING. DESPITE THE PASSAGE OF THE UPPER
LOW...SUNDAY NIGHT TEMPERATURES WILL REMAIN MILD ACROSS OUR
AREA...WITH OVERNIGHT LOWS RANGING FROM THE LOW TO MID 50S EAST...TO
THE UPPER 40S WEST.
IT WILL BE MONDAY MORNING WHEN WE SEE A CHANGE IN OUR WEATHER
PATTERN AS ANOTHER COLD FRONT BRINGS A SHOT OF COOLER CANADIAN AIR
INTO OUR AREA. MONDAY AFTERNOON TEMPERATURES ARE EXPECTED TO REMAIN
MILD ACROSS OUR AREA...ALBEIT A LITTLE COOLER...HOWEVER IT WILL BE
MONDAY NIGHT/TUESDAY MORNING TEMPERATURES THAT WILL BE OF CONCERN AS
LOWS FALL INTO THE 30S ACROSS THE MOUNTAINS. BELIEVE THAT NEAR
FREEZING TEMPERATURES WILL BE CONFINED TO GREENBRIER COUNTY IN
SOUTHEAST WEST VIRGINIA...AS WELL AS THE ALLEGHANY HIGHLANDS IN
VIRGINIA...LOCATIONS THAT HAVE NOT EXPERIENCED A START TO THE
GROWING SEASON TO THE SAME EXTENT THAT HAS OCCURRED IN LOWER
ELEVATIONS. THAT STATED...IT WOULD BE A GOOD IDEA TO CONSIDER
PRECAUTIONS AGAINST THE COLD FOR ANY SENSITIVE VEGETATION WHICH HAS
STARTED TO GROW IN YOUR AREA.
HIGH PRESSURE WILL SLIDE EAST ON TUESDAY AFTERNOON...ALLOWING WINDS
TO BECOME SOUTHERLY ACROSS OUR AREA. WITH A RIDGE OF UPPER LEVEL
HIGH PRESSURE BUILDING IN FROM THE WEST LATE TUESDAY EVENING...
OVERNIGHT TEMPERATURES WILL BE CONSIDERABLY WARMER...WITH LOWS
EXPECTED TO RANGE FROM THE MID 40S IN THE WEST...TO THE UPPER 30S IN
THE EAST.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 330 AM EDT SATURDAY...
ON WEDNESDAY...A HIGH PRESSURE RIDGE WILL SLIDE EAST OFF THE COAST.
SOUTHERLY FLOW RETURNS WITH MODERATING TEMPERATURES FOR THE
REMAINDER OF THE WORK WEEK. LIGHT RAIN SHOWERS ARE POSSIBLE
WEDNESDAY INTO THURSDAY AS A WEAK COOL FRONT PASSES OVER THE REGION.
THIS RAIN WILL NOT BE ANY WHERE CLOSE IN INTENSITY TO THIS WEEKENDS
RAIN EVENT.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
AS OF 1159 AM EDT SATURDAY...
EXPECT SEVERAL PERIODS OF SHOWERS AND THUNDERSTORMS ACROSS
THE FORECAST AREA THROUGH 06Z SUNDAY. CEILINGS AND VISIBILITIES
WILL LOWER TO MVFR/IFR IN ASSOCIATION WITH THE SHOWERS AND STORMS.
SOME OF THE STRONGER STORMS TODAY MAY PRODUCE GUSTY WINDS AND
LARGE HAIL...MAINLY THIS AFTERNOON AND EVENING.
COVERAGE OF PRECIPITATION WILL DIMINISH TONIGHT. LOW CLOUDS AND
FOG WILL FILL IN OVERNIGHT WITH CEILINGS LOWERING TO IFR/MVFR
LEVELS. HAVE LOWERED VISIBILITY TO LIFR AT LYH WITH MEDIUM
CONFIDENCE. IF NORTHWEST SURFACE AND LOW LEVEL WINDS ARE A LITTLE
STRONGER THAN EXPECTED THEN PROBABILITY OF LIFR OR IFR FOG WILL BE
LOWER.
SHRA WILL DEVELOP AGAIN ACROSS THE AREA SUN...BUT WITH
CONSIDERABLE LESS INSTABILITY INDICATED AND A COLDER/MORE STABLE
SFC ENVIRONMENT...DO NOT ANTICIPATE MUCH TSRA ACTIVITY SUN...JUST
SHOWERS.
DRIER WEATHER AND VFR CONDITIONS ARE EXPECTED BEHIND THIS WEATHER
SYSTEM SUNDAY NIGHT THROUGH TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...PC
LONG TERM...PC
AVIATION...AMS/KK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1257 PM EDT SAT MAR 24 2012
.SYNOPSIS...
LOW PRESSURE OVER THE OHIO VALLEY WILL MOVE EAST THEN SOUTHEAST
TODAY AND TONIGHT. BY SUNDAY NIGHT THE LOW WILL BE OFF THE CAROLINA
COAST. HIGH PRESSURE WILL BUILD OVER THE REGION MONDAY AND
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1250 PM SATURDAY...
UPDATED ISC GRIDS FOR SEVERE THUNDERSTORM WATCH 105 IN EFFECT
UNTIL 8 PM EDT THIS EVENING.
AS OF 1150 AM EDT SATURDAY...
CONVECTION WHICH TAPERED OFF THIS MORNING ALLOWING SOME SUNSHINE TO
RETURN FOR THE WEST...WILL REDEVELOP THIS AFTERNOON INTO TONIGHT.
SOME OF THE STORMS WILL BE STRONG TO SEVERE WITH THE POTENTIAL
FOR LOCALLY HEAVY RAINS. THE UPPER LOW TO OUR WEST WILL STEADILY
APPROACH THIS AFTERNOON AND MOVE ACROSS THE SRN APPALACHIANS
TONIGHT. LIKE THE HRRR FOR EARLY THIS AFTERNOON AND SHAPE POPS
CLOSE TO SOLUTION.
AS OF 915 AM EDT SATURDAY...
ADJUSTED TEMPERATURES AND POPS ACCORDING TO LATEST OBS AND RADAR
TRENDS. EXPANDED THE MENTION OF GUSTY WINDS AND HAIL FURTHER NORTH
TO MATCH SPC LATEST DAY1 OUTLOOK. HWO WAS UPDATED. PNS OUT FOR
HIGH MIN TEMPERATURES. ALSO ANOTHER PNS COMING OUT FOR RAINFALL
AMOUNTS. THE UPPER LOW IS MOVING EAST WITH COLD POOL WHICH WILL
RESULT IN NUMEROUS SHOWERS AND THUNDERSTORMS THIS AFTERNOON INTO
TONIGHT. LOOK FOR SEVERAL ISC UPDATES TODAY WITH THE ACTIVE
WEATHER EXPECTED.
AS OF 410 AM EDT SATURDAY...
EXPECTING SEVERAL BANDS OF SHOWERS AND THUNDERSTORMS TODAY AND
TONIGHT. FIRST AREA WAS OVER THE CENTRAL AND EASTERN COUNTY
WARNING AREA EARLY THIS MORNING AND WAS MOVING NORTHEAST AROUND 20
MPH. THE NEXT BAND EXTENDS FROM OHIO INTO EASTERN TENNESSEE. LOCAL
WRF AND HRRR BRING THIS BAND INTO THE WESTERN COUNTY WARNING AREA
BY 8AM.
AS THE UPPER LOW MOVES EAST THIS MOVING SO WILL THE SHOWERS AND
THUNDERSTORMS. ADDITIONAL SHOWERS AND THUNDERSTORMS WILL DEVELOP
OVER THE FORECAST AREA THIS AFTERNOON. COLDER AIR ALOFT
ASSOCIATED WITH THE UPPER LOW WILL REACH THE FORECAST AREA
TODAY...CREATING LARGE LAPSE RATES AND LOWERING THE FREEZING
LEVEL. GUSTY WINDS AND LARGE HAIL WILL BE A THREAT WITH ANY
STRONGER STORMS...ESPECIALLY THIS AFTERNOON AND EVENING.
THE UPPER LOW MOVES SOUTHEAST INTO SOUTH CAROLINA BY SUNDAY
MORNING. EXPECT COVERAGE AND PROBABILITY OF PRECIPITATION TO
DECREASE LATE TONIGHT.
THERE WAS A BREAK IN THE CLOUD COVER AHEAD OF THE SHOWERS AND
THUNDERSTORMS APPROACHING FROM THE WEST. FOG MAY DEVELOP EARLY
THIS MORNING AS THE CLOUDS BRIEFLY CLEAR. WITH ALL THE
PRECIPITATION EXPECTED TODAY...HAVE GONE ON THE COOL SIDE OF
GUIDANCE. STAYED CLOSE TO A BLEND OF BIAS CORRECTED MAV/MET
GUIDANCE FOR LOWS TONIGHT.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 330 AM EST SATURDAY...
SUNDAY MORNING WILL START OUT WITH THE UPPER LEVEL LOW PASSING JUST
TO THE SOUTH OF OUR AREA...POSSIBLY CLIPPING OUR NORTH CAROLINA
COUNTIES. IN ANY EVENT...EXPECT TO SEE GREATER COVERAGE OF SHOWER
ACTIVITY NORTH OF INTERSTATE 81...AS A SLOT OF DRIER AIR WORKS ITS
WAY IN SOUTH CLOSER TO THE LOW. COVERAGE WILL INCREASE FURTHER
DURING THE AFTERNOON AS DAYTIME HEATING HELPS DESTABILIZE THE
ATMOSPHERE...AND WILL NOT BE SURPRISED TO SEE A FEW THUNDERSTORMS
DEVELOP BY LATE MORNING. WITH THE UPPER LOW PASSING SO CLOSE TO OUR
AREA...BELIEVE THAT HAIL WILL BE A CONCERN IN THE STRONGER SHOWER
AND THUNDERSTORM ACTIVITY...BUT EXPECT MOST HAIL TO BE IN THE PEA TO
DIME SIZE RANGE WHERE IT OCCURS. SHOWER AND THUNDERSTORM ACTIVITY
WILL DECREASE FROM WEST TO EAST BY LATE AFTERNOON AS THE UPPER LOW
CONTINUES TO PUSH OFF THE ATLANTIC COAST...AND SHOWER ACTIVITY IS
EXPECTED TO BE CONFINED TO THE MOUNTAINS...MAINLY IN SOUTHEAST WEST
VIRGINIA BY LATE SUNDAY EVENING. DESPITE THE PASSAGE OF THE UPPER
LOW...SUNDAY NIGHT TEMPERATURES WILL REMAIN MILD ACROSS OUR
AREA...WITH OVERNIGHT LOWS RANGING FROM THE LOW TO MID 50S EAST...TO
THE UPPER 40S WEST.
IT WILL BE MONDAY MORNING WHEN WE SEE A CHANGE IN OUR WEATHER
PATTERN AS ANOTHER COLD FRONT BRINGS A SHOT OF COOLER CANADIAN AIR
INTO OUR AREA. MONDAY AFTERNOON TEMPERATURES ARE EXPECTED TO REMAIN
MILD ACROSS OUR AREA...ALBEIT A LITTLE COOLER...HOWEVER IT WILL BE
MONDAY NIGHT/TUESDAY MORNING TEMPERATURES THAT WILL BE OF CONCERN AS
LOWS FALL INTO THE 30S ACROSS THE MOUNTAINS. BELIEVE THAT NEAR
FREEZING TEMPERATURES WILL BE CONFINED TO GREENBRIER COUNTY IN
SOUTHEAST WEST VIRGINIA...AS WELL AS THE ALLEGHANY HIGHLANDS IN
VIRGINIA...LOCATIONS THAT HAVE NOT EXPERIENCED A START TO THE
GROWING SEASON TO THE SAME EXTENT THAT HAS OCCURRED IN LOWER
ELEVATIONS. THAT STATED...IT WOULD BE A GOOD IDEA TO CONSIDER
PRECAUTIONS AGAINST THE COLD FOR ANY SENSITIVE VEGETATION WHICH HAS
STARTED TO GROW IN YOUR AREA.
HIGH PRESSURE WILL SLIDE EAST ON TUESDAY AFTERNOON...ALLOWING WINDS
TO BECOME SOUTHERLY ACROSS OUR AREA. WITH A RIDGE OF UPPER LEVEL
HIGH PRESSURE BUILDING IN FROM THE WEST LATE TUESDAY EVENING...
OVERNIGHT TEMPERATURES WILL BE CONSIDERABLY WARMER...WITH LOWS
EXPECTED TO RANGE FROM THE MID 40S IN THE WEST...TO THE UPPER 30S IN
THE EAST.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 330 AM EDT SATURDAY...
ON WEDNESDAY...A HIGH PRESSURE RIDGE WILL SLIDE EAST OFF THE COAST.
SOUTHERLY FLOW RETURNS WITH MODERATING TEMPERATURES FOR THE
REMAINDER OF THE WORK WEEK. LIGHT RAIN SHOWERS ARE POSSIBLE
WEDNESDAY INTO THURSDAY AS A WEAK COOL FRONT PASSES OVER THE REGION.
THIS RAIN WILL NOT BE ANY WHERE CLOSE IN INTENSITY TO THIS WEEKENDS
RAIN EVENT.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 1159 AM EDT SATURDAY...
EXPECT SEVERAL PERIODS OF SHOWERS AND THUNDERSTORMS ACROSS
THE FORECAST AREA THROUGH 06Z SUNDAY. CEILINGS AND VISIBILITIES
WILL LOWER TO MVFR/IFR IN ASSOCIATION WITH THE SHOWERS AND STORMS.
SOME OF THE STRONGER STORMS TODAY MAY PRODUCE GUSTY WINDS AND
LARGE HAIL...MAINLY THIS AFTERNOON AND EVENING.
COVERAGE OF PRECIPITATION WILL DIMINISH TONIGHT. LOW CLOUDS AND
FOG WILL FILL IN OVERNIGHT WITH CEILINGS LOWERING TO IFR/MVFR
LEVELS. HAVE LOWERED VISIBILITY TO LIFR AT LYH WITH MEDIUM
CONFIDENCE. IF NORTHWEST SURFACE AND LOW LEVEL WINDS ARE A LITTLE
STRONGER THAN EXPECTED THEN PROBABILITY OF LIFR OR IFR FOG WILL BE
LOWER.
SHRA WILL DEVELOP AGAIN ACROSS THE AREA SUN...BUT WITH
CONSIDERABLE LESS INSTABILITY INDICATED AND A COLDER/MORE STABLE
SFC ENVIRONMENT...DO NOT ANTICIPATE MUCH TSRA ACTIVITY SUN...JUST
SHOWERS.
DRIER WEATHER AND VFR CONDITIONS ARE EXPECTED BEHIND THIS WEATHER
SYSTEM SUNDAY NIGHT THROUGH TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...NF
LONG TERM...RCS
AVIATION...AMS/KK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1201 PM EDT SAT MAR 24 2012
.SYNOPSIS...
LOW PRESSURE OVER THE OHIO VALLEY WILL MOVE EAST THEN SOUTHEAST
TODAY AND TONIGHT. BY SUNDAY NIGHT THE LOW WILL BE OFF THE CAROLINA
COAST. HIGH PRESSURE WILL BUILD OVER THE REGION MONDAY AND
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1150 AM EDT SATURDAY...
CONVECTION WHICH TAPERED OFF THIS MORNING ALLOWING SOME SUNSHINE TO
RETURN FOR THE WEST...WILL REDEVELOP THIS AFTERNOON INTO TONIGHT.
SOME OF THE STORMS WILL BE STRONG TO SEVERE WITH THE POTENTIAL
FOR LOCALLY HEAVY RAINS. THE UPPER LOW TO OUR WEST WILL STEADILY
APPROACH THIS AFTERNOON AND MOVE ACROSS THE SRN APPALACHIANS
TONIGHT. LIKE THE HRRR FOR EARLY THIS AFTERNOON AND SHAPE POPS
CLOSE TO SOLUTION.
AS OF 915 AM EDT SATURDAY...
ADJUSTED TEMPERATURES AND POPS ACCORDING TO LATEST OBS AND RADAR
TRENDS. EXPANDED THE MENTION OF GUSTY WINDS AND HAIL FURTHER NORTH
TO MATCH SPC LATEST DAY1 OUTLOOK. HWO WAS UPDATED. PNS OUT FOR
HIGH MIN TEMPERATURES. ALSO ANOTHER PNS COMING OUT FOR RAINFALL
AMOUNTS. THE UPPER LOW IS MOVING EAST WITH COLD POOL WHICH WILL
RESULT IN NUMEROUS SHOWERS AND THUNDERSTORMS THIS AFTERNOON INTO
TONIGHT. LOOK FOR SEVERAL ISC UPDATES TODAY WITH THE ACTIVE
WEATHER EXPECTED.
AS OF 410 AM EDT SATURDAY...
EXPECTING SEVERAL BANDS OF SHOWERS AND THUNDERSTORMS TODAY AND
TONIGHT. FIRST AREA WAS OVER THE CENTRAL AND EASTERN COUNTY
WARNING AREA EARLY THIS MORNING AND WAS MOVING NORTHEAST AROUND 20
MPH. THE NEXT BAND EXTENDS FROM OHIO INTO EASTERN TENNESSEE. LOCAL
WRF AND HRRR BRING THIS BAND INTO THE WESTERN COUNTY WARNING AREA
BY 8AM.
AS THE UPPER LOW MOVES EAST THIS MOVING SO WILL THE SHOWERS AND
THUNDERSTORMS. ADDITIONAL SHOWERS AND THUNDERSTORMS WILL DEVELOP
OVER THE FORECAST AREA THIS AFTERNOON. COLDER AIR ALOFT
ASSOCIATED WITH THE UPPER LOW WILL REACH THE FORECAST AREA
TODAY...CREATING LARGE LAPSE RATES AND LOWERING THE FREEZING
LEVEL. GUSTY WINDS AND LARGE HAIL WILL BE A THREAT WITH ANY
STRONGER STORMS...ESPECIALLY THIS AFTERNOON AND EVENING.
THE UPPER LOW MOVES SOUTHEAST INTO SOUTH CAROLINA BY SUNDAY
MORNING. EXPECT COVERAGE AND PROBABILITY OF PRECIPITATION TO
DECREASE LATE TONIGHT.
THERE WAS A BREAK IN THE CLOUD COVER AHEAD OF THE SHOWERS AND
THUNDERSTORMS APPROACHING FROM THE WEST. FOG MAY DEVELOP EARLY
THIS MORNING AS THE CLOUDS BRIEFLY CLEAR. WITH ALL THE
PRECIPITATION EXPECTED TODAY...HAVE GONE ON THE COOL SIDE OF
GUIDANCE. STAYED CLOSE TO A BLEND OF BIAS CORRECTED MAV/MET
GUIDANCE FOR LOWS TONIGHT.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 330 AM EST SATURDAY...
SUNDAY MORNING WILL START OUT WITH THE UPPER LEVEL LOW PASSING JUST
TO THE SOUTH OF OUR AREA...POSSIBLY CLIPPING OUR NORTH CAROLINA
COUNTIES. IN ANY EVENT...EXPECT TO SEE GREATER COVERAGE OF SHOWER
ACTIVITY NORTH OF INTERSTATE 81...AS A SLOT OF DRIER AIR WORKS ITS
WAY IN SOUTH CLOSER TO THE LOW. COVERAGE WILL INCREASE FURTHER
DURING THE AFTERNOON AS DAYTIME HEATING HELPS DESTABILIZE THE
ATMOSPHERE...AND WILL NOT BE SURPRISED TO SEE A FEW THUNDERSTORMS
DEVELOP BY LATE MORNING. WITH THE UPPER LOW PASSING SO CLOSE TO OUR
AREA...BELIEVE THAT HAIL WILL BE A CONCERN IN THE STRONGER SHOWER
AND THUNDERSTORM ACTIVITY...BUT EXPECT MOST HAIL TO BE IN THE PEA TO
DIME SIZE RANGE WHERE IT OCCURS. SHOWER AND THUNDERSTORM ACTIVITY
WILL DECREASE FROM WEST TO EAST BY LATE AFTERNOON AS THE UPPER LOW
CONTINUES TO PUSH OFF THE ATLANTIC COAST...AND SHOWER ACTIVITY IS
EXPECTED TO BE CONFINED TO THE MOUNTAINS...MAINLY IN SOUTHEAST WEST
VIRGINIA BY LATE SUNDAY EVENING. DESPITE THE PASSAGE OF THE UPPER
LOW...SUNDAY NIGHT TEMPERATURES WILL REMAIN MILD ACROSS OUR
AREA...WITH OVERNIGHT LOWS RANGING FROM THE LOW TO MID 50S EAST...TO
THE UPPER 40S WEST.
IT WILL BE MONDAY MORNING WHEN WE SEE A CHANGE IN OUR WEATHER
PATTERN AS ANOTHER COLD FRONT BRINGS A SHOT OF COOLER CANADIAN AIR
INTO OUR AREA. MONDAY AFTERNOON TEMPERATURES ARE EXPECTED TO REMAIN
MILD ACROSS OUR AREA...ALBEIT A LITTLE COOLER...HOWEVER IT WILL BE
MONDAY NIGHT/TUESDAY MORNING TEMPERATURES THAT WILL BE OF CONCERN AS
LOWS FALL INTO THE 30S ACROSS THE MOUNTAINS. BELIEVE THAT NEAR
FREEZING TEMPERATURES WILL BE CONFINED TO GREENBRIER COUNTY IN
SOUTHEAST WEST VIRGINIA...AS WELL AS THE ALLEGHANY HIGHLANDS IN
VIRGINIA...LOCATIONS THAT HAVE NOT EXPERIENCED A START TO THE
GROWING SEASON TO THE SAME EXTENT THAT HAS OCCURRED IN LOWER
ELEVATIONS. THAT STATED...IT WOULD BE A GOOD IDEA TO CONSIDER
PRECAUTIONS AGAINST THE COLD FOR ANY SENSITIVE VEGETATION WHICH HAS
STARTED TO GROW IN YOUR AREA.
HIGH PRESSURE WILL SLIDE EAST ON TUESDAY AFTERNOON...ALLOWING WINDS
TO BECOME SOUTHERLY ACROSS OUR AREA. WITH A RIDGE OF UPPER LEVEL
HIGH PRESSURE BUILDING IN FROM THE WEST LATE TUESDAY EVENING...
OVERNIGHT TEMPERATURES WILL BE CONSIDERABLY WARMER...WITH LOWS
EXPECTED TO RANGE FROM THE MID 40S IN THE WEST...TO THE UPPER 30S IN
THE EAST.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 330 AM EDT SATURDAY...
ON WEDNESDAY...A HIGH PRESSURE RIDGE WILL SLIDE EAST OFF THE COAST.
SOUTHERLY FLOW RETURNS WITH MODERATING TEMPERATURES FOR THE
REMAINDER OF THE WORK WEEK. LIGHT RAIN SHOWERS ARE POSSIBLE
WEDNESDAY INTO THURSDAY AS A WEAK COOL FRONT PASSES OVER THE REGION.
THIS RAIN WILL NOT BE ANY WHERE CLOSE IN INTENSITY TO THIS WEEKENDS
RAIN EVENT.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
AS OF 1159 AM EDT SATURDAY...
EXPECT SEVERAL PERIODS OF SHOWERS AND THUNDERSTORMS ACROSS
THE FORECAST AREA THROUGH 06Z SUNDAY. CEILINGS AND VISIBILITIES
WILL LOWER TO MVFR/IFR IN ASSOCIATION WITH THE SHOWERS AND STORMS.
SOME OF THE STRONGER STORMS TODAY MAY PRODUCE GUSTY WINDS AND
LARGE HAIL...MAINLY THIS AFTERNOON AND EVENING.
COVERAGE OF PRECIPITATION WILL DIMINISH TONIGHT. LOW CLOUDS AND
FOG WILL FILL IN OVERNIGHT WITH CEILINGS LOWERING TO IFR/MVFR
LEVELS. HAVE LOWERED VISIBILITY TO LIFR AT LYH WITH MEDIUM
CONFIDENCE. IF NORTHWEST SURFACE AND LOW LEVEL WINDS ARE A LITTLE
STRONGER THAN EXPECTED THEN PROBABILITY OF LIFR OR IFR FOG WILL BE
LOWER.
SHRA WILL DEVELOP AGAIN ACROSS THE AREA SUN...BUT WITH
CONSIDERABLE LESS INSTABILITY INDICATED AND A COLDER/MORE STABLE
SFC ENVIRONMENT...DO NOT ANTICIPATE MUCH TSRA ACTIVITY SUN...JUST
SHOWERS.
DRIER WEATHER AND VFR CONDITIONS ARE EXPECTED BEHIND THIS WEATHER
SYSTEM SUNDAY NIGHT THROUGH TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...NF
LONG TERM...RCS
AVIATION...AMS/KK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
253 PM CDT SAT MAR 24 2012
.SHORT TERM...TONIGHT AND SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A LARGE CUT-OFF
LOW PRESSURE SYSTEM MOVING SE OVER KENTUCKY AND TENNESSEE EARLY THIS
AFTERNOON...WHILE A SHORTWAVE OVER LAKE WINNIPEG IS DRIVING A COLD
FRONT OVER THE NORTHERN MISSISSIPPI VALLEY. BETWEEN THESE
FEATURES...CYCLONIC FLOW IS MAINTAINING A FAIRLY EXPANSIVE STRATO-CU
DECK OVER THE WESTERN GREAT LAKES. SOME BREAKS IN THE STRATUS ARE
GROWING LARGER OVER NW WISCONSIN WHERE A DRIER AIRMASS EXISTS
ALOFT. AS THE COLD FRONT MOVES ACROSS THE REGION LATE TONIGHT INTO
SUNDAY MORNING...CLOUDS AND FOG ARE THE MAIN FORECAST CONCERNS.
TONIGHT...LOW CLOUDS SHOULD BE HANGING AROUND MUCH OF NORTHEAST AND
INTO CENTRAL WISCONSIN FOR THE EARLY PART OF THE EVENING...WHERE
MOISTURE IS DEEPER THROUGH THE COLUMN AND WEAK LOW LEVEL CONVERGENCE
LINGERS. EVENTUALLY THOUGH...UPSTREAM DRIER AIR WILL MAKE INROADS
OVER NORTH-CENTRAL WISCONSIN INTO NORTHEAST WISCONSIN THROUGH THE
EVENING. HAVE LEFT SKY CONDITIONS SCATTERED-WEST TO BROKEN-EAST
WITH THE UNCERTAINTY OF COVERAGE. COLD FRONT OVER THE NORTHERN
MISSISSIPPI VALLEY WILL MOVE ACROSS THE AREA AFTER MIDNIGHT. FAIRLY
WIDESPREAD STRATUS DECK BEHIND THE FRONT SO WILL SHOW SKIES
RETURNING TO BROKEN AS THE BOUNDARY WORKS THROUGH. THE PRESSURE
GRADIENT WILL TIGHTEN UP BEHIND THE FRONT AS WELL...WHICH WILL HELP
DISSIPATE ANY FOG. LOWS RANGING FROM THE UPPER 30S NORTH TO THE
UPPER 40S SOUTH.
SUNDAY...THE COLD FRONT WILL MOVE SOUTHEAST ACROSS CENTRAL AND
NORTHEAST WISCONSIN DURING THE MORNING...THEN CLEAR THE REGION FOR
THE AFTERNOON. A VERY DRY AIRMASS WILL BE ARRIVING BEHIND THE COLD
FRONT...SO WILL SEE AMPLE SUNSHINE MOVING IN BEHIND THE STRATUS
ALONG THE FRONT. LOWERED DEWPOINTS OVER N-C WISCONSIN FOR THE
AFTERNOON WHERE TEMPS WILL ONLY REACH INTO THE LOWER AND MIDDLE
50S. CENTRAL AND EAST-CENTRAL WISCONSIN SHOULD SEE HIGHS IN THE
LOWER TO MIDDLE 60S.
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY. THE WARM PATTERN
WILL CONTINUE NEXT WEEK...THOUGH NOT QUITE AS WARM AS THE LAST FEW
WEEKS. LOWS AND HIGHS OF 5 TO 10 DEGREES ABOVE NORMAL ARE EXPECTED
ON MOST DAYS BUT THAT WILL LIKELY FEEL CHILLY AFTER TEMPERATURES
IN THE 70S AND 80S EARLIER THIS WEEK. NOT MUCH IN THE WAY OF
PRECIPITATION IS EXPECTED AND ALL OR NEARLY ALL WILL BE RAIN. THE
FIRST CHANCE OF PRECIPITATION IS MONDAY AS MID LEVEL WARM
ADVECTION MOVES ACROSS THE AREA. WHATEVER FALLS SHOULD BE MOSTLY
IN CENTRAL WISCONSIN AND BE MOSTLY SPRINKLES OR VERY LIGHT
SHOWERS. BETTER CHANCE OF SHOWERS AND THUNDERSTORMS MONDAY NIGHT
AND TUESDAY AS DECENT UPPER LOW LIFTS NORTHEAST FROM THE PLAINS.
THERE MAY BE ENOUGH COLD AIR NEAR THE GROUND FOR THE PRECIPITATION
TO FALL AS SLEET IN NORTHCENTRAL WISCONSIN LATE MONDAY NIGHT AND
EARLY TUESDAY. ANOTHER CHANCE OF SHOWERS THURSDAY NIGHT AND FRIDAY
AS A WEAK SYSTEM PASSES BY TO THE NORTH. OTHERWISE GENERALLY MILD
AND DRY WEATHER. A FROST OR FREEZE IS LIKELY SUNDAY NIGHT. WHILE
THIS IS USUALLY NOT NOTEWORTHY AT THIS TIME OF THE YEAR...IT MAY
BE A CONCERN FOR ORCHARD OWNERS AS SOEM TREES HAVE BEGUN FLOWERING
DUE TO THE RECENT RECORD WARMTH.
&&
.AVIATION...WIDESPREAD IFR AND SOME LIFR CIGS WILL GRADUALLY IMPROVE
TO MVFR EARLY THIS AFTERNOON...AND POSSIBLY BECOME SCT BY LATE THIS
AFTERNOON OR EARLY THIS EVENING. STILL PLENTY OF MOISTURE HANGING
AROUND...SO IF SKIES CLEAR...POSSIBILITY OF FOG EXISTS...ESPECIALLY
OVER NORTH-CENTRAL WISCONSIN. HOWEVER...UPSTREAM COLD FRONT WILL BE
MOVING ACROSS THE AREA OVERNIGHT. BKN MVFR CIGS WILL LIKELY ARRIVE
BEHIND THE COLD FRONT...AND WINDS WILL PICK UP FROM THE NW. THE
COMBO OF THE TWO WILL LIKELY DISSIPATE ANY FOG FAIRLY QUICKLY.
AMPLE DRY AIR BEHIND THE FRONT WILL ERODE BKN CIGS BY
MID-MORNING...LEAVING VFR CONDITIONS THROUGH THE REMAINDER OF THE
DAY.
MPC
&&
.MARINE...
A COLD FRONT MOVING ACROSS THE AREA WILL BRING GUSTY NORTHEAST
WINDS TO THE AREA SUNDAY NIGHT AND EARLY MONDAY. FUNNELING DOWN THE
BAY COULD PRODUCE GUSTS TO 25 TO 30 KNOTS NEAR GREEN BAY. A WARM
FRONT WILL PUSH NORTHWARD ACROSS THE AREA TUESDAY. GUSTS TO NEAR
GALE FORCE FROM THE SOUTHEAST ARE POSSIBLE ON TUESDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/RDM