Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/14/17
Area Forecast Discussion
National Weather Service Albany NY
1038 PM EDT Tue Jun 13 2017
.SYNOPSIS...
A cold front will continue to move south of the region overnight
with the isolated to scattered showers and thunderstorms ending
south of the Capital Region. Cooler and less humid air will move
into the region for the mid week period. Another frontal system will
approach late Thursday night and into the weekend, with the chance
for more showers and thunderstorms.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 1038 PM EDT...The sfc cold front continues to move south
of the mid-Hudson Valley...southeast Catskills...and southwest
New England. The actual dewpt boundary or secondary cold front
is moving south towards the Capital Region, Mohawk Valley, and
southern Vermont. Dewpts are falling into the lower to mid 50s
across the Lake George Region and the southern Adirondacks north
of this boundary. Some isolated to scattered showers continue
from the Capital Region south. There still remains some surface
based instability of 500-1000 J/kg or so over the southeast
Catskills, mid Hudson Valley, and northwest CT based on the SPC
RAP Mesoanalysis. We kept a slight chc of thunderstorms in the
forecast for the southernmost zones for a few more hours. The
latest 3km NAM shows the activity weakening, with the latest
3-km HRRR making it linger a little longer to 06Z. Temps were
adjusted based on observations, and lows in the 50s and 60s will
be common tonight.
Previous near term...
23z surface analysis shows cold front on roughly a Rutland/Glens
Falls line with dew point boundary trailing slightly behind.
SCT/NUM SHRA activity is accompanying the front. HRRR indicates
that these SHRAs will diminish fairly quickly this evening.
Will carry SCT wording in forecast for roughly I-90 corridor
early this evening. South of there ISOLD wording, with dry to
the north. Expect precip to be over by 02Z or so.
Sunny skies and drier air will take hold on Wednesday as the
nose of the 1026MB surface high near James Bay spreads its
influence southward.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
Surface high pressure drifts east Wednesday night and Thursday
as mid/upper level short-wave ridging works across the area. Dry
weather continues with temperatures running slightly below
normal.
Subtle short-wave troughs sliding along the generally zonal
flow will bring a chance of showers for Thursday night into
Friday. Instability remains muted for Thursday night and Friday,
so will call just SHRA with no mention of thunder. Temperatures
remain on the cool side Friday.
Nearly zonal flow gives way to upper level ridging Friday night
and Saturday. Still maintain a low chance of showers and
thunderstorms for Saturday. Temperatures will rise to near
normal levels with dew points rising.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
This will be a wet period of high humidities...with showers and
thunderstorms each day through the weekend. A backdoor cold front
to our west, harboring marine air over our forecast area, will help
to limit the amount of instability initially, but will also help to
keep sunshine to a minimum. This feature begins to break down over
the weekend, and a cold front will slide through from the northwest
Monday night that will finally trigger a drying trend.
Temperatures will grow cooler each day, with high temperatures
from the mid 70s to mid 80s on Sunday, the mid 60s to lower 80s on
Tuesday. Tuesday will be noticeably drier. Saturday and Sunday
night lows will be mostly in the 60s...with lows Monday night from
the mid 50s to lower 60s.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions forecast for all terminals. There is a low
probability that KALB and perhaps KPSF could briefly touch IFR
conditions within the next hour or so as a cold front crosses
those terminals. Thinking now is that visibilities will hold in
the MVFR range as front moves through. Expect precipitation to
dissipate by the time the front reaches POU.
By later tonight, P6SM SKC (or nearly SKC) conditions will
prevail for the remainder of the forecast period.
Outlook...
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
Thursday Night: Moderate Operational Impact. Chance of SHRA.
Friday: High Operational Impact. Likely SHRA.
Friday Night: Moderate Operational Impact. Chance of SHRA.
Saturday: Moderate Operational Impact. Chance of SHRA...TSRA.
Saturday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Sunday: Moderate Operational Impact. Chance of SHRA...TSRA.
&&
.FIRE WEATHER...
Scattered showers and thunderstorms through this evening will
end as a cold front pushes south of the Albany Fire Weather
Zone.
RH values tonight will range from 75 to 100% tonight,
decreasing to 30 to 40% Wednesday, then rising to 85 to 100%
Wednesday night.
Winds will be northwest to north at 5 to 10 mph.
The next chance for widespread rain showers will be Friday into
Saturday.
&&
.HYDROLOGY...
No widespread hydrologic issues are anticipated over the next
several days.
Recent dry weather has allowed elevated river levels to return
closer to normal flows. A cold front will push south of the
Albany HSA this evening. Scattered showers and thunderstorms
will accompany the front. Best precipitation coverage will be
along southern counties of Ulster, Dutchess, and Litchfield.
These showers will not have any impact on main stem rivers and
streams, but brief heavy downpours will be possible within any
thunderstorm. Although flash flooding is not anticipated, poor
drainage and urban areas could briefly see locally high water
during any thunderstorm.
Dry weather will then return once again for Wednesday into
Thursday. The next chance for showers and thunderstorms will be
Friday into the weekend with another frontal system moving
through the area.
For details on specific area rivers and lakes, including
observed and forecast river stages and lake elevations, please
visit the Advanced Hydrologic Prediction Service /AHPS/ graphs
on our website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...BGM/Wasula
NEAR TERM...BGM/Wasula
SHORT TERM...OKeefe
LONG TERM...ELH
AVIATION...OKeefe
FIRE WEATHER...BGM/OKeefe
HYDROLOGY...OKeefe
Area Forecast Discussion
National Weather Service State College PA
1025 PM EDT Tue Jun 13 2017
.SYNOPSIS...
A back door cold will continue to settle south of the region
overnight bringing cooler temperatures for the middle of the
week. An approaching warm front will impact the region by the
end of the week, keeping the mention of showers and
thunderstorms in the forecast into the weekend.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
10 PM update....
The radar shows just a couple of isolated storms left from east
of State College down into northern Dauphin County. They seem
organized about the outflow boundary that was generated by
earlier storms that moved through the Williamsport area with
gusty winds and locally heavy rain.
The HRRR shows the rest of the night mainly quiet as slightly
cooler and drier air starts to filter south behind the cold
front that is pretty much along I-80 as of 00Z.
Lows will remain very mild around 70 for the SE, with cooler
temps in the upper 50s and lower 60s behind the front north of
I-80.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
The front will start to drag over wrn PA and there will be a
higher chance of shra/tsra on Wed there. MRGL risk shifts to SW
third of the state, catching the Laurel Highlands. The shear
will still be low and the CAPE is also supposed to be lower. The
front should provide a focus and lift, but could still not be
enough to overcome an even thicker layer of stable air in the
lowest 4kft on Wed. Will keep POPs in the chc range except for
the highest elevs of the Laurels. Temps should top out in the
u70s/l80s.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
The large scale pattern overview will feature a replacement of
above normal heights/upper ridge over the Great Lakes with
a modestly strong mid/upper level trough by early next week.
With very minor fluctuations in the 500mb flow, sensible wx
will be influenced by a complex surface pattern consisting of a
NW-SE oriented quasi-stationary boundary near/south of the
PA/MD border pivoting and lifting back to the north as a warm
front through the end of the week. Models continue to show an
intrusion of relatively cool/stable air settling east of the
Alleghenies through midweek with rain risk gradually increasing
in somewhat of a clockwise fashion from SW to NW Wed ngt-Thu
then spreading eastward Thu ngt-Fri. A cooler temperature trend
is expected Wed to Fri but departures from average will only be
~1-5 degrees below mid-June climatology.
Warmer and more humid air will return to central PA this
weekend via deep southwest flow in advance of a cold front
pushing eastward through the Great Lakes/Midwest. This should
correspond to an increase in shower/thunderstorm activity with
max POPs focused around FROPA Sunday into Monday. There are
timing differences in the models so the most likely pcpn timing
may change faster/slower in the coming days. What is more
certain is an upward trend in temperatures with ensemble data
supporting +18-20C at 850mb which should translate into mid 80s
to low 90s for daytime highs Sunday and possibly Monday
depending on FROPA timing. Heat index values well into the 90s
would seem probable with this scenario in the urban corridors to
the southeast of I-81 (Harrisburg/York/Lancaster). The hot
spell appears to be short in duration with some relief arriving
by next Tue/6-20.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Short term section of the TAFs will focus on isolated
-SHRA/-TSRA as a frontal boundary shuffles across the forecast
area. As these diminish after sunset, VFR conditions will
prevail through the remainder of the forecast period.
Precipitation in the form of scattered convection will spread north
and east across the area during the afternoon hours Wednesday.
Low confidence in exact location of any one storm this far out
so painted a general VCTS in all but KMDT and KLNS for the last
period.
.OUTLOOK...
Thu...Low cigs poss central Mtns, especially AM and after dark.
Fri...Low cigs, showers/tstorms possible, mainly in the AM.
Sat-Sun...Patchy AM fog possible. Isold PM tsra impacts
possible.
&&
.CLIMATE...
Record high at Harrisburg (95F in 1956) has been eclipsed this
afternoon. More information is available in the evening climate
summary.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...La Corte
NEAR TERM...La Corte
SHORT TERM...RXR
LONG TERM...Steinbugl
AVIATION...Tyburski
CLIMATE...
Area Forecast Discussion
National Weather Service Quad Cities IA IL
756 PM CDT Tue Jun 13 2017
.UPDATE...
Issued at 753 PM CDT Tue Jun 13 2017
Update for expiration of heat advisory. All locations are below
advisory criteria, but very warm and muggy conditions will persist
through the evening. Isolated thunderstorms have dissipated across
the forecast area. Bureau and Putnam counties may be clipped by
the far western edge of an area of thunderstorms moving into east
central Illinois.
UPDATE Issued at 644 PM CDT Tue Jun 13 2017
Isolated thunderstorms are continuing to develop early this
evening along and east of the Mississippi River into northwest
Illinois. The strongest storms may have wind gusts around 30 mph
and some small hail. Activity is expected to diminish between 8
and 9 pm. Made some adjustments to the gridded forecast through
mid evening. Heat indices remain in the upper 90s in some areas
and will keep the heat advisory going until 8 pm.
&&
.SYNOPSIS...
Issued at 330 PM CDT Tue Jun 13 2017
18Z surface data has a remnant boundary from the nocturnal
convection in Wisconsin running from northern Indiana, across
northern Illinois, and into southeast Minnesota. Dew points were
mainly in the 60s north of the boundary with 70s south of the
boundary.
&&
.SHORT TERM...(This Evening through Wednesday)
ISSUED AT 330 PM CDT Tue Jun 13 2017
Heat and humidity will continue with an increased risk of storms on
Wednesday.
Through sunset, isolated showers and a few thunderstorms are possible
north and east of a Dubuque, IA to Princeton, IL line. The
remainder of the area should see hot and humid conditions.
Increased wind speeds this afternoon have allowed dew points across
the area to drop resulting in peak heat index readings of only 95 to
100. The heat advisory will continue until expiration in order to
maintain continuity.
After sunset, humid conditions will be seen across the area.
Internally, RAP trends have been to develop convection in the Plains
and have it move into the western half of Iowa through midnight.
After midnight how the convection evolves through sunrise is in
question. Internally, the RAP suggests convection moving east with
areas west of a Dubuque to Keokuk line at risk of seeing some
showers and thunderstorms.
How the convection develops/evolves overnight will play into what
occurs on Wednesday.
The most reasonable scenario for Wednesday is that convection moving
into eastern Iowa prior to sunrise will continue to move east of the
river before dissipating. Differential heating in the unstable air
will allow new convection to develop by mid to late morning across
the entire area that continues into the afternoon hours.
Given the energy potential built up into the atmosphere, one cannot
rule out strong convection developing as a result of any residual
boundaries across the area. The models do have a respectable upper
level disturbance that moves through the area during the late
morning and afternoon. Thus the slight risk of severe storms for
Wednesday looks reasonable.
.LONG TERM...(Wednesday Night through next Tuesday)
ISSUED AT 330 PM CDT Tue Jun 13 2017
Wednesday night...Expect convective activity to continue out of Wed
afternoon and into the evening, possibly continuing to grow upscale
to organized clusters during the evening. Best shear profiles in
concert with higher thermodynamics will look to occur to
southeastern flank/lee of digging upper trof acrs the eastern
Dakotas into MN, which would be main acrs WI for severe strom
support. But enough going on in the northern half to third of the
DVN CWA for stronger storm potential locally as well, with fcst
sounding suggesting large hail and damaging wind gusts the primary
threats. More widespread storm winds/gushing outflow may occur just
to the east and northeast of the DVN CWA acrs northern IL/WI if
another bowing segment/cool pool mechanics evolves out of the
activity acrs our area of concern. Some isolated to sctrd convection
may linger past midnight with llvl flow continuing to converge on
remnant outflow boundaries, but overall veering low to mid level wind
profiles suggest a decrease in activity into the early Thu morning
hours. Overnight lows in the mid 60s to lower 70s and variable do to
some areas getting rain-cooled storm outflow, and others remaining
mainly dry.
Thursday...Several 12z model run solutions continue to suggest
flattening mean steering flow pattern acrs the upper midwest, with
brunt of heat dome getting shunted more to the south and southwest.
But the local area still to be under the influence of the northern
edge of the thermal ridge, and south to southwest return flow to
boost temps back up to around 90 or the lower 90s in most of the
area. Afternoon sfc DPTS expected to mix down into the lower 60s, but
with the warm ambient temps will still make for CAPEs generally of
1500 to 2500 J/KG by late afternoon. This will set the stage for the
next short wave rippling through the more progressive flow pattern
to set off isolated to sctrd showers and thunderstorms either by
late afternoon, or Thu night. The models do suggest stronger bulk
shear profiles of over 40 KTS possible with this wave, and combined
with the instability may favor large hail and downburst winds with
the stronger storms. Several of the latest model runs do vary in
timing of this incoming wave, as well as the possibility of more
widespread convection occurring MCS-style to the south acrs MO (the
12z GFS) robbing in-feed to the north acrs IA into northern IL Thu
night. Will have to carry POPs for Thu night, and they may need to
be raised in the northwestern CWA by late afternoon if the 12z
NAMNEST has it`s way.
Friday through Sunday...Upper wave timing in evolving broad
westerlies acrs much of the mid CONUS, as well as sfc reflection
frontal systems, will be the challenge to try and define higher
precip chance windows during this period, and the latest run medium
range models continue to diverge. Much will depend on what lingers
out of the previous day and into the next, such as convective
debris, outflow boundaries and MCV`s. But in general, a more
pronounced short wave embedded in the near zonal flow and it`s
associated forcing may kick up sctrd storms or clusters from late
Fri and into Fri night. The 12z ECMWF is earlier in the day, while
the 12z GFS points more to a later Fri night MCS.
The pattern remains more active with the medium range models
suggesting an even stronger short wave and llvl front sweeping
through the region Sat night into early Sunday...another more
significant convective window with extent of low to mid level flow
patterns streaming around this feature. But again, much will depend
on available instability allowed to build after convective debris
clears(or doesn`t clear). This digging western GRT LKS upper trof to
signal a north to northwest influx of cooler air out of Canada late
Sunday and especially into early next week.
Next Monday and Tuesday...Again, these days may be below normal temp-
wise if projected thicknesses down down the upper midwest as GRT LKS
long wave trof evolves and deepens through Tue. Highs will look to
be only in the 70s acrs much of the local area during these early
week days, if the digging upper jet and projected air mass can make
it far enough south like the latest medium range models suggest.
..12..
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
ISSUED AT 644 PM CDT Tue Jun 13 2017
Confidence remains lows regarding timing and coverage of storms
through the TAF period. Have maintained previous VCTS groups at
all sites after 09z to handle possible initial batch of storms.
Additional rounds could develop later Wednesday morning and again
Wednesday afternoon. Did not want to depict such a lengthy period
of storm chances with such low confidence, and have emphasized the
afternoon period with Prob30 groups. Ceilings will be mainly low
VFR with some lower visibilities in more intense storms.
&&
.CLIMATE...
ISSUED AT 330 PM CDT Tue Jun 13 2017
Record Highs for today, June 13th...
Moline.........98 in 1987
Cedar Rapids...99 in 1920
Dubuque........95 in 1920 and previous years
Burlington.....98 in 1987
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...RP Kinney
SYNOPSIS...08
SHORT TERM...08
LONG TERM...12
AVIATION...RP Kinney
CLIMATE...08
Area Forecast Discussion
National Weather Service Indianapolis IN
1153 PM EDT Tue Jun 13 2017
.UPDATE...
The AVIATION Section has been updated below.
&&
.SYNOPSIS...
Issued at 238 PM EDT Tue Jun 13 2017
Pattern has become and will remain relatively active for rain into
Sunday night. A strong upper low in the northern Rockies will
track east across southern Canada through the remainder of the
week and establish northwest flow aloft by early next week.
The Wednesday night-Thursday, Saturday, and Sunday time frames
still appear to be those times which better support aloft
interacts with continued warm and humid air flowing in from the
Gulf. Sunday appears to have more widespread severe potential with
a bit stronger trough and surface low moving east across the Great
Lakes.
Temperatures will back down just a little as more cloud cover from
scattered convection limits insolation. Frontal passages early
Thursday, Saturday day, and late Sunday all will bring a little
Canadian air with them and lower temps and humidity slightly.
Unstable air with no capping inversion today has produced widely
scattered convection. With the approach of the Canadian upper
flow, dynamics and more detectable troughing will approach our
area bringing likelihood of more widespread convection Wednesday
night into Thursday.
&&
.NEAR TERM /Overnight/...
Issued at 945 PM EDT Tue Jun 13 2017
Surface analysis continues to show broad but weak high pressure in
place over eastern Kentucky...continuing to dominate Indiana`s
weather. A very warm and humid air mass remained in place across
Indiana...with dew point temperatures in the upper 60s and lower
70s. Radar shows a few thunderstorms primarily NW of Central
Indiana slowly drifting southeast. Rapid refresh suggests this
devlopment to propagate slowly eastward...which seems
reasonable...given the decreasing instability across the
area...the HRRR still seems overdone. Thus have kept pops mainly
across the northern half of the forecast area overnight...and only
with chc pops as confidence is low in propagation and progression
of the storms. Given the very warm and humid air mass...have
trended lows very close to persistence values as there has been
little change in the overall air mass since this morning.
&&
.SHORT TERM /Wednesday through Friday/...
Issued at 238 PM EDT Tue Jun 13 2017
Unstable air with little capping again suggests more scattered
convection Wednesday and a weak short wave moving in late day
should enhance the likelihood and coverage of rain.
Wednesday night into Thursday early...all models show trough
moving through and surface ridge following in its wake Thursday
afternoon. This results in likely pops for this time frame and
clearing Thursday afternoon.
Thursday night and Friday, tranquil pattern as surface ridge moves
quickly across swing surface winds from NW around the dial to
South by Friday morning.
Models differ some for Friday with several bringing a weak short
wave through the cyclonic flow Friday afternoon with a return
threat for storms while ECMWF holds back on this. Some POPs have
been continued Friday afternoon given this uncertainty.
Temperatures these periods are a blend...and continue a bit above
normal though fewer 90s are expected given cloudiness and then
cold frontal passage.
&&
.LONG TERM /Friday night through Tuesday/...
Issued at 238 PM EDT Tue Jun 13 2017
Friday night should be quiet as southwesterly flow reloads surface
moisture and weak upper ridge moves across.
Saturday all models show a weak short wave trough moving across
which should help to produce scattered convection during the day.
Sunday...all models show a deepening of the upper trough
developing a well organized surface low in the Great Lakes,
sweeping a cold front through during daytime hours. The outcome is
likely to be an organized line of storms with perhaps scattered
convection ahead of the trough. Given the instability in place and
decent dynamics, this likely will produce strong convection.
Sunday night through Tuesday, cooler and drier Canadian air
settles across the area. A few instability showers may occur in
the cyclonic flow aloft, but this will likely stay closer to the
Great Lakes.
Temperatures will be near normal this period and may tend slightly
below normal briefly at the end of this period.
&&
.AVIATION /Discussion for the 06Z Tafs/...
Issued at 1159 PM EDT Tue Jun 13 2017
VFR Conditions continue. TSRA development NW of KIND continues a
slow propagation SE...and may swipe the KIND TAF site early on the
during the TAF period. Brief MVFR conditions will be possible
should a TSRA strike KIND. Propagation and expected diminishing
trends of the thunderstorms suggest KHUF...KBMG and KLAF will not
be impacted after 06Z.
Otherwise...VFR Conditions are expected this TAF period. Broad
high pressure will remain across the region tonight...resulting in
VFR Conditions.
As heating returns on Wednesday...forecast soundings reveal steep
lapse rates...ideal for daytime heating convection. Thus will
expect scattered thunderstorms to develop once again across
Central Indiana. Confidence is not high enough for any specific
mention within the TAF`s. However brief MVFR conditions will be
possible with any storm that strikes a TAF site.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Tucek
NEAR TERM...Puma
SHORT TERM...Tucek
LONG TERM....Tucek
AVIATION...JP
Area Forecast Discussion
National Weather Service Northern Indiana
1034 PM EDT Tue Jun 13 2017
.SYNOPSIS...
Issued at 232 PM EDT Tue Jun 13 2017
Hot and humid conditions will persist through Thursday with highs
generally in the upper 80s to near 90 and lows near 70. This
humidity may also help create scattered showers and thunderstorms
each day near a weak frontal boundary, best chances during the
afternoon and early evening hours. By the weekend, temperatures
will be closer to normal, but still feature periodic chances for
rain.
&&
.UPDATE...
Issued at 1026 PM EDT Tue Jun 13 2017
Convection finally winding down across the majority of the area as
subsidence takes hold in wake of all the convection. The exception
remains in far SW counties near the nose of increased Theta-E air
and subtle lift that continues to produce mainly light to moderate
rain with embedded storms. Outflow boundary from this activity has
been working southwest across central Illinois and will hopefully
begin to disrupt the influx of lift. However, given radar trends
and HRRR 01Z run data which seems to be depicting the current
setup fairly well have increased pops in far SW and expanded out
several hours with a slow decrease overnight. Confidence in
overnight evolution of additional convection is low given
stabalized airmass and no clear signals of any feature that may
enhance convective develop outside of backdoor cold front situated
across NE parts of the area. HRRR would suggest convection will
continue. As such have not gotten too cute with pops in NE areas
and defer to overnight shift to monitor trends.
&&
.SHORT TERM...(Late This Afternoon through Wednesday Night)
Issued at 232 PM EDT Tue Jun 13 2017
Remaining hot/humid with periodic shower/storm chances...
Widely scattered pulse showers/storms will continue across nrn
IN/nw OH/sc Lower MI into the late afternoon and early
evening...in an area of weak low level convergence (marine
enhanced) and ample boundary layer moisture/CAPE. Lacking deep
layer forcing/shear under an upper ridge axis should limit
coverage/intensity, though cannot rule out isolated 40-60 mph wind
gusts, hail, and locally heavy rain with stronger cores.
Diurnally driven stabilizing effects will support a trend toward
mainly dry conditions under the upper ridge axis tonight into
Wednesday morning. However, did hold onto at least some low PoPs
during this time given lingering MUCAPE with 10-20 knots of low
level southwest flow into weak convergence zone (expected to
reorient more nw to se across sw Lower MI/nrn IN).
The best signal for thunderstorm development continues to be later
Wednesday into Wednesday night as the upper ridge axis shifts off
to the east and a lead/convectively aided shortwave tracks east
into this unstable environment/lingering subtle frontal zone.
Locally heavy rain will continue to be the main threat given slow
storm movement and high moisture content. A lesser threat with be
isolated strong/severe storms with slight uptick in deep layer
shear to near 20 knots.
&&
.LONG TERM...(Thursday through Tuesday)
Issued at 232 PM EDT Tue Jun 13 2017
A more active/quasi-zonal northern stream flow regime will take hold
on the region late this week into the weekend...with the result
being a trend toward slightly cooler (closer to normal) temps and
periodic chances for showers/storms as several impulses propagate
through. Confidence in timing of higher PoPs offered by the 12z
model consensus during these periods remains low given reliance on
waves (timing) to take advantage of building heat/instability
each day. Cooler/drier conditions are then expected into early
next week as upper troughing becomes better established forcing
instability axis well south.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 702 PM EDT Tue Jun 13 2017
Storms continue to diminish across the area and look to stear clear
of the TAF sites during the early overnight. However, storms fire
again on Wednesday and continue into the day. With light winds
overnight and the ground being moist from today`s storms, feel there
is a chance for some visibility obstruction at FWA into MVFR
early Wednesday, but a lesser chance at SBN with some day light to
dry out the ground moisture there. VFR conditions look to
continue outside of any decreased conditions as a result of storms
and rainfall.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...Fisher
SYNOPSIS...Steinwedel
SHORT TERM...Steinwedel
LONG TERM...Steinwedel
AVIATION...Roller
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Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
733 PM CDT Tue Jun 13 2017
.SYNOPSIS...
Issued at 235 PM CDT Tue Jun 13 2017
H5 analysis from earlier today had a closed low over
southern Montana with a trough extending to the ssw into western
Arizona. East of the low and trough, a nice shortwave was present
over central North Dakota. To the south of the low, a decent
shortwave was noted over northwestern Arizona. Ht. falls in
association with this feature were most pronounced over Colorado,
Wyoming, Montana the western South Dakota where 50 to 90 meter falls
were noted. East of the trough, high pressure was located over
northern portions of the Gulf of Mexico. A low amplitude ridge
extended north into the Ohio Valley and upper midwest. At the
surface: Low pressure was located over north central Nebraska in the
vicinity of Bassett Nebraska. A warm front extended to the northeast
into east central South Dakota and southern Minnesota. northwest of
the low, an occluded front was located from northern Nebraska into
southwestern north Dakota. south of the low, a cold front extended
into the Texas Panhandle. Across western and north central Nebraska
winds were generally northerly west of a line from Ainsworth to
North Platte. East of this line, winds were southerly wind gusting
as high as 20 MPH. In addition, a dryline was established and
extended from just west of North Platte into Western Kansas (along
the Kansas/Colorado) border. Temperatures as of 2 PM CDT were
generally in the mid to upper 80s, with some mid 70s in the
northeastern panhandle.
&&
.UPDATE...
Issued at 731 PM CDT Tue Jun 13 2017
The threat of severe weather has ended across North Central
Nebraska this evening. Dry stable air will continue to move into
the region.
UPDATE Issued at 627 PM CDT Tue Jun 13 2017
Threat for severe storms shifting north and east. Tornado Watch
323 remains in effect for the far north central to include Boyd,
Holt, Garfield and Wheeler counties through 03Z. WCN product
updated.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 235 PM CDT Tue Jun 13 2017
Tonight and Wednesday: Thunderstorms and the threat
for severe storms is the main forecast threat Tonight. For this
evening. Thunderstorms are expected to initiate sometime around 4 PM
CDT across the central and eastern sandhills. Current satellite
imagery already has convective cloudiness along and east of highway
83 from Valentine to North Platte. The latest HRRR initiates
convection in two locations: First along the back edge of the CU
field (roughly along Highway 97 from Tryon to Merritt Reservoir.
Second along the frontal boundary from Arnold up to Bassett. The 4KM
NAM from this morning initiates convection around the same time as
the HRRR, however it is slightly farther east, initiating it along a
line from Broken Bow to O`Neill. This also has support from the GFS
soln this morning. The 12z WARW is similar to the latest HRRR in
developing convection on the western periphery of the CU field. With
the front being located just to the east of KLBF as of 2 PM CDT,
which is farther west than the NAM and GFS fcst solns, am more
inclined to believe the HRRR and WARW solutions. That being said,
decided to drag pops further west during the early evening hours.
This was reflected in the midday fcst update and will be
incorporated in the afternoon fcst package. Storms which do develop
will quickly become severe, with large hail and damaging winds being
the main threats. Low level helicity is more favorable for tornadoes
further north into eastern South Dakota and srn Minnesota INVOF the
warm front. As for the tornado threat across the CWA, it appears to
be the greatest in the far eastern zones (Holt, Boyd, Garfield and
Wheeler counties). In these areas 0-2 KM helicities are on the order
of 100 to 200 M2/SEC2. Looking at the latest near range model
solutions, thunderstorms should exit the forecast area by 03z this
evening. Drier air will push into the forecast area thanks to light
westerly winds. The drier air will allow temps to reach the mid 40s
in the far west overnight with 50s expected elsewhere. Thanks to
westerly winds, dry air will push east into far eastern Nebraska and
western Iowa Wednesday afternoon. This will lead to dry conditions
across the forecast area with highs in the lower to mid 80s.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 235 PM CDT Tue Jun 13 2017
Mid range (Wednesday night through Thursday Night):
Westerly winds aloft and at the surface, will allow dry boundary
layer air to persist across the forecast area into Friday morning.
No embedded shortwaves are depicted in the models as well, lending
support to a dry forecast from Weds night through Thurs night.
Friday through Tuesday: Southerly winds will shift around to the
south late Thursday night into Friday. This will push boundary layer
moisture quickly northward. Late Friday into Friday night, a
shortwave will track along the Canadian/US border. This will force a
warm front aloft through the eastern Dakotas and Eastern Nebraska
Friday Night with an increased threat for storms in the northeastern
forecast area. This precipitation threat will be followed by a
secondary threat for pcpn Sunday night in association with a surface
cold front. This front will track through the forecast area Sunday
night with even a better chance for rain during the period.
Temperatures will be warmest on Friday with highs in the mid to
upper 80s, while sunday will be the coolest with highs in the upper
70s to lower 80s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 604 PM CDT Tue Jun 13 2017
Expect mainly clear skies over the next 24 hours with some
scattered high clouds possible tonight. winds will be from the
northwest or west at 10 to 15 kts over the next 24 hours.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...CDC
SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Buttler
AVIATION...Buttler
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
610 PM CDT Tue Jun 13 2017
.SHORT TERM...(This evening through Wednesday)
Issued at 302 PM CDT Tue Jun 13 2017
Potentially very active short term is in store, with severe
weather possible this evening/tonight, followed by what could be
our fourth day in a row of severe weather Wednesday.
We`ll start with this afternoon. First, when looking at forecast
shear/instability parameters along with forecast soundings for
today, the first reaction we have been hearing around the office
is wow. The type of environment forecast to be over MN today is
something that we only see maybe a couple of times a decade up
here. 3000-5000 j/kg of MLCAPE, 40-50 kts of deep shear, h85 jet
increasing to between 40 and 50 kts, and effective storm relative
helicity north of the warm front forecast to get up between 300
and 600 m2/s2. That warm front shows up well on the 0.5 degree
reflectivity from MPX just into the far southern Twin Cities metro
area and by most accounts, it is forecast to get up to or a
little north of I-94.
So that leads to the next question of what`s a miss to keep us
from having a major severe weather outbreak? There are three
problems. First, there is strong subsidence in the wake of the
this mornings MCS as evidence by the rapidly clearing skies and
wake low across northern MN and rising h5 heights across the
entire area. Second, we have a very warm EML overhead, with a
pronounced warm nose and capping inversion noted on forecast
soundings at h7, with temps at this level around 14C. This warm
air around h7 also shows up well on 7.34 micron GOES-16 low level
water vapor imagery, with very warm values coming up out of the
central plains. The other problem deals with the orientation of
our shear and horizontal vorticity vectors, which is pretty much
parallel to predicted storm motion. The shear vectors parallel to
storm motion diminishes the tornado threat, as this favors rapid
upscale growth to linear systems, while discrete cells end up
ingesting primarily cross-wise as opposed to stream-wise
vorticity.
SPC did nudge their 10% tornado probability east toward St. Cloud,
which was likely in response to the HRRR this morning, which had
been developing discrete cells this afternoon ahead of the warm
front in west central MN. However, since 17z, the HRRR has
abandoned that idea and instead has joined the rest of the CAMS in
saying the capping wins out today, with the MPX area awaiting the
arrival of a line of thunderstorms out of Dakotas, that will form
in response to falling heights and a weakening cap associated
with a short wave currently working out of southeast Wyoming.
For tonight, current expectations is that the greatest severe
threat will reside across the northern half of the MPX coverage
area, with storm coverage across the southern half of the area
more questionable. Moisture transport on the RAP at h85 shows the
low level jet splitting as it work across MN, with one enhanced
area going up across northeast MN and another area coming up out
of KS into central IA. The 18z HRRR follows this forcing pretty
close taking one MCS northeast across western MN toward Lake
Superior, with it`s south end swinging through the Twin Cities,
while a second MCS moves into southern IA associated with the
southern LLJ enhancement.
Of course, we aren`t done with this tonight as the cold front will
be slow to move east. There is still uncertainty with
if/when/where storms develop Wednesday, but we have seen a slowing
in the cold front in the models, most pronounced with the GFS.
This slowing explains the western shift in the day 2 convective
outlook. CAMs and deterministic models are all over the board with
how convection evolves tomorrow. The problem is upper forcing is
more in question with the front Wednesday. The main upper low will
be up west of the Winnipeg lakes, with a subtle short wave being
the main forcing for storms. The GFS is slowest with the wave,
bringing it through our area during the afternoon, which allows
storms to develop along the I-35 corridor. The ECMWF has this same
wave pushing into northeast WI by the afternoon, with storms
largely east of our area. The severe threat is definitely
conditional, but severe parameters would support all modes of
severe weather if we see convection, though once again, we would
like see a quick transition to a more linear convective mode.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 327 PM CDT Tue Jun 13 2017
Still some uncertainty on where the cold front will be located
Wednesday evening but current consensus suggests it being
oriented roughly along the MN/WI border, keeping thunderstorm
chances constrained to west-central WI & far-southeast MN. MLCAPE
values of 1500-2500 J/kg and deep shear values of 30-40 kts would
certainly be supportive of some strong to severe thunderstorm
segments & clusters across western WI, with damaging wind gusts
and large hail the main threats. The cold front clears the area by
Thursday morning with clearing & drying behind the front leading
to a warm but pleasant day.
Unsettled weather returns Friday & through the weekend as a 100 kt
upper level jet & deepening trough over the western Great
Lakes provides forcing for at least some scattered precip chances
each day. Instability looks to be low each day as the warm front &
greatest CAPE looks to set up further to the south over Iowa so
strong/severe thunderstorms are not expected. The heaviest rainfall
is expected Friday night into early Sunday morning where PW values
potentially over 1.5" could result in locally heavy rainfall,
primarily over southern MN. Decent rain chances will continue
through the day Saturday into Sunday morning as the strong forcing
aloft will continue to kick off scattered showers & thunderstorms,
but we will be looking at on & off showers & thunderstorms vs an all
day washout.
The upper level trough moves east of the area by Sunday afternoon
ushering in NW flow with drier weather & much cooler temperatures,
though still close to normal. Models begin to diverge towards
Tuesday with the Euro placing us in a drier pattern stuck between
the broad trough off the east coast, & a developing ridge over the
west. The GFS returns to zonal flow across the northern tier of the
US & brings another strong upper level jet into the area, which
would result in a more unsettled pattern for midweek.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 605 PM CDT Tue Jun 13 2017
Several storms developed in west central Mn over the past hour and
were moving into an environment that is conducive of rapid
development. Will include near severe wind gusts at KAXN due to
this scenario between 1-2z. KRWF will likely see the activity in
eastern South Dakota to move into the area between 3-4z, with KSTC
between 4-5z. Otherwise, most of the MPX TAF sites will see
thunderstorms overnight, it is just a timing issue based on
movement and speed. There could be additional thunderstorms in
south central/east central Minnesota by 12z Wednesday as a
secondary area of storms move northeast from Iowa. Otherwise,
after 12z, most of Minnesota will see VFR conditions with a brief
period of MVFR/IFR cigs due to ample boundary layer moisture in
the wake of the thunderstorms overnight. These lower clouds/cig
should lift and dissipate as winds shift to the southwest.
KMSP...
Showers, isolated storms in southwest Minnesota should weaken as
it moves northeast into east central Minnesota this early evening.
Thunderstorms in South Dakota will likely affect the airport
after 5z, with a period of 1-2 hrs of heavy rain, gusty winds and
a brief period of MVFR/IFR conditions. Otherwise, a few storms are
possible around 12z Wednesday. The front will move across the
state Wednesday morning, with some redevelopment possible after
18z at the airport.
/OUTLOOK FOR KMSP/
Thu...VFR. Wind W 5-10kt.
Fri...VFR. Chc MVFR/TSRA. Wind VRB05kt.
Sat...VFR. Chc MVFR/TSRA. Wind bcmg W at 5-10 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&
$$
SHORT TERM...MPG
LONG TERM...ETA
AVIATION...JLT
Area Forecast Discussion
National Weather Service Omaha/Valley NE
310 PM CDT Tue Jun 13 2017
.SHORT TERM...(Tonight through Friday)
Issued at 310 PM CDT Tue Jun 13 2017
The timing and intensity of thunderstorms through the overnight
is the main forecast problem.
Upper air charts from 12z showed a closed low centered near
central MT, with height falls of up to 140 meters. There was a
95 knot jet max south of the low across UT and WY. Thermal ridge
at 700 mb extended from TX up into KS and NE. Cap is fairly strong
in much of the forecast area but a rogue cell did track quickly
northeast over parts of our area toward KSUX. Cap has weakened
farther to the west in central NE. MLCAPE values locally are
3000-4000 J/kg and Sfc to 6 km shear is 30-50 knots in the area
where main area of storms should initiate. Latest HRRR runs
suggest development in the next hour or so, with varying model
solutions as to how far and how fast things spread east this
evening. Looks like most of the area should see at least some
storms. Highest hail threat should be before dark, with a
transition more to outflow dominated storms. There does also
appear to be some tornado risk, but chances seem higher north of
our area. High PW (Precipitable Water) values across the forecast
area are mostly 1.0 to 1.4 inches, so there is some threat of
heavy rain.
Expect that most activity will be east of our area by sunrise
Wednesday but will keep some low POPs going in far southeast NE
and southwest IA into Wednesday. Currently have the period from
Wednesday night into Thursday morning dry. Both the 12z NAM and
GFS suggest that a convective complex may develop over parts of
southern NE and northern KS Thursday afternoon and evening. That
has been a fairly consistent trend and will stay with that
thinking. There are signals for storm potential again Friday
into Friday evening as well.
Lows tonight should drop to the lower and mid 60s in much of
northeast NE, ranging to lower 70s near the MO border. Highs
Wednesday should reach the mid 80s to lower 90s, with Thursday
a few degrees warmer.
.LONG TERM...(Friday night through Tuesday)
Issued at 227 PM CDT Tue Jun 13 2017
At the beginning of this period, we should be in modest west/
northwest flow at 500 mb. This flow should buckle a big as a
fast moving shortwave crosses the northern Plains. Otherwise a
warm mid tropospheric anticyclone should develop over AZ and NM
but extend north into western Canada. Model solutions vary a bit
in regards to waves moving toward us from the northwest, and
there will some intermittent chances for storms. Highs should
average in the 80s, with lows in the upper 50s to mid 60s.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1230 PM CDT Tue Jun 13 2017
VFR conditions to continue with gusty south/southeast surface
winds. Scattered thunderstorms are expected to develop to the west
of the TAF sites and spread east through the night. Best time
frame for KOFK looks like 23-02z, KLNK 03-06z and KOMA 04-07z.
Some of these storms could be severe.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
SHORT TERM...Miller
LONG TERM...Miller
AVIATION...Kern
Area Forecast Discussion
National Weather Service Norman OK
1027 PM CDT Tue Jun 13 2017
.DISCUSSION...
Aviation discussion for the 06 UTC TAFs is below.
&&
.AVIATION...
VFR conditions are generally expected.
Chances of SHRA/TSRA remain too low to include at any TAF site in
the next 24 hours. Brief MVFR conditions or lower along with
variable gusty surface winds would be possible with any SHRA/TSRA.
Patches of MVFR conditions may occur at many sites 09-18 UTC.
Surface winds will remain gusty at some sites. A weak surface
front will bring a wind shift to the north across northwestern
Oklahoma sometime after 13 UTC. Otherwise, a mainly southerly
surface wind can be expected.
MBS
&&
.PREV DISCUSSION... /issued 843 PM CDT Tue Jun 13 2017/
UPDATE...
Adjusted rain chances this evening, mainly to lower them slightly
across western Oklahoma and far western north Texas. Added 20%
chances of showers and thunderstorms north of I-40 after midnight
tonight. Made small adjustments to hourly elements tonight.
DISCUSSION...
Severe potential is quickly winding down tonight. Warm and muggy
conditions will continue tonight.
Showers and storms have overall been weakening across far western
Oklahoma over the past hour due to the loss of daytime heating as
well as the storms moving east into an area with stronger capping
with higher amounts of MLCIN. Think this trend will generally
continue this evening, though cannot rule out a stray
strong/severe storm with hail/gusty winds for the next few hours
in far western Oklahoma.
After midnight tonight, added 20% chance for showers and
thunderstorms over the northern half of Oklahoma as latest HRRR
and NAM12 runs have been depicting some possible redevelopment of
elevated storms in these areas, possibly due to an increasing low
level jet. If these storms do occur, chances of severe remain
low, though small hail, gusty winds, and brief downpours could
be possible. Not confident this storm development will occur.
Products will be updated shortly.
MBS
PREV DISCUSSION... /ISSUED 253 PM CDT Tue Jun 13 2017/
DISCUSSION...
Main concern for this forecast is the chance for thunderstorms
across western Oklahoma and western north Texas tonight. There`s a
consistent signal for convection developing along the dryline in
the panhandles. The questions are how extensive the coverage will
be, how far north the line will stretch where instability starts
to drop off, and how far east the line will make it. Most of the
CAMs have storms dying off within one to two counties of the
Oklahoma Texas border, so while coverage may initially be fairly
extensive, it is expected to drop off pretty quickly upon entering
our CWA. There is a potential for severe hail and winds with some
of these storms.
Beyond tonight, a upper level ridge slowly builds into the area,
keeping rain chances down and allowing temperatures to rise. By
Friday and Saturday, western Oklahoma will likely see some 100s. Most
days maintain a slight chance for rain across some portion of the
area as a few shortwaves make their way through the area.
Sunday, a cold front is set to come through bringing cooler
temperatures and a better chance for rain.
Day
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
17
Area Forecast Discussion
National Weather Service Blacksburg VA
1135 PM EDT Tue Jun 13 2017
.SYNOPSIS...
Strong high pressure centered along the southeast Atlantic
coast will keep the area very warm and humid conditions.
Increasing moisture will lead to a daily threat of showers and
thunderstorms into early next week.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 1117 PM EDT Tuesday...
Been an active afternoon over the region with pulse strong to
severe storms. A few areas saw some wind damage.
Late this evening, the airmass remains moist with 00z rnk
sounding showing pwats of 1.43 inches, which is 90 percent of
average. Mesoanalysis shows best moisture convergence and
instability across the TN valley, with limited moisture
convergence over the foothills/piedmont. Based on latest high-
res models and radar trends, lowered pops considerably
overnight, to no more than isolated, if that. Some fog will come
into play overnight where it rained and in the river valleys, as
long as we clear out enough. Lows running 3 to 8 degrees above
normal with lower 60s mountains, to mid to upper 60s east of the
mountains.
Previous evening discussion...
HRRR a little too aggressive in developing more storms along
outflow in the mountains of SW Va/NC as of 6-7pm this evening
but overall had a good idea of where showers/storms would be.
Based on mesoanalysis appears threat of svr storms is over, and
should see weakening trend in the shower intensity this evening.
Will keep token thunder given some MLCAPEs around 500-1000 J/KG.
Previous discussion from earlier this afternoon...
High pressure located off the southeast Atlantic coast will continue
a warm moist southwesterly flow of unstable air across the region.
A mid-upper level low and related cold pool aloft will travel slowly
east across our area this afternoon into tonight. Outflow boundaries
from this morning convection across West Virginia associated with
shortwave rolling around the upper ridge helping enhance convection.
Scattered to numerous shower and thunderstorm along the mountains
will travels eastward into Piedmont into tonight. Some of the storms
will contain heavy rains and gusty winds. Any training or slow
moving storms could contain heavy rains and potential flooding. The
higher pwats values around 1.5 inches and mean wind less than 15 kts
support better flooding potential in the west as highlighted with
the marginal area in day 1 excessive rainfall. The Day One
convective outlook only indicated general thunderstorms for forecast
area. However, the combination of healthy DCAPE and decent LIs may
result in pulse severe thunderstorms. The main threats will be hail
and damaging winds. Showers and thunderstorms will taper off quickly
tonight with the loss of solar heating. However, a few showers may
linger tonight mainly in the west. The combination of low level
moisture and light winds will result in areas of fog overnight
especially where it rains. Low temperatures tonight will range from
the the upper 50s in the mountains in the mountains the upper 60s in
the Piedmont.
Scattered showers and thunderstorms are expected Wednesday with
abundant moisture lifting northward along the Appalachians and
strong daytime heating. A backdoor cold front will move
southwestward over the area Wednesday into Wednesday night. Very
weak flow aloft and negligible vertical shear suggest development of
loosely organized pulse storms with potential for some cells to
produce microbursts with strong surface winds during the afternoon
and evening. The Day Two convective outlook has highlighted
entire forecast area in a marginal risk for Wednesday.
Convection will begin along the ridges and gradually spread east
during the afternoon. Locally heavy rains are possible with
slow moving or training thunderstorms with increasing PWAT.
Light winds aloft may also promote slow storm movement
especially in the west, making for prolonged periods of heavy
rain for some locations. High temperatures Wednesday will vary
from the upper 70s in the mountains to the lower 90s in the
east.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 340 PM EDT Tuesday...
Scattered showers and storms likely to linger into the
overnight hours, especially in the northeast part of the County
Warning Area closer to the support of the backdoor frontal
boundary. Any severe threat should diminish by late evening
with loss of heating but will need to watch for isolated flash
flooding with potential for training of storms as weak steering
flow from west will be fighting slow movement of boundary from
the opposite direction.
By Thursday the focus shifts more to the west with convergence
near mountains with the weak surface boundary and also an
approaching weak upper wave moving in from the west. Some models
suggest a more organized system coming in late evening to
overnight, while most show typical diurnal development over
higher terrain earlier in the afternoon. In any case, Thursday
looks like potentially a higher coverage day, at least west of
the Blue Ridge, as well as better chances for isolated flash
flooding and isolated severe. Storm motions should still be
relatively slow from the west as well.
Friday could be more of the same but with a focus more along and
east of the Blue Ridge if timing of models is correct, with a
weak surface trough just east of the Blue Ridge and another weak
upper wave approaching late in the day. Keeping likely showers
and storms both Thurs and Fri with some lingering thunderstorm
chances into overnight hours but diminishing in coverage,
especially late Friday night.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 355 pm EDT Tuesday...
Moist pattern persists through the weekend but upper ridge
shifts deepens in amplitude a bit as upper trough slowly digs in
across the Great Lakes region and turns the mean flow more from
the SW as opposed to W. No obvious upper disturbances over the
weekend so coverage of diurnal convection may be a little
reduced compared to the previous couple of days, and may die
off more quickly overnight. Warm and humid conditions during the
day will continue.
Then upper trough swings through most likely on Monday as models
are in fairly good agreement with this, and associated cold
front appears likely to come through during the daytime hours.
If so, Monday could be the best chances for more widespread
severe activity as shear increases just enough for better
organization. With many days of scattered convection preceding
it, this would likely also bring an increased flash flood threat
as most locations bound to have more saturated conditions. At
this point Tuesday appears to be somewhat drier behind the
front, although some ensemble model members as well as the
Canadian model suggest front may not get too far east and may be
lingering precip chances. For now kept PoPs below 15 percent
and lowered temps and dew pts a few degrees from Monday, but not
highly confident in the front moving all the way through and
will have to watch closely the signals from a couple models
showing more tropical moisture trying to get up here by mid next
week, but for now those solutions do not seem likely.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
As of 714 PM EDT Tuesday...
Except for a few weakening showers near DAN/BLF/BCB will see
drier conditions overnight, though some models show showers
possibly impacting BLF/LWB again after midnight, but confidence
is low on this happening.
Should see VFR conditions, but overnight where it rained could
be foggy if we clear out enough. At the moment will have LWB/BCB
with MVFR to IFR fog, but could see others drop as well, and
will amend as necessary.
Wednesday will be another stormy day with backdoor front
situated from Ohio to Northern VA. Numerous showers/storms
should fire in the afternoon. At the moment keeping VCTS in for
all sites after 18z, until timing in the radar/sat trends
Wednesday will dictate amendments or better timing for assigning
thunder/showers in the tafs.
High confidence in ceilings, visibilities and winds during the
taf period.
Extended Aviation Discussion...
Deep Gulf moisture will spread north and northeast from the
Midsouth and Southeast U.S. into the Mid-Atlantic region through
late week. The backdoor front will linger in the area Wednesday
night through Thursday before retreating back to the north. A
stronger cold front and upper-level disturbance will arrive from
the west late in the week. Therefore, expect scattered to
numerous convective activity, mainly during the afternoon and
evenings, throughout the week. This will allow for extended
periods of sub- VFR ceilings and visibilities. In addition,
radiational late night/early morning fog will be on the
increase. Unsettled weather continues into the weekend.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...KK/PM
NEAR TERM...KK/WP
SHORT TERM...SK
LONG TERM...SK
AVIATION...KK/PM/WP