Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/29/17
Area Forecast Discussion
National Weather Service Wakefield VA
800 PM EDT Sun May 28 2017
.SYNOPSIS...
A frontal boundary will linger near the Virginia North Carolina
border tonight. A cold front approaches from the northwest on
Memorial Day and stalls north of the region into Tuesday.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Current analysis indicating surface low pressure over the Great
Lakes, extending SE into the local area with some weak surface
low pressure reflection along the coast of southeast VA and
northeast NC. Shortwave energy aloft has pushed well offshore
over past few hrs and airmass is only marginally unstable
(greater instability resides across southern NC and SC). While
PoPs have been raised a little, to likely through around 02Z
across the NW with another area of high chance (40-50%) into
south central and southside VA, the threat for any strong tstms
appears very unlikely now. May see a few isolated tstms this
evening but decided to update the HWO to remove the mention of
strong/severe tstms. Near term models and HRRR reflectivity suggest
the showers diminish in coverage later tonight with just
variable cloudiness and genly dry conditions overnight. Low
levels are already rather saturated and winds will be light
enough to support patchy FG and/or low stratus overnight as
well. Lows ranging through the 60s.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
A cold front will be crossing the mountains Mon morning...then
continue E Mon afternoon. Models continue to show drying over
most of the area...w/ the instability/moisture axis shifting SE
into far SE VA-NE NC...where additional SHRAS/tstms are
possible in the afternoon/evening. Partly sunny on Memorial Day
with highs in the l-m80s N to the m-u80s S (70s along the
Atlantic beaches of the eastern shore).
12Z/28 guidance continues to show that the cold front becomes
aligned parallel to WSW flow aloft...stalling immediately N of
the region to perhaps pushing into the MD Ern Shore. The chc for
aftn/evening SHRAS/tstms will diminish Tue...though will
continue w/ 20-40% PoPs in far srn and SE VA/NE NC. Highs
Tue from the u70s-l80s at the coast to the m80s inland...after
morning lows ranging through the 60s.
Little change in conditions Tue night-Wed. Upper level trough
to sharpen into the ern CONUS...though a strong enough trigger
for widespread convective development (esp Wed) ill-defined.
Maintaining PoPs (15-25%) in far SE VA-NE NC...mainly Wed
afternoon. Lows Tue night in the 60s. Highs Wed in the u70s-
l80s.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
The long term period beginning Wednesday night will start off mainly
dry with high pressure over the Mid Atlantic States Thursday. The
high will merge with the Bermuda High pressure ridge. This will
promote a slight warming trend and an increase of moisture. A
frontal boundary will settle over northern portions of the Mid
Atlantic States and help to trigger scattered mainly afternoon and
evening thunderstorms over the region.
High temperatures will range from 80 to 85 but slightly cooler at
the beaches. Lows of 60 to 65 Thursday and Friday mornings warm to
the mid to upper 60s Saturday and Sunday mornings.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Most of the strongest showers and thunderstorms have ended
across the CWA but some scattered light showers remain to the
west. These showers are not expected to be significant and will
likely end after midnight as the airmass continues to become
more stable. A weak frontal boundary continues to lie just
south of the Va/NC border and has been the focus for most of
the showers/tstms that have occurred today. Some stratus and fog
will occur over the region bringing MVFR/IFR conditions during
the overnight. Expect SBY to have the worst of the fog/stratus
conditions. RIC/PHF/ORF also expected to have some fog and
visibilities issues overnight with light NE flow. Guidance seems
favorable for ECG with mostly NW wind.
OUTLOOK...Mostly VFR conditions expected Monday with a slight
chance of some afternoon/evening showers/tstms. There will be a
chance for thunderstorms southeast portions Tuesday. Otherwise
mainly dry weather is forecast through Thursday with only a
stray shower or thunderstorm possible. The chance for afternoon
and evening thunderstorms increase on Friday mainly in southern
Virginia and northeast North Carolina. Patchy fog or stratus
will be possible each morning within a few hours of sunrise.
&&
.MARINE...
Late this aftn, weak low pressure was near the SE VA/NE NC
border. That low will move ENE and out to sea tonight thru Mon.
A weak cold front will push acrs the area during Mon, then
washes out over the Carolinas during Tue. Another weak cold
front slides acrs the region Tue night into Wed morning, with
yet another cold front moving thru the waters Wed night. High
pressure will build over the waters then out to sea Thu into
Fri. Winds/waves/seas will remain below SCA criteria thru the
period. Variable direction winds will be 15 kt or less, with
waves 1 to 2 ft and seas 2 to 4 ft.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...None.
&&
$$
SYNOPSIS...AJZ/ALB
NEAR TERM...LKB
SHORT TERM...AJZ/ALB
LONG TERM...LSA
AVIATION...JEF/LSA
MARINE...TMG
Area Forecast Discussion
National Weather Service Caribou ME
1004 PM EDT Sun May 28 2017
.SYNOPSIS...
A cold front will move into the area tonight and then stall
through Monday. An occluded front from the west will cross the
region later Monday night with unsettled conditions continuing
behind this front through midweek.
&&
.NEAR TERM /THROUGH MONDAY/...
945pm Update...
Main changes were to tweak T/Td and also POPs for current
situation as well as most recent model trends. Temps are staying
up a bit more than originally forecast up north, likely a
result of the cloud cover, so the temp decrease was slowed up
north. Td was also a bit low compared to recent obs north of
Katahdin, thanks to the numerous showers in northern Maine. So
Td was also bumped up some through 06z or so. Max POPs were
dropped some over the Crown of Maine as the 00z NAM and recent
HRRR runs have backed off on precip coverage up north. However,
didn`t go as far as some of the models in dropping POPs, as some
shower activity could continue around the weak front as it
lingers and then lifts north overnight.
Original Discussion...
Expect showers and isolated thunder over northern areas tonight
as a cold front stalls. Skies will remain partly to mostly
cloudy tonight into Monday across southern areas. The front will
move northward into Canada Monday Morning. An occluded front
will approach from the southwest later in the day Monday with
more showers breaking out ahead of this front.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
The first round of shwrs will traverse across the FA ahead of a
weak occluded front Mon ngt, with fcst rnfl amts durg this pd a
quarter inch or less and max PoPs about 80 percent attm. After
a relative break in shwrs erly Tue morn, another round of shwrs
with isolated Tstms looks like a good bet for Tue aftn into erly
eve with max PoPs in the high likely range as spokes of upper
lvl energy rotate arnd a broad upper low ovr Ont prov. These
shwrs will move E/dissipate by ovrngt Tue, leaving late ngt
patchy fog.
Otherwise, the same process will begin on Wed with another s/wv
movg WSW to ENE from the Great lks as the upper low remains ovr
Ont prov. Shwrs will increase again in the aftn with the
addition of day tm htg to destabilize the lower to mid
atmosphere. This time, there appears to be a little more of
MUCAPE upwards to arnd 500J/KG for a better chc of tstms in the
aftn into erly eve with max PoPs in the likely range. Shwrs and
any tstms will weaken and lessen in cvrg again ovrngt Wed.
Temps in the short term will be below avg for hi temps on Tue
but then recovering closer to normal hi temps on Wed with a
little more in the way of morn sunshine xpctd this day.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
The overall LW pattern will feature weakly positive PNA and NAO
teleconnection forcing ovr NA, which will keep upper lvl
troffing ovr the Ern U.S. alg with contd unsettled conditions
for the late weekend for our Rgn with perhaps a break in shwrs
for the Rgn by Sun. Until then, there will be a chc of shwrs
every aftn and erly eve from Thu thru Sat, with isold thunder
possible Thu aftn/erly eve. Despite day tm cld cvr and shwrs
spcly aftn, most of the really cool llvl air will remain in
Cntrl Can, so temps will be close to seasonal norms.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
NEAR TERM: Expect MVFR/IFR conditions tonight and Monday, with
some isolated showers also to be dodged north of KHUL through
tonight, and.
SHORT TO LONG TERM: Msly VFR all TAF sites, with intervals of
MVFR clgs and vsbys in heavier shwrs and patchy late ngt IFR
clgs Mon ngt, Tue ngt and perhaps Wed ngt.
&&
.MARINE...
NEAR TERM: Have used the NAM for sustained winds. For waves:
Currently a southerly swell is the primary wave system (2-3
feet/8-9 seconds). With light winds expected this wave group
will continue to be the primary wave group through tonight.
During the day Monday expect easterly winds to increase in speed
producing a secondary wave system. Will use the Nearshore
prediction system for wave grids.
SHORT TO LONG TERM: No hdlns anticipated attm, with winds and wv
hts msly below SCA criteria. Went with about 85% of WW3 wv
guidance for fcst wv hts this update, with wv pds msly between
5 to 7 secs.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.
&&
$$
Near Term...Kredensor/Mignone
Short Term...VJN
Long Term...VJN
Aviation...Kredensor/Mignone/VJN
Marine...Kredensor/Mignone/VJN
Area Forecast Discussion
National Weather Service Cleveland OH
946 PM EDT Sun May 28 2017
.SYNOPSIS...
A warm front will lift north of the area by this evening as a
weak cold front moves across the area from the west tonight. A
surface ridge will expand from Plains across the Ohio Valley on
Memorial Day followed by a stronger cold front on Tuesday. High
pressure will build into the area on Wednesday.
&&
.NEAR TERM /THROUGH MONDAY/...
Update...Updated most elements for the overnight beginning with
current conditions and using HRRR for timing of precip through
the area.
Original...Warm front attempting to lift northward across Lake
Erie with a humid airmass over northern Ohio and NW PA. Already
seeing convection that initiated on a lake boundary and near a
cold front that is moving toward NW Ohio. Expect these strong to
severe thunderstorms to persist into the evening. The front
should sweep across the area after midnight as the low lifts
into southern Ontario.
There should then be a dry period late tonight through early Monday
afternoon. We then will watch for the next piece of energy that will
move into the region as an upper level trough takes up residence
over the central Great Lakes. Showers and a few thunderstorms will
be possible monday afternoon into the early evening.
Slightly cooler on Monday but still above average.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
A weak cold front will swing through the area Monday night. Will
maintain chance pops diminishing to slight chance through the night
as the front pushes east. The front will linger across the far
eastern part of the forecast area on Tuesday, so will maintain the
slight chance/chance pops through the day. Another
shortwave/attendant surface trough will swing through the area
Tuesday night through Wednesday. Will maintain slight chance pops
Tuesday night into Wednesday, increasing to chance pops east
Wednesday. High pressure will move into the area Wednesday night
with dry conditions expected. Temperatures will be seasonable
Tuesday in the upper 60s to low 70s, and slightly cooler for
Wednesday with highs in the upper 60s.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
Long term period will start out quiet on Thursday as high pressure
moves across the area, but precip activity will pick up into the
weekend as a frontal boundary settles south into the region into
next weekend. Will go ahead with chance to slight chance pops
Thursday night through Saturday to account for this. Temps will
generally be seasonable through this period, but slightly cooler
(around 70 degrees) heading into the weekend as the front settles
south of the area.
&&
.AVIATION /00Z Monday THROUGH Friday/...
Warm front near the Ohio/PA border will lift NE next couple of
hours. A cold front near the Indiana/Ohio border will move
across the forecast area this evening. Scattered TSRA will
continue east of the front. Wind gusts into 30 to 35 knot range
still possible in the stronger storms. Storms should begin to
diminish somewhat after sunset.
OUTLOOK...Non- VFR at times Monday night through Thursday in
showers/thunderstorms as an upper level trough persists over the
central Great Lakes.
&&
.MARINE...
Easterly winds late this afternoon will veer around to the southwest
overnight as a warm front lifts north through the area. Winds will
increase towards tomorrow morning in the 15-20 kt range, with the
highest winds across the eastern part of the lake. Southwest to
occasionally westerly flow will persist through Thursday, generally
in the 10-15 kt range. Some diurnal peaks to around 20 kts possible
during the afternoon hours Tuesday and Wednesday, and may be enough
for small craft conditions for a few hours each day.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...Greenawalt
NEAR TERM...TK/Mullen
SHORT TERM...Greenawalt
LONG TERM...Greenawalt
AVIATION...DJB
MARINE...Greenawalt
Area Forecast Discussion
National Weather Service State College PA
1118 PM EDT Sun May 28 2017
.SYNOPSIS...
A warm front over western Pennsylvania will drift slowly
northeast across the state tonight and early Monday. A cold
front will push east from the Ohio Valley and cross the state
during the day Monday. Low pressure will become stalled over
northern Ontario during mid-week and will lead to a period of
slightly cooler than normal temperatures and occasionally
unsettled weather during the upcoming week.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Meso anal shows a stark contrast between the warm-humid air
streaming into western PA and the cold dome of cool-air damming
stuck over central PA. The warm front has not moved from its
north-south position pretty much stalled along and parallel to
the Laurel Highlands.
Radar shows an MCS, the result of an earlier southward sagging
outflow boundary over NWRN PA, now approaching my central zones
from the west. The HRRR keeps the convection active well into
the wee hours of Monday morning in the warm advection ahead of
the approaching front. The airmass is marginally unstable
judging by the RAP Cape, and guidance suggests a continued slow
erosion of the low level instability as the cold front works
into the area later tonight and early Monday. There are also
indications of inertial instability looking aloft along the
strong jet streak sliding into the lower Gr Lakes.
So the radar should remain active with the threat for the next
several hours being for additional locally heavy rains. We had
some significant flooding in and around Somerset but the rain
has finally tapered off to light showers over my SWRN zones. The
Flash Flood Watch has been canceled and any additional flooding
if it occurs is expected to be minor.
Average rainfall is expected to total from around .50" over the
far SE to between 1.00 and 1.50" over much of my central and
western zones. Locally higher amounts have already been
observed in the earlier heavier thunderstorms.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
Cold Front will be slicing through Central PA during the mid to
late morning hours, crossing the Susq Valley during the early-
mid afternoon hours.
It should turn out to be a really nice day with just a westerly
breeze in the west, but the slowing front may keep it muggier
in the east and isold storms would then be possible in the east
early in the aftn. Temps may be a bit higher than currently
advertised due to some earlier clearing and the downslope
effect (especially near the I-99/Route 220 Corridor.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
The long term period will be dominated by a large upper level
low the will slowly moving through the upper Great Lakes and
southern Canada. As that quasi stationary low slowly moves to
the northeast, it will bring surges of cool moist air across the
region.
The first surge of cooler air moves across Monday night. This
will bring showers in from the W/NW. However, any precipitation
will cease as the night continues due to lack of diurnal
heating.
A reinvigorated boundary should bring a chance of precipitation
through the northern half of PA. Several successive shortwave
will move through mid to late week which will bring the
possibility of scattered showers with preference for the
majority of the QPF (albeit quite light at that)to be across the
typical west-nwrly flow upslope prone areas of the Laurel
highlands and NW mtns. The chance for any thunder will be very
minimal Tuesday through Thursday.
Generally dry NW flow occurs late in the week into next weekend as
a 1020 sfc high over the upper midwest Friday evening builds SE twd
the region. Pops Thur night through Fri night will be 30 percent or
less.
Late in the week the models begin to diverge on the location
and timing of the upper level low so there is less confidence on
precipitation late in the week. However depending where the
boundary sets up there could be periods of showers Friday
through Saturday, though currently should be mainly along the
Southern border.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Adjusted thunder for 03Z TAF package.
Poor night for aviation, given low CIGS in spots, showers
and still some thunderstorms.
Conditions should improve from west to east on Monday, as
weak cold front moves across the area.
.OUTLOOK...
Tue...Chance of showers and thunderstorms.
Wed...Chance of showers.
Thu...No sig wx expected.
Fri...Chance of showers and thunderstorms.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...La Corte
NEAR TERM...La Corte
SHORT TERM...Dangelo
LONG TERM...Lambert/Ceru/Martin
AVIATION...Martin
Area Forecast Discussion
National Weather Service Des Moines IA
636 PM CDT Sun May 28 2017
...Updated for 29/00Z Aviation Discussion...
.SHORT TERM.../Tonight through Monday/
Issued at 311 PM CDT Sun May 28 2017
Mixing will continue through around 23z-00z before decoupling and
should expect the gustiness to diminish by this time frame. A few
fair weather cu have develop this afternoon but expecting them to
go away as well with the sunset. Large upper level low pressure
looks to remain over Ontario and provide northwest flow aloft
through tomorrow. The GFS and even the RAP suggest a weak
shortwave to quickly transition across the state overnight tonight
towards 12z Monday. Mainly looking to bring a few clouds past 06z
and possibly a stray shower. However, left forecast dry attm due
to the lack of significant moisture available tonight. Another,
slightly strong shortwave, moves through Minnesota by tomorrow
afternoon. This system has a better chance of providing showers
across northern Iowa and much more cloud cover across the forecast
area.
.LONG TERM.../Monday night through Sunday/
Issued at 311 PM CDT Sun May 28 2017
From Monday night through Wednesday Iowa will be beneath broad
cyclonic flow surrounding a gyre over Ontario. This will keep
temperatures slightly below normal, while clouds and a few light
showers may affect our northeastern counties at times, but with no
real impact. From Wednesday night through Friday night, as the
gyre moves slowly eastward, we will enter a more zonal flow regime
punctuated by several shortwave impulses moving overhead. The
first of these will come late Wednesday night and Thursday, with a
quick return of southerly low-level flow and instability along
with a slug of forcing, supporting the development of showers and
thunderstorms. Several prognostic forecast models indicate the
potential for a complex of thunderstorms moving across southern
Iowa or northern Missouri on Thursday morning, and while the
synoptic scenario supports this generally, confidence in
timing/location being pinned down that specifically is not very
high at this range. Nevertheless have included likely POPs, even
though the intensity inferred from some of the QPF output may be
too aggressive. Meanwhile the southerly flow established in the
latter half of the work week will allow for notable warming on
Thursday and Friday, with temperatures likely climbing into the
lower 80s across much of the area. Accordingly, destabilization on
Thursday afternoon may allow for additional thunderstorms late in
the day, with a repeat on Friday, though most of the forcing will
be diurnal/thermodynamic with no strong dynamic systems foreseen.
Next weekend the long range models diverge rapidly and
significantly, with the EC for example indicating modest deep layer
ridging and dry weather, while the GFS indicates a return of
cyclonic flow with two fairly robust troughs moving overhead and
prolonged thunderstorm chances. This discrepancy stems from their
respective evolutions of a mid/upper level trough coming ashore over
the Pacific northwest coast late this week. While the depiction of
this evolution in the EC appears more consistent with climatology,
have maintained low POPs in deference to the very wet solution of
the GFS.
&&
.AVIATION.../For the 00Z TAFS through 00Z Monday evening/
Issued at 636 PM CDT Sun May 28 2017
VFR conditions will prevail through the valid TAF period. Line of
SHRA/TSRA will enter northwest IA by 01Z and continue movg SE. Have
introduced VCSH at KFOD and KMCW. Localized wind gusts to 30-40 kt
are psbl with even the SHRA. Otherwise the only concern is mixing
Monday afternoon with gusts of 20-30 kt psbl.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...Podrazik
LONG TERM...Lee
AVIATION...Zogg
Area Forecast Discussion
National Weather Service Sioux Falls SD
1036 PM CDT Sun May 28 2017
.SHORT TERM...(This evening through Monday)
Issued at 415 PM CDT Sun May 28 2017
Very breezy afternoon across the region, as deep mixing is allowing
20 to 30 knot gusts to mix downward. Relatively quiet short term
continues, but we are watching convection across North Dakota
quickly race southeast. This convection is tied to a PV anomaly
pivoting across eastern North Dakota this afternoon, and focused on
the nose of an upper jet streak plunging down the western side of
the broad Canadian upper trough.
High resolution models are doing a good job handling this
convection, with expectations that the leading edge of this activity
may push into the northwestern portions of the CWA along the Highway
14 corridor by 6pm. With this activity no solely diurnally based,
expecting this scattered activity to persist southeast towards NW
Iowa by the late evening hours. While instability really isn`t that
high, will maintain an isolated thunder wording in the grids.
Perhaps the biggest concern would be the continuing steep low level
lapse rates and high storm bases, which could support brief wind
gusts up to or higher than 40 knots this evening. Simulated HRRR
gusts speeds support this idea as well.
Memorial Day could turn into a somewhat cloudy and cool day, as
strong cold air advection pivots southwest in the morning. With the
large upper trough dropping southward into the western Great Lakes,
any breaks in cloud cover should result in scattered showers or even
a few thunderstorms over western Minnesota and far eastern South
dakota by mid-day. Increased cloud cover, combined with cold
advection, will force temperatures slightly downward into the lower
and middle 60s. Afternoon winds will again be rather gusty, have
have increased speeds a few knots over populated guidance.
.LONG TERM...(Monday night through Sunday)
Issued at 415 PM CDT Sun May 28 2017
The showers Monday will rapidly wane as the daytime heating subsides
in the evening, enough to not warrant a mention of pops. As the
winds subside, cool high pressure will produce below normal lows in
the 40s. On Tuesday, the very large upper cyclone is still northeast
of our CWA greatly influencing our weather with an upper cyclonic
flow. Despite a high degree of mixing, cumulus and cool temperatures
above the surface will help to keep highs below normal with readings
in the 60s. The one exception is in our MO River valley zones where
highs should reach the lower 70s. Despite the upper cyclonic flow,
at this time decided to leave the northeast half of our forecast
area with no mention of pops in the afternoon as the cumulus field
builds. There is some subtle warm air advection in the 700-500mb
layer of about +2 to +4C which could keep light showers at bay, and
a lack of discernible short wave. It will be breezy again however,
with mixed layer winds of 20 to 30 knots suggesting a lot of 15 to
30 mph winds at the surface from a northwest direction. As surface
high pressure moves close to the forecast area Tuesday night, lows
will be very chilly for this time of year. Hedged toward cool
guidance readings such as MOS and the ECMWF to give a lot of 40 to
45 degrees under light winds.
The pattern then begins to warm on Wednesday with less wind. The
large upper cyclone is still situated over southeast Canada and the
northeast United States Wednesday through Friday. To the west, a
weak upper ridge of high pressure moves into the western plains. As
this happens, the low level jet increases Wednesday night with warm
air advection. This CWA is placed in speed convergence with 40 knots
in south central Nebraska feeding into only 20 knots in our southern
zones which gives some broad ascent. Furthermore, there is some
model consensus in showing MCS development to our south toward I 80.
The question is, will any rain fall on the northern side of it this
far north. This is similar to what happened last late Thursday night
and Friday morning. The GFS and GEM Global are similar in producing
some light rain and general TSRA in our forecast area Wednesday
night and Thursday morning, with the ECMWF less bullish. Solid
chance pops are certainly warranted with this disturbance, and if
the ECMWF comes more into line with the GEM and GFS in future model
runs, likely pops may be warranted at least from I 90 southward.
From Friday through Sunday, an upper trough begins to form behind
the upper ridge over MT, then moves southeastward into the plains on
Saturday. Friday is likely the most problematic in terms of highs as
to where the warm front sets up. The GEM Global and GFS has the warm
front well south of our area, whereas the ECMWF brings up warm air.
For now, used superblend with this much discrepancy which produces
highs in the upper 70s to lower 80s. If the ECMWF pans out as is,
then readings will be 5 to 10 degrees warmer. But as the upper
trough moves through on Saturday, with the ECMWF the quickest,
temperatures will cool some with a weak cold front following
Saturday night. At any rate, chance pops are certainly warranted for
rain and some TSRA late Friday night and Saturday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1032 PM CDT Sun May 28 2017
Spotty showers are expected to continue to diminish through the
evening. Otherwise, northwesterly winds will increase by mid
morning on Monday, gusting to around 20 to 25 kts through the
afternoon.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
SHORT TERM...Dux
LONG TERM...MJ
AVIATION...JM
Area Forecast Discussion
National Weather Service Hastings NE
603 PM CDT Sun May 28 2017
.SHORT TERM...(This evening through Monday)
Issued at 237 PM CDT Sun May 28 2017
Scattered showers have developed across central and west central
Nebraska this afternoon. These are aided by a weak perturbation that
is best visualized on the 305K isentropic surface. RAP and HRRR
soundings also show as much as 500 J of CAPE for western parts of
the area, so I`ve included a chance of thunder for areas along and
west of Highway 281. This activity is expected to dissipate late
this afternoon as we lose diurnal heating and as this feature moves
to our southeast.
Later tonight, another such wave will move from north to south
across the area, bringing us another chance for light showers. This
should exit our Kansas counties tomorrow morning. Overall, any rain
accumulation will be minimal.
Tomorrow afternoon, expect another day of breezy northwest winds and
highs in the mid to upper 70s.
.LONG TERM...(Monday night through Sunday)
Issued at 237 PM CDT Sun May 28 2017
Overall, there is little change in this forecast from the previous
packages.
Chances for thunderstorms return to north-central Kansas on
Tuesday as a warm front starts lifting northward and stalls in
that area. Models are showing 1000-1500 J/kg of CAPE in that
vicinity along with around 40 kts of bulk shear. Therefore a
strong storm isn`t out of the question. The main uncertainty is
how far north storms can make it. The GFS certainly looks to keep
the best of the instability in central Kansas.
Our best chance for thunderstorms arrives late Wednesday
afternoon into Thursday morning as this front lifts northward,
aided by an intensifying low-level jet. While this doesn`t look
particularly favorable for severe weather, the GFS does show
1500-2000 j/kg of MUCAPE and a 50 kt low-level jet to work with so
this trend will need to be monitored by upcoming shifts.
Temperature-wise, we will see seasonably warm conditions. Highs in
the 70s and low 80s...possibly reaching the mid 80s Thursday and
Friday as we stay in warm southerly flow.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday)
Issued at 600 PM CDT Sun May 28 2017
Isolated to scattered showers have dotted the area this afternoon
with the next round of potential rain showers and possibly a
thunderstorm arriving later this evening and into tonight as an
upper disturbance crosses the plains. With the potential for
convection, have went with a VCSH in the tafs at this time. The
gusty winds of today will subside tonight but increase again on
Memorial in deep mixing.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Mangels
LONG TERM...Mangels
AVIATION...Fay
Area Forecast Discussion
National Weather Service Green Bay WI
708 PM CDT Sun May 28 2017
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Monday
Issued at 309 PM CDT Sun May 28 2017
An area of showers moved out of eastern Wisconsin by early
afternoon but another round of showers, and thunderstorms, was
moving through north central and parts of central Wisconsin. This
second round was associated with a mid level short wave and
surface cold front. The latest RAP and HRRR showed the second area
of showers exiting the state by early evening, with convection
that was moving into western Wisconsin this afternoon dissipating
or at least weakening considerably with loss of daytime heating.
There looks to be a lull in the convective activity during the
night, but still have some PoPs mainly across north central
Wisconsin closer to the surface and upper level cyclones. The
chance for showers, and some thunderstorms, will increase again on
Memorial Day with daytime heating destabilizing the atmosphere and
another mid level short wave moving across Wisconsin.
A cooler air mass, clouds, and rain will keep temperatures cooler
on Memorial Day than they were today. Highs are expected to range
from the middle 50s to the middle 60s.
.LONG TERM...Monday Night Through Sunday
Issued at 309 PM CDT Sun May 28 2017
Cyclonic upper flow will keep mostly cloudy and cool
weather across our area through Wednesday along with scattered
showers mostly in the afternoon and evening hours.
Northwest upper flow forecast Thursday and Friday, though
scattered showers or thunderstorms are possible Thursday night
and Friday as a shortwave trough moves through the flow.
Saturday and Sunday`s forecast is a little less certain, as the
models have big differences in the movement of upper jet energy
from the Plains states. The GFS looks more reasonable with a
chance of showers versus the ECMWF idea of heavy rain Saturday.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 658 PM CDT Sun May 28 2017
Scattered thunderstorms will exit Door county in the next hour or
so, as a cold front moves through. Additional showers and
isolated storms associated with an upper level disturbance will
impact mainly north central WI this evening.
VFR conditions are anticipated over most of northeast and east
central WI through the TAF period, but MVFR ceilings are
expected to arrive over north central and central WI late tonight
into Monday morning. Showers will increase in coverage during the
late morning and afternoon on Monday, and become numerous over
north central WI later in the day. The steadier rain may cause
ceilings to drop to IFR at RHI during the late afternoon.
Gusty west winds will subside early this evening, then pick up
again by mid to late Monday morning.
&&
.MARINE...
Issued at 309 PM CDT Sun May 28 2017
Westerly winds, occasionally gusting to near 25 knots, are
expected Memorial Day.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MG
LONG TERM......RDM
AVIATION.......Kieckbusch
MARINE.........RDM
Area Forecast Discussion
National Weather Service Lincoln IL
840 PM CDT Sun May 28 2017
.UPDATE...
Issued at 840 PM CDT Sun May 28 2017
Updates this evening mainly for a band of showers and isolated
thunderstorms passing by to the south of Lincoln as a result of
lift associated with a weak surface trough. Late this evening,
stabilization should take place causing scattered cloud cover to
diminish and showers to diminish. Lows in the mid to upper 50s
still look good tonight, while 5-10 mph W-SW winds continue
through the night.
&&
.SHORT TERM...(This evening through Monday)
ISSUED AT 252 PM CDT Sun May 28 2017
A slow-moving cold front is triggering widely scattered convection
across east-central Illinois this afternoon...primarily along/south
of a Danville to Decatur line. Based on speed of frontal boundary
dropping southeastward through the area and the latest HRRR
analysis, think most of this activity will push into Indiana prior
to 00z. Will linger just a slight chance PoP south of I-70 into the
early evening hours...followed by dry conditions across the board
for the remainder of the night. Skies will clear in the wake of the
front, with overnight lows dropping into the middle to upper 50s.
Monday will start out sunny, but diurnal clouds will develop in
advance of a weak trough pivoting around low pressure centered over
the Great Lakes as the day progresses. Moisture will be limited:
however, NAM indicates MUCAPE values of 1500-2000J/kg across mainly
the southern KILX CWA by late afternoon. NAM/GFS/WRF-ARW/WRF-NMM
all agree that widely scattered convection will develop in advance
of the trough, so have included 20 PoPs across all but the far NW
late Monday afternoon. Have lingered low chance PoPs south of I-70
into Monday evening as the trough slowly settles southward into the
Ohio River Valley.
.LONG TERM...(Monday night through Sunday)
ISSUED AT 252 PM CDT Sun May 28 2017
Upper low centered over Ontario will be the primary influence over
the weather across central Illinois through the middle of the week.
Another weak impulse rotating around the low may bring a few showers
to northern Illinois on Tuesday: however, most model solutions
keep this activity just north of the KILX CWA. Yet another wave
tracking through the northwesterly flow pattern around the low
will skirt across Missouri and south-central Illinois Tuesday
night. Despite an overall lack of deep-layer moisture, enough
synoptic lift will be generated to create cloud cover and perhaps
a few showers. Have therefore included low chance PoPs across
all but the far NW CWA Tuesday night.
Surface high pressure will build into the Midwest on Wednesday,
bringing sunny skies and mild temperatures in the 70s. Once the
high shifts off to the east, a warm front will lift northward into
the area on Thursday. Models have been suggesting an MCS will
develop across the Plains Wednesday night, then track E/SE toward
central Illinois by Thursday morning. The exact track of this
system is still in question, but it appears chance PoPs are
warranted on Thursday with the frontal boundary in the vicinity.
After that, unsettled weather will be on tap for the end of the
week with daily rain chances through Sunday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 629 PM CDT Sun May 28 2017
VFR conditions expected for the next 24 hours. Diurnal cloud cover
will diminish this evening then another cold front will approach
from the NW for Monday afternoon. Included VCTS in TAFs after 20Z
as widely scattered thunderstorms are likely to develop ahead of
this cold front. Winds W under 12 kts through Monday
morning...increasing to 12-15kts with gusts 20-25 kts for Monday
afternoon.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...37
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...37
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
604 PM CDT Sun May 28 2017
.SHORT TERM...
151 PM CDT
Through Monday...
A cold front has pushed across northern Illinois and northwest
Indiana earlier today with convection early this afternoon in the
vicinity of the front, primarily over northern Indiana, but
clipping Benton County. Behind the front, northwest winds have
overspread most of the CWA with modest instability in place, but
weakly capped or uncapped per RAP soundings. There will be two
areas to keep an eye on through the afternoon and evening for
potential showers and thunderstorms. The first will be associated
with the lake Breeze in and around the Chicago Metro area this
afternoon. A strong thunderstorm has already developed on the
boundary and additional isolated showers and storms will be
possible through the afternoon. Farther west, a secondary surface
trough is evident in obs while a cu field has developed within the
vicinity of the trough that stretches from central WI into far NW
IL an eastern IA. There is potential for isolated to widely
scattered convection as this area moves across the CWA mid to late
this afternoon and into the early evening. With only 500-700 J/kg
MLCAPE and 20-30kt deep layer shear in place, severe threat is
not a big concern, but cannot rule out the potential for a few
storms to become strong. Cloud to ground lightning and gusty winds
would be a concern for any outdoor events.
Threat for precipitation should wane diurnally with dry conditions
expected overnight into Monday morning. Upper low is expected to
pivot across the western Great Lakes tomorrow while a sheared vort
lobe drops into northern Illinois. Forecast soundings tomorrow
are not too terribly different than today indicating steep low
level lapse rates with modest instability and little or no
convective inhibition. Given the favorable diurnal timing of the
shortwave, anticipate widely scattered showers and thunderstorms
will once again be a possibility. Temperatures will also be
fairly similar tomorrow with highs in the mid 70s. Deep mixing and
breezier conditions will be in place though, so there is a lower
likelihood of a lake breeze.
Deubelbeiss
&&
.LONG TERM...
213 PM CDT
Monday night through Sunday...
The upper level trough spreads over the region Monday night. Cooler
air will lead to lows in the low 50s. Soundings are pretty dry so
kept a dry forecast going after any lingering showers exit to the
east Monday evening. Another vorticity streamer rotates around the
upper level low and it may kick off showers and storms Tuesday
afternoon. Tuesday will also be cooler with highs around 70.
High pressure builds over the plains Tuesday night and Wednesday,
and the upper level low slowly shifts east. Wednesday will be
dry and cooler day with highs around 70.
My confidence is lower when it comes to Thursday`s forecast. The
GFS features a shortwave trough and convection spreading across the
region Thursday afternoon. The 12Z EMCWF, on the other hand, has a
much subtler wave, but does have a little QPF Thursday afternoon.
Decided to keep a chance of showers and storms in for Thursday, but
think the GFS is suffering from convective feedback. Warmer air
moves in aloft, but not sure how much cloud cover we will have, so
kept temps in the 70s.
Late this week looks active with many periods of showers and storms.
A low is forecast to form and move through the midwest Saturday
night with another push of cooler air moving in behind it Sunday.
JEE
&&
.AVIATION...
For the 00Z TAFs...
Weather of note with the TAFs are gusty west-southwest winds
during the day Monday. Also cannot rule out isolated showers
Monday afternoon and early evening, but they should have little
impact.
Broad weather system centered over Ontario will basically remain
in place through Monday night, with its influence of gusty winds
being felt as far south as the airports. The current late day
westerly gusts will diminish by sundown with a lighter southwest
wind tonight. Cold advection aloft on Monday and morning sunshine
will allow for mixing of gusts by late morning. Afternoon gusts
in the mid-upper 20s knots will be frequent and cannot rule out
lower 30 knot gusts, especially if afternoon clouds are less.
Confidence in direction is high and in peak gusts is medium-high.
Upstream this afternoon over Minnesota there were scattered
showers and even a couple storms. Do expect on Monday that these
will be seen further east and south, although think coverage
could be pretty limited in northern Illinois and northwest
Indiana with probably the better chance near the WI/IL state line
during the afternoon.
MTF
&&
.MARINE...
213 PM CDT
Winds become west overnight and increase to 15-25 kt Monday. Issued
a small craft advisory for gusty winds Monday for points north of
Gary, Indiana. Winds will be 15-25 kt east of Gary, IN, but do not
have enough confidence in persistent 20-25 kt winds.
West to southwest winds of 15-25 kt are expected through Wednesday
night as a low over Ontario slowly drifts north to James Bay. High
pressure builds over the plains Tuesday night and then shifts south
of the lake Wednesday night. Winds become north behind a cold front
Friday.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory...LMZ740-LMZ741-LMZ742-LMZ743...10 AM
Monday to 7 PM Monday.
&&
$$
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Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
922 PM CDT Sun May 28 2017
.DISCUSSION...See updated information for land areas below.
&&
.UPDATE...A complex mesoscale setup with evening analysis showing
a weak outflow boundary having settled southward to the coast
thru the day and is now stalled near the central Gulf coast. To
the west, a very impressive eruption of cold cloud tops and storms
has been evolving from Louisiana to central and southern Texas in
the vicinity of a surface frontal zone where 29.00Z precipitable
water values range from 1.4 to 1.8 inches. Given latest satellite
trends, clouds will continue to thicken overnight from west to
east and will maintain the eastward shift in rain chances thru
the pre-dawn hours to daybreak as shown in latest gridded
forecasts. This is also consistent with the latest high resolution
HRRR model radar reflectivity output. This also out of respect
for the passage of mid-level impulses in the southwest flow aloft, which
will bring a contribution to deep layer ascent. /10
&&
.PREV DISCUSSION... /issued 628 PM CDT Sun May 28 2017/
DISCUSSION...Updated for latest aviation discussion below.
AVIATION...
00Z issuance...Generally a few cu around 5 kt with broken, thin
high based cirrus carrying over into the evening. Vsby ok. Winds
are forecast to become light and variable. Potential for late
night low stratus developing with bases ranging from IFR to MVFR
categories. Indications are that some storms could be in the vcty
of the coastal terminals by daybreak Monday due to a weak
boundary near-by. /10
PREV DISCUSSION... /issued 417 PM CDT Sun May 28 2017/
NEAR TERM /Now Through Sunday night/...The outflow boundary
produced by last night`s MCS has made it all the way to the I-10
corridor in AL/NW FL. The boundary has been slowing down over the
past few hours as the remnant cold pool weakens. While scattered
showers and storms have developed at times along and ahead of the
boundary, the lack of upper forcing and a warm layer near 850mb
has kept most storms from getting strong even with MLCAPES of
2500-3000 J/kg. The outflow boundary will wash out along the coast
or just offshore by late this afternoon/early evening. Not much
in the way of precip expected through the evening as there will be
some CIN to overcome in the wake of the outflow. However, cannot
rule out an isolated storm along the coast due to the outflow and
over far inland SW AL/SE MS as isolated storms approach from the
west. The big question is when/where does the next best chance of
storms develop. Guidance has struggled through the day with the
mesoscale pattern so confidence is lower than normal. At this
point, it appears a subtle shortwave will approach from the west
early in the morning and serve to initiate scattered convection
along the coast or just offshore around daybreak (potentially
aided by the remnant outflow boundary). Any convection that
develops will move to the northeast with coverage increasing over
inland areas by late morning into the afternoon. Convective
coverage should also be enhanced by a surge of deep layer moisture
with precipitable waters increasing to 1.75-2 inches during the
day. The severe weather risk appears low at this time with 0-6km
shear only 25-30 kt. However, a few strong storms with gusty
winds/small hail are possible. In addition, torrential downpours
and localized nuisance flooding is possible with the increasing
precipitable waters. Lows tonight will be muggy in the lower to
mid 70s. Highs tomorrow tempered some by the increased convection
and will generally be in the low to mid 80s. 34/JFB
SHORT TERM /Monday Through Tuesday night/...Broad upper trof
moving east of the central plains states late Mon will shift east of
the north central gulf gulf states and forecast area by early Wed
morning. Ahead of the upper system a weak frontal boundary near
the surface is still expected to move south and stall near the
MS/AL/NWFL coast by early Tue morning. This frontal boundary will
be the main focus for heavier showers and thunderstorms through
the short term period due to better moisture convergence near and
along the front. Aloft several mid level impulses are noted in the
model guidance generally tracking from east Texas to central and
lower parts of MS and AL through early Wed morning. For Mon night
expect scattered pops across most locations in the forecast area
followed by likely to scattered pops across the forecast area
during the day on Tue, with the best chance of rain generally
along and west of the I-65 corridor. With continued forcing in the
mid levels combined with moderate instability near the surface a
few strong thunderstorms will be possible Mon night through early
Wed. Gusty straight line winds, frequent cloud to ground lightning
and periods of very heavy rain will be the main threats with the
stronger thunderstorms. With training cells over the same location
especially near the front some localized/nuisance flooding will
be possible especially over the western half of the forecast area.
Nighttime lows will continue to be slightly above seasonal averages
through Wed morning with highs running a tad below seasonal averages
each day due to clouds and rain. Lows Mon night will range from the
upper 60s to lower 70s inland and the lower to middle 70s near the
coast. Highs Tues will range from the lower to middle 80s for
most areas except the middle to upper 80s over inland areas well
to the east. Lows Tue night will range from the middle to upper
60s inland and the lower 70s near the coast. Highs Wed will range
from the middle to upper 80s inland and the middle 80s near the
coast.
LONG TERM /Wednesday Through Saturday/...By Wed a weak upper ridge
will be approaching the central gulf coast region from the west with
ridge axis moving east of the forecast by early Fri morning. Expect
drier conditions late Wed through early Fri followed by scattered
pops during the day Fri and Sat. The better rain chances late in the
week are in response to next upper trof approaching from the west
late in the week. Daytime highs look to be near seasonal averages
with night time lows running a few degrees above average. 32/ee
MARINE...A light to moderate south to southwest wind flow will
continue through Mon as high pressure slowly shifts east. Southerly
winds will diminish slightly Tue through midweek as a weak frontal
boundary stalls near the coast. Winds and waves will be higher near
scattered to numerous showers and thunderstorms through midweek. A
light to moderate southerly wind flow can be expected later in the
week. Seas will range from 2 to 3 feet through early in the week
then 2 feet or less from mid to late week. Less coverage of
showers and thunderstorms can be expected late Wed through Thu
night. 32/ee
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...None.
FL...None.
MS...None.
GM...None.
&&
$$
This product is also available on the web at:
http://weather.gov/mob
Area Forecast Discussion
National Weather Service Nashville TN
854 PM CDT Sun May 28 2017
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
The narrow band of showers and storms that developed late this
afternoon northwest of Middle TN...near the MS River...had
completely fizzled out by 01Z. Would not expect too much
redevelopment overnight despite the approaching weak cold front so
plan to lower/drop POPs over the northwest 1/2 of Middle TN.
The next chance for precip may be along the extreme southern
counties as early as 09Z to 12Z as area of moisture and weak lift
moves from AR/LA northeastward toward TN/AL border. HRRR and NAM
are the most aggressive models with the extent of this
precip...while most other models show less and/or focus on northern
AL rather than southern TN. Our current forecast of 40-50 POPs
for southern counties seems appropriate for this situation so will
keep those intact. This precip chance will continue through the
morning hours on Memorial Day...and possibly into the afternoon...
generally across the southeastern 1/3 of the midstate.
&&
.AVIATION...
00Z TAF DISCUSSION.
Current regional radar imagery along with consensus model
solutions illustrating fact that prefrontal convection impacting
terminals ahead of/along approaching sfc cold front may be iso
at best. More confident in VCSH wording at terminals than actual
impacts. VCSH 29/03Z W - 29/07Z E with BKN stratus deck around
5KFT. Some MVFR fog possible CKV/BNA 29/07Z-29/14Z. Best
potential MVFR to IFR fog CSV per best low level moisture pooling
potential. Did not lean toward latest GFS Lamp guidance suggestion
for LIFR fog formation CSV 29/09Z-29/13Z as patchy bkn ci could
prevent max radiational cooling potential. After 29/14Z, sct cu
CKV/BNA to sct/bkn cu CSV will prevail per weak sfc ridging/zonal
flow aloft. Generally sfc W winds 5-7kts thru 29/24Z.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......49
AVIATION........31
Area Forecast Discussion
National Weather Service Pittsburgh PA
928 PM EDT Sun May 28 2017
.SYNOPSIS...
Shower and thunderstorm chances continue until the passage of
the cold front overnight. Weak high pressure will keep Memorial
Day mostly dry with seasonable temperatures.
&&
.NEAR TERM /THROUGH MONDAY/...
Evening update made to nix the flash flood watch as the focus
for heavy rain and localized flooding has shifted northward in
the vicinity of the warm front with residual outflow boundaries
allowing for additional storms to develop. Overall, expect
strength of storms to diminish with time with the loss of
heating, but threat for heavy rain will linger until the
approach of the cold front tonight. Latest HRRR keeps this
reasoning, as the bulk of the precipitation remains situated
north and east of the turnpike. Will outline this area in the
hazardous weather outlook for the night with the thought that
most of the water issues will remain localized.
Cold front is still progged to pass overnight, with it east of
the region by 8am. Warm advection and low level mixing should
be sufficient to keep temperatures above seasonal averages
tonight.
Weak surface and mid level ridging should keep most of Monday
dry before a shortwave, pivoting through the broad upper trough
centered over the Great Lakes, brings the return of moist,
southerly flow and convergence for precipitation late.
Temperatures should be close to or just above seasonal norms.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
Shortwave will skim the region to our north Monday night and
Tuesday, bringing another front across the region that should
provide some scattered showers. Held off on thunder for Tuesday
for now as models disagree on stability, however steepening
lapse rates may allow for it. Precipitation coverage will wane
behind the boundary Tuesday night. Fairly seasonable
temperatures are expected.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
The Great Lakes/northeast CONUS trough will remain through the
end of the week, with periodic shower chances from shortwaves
moving through the flow. By next weekend, the upper pattern
becomes more zonal, and a frontal boundary could stall out
somewhere near or in our region. This boundary could provide
more focused rainfall chances, but its placement remains in
question. Temperatures will remain near or just a few degrees
below normal.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
Restrictions will continue at KFKL and KDUJ, mainly for
visibility in thunderstorms, until the passage of the cold front
tonight. Outside of these two locations, VFR will generally
prevail until the front approaches, with deterioration to MVFR
and IFR likely in showers and post-frontal stratus/fog.
VFR will return after sunrise under brief high pressure.
Wind shift from wsw to wnw is expected with the cold front
overnight. Wind gusts of 15-20kts are possible tomorrow
afternoon.
.Outlook...
Restrictions are possible Tue/Wed with an upper trough.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...None.
OH...None.
PA...None.
WV...None.
&&
$$
Area Forecast Discussion
National Weather Service Raleigh NC
817 PM EDT Sun May 28 2017
.SYNOPSIS...
In southwesterly flow aloft around a broad trough centered over the
upper Great Lakes and southern Ontario, a weakening cold front will
settle into and stall over the southeastern U.S., and become
increasingly diffuse and modulated by convection, through Mon.
Another cold front will cross VA and NC late Wed and Wed night.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 815 PM EDT Sunday...
An aggregate cold pool/outflow and apparent weak MCV from convection
over TN this morning crossed the srn and central Appalachians and
supported the development of scattered storms over the NC Foothills
and wrn piedmont during the past several hours, which now stretch
from near VUJ to FQD. These storms have generally lacked intensity
largely owing to a mixing out of surface dewpoints into the lower
60s and an associated instability minimum characterized by MLCAPE of
less than 1000 J/kg. More organized and stronger to severe storms,
also immediately downstream of the MCV, developed along a surface
trough from sern NC WSWwd through central SC, in an environment
characterized by much stronger instability (1500-3000 J/kg) owing to
both upper 60s-lower 70s surface dewpoints and the presence of the
lingering northern periphery of the EML that resided previously over
central NC during the past 36 hours.
Some of this latter activity will move across srn Sampson county in
a strong state for the next couple of hours, while the fate of the
former remains more unclear. Earlier HRRR runs indicated continued
multi-cell growth would be possible as the those storms tracked east
across the srn Piedmont and Sandhills through this evening, while
the past couple of runs show complete dissipation of this activity
by 01Z. Given that surface dewpoints have begun to nocturnally-
recover into the upper 60s to around 70 degrees in this area (and
throughout central NC), and since the convection is expected to
track along the moisture gradient accompanying a moisture maxima in
the low levels over east-central SC per RAP-initialized 925 mb
moisture fields, it seems more reasonable that earlier runs of the
HRRR may prove more accurate in their depiction of continued Ewd
propagation of this activity across the Srn Piedmont and Sandhills
through the next few hours. Gusty, sub-severe winds may result. But
in the absence stronger instability that appears will not
materialize there, updrafts are not expected to become vigorous
enough to interact with relatively strong environmental winds
characterized by 40-50 kts of 0-6 km bulk shear, so severe storms
are not anticipated there. Elsewhere across central NC, a lack of
instability and/or subsidence on the nrn and wrn edge of the
aforementioned MCV will likely result in dry conditions tonight.
Previously forecast lows in the mid-upper 60s north to lower 70s
south remain unchanged.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 300 PM Sunday...
Monday and Monday night:
The closed low over the Upper Great Lakes will wobble slowly east on
Monday. The primary northern stream shortwave trough is expected to
weaken as it lifts northeast away from the area, shearing out across
the northern Mid-Atlantic and NE U.S., with attendant trailing sfc
cold front expected to stall out across the area late Monday into
Monday night. The arrival of this front into the area Monday
afternoon/night coupled with individual perturbations ejecting NEWD
in the broad cyclonic flow, along the southern fringes of the strong
belt of westerlies, will bring another round of showers and
thunderstorms to the area that could linger well into the overnight
hours as the front begins to stall out.
Strong daytime heating within the moist and moderately unstable
airmass combined with continued strong mid-level flow that will
support favorable/strong deep layer shear of 40-45 kts, will result
in another slight risk for severe storms across the area with
damaging winds and large hail the primary threats. Storm intensity
should weaken significantly with loss of daytime heating, so the
severe threat should fall between 2 to 10 pm.
Highs in the mid 80s north to lower 90s south. Lows Monday night
will depend on the location of the front, ranging from lower/mid 60s
NW to lower 70s SE.
Tuesday and Tuesday night: As the upper low continues to wobble
slowly eastward over southern Ontario/Upper Great Lakes, the quasi-
stationary frontal zone and attendant axis of deeper moisture
bisecting central NC Tuesday morning will inch ever so slightly
east/southeastward through Tuesday night/early Wednesday. Any
shortwave energy moving through the upper jet streak extending from
the Tn Valley into the Mid-Atlantic region could result in a
convective flare-up and locally heavy rain near the front. As such,
expect areas south of east of the Triangle to see the highest rain
chances Tuesday afternoon and evening. While, deep layer shear won`t
be as good as in previous days, 30-35 kts will still be sufficient
to support a few strong to severe multicell clusters during peak
afternoon heating.
Highs ranging from lower to mid 80s north to upper 80/near 90 south.
Lows in the lower 60s NW to upper 60s/near 70 south.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 245 PM EDT Sunday...
General model consensus for the mid to late week period is that the
closed low over Ontario and associated northern stream trough will
get kicked east-northeastward late Wednesday, only to get replaced
by a reinforcing closed cyclone diving SE out of central Canada. The
eastward progression of the lead trough passage through the NE U.S.
and Mid-Atlantic States late Wednesday will push another cold front
from the northwest late Wednesday afternoon and evening, which will
allow for a continued threat of showers and storms area-wide
Wednesday.
West-northwesterly flow in the wake of the trough passage on
Thursday, may be just enough to push the front south of the region
with drier more stable air advecting in from the west, potentially
keeping central NC convection free on Thursday. However, these dry
conditions look to be short-lived with low-level SWLY flow in
advanced of a phased shortwave trough approaching from the west,
marking the return of higher humidity and instability, along with
the daily chance of mostly diurnal convection Friday and into the
weekend.
Seasonable temperatures Wednesday and Thursday will return into the
above normal ranges by the weekend.
&&
.AVIATION /00Z MONDAY THROUGH THURSDAY/...
As of 732 PM EDT Sunday...
24-HR TAF Period: VFR conditions will prevail through the period.
Isolated convection could impact all sites over the next several
hours before diminishing across the area tonight. Potential at any
particular site is too low to mention at this time. Winds will
remain from the SW at 5-10 kts.
Looking ahead: Aside from a potential for isolated/scattered diurnal
convection during the afternoon/evening hours each day, VFR
conditions are expected to prevail through mid-week. -Vincent
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...CBL
LONG TERM...CBL
AVIATION...30/Vincent
Area Forecast Discussion
National Weather Service Shreveport LA
957 PM CDT Sun May 28 2017
.DISCUSSION...
Cancelled remaining portions of SVR TSTM WATCH. Isold to sct
convection may redevelop across mainly southern portions of area,
however, airmass has been worked over and stg storms not expected
for remainder of the overnight. Rain cooled air and very wet
ground may yield patchy fog later tonight so added to fcst
areawide after midnight. Also made temp and dewpoint adjustments
to account for current mesoscale trends, with some areas where
temps and dewpoints have dipped, may see steady to rising values
by daybreak./07/
&&
.PREV DISCUSSION... /issued 827 PM CDT Sun May 28 2017/
DISCUSSION...
Updated to remove northern portion of SVR TSTM WATCH in effect
until midnight. East TX lakes, Toledo Bend, and northcentral LA
portions of the original watch area remain in effect. Will issue
another update when the threat of svr wx clears out of more of the
area, along with any possible adjustments regarding the overnight
low temps./07/
PREV DISCUSSION... /issued 718 PM CDT Sun May 28 2017/
AVIATION...
For the ArkLaTex, a large SQ line well S of KELD, and other cells
W still near KTXK, but the line snakes down across Toledo Bend
toward KLFK. KMLU will see it as well in the next couple of hrs
with gusty winds and small hail possible. Overnight this system
will push out of the area with a weak cold front sinking in shftg
S winds to N/NE perhaps down to along I-20, but the front will
wave back N a bit Mon. w/ another round of mainly p.m. tstms w/
gusty winds. This pattern will slowly erode by mid to late week.
/24/
PREV DISCUSSION... /issued 412 PM CDT Sun May 28 2017/
DISCUSSION...
The cold front, weak as it is, is nosing into Northeast Texas to
Mineola and Gilmer. Thunderstorms will lend a convective outflow
assist and help to foster a good push into much of the ArkLaTex.
The HRRR has been playing catch up all day and is not too far off
now, but really explodes with much more widespread activity into
the evening along and South of I-20.
The models nudge a weak surface high down to along I-30 and put
the shields up with an active week for many rain wise South of the
boundary, which is still much of our area. The cold front will
sort of run out of gas and remain parked in the ArkLaTex just
drifting back and forth in the light South wind and numerous
outflows to boost coverage for the next few days. Some maybe heavy
at times and all with dangerous lightning. If thunder roars, go
indoors. Good advice for the kiddo`s going forward into the rest
of spring 2017. /24/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 70 80 68 80 / 30 50 30 30
MLU 72 81 67 80 / 30 60 30 30
DEQ 64 86 62 85 / 10 10 10 20
TXK 68 82 64 82 / 20 20 10 20
ELD 68 78 66 81 / 30 40 20 30
TYR 68 79 66 82 / 30 40 20 30
GGG 70 80 66 81 / 30 40 20 30
LFK 67 81 68 82 / 40 60 30 30
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
07/07