Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/17/21
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
913 PM MDT Tue Mar 16 2021
.UPDATE...
Have made some significant changes to highlights for tonight and
Wednesday. NAM12, RAP13, and HRRR all suggesting there will be a band
of precipitation in the form of snow stretched from east to west
through eastern Guadalupe and through Quay county, possibly clipping
nortern Curry county. At the same time, strong north winds will
develop, and thinking that the combo of snow and wind will be
sufficient for winter storm warnings for part of the northeast and
east central plains. Farther south, it may be warm enough that wind
will be the dominant weather feature. In Union county, the combo of
snow and wind looks significant enough to upgrade to a blizzard
warning. In addition, have converted the wind advisory for portions
of the I-25 corridor to a winter weather advisory. Also, dropped the
wind advisory for portions of the southwest and south central, but
winds may ramp up again later tonight, especially over the ridgetops,
and for that reason also kept the high wind warning going for most
of Lincoln and Chaves counties. Updated ZFP has been sent, as well as
the updated WSW and NPW, and will be sending the grids shortly.
&&
.PREV DISCUSSION...535 PM MDT Tue Mar 16 2021...
.AVIATION...
00Z TAF CYCLE
Upper low and associated cold front will move rapidly from central NM
and into the TX Panhandle by 17/12Z with strong winds, areas of
reduced vsbys and higher terrain obscurations in blowing dust and
showers. MVFR to IFR conditions in dust and precipitation will be
focused over ern NM. Winds from the central mt chain and over ern NM
will trend from sw to nw-nly with gusts to around 40-50kts continuing
through along the central mt chain until around 17/07Z and over ne
NM until around 17/19Z. Showers will taper off over wrn NM aft
17/06Z.
&&
.PREV DISCUSSION...310 PM MDT Tue Mar 16 2021...
.SYNOPSIS...
A storm system will continue to cross from the west tonight through
Wednesday morning with snow accumulation across the northern
mountains, northeast and east central New Mexico. Strong north and
northwest winds will also continue through tonight along and east of
the central mountain chain, then through Wednesday morning along New
Mexico`s eastern border. Heavy snow, blowing snow, and drifting snow
are expected tonight into Wednesday morning from Raton Pass to
Clayton, where there will be periods of near zero visibility. After
drier, warmer, and less windy weather during the latter half of the
work week, winds will strengthen again this weekend. Another storm
system will cross with a chance for rain, snow and thunderstorms
Sunday and Monday.
&&
.DISCUSSION...
SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)...
Potent upper low and associated cold front are moving into western
NM currently and will progress east across the area tonight. Wind,
snow and blowing dust impacts are all expected with this quick-
hitting system. We`re still anticipating the main action across
northeast NM overnight, where the combination of heavy snow and
strong winds will create potential for blizzard conditions near the
Colorado border from Raton Pass through Capulin to near Mt. Dora.
Snow amounts between Raton Pass and Capulin will range from 4-8"
although up to one foot is possible. Significant impacts to US 64/87
and I-25 through Raton Pass are likely, with potential for road
closures. Further south into the east central plains, wrap-around
snow/rain mix will turn over to all snow by early morning and will
accumulate to between 1-3 inches along the I-40 corridor from near
Santa Rosa to the TX border. The plan is to upgrade the watch to a
warning and mention possible blizzard conditions near the CO border,
then issue advisories south to Guadalupe and Quay Counties. Will add
a Wind Advisory for the far NE and NE highlands, but blowing snow
and accumulations of less than 2" are likely as well. Raton will
likely get downsloped/shadowed from the ridge to the north. As far
as the existing wind highlights, strong winds will continue through
the evening hours, but the lower RGV and western zones will likely
be canceled prior to expiring. Snow will diminish rapidly Wednesday
morning and the winter highlights will likely be canceled prior to
expiring.
Moderate northwest flow aloft will prevail Wednesday in the wake of
the departing upper low, with breezy to locally windy conditions
developing by afternoon across western and central NM. Windy
conditions will persist through the day across the far eastern
plains near the TX/OK borders where the surface pressure gradient
will remain stronger. Otherwise, daytime temperatures will generally
range from 5-15 degrees blow normal except across the far northeast
plains were temperature may hold 20 degrees blow normal thanks in
part to fresh snow on the ground.
11
LONG TERM...(THURSDAY THROUGH TUESDAY)...
A ridge of high pressure will cross gradually from the west during
the latter half of the week with warming temperatures and dry
weather. High temperatures should peak Saturday 3 to 13 degrees
above normal. After weaker winds during the latter half of the work
week, southwest flow will become breezy again Saturday as a lee
trough develops and the flow aloft strengthens ahead of our next
storm system.
Sunday through Monday, an upper level trough is forecast to cross
from the northwest with rain showers, snow showers, and some
potentially strong thunderstorms, as well as breezy to windy
conditions both days. Recent model runs show the system crossing
with less of a subtropical moisture tap than they were showing
yesterday, and there is not much agreement on whether a backdoor cold
front will precede the system. Thus, there is a fair amount of
uncertainty about how much snow will accumulate and where. Models
keep the system progressive, and given the lack of a subtropical
moisture tap, it should not be a heavy snow producer.
Models show a stronger upper level low pressure system approaching
from the northwest and spreading rain showers, snow showers, and
thunderstorms over the area again starting Tuesday.
44
&&
.FIRE WEATHER...
...RED FLAG WARNING FOR THE EAST CENTRAL PLAINS FROM NOON TO
7 PM MDT TUESDAY...
Critical fire weather conditions will persist into the early evening
hours across the east central plains, with elevated conditions
further west as very windy conditions persist. A strong upper low
and associated cold front will move across tonight bringing chances
for wetting precipitation and continued strong winds, especially
across eastern New Mexico. The best chances for wetting
precipitation will be over/near the northern mountains and the
northeast/east central plains through early Wednesday morning.
Breezy to locally windy conditions will prevail Wednesday with below
normal temperatures. An upper level ridge will progress east across
the region Thu/Fri, bringing a warming trend with above normal
temperatures returning areawide by Saturday. Winds and vent rates
will be on the uptrend Friday into Saturday with increasing
southwest flow aloft, which will bring the potential for critical
fire weather conditions by Saturday afternoon. Critical fire weather
conditions may redevelop Sunday, but will be dependent on the timing
and orientation of an approaching upper level trough. A widespread
wetting event may be in the cards for the middle of next week as
both the latest ECMWF and GFS show a slow-moving upper low and
backdoor cold front combo over the state.
11
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 9 AM MDT Wednesday for the following
zones... NMZ210-211-213>215-221>223-228-229.
Winter Storm Warning until noon MDT Wednesday for the following
zones... NMZ227.
High Wind Warning until 6 AM MDT Wednesday for the following
zones... NMZ226-238>240.
Wind Advisory until noon MDT Wednesday for the following zones...
NMZ235>237.
Winter Storm Warning from midnight tonight to noon MDT Wednesday
for the following zones... NMZ231>234.
Blizzard Warning until noon MDT Wednesday for the following zones...
NMZ230.
&&
$$
Area Forecast Discussion
National Weather Service Bismarck ND
950 PM CDT Tue Mar 16 2021
.UPDATE...
Issued at 947 PM CDT Tue Mar 16 2021
Smattering of drizzle, flurry, and fog reports across western and
central North Dakota this evening. Generally temperatures in areas
with the very light precipitation remain at or above freezing
with dew point depressions of zero, thus not as concerned about
widespread freezing drizzle issues at the moment. No changes
needed with this update.
UPDATE Issued at 645 PM CDT Tue Mar 16 2021
Frontal boundary at 23Z placed from north central through
southwest North Dakota, with RAP mesoscale analysis depicting the
700mb wave centered over southeast/south central North Dakota. The
general precipitation type pattern has been for light rain and
snow reports to remain under areas of greater 700mb RH in the west,
which line up with ice growth aloft, with more mist/drizzle in the
central where there is less saturation aloft. -SN recently at
KJMS is the exception where RAP soundings show slightly cooler
lower tropospheric temperatures may favor ice generation below
700mb. With this update we extended the time of precipitation in
the south central/east through the evening, to cover the slowly
exiting mid-level wave. This area still favors light snow with the
slightly cooler temperatures, which was included in the forecast.
Further west there may be some brief periods of isolated freezing
drizzle as previously described on the peripheries of the better
ice growth aloft regions, though timing/location predictability is
low. No other changes made to precipitation types or hazards for
now, will continue to monitor this evening.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 230 PM CDT Tue Mar 16 2021
Current surface analysis places low over the central into the
Northern Plains, with high over southern Saskatchewan into the
northern Rockies. Frontal boundary noted over northwest into far
southwest North Dakota. Upper level analysis places low over
Arizona, with secondary low over eastern South Dakota. These
features have kept a cloudy and cool day over our area. In the
vicinity of and behind the frontal boundary, some light
precipitation continues to occasionally fall.
For the rest of this afternoon into tonight, frontal boundary
meanders a bit easterly. This will keep the opportunity for some
light precipitation going into the evening and possibly overnight
hours, albeit light. Have decided to go with a mention of mainly
patchy drizzle, freezing drizzle, or a little snow, as soundings
are rather questionable on the availability of ice to work with,
especially overnight. In addition, models have been consistently
hinting at the possibility of some fog overnight, so have
broadbrushed patchy fog over the area.
On Wednesday skies will gradually clear from northwest to
southeast as upper ridge to the west gradually pushes in. With the
ridge pushing in, temperatures will rebound to a bit above
average.
.LONG TERM...(Thursday through Tuesday)
Issued at 230 PM CDT Tue Mar 16 2021
Quiet through the work week as upper ridge builds and pushes
through the region. It may become a bit windy, though, especially
on Friday as pressure gradient tightens between high over the
midwest and low to the lee of the Rockies. Temperatures will
become quite mild.
Ridge pushes east for the weekend as a Pacific trough pushes east,
bringing modest precipitation chances, which continue into the
start of the work week. Mild temperatures remain.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 645 PM CDT Tue Mar 16 2021
Widespread MVFR to IFR ceilings continue across much of the area
tonight. KXWA should see clearing first, more likely after 07Z.
Across all other areas, isolated LIFR is possible tonight with
periods of lower visibility due to light precipitation and fog.
Precipitation should continue this evening but taper off after
08Z, but some fog may linger into Wednesday morning.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AE
SHORT TERM...JJS
LONG TERM...JJS
AVIATION...AE
Area Forecast Discussion
National Weather Service State College PA
1107 PM EDT Tue Mar 16 2021
.SYNOPSIS...
A weak area of low pressure near Cape Hatteras will slowly push
out to sea tonight and Wednesday. A more significant southern
stream shortwave and associated surface low will lift out of the
Mississippi Valley, tracking just south of Pennsylvania late
Thursday into early Friday. Upper level ridging is likely to
build into the region this weekend into early next week.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
Radar loop at 0245Z is showing the last of the light rain
showers exiting the southeast part of the forecast area. Latest
RAP continues to show lingering elevated CAPE of around 50 j/kg
over York and Lancaster counties, so will maintain a slight
chance of a shower down there until midnight.
Models continue to underestimate the low level dryness of this
air mass. Have trended dewpoints lower overnight and removed
mention of patchy drizzle/fzdz. Persistent southeast flow could
moisten the low levels enough to produce a touch of drizzle
along the spine of the Appalachians, but odds appear low given
current trends. Earlier clearing over the Alleghenies is filling
in late this evening due to southeast flow. Overcast skies
should hold temperatures nearly steady overnight in the 30s.
Low level southeast flow associated with high pressure east of
New England and a low off of the Mid Atlantic coast is likely to
maintain stratus over much of central Pa Wednesday. Breaking
clouds along and east of the spine of the Appalachians should
push temperatures well into the 50s across the western edge of
the forecast area, while persistent cloud cover and upsloping
southeast flow holds readings down over the rest of the area.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
Lowering cloud cover and rain will be on the approach from the
southwest Wednesday night into early Thursday as an upper low
tracks east into the downstream portion of the Ohio Valley.
Isentropic lift will lead to light to moderate rain
overspreading central PA Thursday morning, continuing through
the day. As the low progresses east across the Bluegrass State
and opens up/weakens, local lift will gradually wane late
Thursday into early Friday as central PA becomes positioned
underneath the trough axis. By the time all is said and done,
rainfall totals should largely range from 1 - 1.5 inches, with
the highest amounts in southern PA.
Surface low reintensification off the mid-Atlantic Coast early
Friday will lead to breezy/gusty north winds and a brisk day
with 850 mb temperatures cooling to around -10C. Could very well
see one to two tenths of an inch of snow as the colder air
filters in and prior to the precipitation completely scouring
out. This should be most notable on ridges across the Poconos as
high temperatures only make it into the low 30s across northern
PA and low 40s in the southern tier of the state. Afternoon RH
values do look to drop into the 30-40 percent range as drier air
filters in on Friday as north winds of 15-20 mph occur, but
recent rainfall should preclude a greater fire threat.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
Medium range guidance indicates fair and increasingly milder
weather is likely over central Pa Saturday into early next week,
as upper level ridge expands eastward from the northern plains
and Grt Lks. There is some indication that a weak upper low will
become cut off south of the building ridge. However, all guidance
currently keeps this feature well south of Pa in the Carolinas.
Latest GEFS and ECENS support abundant sunshine and light winds
Saturday into early next week, as surface high and low-pwat air
mass settle over Pa. Latest GEFS plumes and NBM support high
temperatures reaching the low 60s by early next week.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
MVFR cigs blanket central PA early this evening in moist
southeast flow. Cigs will likely lower to IFR around midnight in
the central ridge and valley region, with a period of LIFR cigs
and reduced visby likely in JST and BFD later tonight. No precip
is expected, other than patchy drizzle. Conditions will improve
from SW to NE through the day on Wed with all airfields MVFR or
VFR by afternoon.
Outlook...
Wed...AM low cigs possible.
Thu...Reductions probable in rain.
Fri...Improving conditions. Breezy.
Sat and Sun...VFR/no sig wx.
&&
.CLIMATE...
The first day of astronomical spring will be on Saturday, March
20th with the equinox to occur at 5:37 AM EDT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Fitzgerald
NEAR TERM...Fitzgerald
SHORT TERM...Guseman
LONG TERM...Fitzgerald
AVIATION...Gartner/Colbert
CLIMATE...
Area Forecast Discussion
National Weather Service Dodge City KS
607 PM CDT Tue Mar 16 2021
...UPDATE TO AVIATION...
.SHORT TERM...(This evening through Wednesday)
Issued at 216 PM CDT Tue Mar 16 2021
Cooler air along with an area of low clouds were spreading into
southwest Kansas earlier this Tuesday afternoon behind a cold
front which was moving into the panhandle of Oklahoma. An area of
low pressure at the surface appears located just south of Dodge
City at 17z Tuesday. Models were in decent agreement and verified
well with these features earlier today. The models today also were
in good agreement with taking the surface cold front into
Northern Oklahoma by evening as our next upper level storm system
crosses northern New Mexico towards the Panhandle of Texas. Ahead
of this system and near the surface boundary in Oklahoma there
will be a chance for some early evening convection but given how
far south this boundary will be early this evening and the more
stable air filtering into southwest Kansas any thunderstorm that
does develop late today is not expected to move into southwest
Kansas until after sunset when better lift develops north of this
boundary. Latest RAP has 850mb warm air advection and 850mb to
700mb moisture transport increasing early tonight, especially near
and east of Dodge City. Based on this and the forecast
0-6/effective shear, anvil level winds along with mid level
instability it appears that the main hazards tonight from these
elevated thunderstorms will be hail larger than 2 inches and wind
gusts in excess of 60 mph. Earlier this evening there may even be
a few tornadoes near the surface boundary but given its forecast
location any tornado that does develop will likely occur south of
the Oklahoma border. It may be close however for southern Barber
county.
The thunderstorms over south central Kansas will move east of the
Pratt and Medicine lodge area between 1 and 3 am tonight. As
these storms track east/northeast another area of light to
moderate rain or snow will begin to develop/spread into far
southwest Kansas based on the location of an area of improving 850
to 700mb frontogenesis ahead of the upper low that will exit
northeast New Mexico and start to cross the Panhandle of Texas.
This precipitation may begin as rain but is expected to quickly
change over to all snow overnight as cold advection develops
overnight from the developing strong north. Wind speeds are
forecast to range from 50 to near 60 knots early Wednesday morning
based on the latest BUFR RAP and NAM soundings in the 15000 to
3000 ft level. Also early Wednesday morning there will be
improving frontogentic forcing that will not move very much
between 09z and 15z Wed along with high relative humidity values
in the -10 to -30C temperature level. This could result in
anywhere from 2 to 4 inches of snow across portions of far
southwest Kansas, wherever this frontogentic zone sets up. The
combination of this snow along with the strong winds late tonight
and early Wednesday could produce blizzard or near blizzard
conditions at times and as a result have decided to upgrade part
of the current winter storm watch to a Blizzard warning. Areas
where confidence of blizzard conditions are not as high have
decided to keep the Winter Storm Watch going.
Strong damaging winds gusts of near 60 mph will also be possible
on Wednesday outside this band of steadier snowfall so will also
go ahead an issue a High Wind Watch for much of the remaining
parts of southwest Kansas.
Areas east of the band of snow early Wednesday morning can expect
widespread light to moderate rainfall during the day on
Wednesday. Rainfall totals from this event may be as high at 1.5
to .175 in some locations east of highway 283. Along with this
higher rainfall totals the precipitation here may also mix with or
even change over to snow before ending as the atmosphere cools
during the day. How much snowfall is still unclear at this time
given the uncertainty of when the cold rain will change over to
snow. Some locations could see up to an inch of snow from this
event before the precipitation tapers off late Wednesday.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 216 PM CDT Tue Mar 16 2021
Once this midweek system exits western Kansas Wednesday night an
upper level ridge will begin to build across the Rockies and dry
and warmer conditions will be returning to the area late week into
early this upcoming weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 602 PM CDT Tue Mar 16 2021
Prevailing low level stratus along and behind a cold front bisecting
southwest Kansas will continue to spread slowly southeast across the
remainder of southwest Kansas and into south central Kansas and
northern Oklahoma through late evening. MVFR cigs will persist at
KGCK while developing farther east/southeast into the vicinity of
KHYS, KDDC, and KLBL generally after 01-03Z this evening. The
stratus layer is expected to further lower overnight increasing
the potential for periods of IFR cigs mainly after 06Z. Additionally,
shower and thunderstorm development is likely later this evening
across the panhandles of Texas and Oklahoma with storms spreading
northeast into south central and portions of southwest Kansas,
potentially affecting KLBL, KDDC, and KGCK after 03-05Z. Gusty
north-northeast winds around 15 to 30kt will persist through late
evening as a deepening surface low moves out of northeast New
Mexico into the Texas Panhandle. Winds are then expected to turn
more northerly overnight, increasing to around 25 to 40kt through
early Wednesday morning as the strong surface low pushes farther
east into western Oklahoma.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 35 36 29 49 / 90 90 30 0
GCK 32 36 26 49 / 70 80 20 0
EHA 30 36 25 53 / 100 90 10 0
LBL 30 33 24 52 / 90 100 10 0
HYS 34 39 30 50 / 80 60 40 0
P28 41 44 32 52 / 90 90 40 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from Wednesday morning through Wednesday
evening for KSZ077-078-080-088-089.
High Wind Watch from Wednesday morning through Wednesday evening
for KSZ063>066-079-081-090.
Blizzard Warning from 1 AM to 7 PM CDT Wednesday for KSZ074>076-
084>087.
&&
$$
SHORT TERM...Burgert
LONG TERM...Burgert
AVIATION...JJohnson
Area Forecast Discussion
National Weather Service Des Moines IA
632 PM CDT Tue Mar 16 2021
.DISCUSSION.../Tonight through Tuesday/
Issued at 312 PM CDT Tue Mar 16 2021
The primary weather concern will be a large system impacting the
MO Valley overnight through Thursday with widespread moderate
rains south and east, with some snow concerns as well. At the
moment, broad warm/theta-e advection continues to push into the MO
Valley this afternoon with contributions from both the lingering
SD upper low and increasing forcing upstream in the southwest
flow. One last rotation of kinematic support from the SD low
appears to be in place as well. This will continue to spread
patchy light precip into the state tonight, with the approaching
southwest system becoming dominate by daybreak.
During the day Wednesday, warm/theta-e advection, frontogenetical
forcing and then kinematics in the maturing deformation zone will
spread persistent precip into mainly the southeast half of the
state Wednesday Night into Thursday. This should last through
early Thursday morning, and predominately be in the form of rain
with periods of at least moderate rainfall expected. While much of
the deterministic and ensemble guidance suggests this event will
primarily be in the form of a cold rain, there are a non-trivial
amount of GEFS and EPS ensemble members as well as the NAM that
suggest a period of dynamic cooling and fairly intense snowfall
rates. While confidence in significant precip amounts is moderate
to high, confidence in precip type is diminished because of a pool
of disconcerting ensemble solutions. At the moment, have
introduced an inch or so of snow accumulations southeast late Wed
Night into early Thu morning but either side of that range is
certainly in place. Confidence is low however due to thermal
considerations surface and aloft, as well as the degree of
melting.
The precipitation should then end later Thursday leading to fair
weather and warming temperatures into the weekend with a period of
MO Valley ridging and highs back into the 50s and 60s. Our pattern
will then shift to southwest flow aloft by Sunday however with
Rockies long wave trough development and the first iteration of
short waves traversing it reaching the MO Valley early Tue.
Increasing 1-3km moisture and frontogenetic forcing along the
baroclinic zone will introduce PoPs Sunday following by additional
kinematic support as the short wave moves through the MO Valley
either Monday or Tuesday depending on how the timing plays out.
Confidence is low on temps and surface track, anywhere through IA
and either side, but little of the ensemble solutions suggest much
instability keeping it more rain or showers than thunderstorms.
&&
.AVIATION.../For the 00Z TAFS through 00Z Wednesday evening/
Issued at 631 PM CDT Tue Mar 16 2021
Main concerns continue to be clouds, fog and eventual rain moving
into the region. Showery precipitation tonight with VCSH mainly as
cigs and vsbys lower through 12z to IFR most sites between 02 and
06z...continuing IFR most sites through period other than KALO
which may see MVFR return aft 20z Wed. Rain expected to increase
in coverage and more confidence for southern/east sites KDSM, KOTM
and KALO to see -RA increasing to RA aft 06z. Will monitor trends
for fog and may need to lower vsby south sites if trends lower.
Currently HRRR a bit aggressive on vsby between 00 and 06z this
evening. /rev
&&
.HYDROLOGY...
Issued at 312 PM CDT Tue Mar 16 2021
General QPF amounts of 1-2 inches are anticipated across the
southeast corner of the forecast over the next 48 hours with
locally higher amounts possible. RFC forecasts with expected
precipitation through 12z Thursday suggest only within bank rises
should occur with no river flooding anticipated at the moment due
to relatively dry antecedent conditions and the prolonged nature
of the rainfall. Certainly soils and fields will be soggy however
with standing, running water in fields. Cedar Creek, the Des
Moines River below Red Rock, the Chariton River, and Thompson
River will need to be monitored in the coming days however.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...Small
AVIATION...REV
HYDROLOGY...Small
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
958 PM EDT Tue Mar 16 2021
.SYNOPSIS...
Rain chances decrease overnight tonight as drier air filters in.
Unsettled weather is expected Wednesday as precip chances ramp back
up in the presence of a moist frontal zone crossing the area, which
should bring a chance for convective activity Thursday. The
forecast becomes more settled and cooler over the weekend and the
early part of next week.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 940 pm: Showers continue to fizzle across the northern
GA/SC zones, as frontogenesis/convergence diminishes there. A
pocket of elevated convection however will shift across the
southern Lakelands in the next couple of hours; this will bring
our southernmost zones a brief round of moderate to heavy rain
along with some stray rumbles of thunder. PoPs have been updated
to these effects; HRRR seems to be doing a reasonable job keeping
up, so it was the primary input to the revised trends. A general
decline from north to south is still expected overnight.
Otherwise, in-situ cold air damming will persist, resulting in
widespread low cloud cover and nearly steady temps overnight. The
CAD likely will weaken overnight and Wed morning as some degree
of cold advection occurs, with baroclinic zone generally advecting
away from our southern periphery, and weak high pressure building
across the Mid-Atlantic for the time being. As the cool pool becomes
increasingly shallow, the low cloud layer will tend to turn into
more of a fog layer. While some degree of drying is seen aloft on
850-700mb charts overnight, models do not seem to have resolved
the convective debris now expanding from the late-day convection
along the aforementioned baroclinic zone. That may ride over the
fog layer for at least a portion of the night, and keep it from
getting too dense, and/or delaying the decline in vsby. Won`t rule
out a Dense Fog Advisory later tonight, but do not currently have
the confidence to issue a Special Wx Statement for fog risk.
A major storm system organizing over the southern Great Plains
tomorrow will result in warm frontal activation/movement across
the Southeast throughout the day, with some showers and possibly
an elevated TS or two likely making a run for the western third or
so of the forecast area anywhere from late morning on. As such,
likely to categorical pops will be carried for these areas from
late morning into the afternoon. With lingering/albeit weak in-situ
CAD lingering and the warm front on the move across the region, the
temperature forecast for Wed has major bust potential. The synoptic
moisture fields do suggest that continued drying and, initially, the
CAA will continue to thin the low clouds for a portion of the day,
but the warm frontal activation will also bring in new cloud layers
from the SW. Some sources like the NAMNest and Canadian Regional
model actually show the coolest max temps being in the SW CWA,
which will see the warm frontal clouds earliest. Overall, thinking
our short-term consensus product is a reasonable compromise;
revised maxes are a little warmer in the NE and cooler in the SW.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 100 PM Tuesday: Showers still expected to become widespread as
Wednesday night wears on, mainly forced by the increasingly moist
upglide flow and terrain lift. Best forcing along with the threat
of heavy showers and embedded thunder are progged to quickly
traverse the cwfa from about 12-18z as 50-55 kt 85h SSWly jet
translates from the mountains to the piedmont. Actual sfc cold
front will trail this initial band of deeper convection by several
hours, and the magnitude and extent of sb instability is still
uncertain ahead of the eastward moving cold front. Nonetheless, the
model consensus does prog a bubbling up of SBCAPE on the order of
500-1000 j/kg. Wind shear values remain in line for organized
convection to develop with 0-1 km shear of 30-40 kts and 0-6 km
shear near 60 kts for throughout SPC`s enhanced Day 3 risk, roughly
from about 20 until 03z Thursday.
Closed upper low remains progged to progressively become absorped
into the mean trough Thursday night through Friday while dry slot
punches in from the SW. A swath of wrap around moisture along the
occlusion zone behind the cold front will allow for precip to linger
during the day Friday before a Canadian high suppresses this zone to
the south. Friday will likely remain cloudy and showery throughout
the day, while N to NE-ly CAA regime filters in.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 200 PM Tuesday: For the upcoming weekend, dry but chilly
hipres is fcst to nose swwd into the region on Saturday. Depsite
sunshine returning, llvl NE to E flow will only be able to support
widespread 50s for high temperatures. Sfc ridging looks to remain
in position through Sunday along with sunshine and a weaker easterly
pressure gradient. With the core of the chilliest air starting to
erode, expecting maximums warm about 5 deg F from Saturday`s
readings. Upper level ridge axis will build atop the SE CONUS
throughout Monday and Tuesday keeping the wx dry and with the
gradual weakening of sfc ridging, aid in temperatures returning to
climatology on Monday and above normal for Tuesday.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: Shallow, late-stage cold-air damming
will persist tonight, supporting widespread IFR to LIFR
conditions. Moisture is becoming increasingly shallow, and a few
sites have managed to scatter to MVFR or even low VFR at issuance
time; in some cases this was the result of SHRA, which generally
are advecting south and out of the area. Expecting that the PBL will
remain soupy enough for the holes to fill back in to IFR within the
first couple hrs of the TAF. Vsby will worsen overnight mainly over
the NC Piedmont and eastern Upstate, likely falling below 1SM by
early morning, along with cigs near minima. Improvement unlikely
until mid to late morning; most sites will return to MVFR or even
low VFR by aftn. Redeveloping WAA ahead of approaching low pressure
will bring increasing precip chances from SW to NE beginning in
late morning, with chances trending upward thru Wed evening.
Outlook: Restrictions will likely remain widespread and precip
chances increase, especially from Wed evening through Thu morning
as a warm front returns from the south. Isolated to scattered
thunderstorms will be possible Wed night and Thu, a few of which may
be severe, particularly across the Upstate and near KCLT. Precip
and restrictions come to an end Friday with VFR expected over
the weekend.
Confidence Table...
02-08Z 08-14Z 14-20Z 20-00Z
KCLT Med 62% Med 79% Med 68% Med 76%
KGSP Med 65% High 84% Med 63% High 83%
KAVL Med 79% Med 77% High 89% High 83%
KHKY Med 75% Med 64% Med 73% High 80%
KGMU Med 67% High 81% Med 61% High 80%
KAND Low 59% Med 77% High 87% High 82%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables are available at
the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...MPR
NEAR TERM...JDL/Wimberley
SHORT TERM...CSH
LONG TERM...CSH
AVIATION...Wimberley
Area Forecast Discussion
National Weather Service New York NY
1042 PM EDT Tue Mar 16 2021
.SYNOPSIS...
High pressure continues moving offshore this evening. Weak low
pressure passes well south of Long Island tonight into
Wednesday. High pressure returns late Wednesday and Wednesday
night. Low pressure and its associated frontal system will slide
south of the area late Thursday through Friday morning. Strong
high pressure then builds in from the north and west Friday
afternoon and Friday night, remaining in control into the start
of next week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
A weak wave of low pressure developing off the NC coast and
high pressure moving offshore sets up a SE return flow. This
should help moisten the low levels tonight.
A flat northern stream shortwave approaches tonight. Some lift
provided by an increase in low to mid level frontogenesis and
increase in low level moisture will result in some light
precipitation. This is evident as weak radar reflectivity
returns and have been in the form of light sleet, light rain,
and light snow. No snow accumulations are expected. Lowest
visibility seen thus far with any of the snow was 2.5 miles.
POPs are slight chance to chance this evening and maintained
slight chance overnight with just some snow flurries or rain
sprinkles expected.
A closer look at the low to mid levels of the atmosphere this
evening from GOES-R IR satellite indicates cloud tops in the -15
to -20 degree C range. From RAP soundings, these temperatures
correspond to around 15 to 20 kft. Most observed cloud bases are
around 4 to 6 kft. This is a sufficient amount of moisture in
the column that is below freezing to allow for ice nucleation.
Some areas have low levels from surface to around 1kft that are
above freezing that is allowing for light plain rain as a
precipitation type. Some sleet and snow will mix in at times
with the rain.
Farther north, there is more moisture in the ice nucleation range of
-10 to -30 degree C allowing for mainly snow as the primary
precipitation type.
Without much lift, the intensity of all precipitation will remain
light. No snow or sleet accumulations are expected with at most
a localized coating of snow where moderate snow showers occur.
The chance for measurable precip appears very low and most high
resolution simulated reflectivities are indicating mainly
isolated coverage at most overnight. Have therefore maintained
a slight chance PoP overnight, but will use isolated flurries or
sprinkles. Slightly warmer air will advect northward through
the night with the onshore flow supporting light rain sprinkles
near the coast.
Otherwise, overcast conditions will persist overnight with
temperatures generally being steady in the lower to upper 30s.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Any lingering sprinkles near the coast at day break should end
quickly. Mostly cloudy conditions are then expected for the
remainder of Wednesday. The northern stream shortwave trough axis
will swing through late morning into the afternoon. The low
pressure to our south passes well offshore and high pressure
begins to return briefly late in the day. Time height cross
sections show a decent amount of low level moisture through the
day. Thinking the NAM profiles are too aggressive with the depth
of the low level moisture, especially in the afternoon. Have
followed more closely to the GFS which indicates some breaks in
the clouds. There is a chance that the northern portion of the
area sees a period of partly cloudy skies as well. Highs on
Wednesday will return to near normal levels in the middle and
upper 40s.
A northern stream trough passes across southeast Canada Wednesday
night. The next system to impact our region organizes across
the southern Plains Wednesday night. Dry conditions will
prevail, but lingering low level moisture supports at least
mostly cloudy skies. Any partial clearing during the afternoon
should fill back in and become overcast Wednesday night. High
pressure will otherwise slowly shift offshore.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
The long term period starts off rather active as low pressure
over the Ohio Valley moves from west to east, passing south of
the area late Thursday into Thursday night. POPs will gradually
increase Thursday morning with POPs becoming likely by late
afternoon/evening everywhere. We are generally looking at a rain
event for much of Thursday and most of Thursday night, however
as the low starts to move off to the east late Thursday night,
winds turn to the north and colder air will work into the
region. This colder air, may change some of the precipitation
over to snow or a rain/snow mix.
The difficult part of the forecast pertains to how quickly
colder air moves into the area late Thursday night into Friday
morning. There appears to be enough disagreement around this, as
to how much moisture will be left when the cold air arrives.
Precipitation ends Friday morning with good cold air advection
expected on a gusty NW flow. Expect highs on Friday to only be
in the upper 30s and lower 40s. The gusty NW flow will make it
feel even colder, with wind chills in the 20s and lower 30s.
High pressure then settles over the region for the weekend and
start of next week with dry conditions expected. Temperatures
will gradually rise through the weekend with highs on Saturday
in the 40s, Sunday in the upper 40s and 50s, with 50s and lower
60s both Monday and Tuesday.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
A weak low pressure area approaches from the southwest tonight.
The weak low moves off the North Carolina coast and well south
of Long Island going into early Wednesday.
VFR to MVFR conditions late this evening with MVFR to IFR
conditions expected overnight as low levels moisten. Other than
some light snow and light sleet near KGON, any precipitation
through tonight at other terminals will just be some brief snow
flurries or light rain sprinkles along the coast. Dry conditions
expected Wednesday with MVFR to IFR conditions in the morning,
becoming mainly MVFR in the afternoon.
Winds are light under 10kt generally out of the SE. Winds then
shift back primarily to the E overnight and at times could be
variable in direction. Winds return to a SE direction for
Wednesday.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments likely to refine timing of MVFR and IFR which could
be off by a few hours between observations and forecast.
.OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...
.Wednesday night...Mainly MVFR.
.Thursday...MVFR or lower in rain. NE G15-25kt at night,
especially overnight.
.Friday....MVFR or lower in rain, transitioning and ending as
snow and rain/snow mix. NE G25-30kt. NE gusts decrease closer
to 20 kt Friday night. Dry conditions and VFR return Friday
night.
.Saturday...VFR. N-NE G15-20kt, mainly in the morning.
.Sunday...VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: http:/www.weather.gov/zny/n90
&&
.MARINE...
A weak pressure gradient over the waters will lead to sub-SCA
conditions through Wednesday night.
Low pressure approaches the area waters on Thursday and move
across the area Thursday night. Sub-SCA conditions are expected
on Thursday. By Thursday night winds and seas will build from
south to north across the waters, with SCA conditions likely
Thursday night. On Friday there is now a good chance of gale
force winds gusts throughout much of the ocean waters, with SCA
conditions elsewhere. SCA conditions should linger throughout
all the waters Friday night, with SCA conditions coming down
from west to east across the waters on Saturday. Sub-SCA
conditions are expected Sunday and the start of next week.
&&
.HYDROLOGY...
1 to 1.25 inches of liquid equivalent is forecast Thursday into
Friday morning with locally higher amounts possible. However, no
hydrologic concerns are anticipated.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...BC/DS
NEAR TERM...JM/DS
SHORT TERM...DS
LONG TERM...BC
AVIATION...JM
MARINE...BC/DS
HYDROLOGY...BC/DS
Area Forecast Discussion...UPDATED
National Weather Service Norman OK
803 PM CDT Tue Mar 16 2021
...MESOSCALE UPDATE...
.MESOSCALE UPDATE...
Issued at 802 PM CDT Tue Mar 16 2021
Convective initiation has occurred with one severe storm southwest
of Childress during the past hour, and new CI now occurring in
the north central Texas Panhandle. A warm front is oriented sw-ne
from the northern Texas Panhandle across northwestern Oklahoma
from roughly Gage...to Woodward...to Ponca City. The southeastern
Texas Panhandle storm/s were likely rooted near the boundary layer
but high based. Newer convective now originating over the
northern Texas Panhandle is likely elevated north of the front.
Moisture return today continues to lag, but some mid 50 degree
dewpoints are now near the Red River, but 60+ deg dewpoints
continue to lag south of DFW to near/east of Abilene. Still strong
forcing for ascent is advancing eastward over the Panhandles and
will promote more widespread convective development in the next
1-4 hours. Effective shear supports more discrete modes with
activity along the dryline emerging from the southeastern Texas
Panhandle/southwestern Oklahoma, while storm modes will quickly
become messy over the northwestern area. Thus, large hail and
damaging winds remain the primary hazard south of the front with a
threat of mainly large hail and heavy rainfall north of the
boundary. Given the wind profile, an isolated tornado threat may
not be out of the question as moisture rapidly returns later
tonight and if any storm can remain discrete in proximity to the
warm front.
TL
&&
.SHORT TERM...
(This evening through Wednesday)
Issued at 416 PM CDT Tue Mar 16 2021
The main concerns for the short term: 1) severe thunderstorms
likely tonight, 2) snowfall over far NW counties tomorrow, and 3)
strong northwest winds tomorrow.
Latest water vapor imagery depicts the location of a strong upper
trough near the AZ/NM border. The 7.34 micron water vapor imagery
shows an EML moving across west Texas and towards northwest OK.
This may keep capping in place and promote severe storm
development tonight. The 20Z surface observations chart indicates
a surface low developing near Woodward with a dryline extending
to near Watonga to Hinton to Altus, and a warm front draped
across north-central Oklahoma. Very warm temperatures are
observed with widespread mid to upper 70s, and dewpoint
temperatures have increased into the low 50s over portions of
central Oklahoma as that plume of moisture moves northwestward.
The potent upper low continues east towards our CWA and is prog`d
to reach the TX panhandle overnight into early Wednesday morning,
as a low level jet develops across western OK/TX. MUCAPE will
rapidly increase between 03-06Z Wednesday up to NW OK with SBCAPE
increasing to 2000 J/kg (central OK) and 2500 J/kg (southern OK)
by 09Z. With bulk shear upwards of 70kts near the triple point,
supercell thunderstorms are expected to develop over NW OK between
03-06Z Wednesday. These storms will be capable of producing very large
hail up to the size of baseballs. Supercells are then forecast to
fire along the dryline over western Oklahoma and adjacent
portions of western north TX by 06Z. Mean wind vectors indicate
quick storm movement tracking northeast at a 40-50 knots.
Interestingly, the synoptic models and the latest HRRR trends
indicate a drying over central Oklahoma which suggest the OKC
metro may be spared storms. Given the environment, however, will
have to watch this closely. Time of arrival for central OK would
be around 09Z as the surface low moves overhead.
By mid morning tomorrow, wrap-around precipitation should turn to
snow over far NW Oklahoma and a Winter Storm Watch is in effect
from 12Z Wed to 00Z Thurs. Given impressive QPF amounts (1.5-2.0
inches) over NW Oklahoma, and surface temperatures in the
mid/upper 30s, there is a lot of uncertainty with to how much
snowfall will accumulate. For now, have around 2 to possibly 4
inches of snow near Harper, Woodward, and Ellis Counties. Very
strong northwest winds are expected to enter are area from the
west by Wednesday morning, and a Wind Advisory has been issued for
areas north/west of I-44. Sustained winds near 40 mph and gusts to
50 mph will be possible, particularly for western Oklahoma and
western north TX.
Thompson
&&
.LONG TERM...
(Wednesday night through next Monday)
Issued at 416 PM CDT Tue Mar 16 2021
Wednesday night into Thursday morning, precipitation exits the area
in northern Oklahoma, with precip ending west to east. Most of this
precipitation is expected to remain rain, with some possible
lingering snow in far northwestern Oklahoma. Clearing skies and a
return to normal temperatures is expected to follow late in the week
into the weekend. Precipitation chances return to the region
starting Monday into early next week as another long wave upper air
trough moves through the region. Most of the precip will be showers,
however a few thunderstorms are possible as the trough traverses the
area.
Zwink
&&
.AVIATION...
(00Z TAFS)
Issued at 611 PM CDT Tue Mar 16 2021
VFR conditions this evening will give way to MVFR as moisture
advects northward into the area. Showers and thunderstorms will
also likely impact central and northern sites later this evening
and through the overnight and will likely liner across the north
during the day Wednesday. Colder air will also allow a transtion
to snow at WWR by 18Z. As the storm system moves across gusty
southeast to east winds will shift to the north overnight and
through the day tomorrow with very strong gusty northwest winds
expected at most sites by Wednesday afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 76 50 62 37 / 0 70 20 10
Hobart OK 76 43 54 35 / 0 50 20 0
Wichita Falls TX 80 48 61 39 / 0 50 0 0
Gage OK 75 39 39 30 / 0 80 80 10
Ponca City OK 74 51 62 36 / 0 90 50 50
Durant OK 78 56 69 42 / 0 80 20 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Wind Advisory from 7 AM to 7 PM CDT Wednesday for OKZ004>029-
033>039-044-045.
Winter Storm Watch from 7 AM CDT Wednesday through Wednesday
evening for OKZ004-009-010.
TX...Wind Advisory from 7 AM to 7 PM CDT Wednesday for TXZ083>090.
&&
$$
SHORT TERM...01
LONG TERM....50
AVIATION...30
Area Forecast Discussion
National Weather Service Blacksburg VA
1055 PM EDT Tue Mar 16 2021
.SYNOPSIS...
High pressure returns tonight into Wednesday bringing with it
warmer conditions. Another strong storm system arrives Wednesday
night into Friday bringing widespread heavy rain and the
potential for strong thunderstorms to the region. Sunshine and
high pressure for the weekend ahead.
&&
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
As of 930 PM EDT Tuesday...
Sprinkles over southeast West Virginia...
Some very patchy light rain was located across parts of West
Virginia, south through eastern Kentucky and Tennessee. A few
sprinkles from this activity was located over our area of
responsibility in West Virginia, in the region where we
currently have around a 20 percent chance of precipitation.
These numbers however are expected to trend downward as we
approach and cross the midnight hour.
Have tweaked hourly temperatures and dew points across the area
based upon the latest observations and expected trends into the
early morning hours of Wednesday.
As of 650 PM EDT Tuesday...
No big changes for our latest forecast update...
We continue to see the flip-flop of typical temperatures across
the region with the warmest across the mountains and the coolest
across the Piedmont region. Values range from 62 at Bluefield to
42 at South Boston. Skies ranged from partly to mostly cloudy
across the mountains to mostly cloudy to cloudy across the
Piedmont. Winds were generally calm or light and variable except
across portions of the Mountain Empire region where southwest
winds were gusting 10 to 20 mph. After sunset we should see
these winds decrease to light and variable.
Have tweaked hourly temperatures, dew points, winds/gusts, and
sky cover based upon the latest observations and expected trends
through the evening.
As of 255 PM EDT Tuesday...
Mostly dry conditions for the remainder of the afternoon as low
clouds hang tough through tonight. Warmer air returns St.
Patrick`s Day...
It`s an afternoon where location matters when it comes to
temperature and cloud cover. If your west of Blue Ridge pockets of
sunshine have broken through our shallow wedge allowing temperatures
to warm into the 50s and 60s from Lewisburg/Bluefield back south
toward Blacksburg/Wytheville/Boone. Further west into central West
Virginia temperatures have surged toward 70 degrees.
Areas out east of the Blue Ridge Parkway into the Virginia and
North Carolina Piedmont the wedge continues to hold tough.
Clouds remain intact via visible and infrared satellite imagery
with temperatures in the low to mid 40s from Lynchburg/Farmville
south to Danville/Eden. Pockets of fog and drizzle can also be
noted across central and eastern North Carolina as precipitation
lags with our departing weak area of low pressure.
Low pressure will continue up the coast and out to sea later this
evening with weak high pressure building in. Mean flow though will
remain out of the west southwest filling the wedge back in and
promoting even some light precipitation over the western facing
slopes. This is evident in both the NAMnest, ARW, and HRRR solutions
which show a little bit of scattered light shower activity from
Lewisburg/Hot Springs south toward Richlands/Bluefield. This
activity will be relatively short lived with precipitation chances
trending downward heading into daybreak Wednesday. One concern will
be patchy areas of fog that look to develop during the overnight
into the Wednesday morning commute. Visibility will improve for
everyone by mid Wednesday morning as our wedge erodes and south to
southeasterly flow takes over.
With the low clouds and patchy fog in place tonight expect overnight
lows to not be as cold and close to NBM guidance. Widespread low to
mid 40s are expected east of the I-81 corridor into the Piedmont
with mid to upper 40s west of the I-77 stretch. Widespread mid to
upper 60s are expected for highs Wednesday despite morning cloud
cover and our cold air wedge slow to erode during the morning
period.
Confidence remains moderate in the near time period.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 155 PM EDT Tuesday...
A cold front will bring rain starting Wednesday night and may spark
a severe weather threat in the Piedmont late Thursday.
A compact upper level trough in the southern stream should allow a
potent low pressure system to cross over the Appalachian Mountains
during this forecast period. The warm front from this system will
spread overhead on Wednesday night and bring widespread rainfall.
There could be a gusty southeast flow ahead of this front from
Bluefield to Boone as a decent upper level jet passes overhead.
The rain should be stratiform in nature and could dump one to two
inches of QPF, which may be a hydrological concern for small creeks
and streams if the rain rates are high enough. By Thursday, the cold
front should cross over the Mid Atlantic and exit offshore during
Thursday night.
As the cold front heads eastward, there will be increasing amounts
of wind shear but limited instability along and west of the Blue
Ridge. That instability could be higher toward the Piedmont,
especially in southside Virginia and into North Carolina by late
Thursday evening. A slight risk of severe weather spans the entire
region, but confidence in that risk increases more toward the
southeast where the higher instability could coincide with the wind
shear. If any storms develop and become severe, there is a threat
for damaging winds and maybe an isolated tornado. The models still
have subtle discrepancies on the timing of the cold front passage
with the ECMWF a few hours slower than the GFS and the NAM. Leftover
showers from the trailing upper level trough will span most of
Friday along with a gusty north wind before drier air can arrive on
Friday night with high pressure building from the northwest.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 155 PM EDT Tuesday...
High pressure should bring drier weather for the weekend with warmer
air arriving by early next week.
High pressure will settle over the Mid Atlantic on Saturday to bring
drier weather through the weekend. Temperatures will stay on the
cooler side at first but start to moderate as heights begin to build
aloft. An upper level ridge should occupy the eastern United States
for Monday and Tuesday, which means another notable warming trend
should take place. Another upper level trough will dive into the
western United States but may take a while to eject the energy
eastward into the Plains. The GFS is considerably faster with
developing a low pressure system from this energy and bringing the
next chance of rain late on Tuesday, but the ECMWF is more preferred
here with its slower solution and keeping any threat of rain until
beyond this forecast period.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
As of 1000 PM EDT Tuesday...
Predominantly VFR conditions in the west with MVFR conditions
developing across the east where the wedge just barely scoured
out at the end of the day. The wedge is expected to expand back
to the southwest through the night reaching the BLF/LWB area
late tonight/early Wednesday morning. Low clouds and fog will
spread across areas east of the Blue Ridge within the next few
hours resulting in IFR-LIFR ceiling and visibilities holding for
areas such as LYH/DAN much of the night and eventually into ROA
after 08Z. These IFR-LIFR conditions should hold in these areas
until around 15Z Wed morning. Further west, VFR conditions
should hold a bit longer, perhaps as long as 09Z/10Z Wed
morning. Then as winds come around to the east-southeast in
these areas, they should also become IFR to LIFR, including BLF
and LWB by morning. Conditions should improve there a bit
quicker to VFR by late morning/early afternoon leaving most
areas except parts of the Piedmont/east of Blue Ridge VFR with
MVFR conditions possible in these later areas.
Winds are expected to be mostly southwest west of the Blue Ridge
and northeast to east east of the Blue Ridge overnight becoming
east to southeast all areas late tonight/early Wed and
continuing mostly southeast through the day Wed. Speeds should
be mostly 6-8 mph or less through the period, but some low end
gusts are possible around BLF during the day Wed.
/Confidence Levels in Forecast Parameters/
Ceilings - Moderate,
Visibilities - Moderate,
Winds - Moderate to High.
Extended Aviation Discussion...
A strong upper low pressure system will rotate out of the
southwestern U.S. Wed-Thu. This system will bring widespread
rain and a few thunderstorms to the area Thursday. There is a
slight threat for severe thunderstorms across the Virginia and
North Carolina piedmont. Gusty southwest winds will also be
possible in advance of this system. Conditions should be mostly
VFR Wednesday becoming sub-VFR Thursday and Friday.
Dry weather and VFR conditions are expected behind this system
for Friday night and Saturday.
&&
.EQUIPMENT...
As of 645 PM EDT Tuesday...
The KFCX National Weather Service radar is back in service.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...DS/ET
NEAR TERM...DS/ET
SHORT TERM...PW
LONG TERM...PW
AVIATION...ET/RAB
EQUIPMENT...DS
Area Forecast Discussion
National Weather Service Springfield MO
616 PM CDT Tue Mar 16 2021
.SHORT TERM...(This evening through Wednesday)
Issued at 330 PM CDT Tue Mar 16 2021
Focus is on late tonight through Wednesday evening with two rounds
of severe convection possible.
The first round will consist of elevated storms moving in from the
west late tonight and continuing into the morning hours. This
round looks to focus north of I-44 generally. The threat should
diminish as storms move east. Large hail is the primary threat,
with a lower threat of damaging winds. Models vary on the amount
of elevated instability, with the NAM and RAP showing 1,500 J/kg
of elevated CAPE that will be maximized through the hail growth
zone over the western CWA late tonight. Have increased the hail
size being advertised to golf ball size.
As the low pressure system moves in from the west in the
afternoon, a warm front will extend roughly along I-44. Additional
severe thunderstorms are expected to develop along and south of
the front in the afternoon with all modes of severe weather
possible. The severe threat would continue into the evening. The
amount of destabilization south of the front remains in question,
but overall have increasing confidence in severe storms given
strong wind shear, favorable wind profiles, and increasing
consensus for afternoon clearing. Greatest threat appears to be
along and south of Highway 60 and along and east of Highway 65
where very large hail, destructive winds, and a greater tornado
potential exists. Again, this is highly dependent on how much
clearing and destabilization can occur. Expect to be releasing a
special RAOB around mid day to help assess the environment.
Flooding will also be a concern due to soil moisture and stream
levels from previous rain, combined with excessive rainfall.
Current forecast has 2-3 inches of rain over the NW portions of
the CWA, with generally up to an inch elsewhere.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 330 PM CDT Tue Mar 16 2021
Rain sticks around into Thursday with wrap around moisture. There
is some potential to see some snow flakes or sleet with that if
the colder guidance works out, but kept the forecast liquid for
now. Thursday will be the coldest day with highs mainly in the
40s. Dry weather is expected Friday through Sunday with highs
warming into the 60s by Sunday. Another system is possible early
next work week, but confidence is low at this time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 616 PM CDT Tue Mar 16 2021
VFR conditions will continue tonight as high cloud cover builds
overhead ahead of an approaching low pressure system. Showers and
some thunderstorms will move into the region from the west very
late tonight into tomorrow morning, primarily after sunrise for
SGF/BBG. Some LLWS will also be possible mainly at JLN early
tomorrow morning. Additional thunderstorm development is possible
during tomorrow afternoon and evening depending on how quickly the
morning convection moves out of the area. All modes of severe
weather will be possible with the tomorrow afternoon/evening round
of storms.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Titus
LONG TERM...Titus
AVIATION...Rothstein
Area Forecast Discussion
National Weather Service Shreveport LA
948 PM CDT Tue Mar 16 2021
.UPDATE...
Continuing to watch a pseudo-warm front designated by slightly
higher dewpoints located near or just south of the I-20 Corridor
in NE TX to north of MLU continuing to slowly shift northward
attm. Isolated supercells earlier during the late afternoon/early
evening across NE LA formed along this boundary but have since
dissipated. Just in the last hour, isolated convection has
redeveloped once again across NW LA east of SHV and also west of
SHV. 00z SHV sounding did show weak capping near 10kft and as we
go through the remainder of the overnight hours, that CAP should
continue to strengthen.
00z NAM output along with latest HRRR suggests that any new
convection should remain near or north of the I-20 Corridor later
tonight as the pseudo-warm front continues to move northward with
the greatest coverage expected across portions of SW and SC AR.
Some of this could be strong to severe with large hail being the
main threat. After 3 AM towards sunrise, upper forcing should
really begin to ramp up near and northwest of the I-30 Corridor of
NE TX, SE OK and SW AR with the ejection of the upper trough to
our west and while much of this should remain elevated, cannot
rule out a large hail, damaging wind threat with this new
convection.
For the update, did not make much in the way of changes to
overnight low temps but did adjust pops based on the latest
guidance.
Updated forecast already sent...13.
&&
.PREV DISCUSSION... /issued 528 PM CDT Tue Mar 16 2021/
AVIATION...
A maritime warm front will continue to lift northward across our
airspace tonight and near and north of this boundary, we will
continue to see the possibility of isolated to widely scattered
thunderstorms. Have inserted VCTS with TEMPO weather remarks
through most terminals through the overnight hours. VFR conditions
currently prevailing will become MVFR overnight regardless of
storm coverage and cannot rule out some IFR ceilings possible
closer to sunrise across our. airspace as well. As we go through
the day Wednesday, a line of strong to severe thunderstorms will
be likely across our NE TX terminal locations mainly during the
morning hours with this line of convection moving eastward,
impacting SC AR and N LA during the afternoon. Have handled all
this with VCTS along with TEMPO weather remarks with the eastward
movement of the line.
S to SE winds overnight near or less than 10kts will become S to
SSW during the day Wednesday with sustained winds of 15 to 20 mph
with much higher gusts. Strongest winds will likely be felt
across our NE TX terminal locations. Should see a return to VFR
conditions by late in the TAF period across our NE TX terminal
locations.
13
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 66 78 47 65 / 30 80 0 0
MLU 67 81 48 64 / 30 90 10 0
DEQ 62 76 44 59 / 80 80 10 0
TXK 65 77 48 61 / 60 90 0 0
ELD 64 77 46 61 / 40 90 0 0
TYR 64 74 45 63 / 80 70 0 0
GGG 64 76 45 63 / 60 70 0 0
LFK 66 79 46 67 / 30 80 0 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
13/13
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
755 PM EDT Tue Mar 16 2021
.UPDATE...
No changes made to existing forecast. Ridging remains over the
area for another day or so before a low pressure system moves
across the eastern CONUS dragging a cold front over the peninsula
Thu night/Fri morning with showers and a few thunderstorms.
Expected continued warmth in the meantime with patchy late
night/early morning fog. Morning lows will fall into the low/mid
60s with afternoon highs reaching the mid/upper 80s away from the
coast along with a few interior locations flirting with 90
degrees.
&&
.AVIATION...
Mainly VFR expected through period with the exception of patchy
early morning fog introducing MVFR vsbys across terminals...with
greatest likelihood for KLAL/KPGD. Light/variable winds overnight
increase out of SE during morning, shifting/increasing to S/SW in
afternoon with higher gusts before decreasing to light/variable
to southerly late evening/overnight.
&&
.Prev Discussion... /issued 135 PM EDT Tue Mar 16 2021/
DISCUSSION...
17z water vapor and H4 RAP analysis continues to show the region
dominated by broad mid/upper level ridging. This ridge may have
relax just a tad in the past 24 hours, as we do not see as
pronounced a subsidence inversion the the 12Z KTBW sounding
profile, however, the impact of the ridge through the middle of
the week remain unchanged. Inclement weather along a frontal
boundary over the deep south and supported by series of shortwaves
ejecting out of the southern plains will remain anchored to our
north through Wednesday. This these features staying well removed
from west-central and southwest Florida...our weather will stay
dry and warm. Temperatures were already rising into the 80s in
many locations, even close to the coast, although sea-breeze
formation during the early afternoon will likely keep the
immediate coast in the upper 70s.
SHORT TERM (Tonight through Thursday)...
As mentioned in the synopsis, fair and warm weather will continue
to dominate our forecast through the middle of the week.
Wedneday`s synoptic pattern will be similar to today`s...keeping
the forecast similar.
As we head into Thursday the ridge will begin to break down in
advance of a strong shortwave/cutoff low ejecting out of the lower
MS valley. A cold front associated with the feature will cross the
Florida panhandle Thursday morning into early afternoon. At this
point, do not anticipate any rain chances in our forecast area
until at the second half of Thursday, and this will be confined to
the Nature Coast zones late in the afternoon/early evening. It is
unlikely that any shower or potential storms reach the I-4
corridor and southward until sunset or beyond. The storm
prediction center has outlooked much of area are in a "marginal"
risk for severe weather. This seems appropriate with respect to
the threat. Conditions do not support a widespread severe weather
outbreak within west-central and southwest Florida, however, at
atmosphere will still have the capability for an isolated
stronger storms or two this far south. Will continue to monitor
the situation, but remaining optimistic that this will not be all
that significant an event for our region.
The band of showers and storms will only continue to become more
disorganized as it progresses into southwest Florida during the
overnight Thursday night. Certainly the best potential for a
wetting rainfall is from the I-4 corridor northward, but even here
the amounts are going to be light.
LONG TERM (Friday through Next Monday)...
The work week looks to end on a cooler and drier note behind the
departing front.
The upcoming weekend remains of lower confidence, however,
indications are that the weather may not be as nice as was hoped
with earlier long term projections. Upper level energy will be
interacting with the baroclinic zone off the NE Florida coast and
result in some form of cyclogenesis or development of an inverted
trough across the peninsula/eastern Gulf. Convergence along this
trough and a tightening pressure gradient looks to provide focus
for showers/moisture off the Atlantic crossing from peninsula from
east to west. Given the pattern, one would expect the wettest
potential to be on the east coast of Florida. However, thinking
we would at least see sct showers making it a ways inland and
perhaps all the way to the Gulf coast. Feel the forecast still has
room to change before the weekend and do not want to get to
detailed with things before it is appropriate to do so.
MARINE...
High pressure will dominate our weather through Wednesday night
with a southeast to south flow that will turn onshore each
afternoon at the coast. Expect winds to pick up to cautionary
levels by later Thursday ahead of an approaching cold front, and
then remain elevated and turn to the northwest behind the front
Thursday night into Friday. Winds are expected to briefly relax
later Friday into Friday night. However, it now appears as through
winds will increase once again our of the northeast and east for
much of the upcoming weekend. Cautionary to advisory level winds
and seas are becoming more likely over the weekend and boaters are
asked to keep updated on the latest forecasts before making any
plans, especially for heading offshore, this coming weekend.
FIRE WEATHER...
High pressure keeps our forecast dry and warm through the middle
of the week. Despite the warm temperatures, relative humidity
values are expected to generally remain above critical levels
through Thursday. Late Thursday and Thursday night, a cold front
will approach and cross the region with a band of showers and
potential thunderstorms. The best potential to see a wetting
rainfall will be to the north of the I-4 corridor. Drier and
cooler conditions arrive for Friday.
Areas of shallow fog are expected to be more prevalent early
Wednesday morning compared to previous days, but should burn off
quickly after sunrise.
&&
.Preliminary Point Temps/PoPs...
TPA 67 84 69 83 / 0 0 0 20
FMY 64 86 67 86 / 0 0 0 0
GIF 65 89 67 89 / 0 0 0 10
SRQ 65 83 67 82 / 0 0 0 10
BKV 60 88 61 86 / 0 0 0 30
SPG 68 81 70 81 / 0 0 0 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...None.
&&
$$
UPDATE/AVIATION...Hurt
PREV DISCUSSION...Mroczka
UPPER AIR/DECISION SUPPORT...Shiveley