Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/28/18
Area Forecast Discussion
National Weather Service Wakefield VA
927 PM EDT Wed Jun 27 2018
.SYNOPSIS...
Low pressure weakens off the Carolina coast tonight. A cold
front crosses the area Thursday. High pressure returns for the
weekend and slides offshore by next Monday, bringing hot and
mainly dry conditions to the region.
&&
.NEAR TERM /THROUGH THURSDAY/...
As of 927 PM EDT Wednesday...
Evening storms have left a N-S oriented mesoscale boundary from near
Richmond down through Emporia. The warm front has virtually washed
out over the CWA with the best moisture/instability remaining
focused well to the north.
Radar analysis advises keeping chance PoPs in for the evening across
central counties...as light showers meander eastward toward the
I-95 corridor. Hi-res guidance continues to suggest that any
rain chances overnight will exist across extreme northern
VA/southern MD. The HRRR is trying to sell a few showers over SE
VA/NE NC early Thursday morning, so will keep low PoPs in there
for now; however, these may be removed as soon as the next
update.
As of 400 PM EDT Wednesday...
Latest analysis indicates a weak sfc frontal boundary now
washing out across the region. Still not a lot of organized
convection but seeing a few storms begin to ramp up along the
I-95 corridor. Will keep PoPs mainly in the 30-50% chance range
and use "SCATTERED" wording into the evening with highest PoPs
along and east of I-95 initially, then with potential for a
broken line moving in from the west after 00Z will have chance
PoPs for all areas except in the far SE.
SPC has backed off on the marginal risk of svr tstms for the
local area, though heavy rain in slow moving storms will be a
concern through this evening. Best lift/moisture transport
progged across northern zones later this evening/overnight so
after midnight have only 20% or less except acrs the far N. Lows
upr 60 NW to lwr-mid 70s SE.
The cold front progged across the local area Thurs morning, slows
its eastward movement along the coast Thurs afternoon. Meanwhile,
data continues to show drier air filtering in from the west post
fropa. Given this scenario, kept chc tstms mainly SE during the
afternoon. No svr expected with this activity attm. Increasing
sunshine, especially across the west, and rising H85 temps
results in temps rising into the lwr 90s most areas west of the
bay, 85-90 ern shore areas.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 400 PM EDT Wednesday...
Looking like a transition to dry conditions and hotter
temperatures as an upper ridge builds east from the lwr/mid MS
Valley. Mostly sunny Fri and hot, but with dew pts genly into
the mid/upper 60s in the aftn (lwr 70s NE NC). This will make it
relatively comfortable despite highs into the lower 90s most
areas away from the coast. Mostly clear with lows in the upper
60s to lower 70s Fri night, mostly sunny and a few degrees
hotter for Sat (highs into the lower-mid 90s). Upper height
building aloft should keep it dry. Heat indices Sat peak in the
upper 90s to around 100 F but again some lowering of aftn dew
pts will keep it from being too bad given the time of year.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 400 PM EDT Wednesday...
The medium range period will be dominated by the ongoing upper
ridge and it`s gradual breaking down late in the period. The
consensus of the models has the upper ridge centered across the
northern mid-Atlc region Sat night/Sun, then sliding off the
coast of NJ to the Delmarva while weakening gradually Mon-Tue.
By late Tue/Wed, another upper ridge will be centered from the
mid-MS Valley to the OH Valley with weak troughing across the
local area. Sfc high pressure will be centered over the local
area over the weekend, sliding farther offshore by Mon/Tue with
a weak cool front moving in from the NW later Tue/Wed.
While it will be hot (and increasingly humid), the pattern does
not fit local heat climatology for excessively high
temperatures (which at this time of year would be upper 90s to
100+). Highest 850 mb temperatures suggest that the core of
hottest wx will likely align a little N of the AKQ CWA from
northern VA to NJ and perhaps into southern New England.
Locally, expect high temperatures generally in the lower- mid
90s Sun/Mon (hottest over the N/NW interior of the CWA where a
few upper 90s will be possible). Highs Tue/Wed will likely be a
touch cooler but still mainly into the upper 80s along the coast
and lower 90s inland. The immediate coast from the eastern
shore to VA Beach and NC Outer Banks will likely have some
seabreeze influence even on Sun/Mon with highs primarily in the
upper 80s to around 90 F. Heat indices look to avg a little over
100 F Sun-Tue but overall probably staying below 105 F. A heat
advisory can`t be ruled out but at this time looks like less
than a 50% probability. Lows Sat night/Sun night/Mon night/Tue
night will be mainly in the lower to mid 70s (with some upper
70s possible across the urban locales). In contrast to the very
wet conditions over the past 30-60 days, this period at least
"appears" as if it should be devoid of any organized rain until
Tue given high heights aloft and what should be a capped
atmosphere. Of course, an isolated sea /Bay- breeze storm and a
stray storm off the mountains can`t be ruled out but the
coverage of this would be minimal. Will keep the forecast mostly
dry Sun, with just a slight chance (20%) by Mon primarily over
the Piedmont and interior NE NC as the upper ridge begins to
slowly break down and shift farther off to the NE of the local
area. By Tue and especially Wed will carry chc PoPs by the
aftn/evening periods.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
As of 200 PM EDT Wednesday...
Conditions should remain VFR through the next 24 hours, although
there is a small chance that MVFR could occur at SBY or PHF if a
shower moves overhead this evening. Additional isolated
shower/thunderstorm development is possible mainly close to the
coast as a weak cold front moves through Thu, but they will be
very isolated and unlikely to cause impacts.
Outlook...A high pressure ridge builds in behind the cold front
Friday. The high moves offshore for the weekend, leading to the
small chance for aftn/evening showers and storms each day.
&&
.MARINE...
As of 330 PM EDT Wednesday...
A quasi-stationary frontal boundary currently extends from a weak
low pressure center off the NC coast ENE into the NW Piedmont of
NC. Meanwhile, high pressure is situated off the New England coast.
The resultant wind flow is generally from the SE 10-15 kt this
afternoon which should continue into this evening. Waves 1-2 ft;
seas 3-4 ft. The frontal boundary to our south will lift back north
as a warm front tonight, with winds becoming SSW 10-15 kt after
midnight. Winds then remain SW 10-15 kt Thursday morning/early
afternoon ahead of the next cold front approaching from the NW. Both
NWPS and Wavewatch guidance indicate a brief period of 5 ft seas out
around 20 NM Thursday morning. However, given low confidence will
not issue an SCA at this time. Cold front passes Thursday evening
with high pressure building in from the north on Friday. Winds will
veer to the NW then N but remain less than 15 kt. No SCA anticipated
into the upcoming weekend. However, as often happens during the
summer, there could be periods in the late afternoon/evening both
Saturday and Sunday where S/SE winds increase to around 15 kts on
the Bay and adjacent coastal waters.
&&
.HYDROLOGY...
As of 1030 AM EDT Wednesday...
Flood Warnings have been extended for another 12 hrs (through
tonight) for the Mattaponi River at Beulahville based on latest
gauge readings.
&&
.TIDES/COASTAL FLOODING...
Tidal anomalies running 1.0-1.25 ft above normal along the
Chesapeake Bay side of the lower MD Eastern Shore and the
Potomac side of the Northern Neck will bring water levels near
or just above minor flooding thresholds during the early
Thursday morning high tide cycle.
Additionally, there will be a moderate risk of rip currents at
area beaches on Thursday.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...Coastal Flood Advisory until 7 AM EDT Thursday for MDZ021>023.
NC...None.
VA...None.
MARINE...Small Craft Advisory until 5 AM EDT Thursday for ANZ630>632.
&&
$$
SYNOPSIS...LKB
NEAR TERM...BMS/LKB
SHORT TERM...LKB
LONG TERM...LKB
AVIATION...MRD
MARINE...JDM
HYDROLOGY...
TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Denver/Boulder CO
827 PM MDT Wed Jun 27 2018
.UPDATE...
Issued at 807 PM MDT Wed Jun 27 2018
Isolated high-based showers and thunderstorms continue along the
I-25 Corridor and northeast plains of CO this evening. Latest HRRR
vary quite a bit in the location of thunderstorms, further north
earlier, with the latest run targeting the Palmer Divide.
Nice inverted-v profile on the KDEN sounding this evening, with a
58 mph gust at the ASOS station at Denver International Airport
earlier this afternoon to support it. Do not expect the gusts to
be as strong this evening, but gusty winds in the 35-40 mph not
out of the question. Will keep the mention of isold tstms in the
grids until midnight, then diminishing overnight. Better low level
moisture to the north and east of Denver this evening with a
dewpoint of 62 at KAKO. There has been some recovery this evening
as some of this has advected west/southwest this evening. Shallow
as well and will quickly mix out of Denver Thursday morning.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 330 PM MDT Wed Jun 27 2018
Showers and storms will develop this afternoon and will continue
into the evening over far northeastern Colorado. The strongest
storms will be north and east of Fort Morgan as good moisture with
dew points in the 60s and instability with forecast mixed layer CAPE
values near 3000 J/kg will be in that area. These storms will be
capable of producing strong wind gusts and possibly a few large
hailstones. Storms across the rest of the CWA could produce gusty
winds as well since dew point depressions are starting to
approach 70 degrees in spots.
Any showers and storms will end by 1 AM tonight and clouds will
begin to dissipate. Low temperatures will be about 5-15 above
average tonight.
The stage is set for record high temperatures on Thursday with most
areas east of the foothills reaching 100 degrees or above. Most
synoptic scale features will be generally the same but there is
reason to increase the high temperatures a couple degrees above a
persistence forecast from today. These reasons include northeast
Colorado being under the right exit region of a mid level jet
streak that will be working its way through the Great Basin area.
In addition, a lee cyclone developing over Wyoming will enhance
the downslope flow leading to further compressional warming. Am
currently thinking the high at DIA will be around 103 degrees but
an attempt at the all time record high of 105 degrees will be
possible. A few stray showers and storms may develop near the
Palmer Divide tomorrow afternoon but with very high dew point
depressions it is unlikely that rain will reach the ground. Gusty
winds will be the biggest threat from these showers and storms.
.LONG TERM...(Thursday night through Wednesday)
Issued at 330 PM MDT Wed Jun 27 2018
Long wave upper trough over the West Coast and western Great Basin
Thursday night shows some deamplification as it propagates
eastward the northern and central Rocky Mountain region this
weekend. Ahead of the trough, models indicate a couple of weak
cold fronts slipping south through eastern Wyoming during the day
Friday. The first of these boundaries is forecast to slip into
nern Colorado late Fri afternoon, the second somewhat stronger
front late Friday night. With each arrival, should see an increase
in low-level moisture on the plains, especially with the second
front according to the NAM and ECMWF. Not so much according to the
GFS and Canadian models. Based on the two wetter models, could
see sfc based CAPEs by late afternoon anywhere from 2000-3200 j/kg
acrs the northeast corner. The NAM once again is the bullish of
the two models. Whereas the NAM and GFS both indicate decent
0-3km/0-6km bulk shear/helicity suitable for at least single cell
storm formation across the northern third of the CWA plains late
Fri afternoon, and acrs remaining ern portions of the CWA during
the evening hours within a more humid post-frontal environment.
It`s possible the nern corner of the state could see an isolated
severe t-storm or two, with large hail the main threat. Can`t rule
out localized heavy rainfall with PWs approaching an inch near t
he corner by evening. Still some question as to how close storms
will come to the Front Range, i.e., the Denver metro area. Latest
thinking would warrant mentioning at least a slight chance mainly
north of the metro area during the evening hours when east-
northeasterly/upslope flow will be deepest. At this time, do not
see severe storms developing within the I-25 corridor. Mtn and
western slope areas should remain mostly dry and breezy, with low
RHs and very warm temps, resulting in high fire danger in some
areas. For now, no fire weather highlights.
In advance of the upper trough, subtropical moisture pooling over
northern Mexico is progged to spread northward over New Mexico on
Friday and eventually up across the Texas panhandle, Kansas and
Nebraska on Saturday. Eastern Colorado appears to be west of this
moisture plume through at least Saturday morning. As the 700-500mb
trough axis passes overhead Saturday afternoon, models show another
frontal bndry sliding south through nern Colorado, causing the 850-
700mb flow to turn east-southeast. The shift in flow appears to tap
into some of the Great Plains moisture plume, advecting it up
against the Front Range late in the day. It`s arrival should be
marked by a gradual slide in temperature, at least for lower
elevations. A moist upslope flow, destabilization with cooling aloft
with the passing trough sufficient reasons to go with 10-30 pct PoPs
on the plains, and 20-50 pct PoPs for the Front Range mtns and
foothills on Sat. Cooler temps are on tap for Sat with readings near
to slightly below average.
The upper trough flattens and its axis moves just east of Colorado
by late Sunday. Beneath the zonal flow aloft, models show more
subtropical moisture feeding northward over the central U.S. and
curving back into eastern Colorado where it appears to hang out
through early next week. This should keep temperatures from
warming much above average and keep showers and t-storms in the
forecast each day.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 807 PM MDT Wed Jun 27 2018
VFR conditions will persist through Thursday evening. outflow
boundaries from high based showers and thunderstorms still
passing through the terminals this evening, but not as strong.
Should see northeast winds at KDEN slowly shift to drainage by
late this evening. Will not include any tempo groups for gusty
outflow winds in the terminals, but potential microburst wind
gusts from a passing showers/tstm of 25-30 kts could impact the
arrival/departure gates surrounding KDEN. Stray thunderstorms may
develop tomorrow afternoon with gusty winds possible again.
&&
.FIRE WEATHER...
Issued at 425 PM MDT Wed Jun 27 2018
Have decided to include fire weather zone 218 in the Red Flag
Warning on Thursday. Dry fuel, low rh and strong winds bad enough
to included the Medicine Bow and Front Range Mountains in Larimer
and Boulder Counties. Also marginal for zone 212 and possible the
Palmer Divide, but will let the mid shift have the final say on
those areas.
Relative humidities will be very low on Thursday with the lowest
values approaching 5 percent and most of the CWA under 15 percent.
As a lee cyclone develops over Wyoming tomorrow, southwesterly
winds will begin to increase with gusts up to 30 mph possible at
higher elevations. Therefore, a Red Flag Warning has been issued
for fire zones that have dry fuels. These fire zones are listed
below. Furthermore, stray showers and storms tomorrow could
produce winds up to 40 mph at times mainly near the Palmer Divide
and over Park county.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 11 AM to 9 PM MDT Thursday for COZ211-
213>215-217-218-238.
&&
$$
UPDATE...Cooper
SHORT TERM...Danielson
LONG TERM...Baker
AVIATION...Cooper
FIRE WEATHER...Cooper
Area Forecast Discussion
National Weather Service Grand Forks ND
919 PM CDT Wed Jun 27 2018
.UPDATE...
Issued at 919 PM CDT Wed Jun 27 2018
Updated forecast to add thunderstorms to the showers late tonight
in the southern Red River Valley. The NAM has 1500-2500 J/kg of
MUCAPE and the SREF has 1500-2000 J/kg. Both indicate that
effective shear will be around 40 kts late tonight as well.
However, will the isentropic lift in the 900-700 mb layer be
enough to fire some storms? It appears to be enough for the HRRR
and NAM Nest, which have some thunderstorms in the region. The
HRRR has jumped around with placement the last couple of runs,
though. Will keep chances at 20% for now. The SPC has the far
southwestern zones in a marginal risk tonight.
&&
.SHORT TERM...(This afternoon through Thursday)
Issued at 330 PM CDT Wed Jun 27 2018
Stable air mass has settled into our CWA from the west behind a cold
front, with main shortwave trough/PV anomaly east. Near frontal
zone in our far east we still have a window for thunderstorm
development and axis of 1500-2000 J/KG ML CAPE and 30-50kt
effective shear could support a few strong or marginally severe
storms before sunset. Trend would be for this threat to transition
further east over the next few hours as front continues to move
out of our area. Some CAMs are still hinting at redevelopment in
our northwest, but if there were to happen it would be before
sunset and very weak (most likely light showers).
Tonight: Low level southeast return flow is advertised as cold front
washes. Region of ascent associated with weak mid level impulse and
WAA may support showers or thunderstorms in our south late tonight
and tomorrow morning.
Thursday: Low level southeast flow will continue to increase
moisture/instability across our CWA, with baroclinic zone/stalled
front over our west and south. Instability increases thorugh the
day, and by the afternoon ML CAPE may range from 3000-4000 J/KG.
Strong deep layer shear is expected to be in place, but better
chances remain in the evening/overnight period. If CAP weakens and
activity develops earlier we could have strong to severe storms in
our west or south and some CAMs actually support isolated to
scattered activity earlier ahead of main complex that would be
expected Thursday night. Activity could be discrete/supercellular
in nature early on and this may need to be monitored, the question
is if there is enough organized forcing before Thu evening.
.LONG TERM...(Thursday night through Wednesday)
Issued at 330 PM CDT Wed Jun 27 2018
Period begins with the potential for ongoing convection, with a warm
frontal boundary situated somewhere around the ND/SD border. An
embedded strong shortwave trough is also forecast to move through
the region late Thursday into early Friday, and with plenty of CAPE
available a supercellular convective mode featuring 2 inch hail and
a few tornadoes could very well be favored. As evening shifts to
overnight, a stout LLJ of up to 40 kts would likely transition the
mode to an MCS with damaging wind and heavy rain becoming the main
threat.
On Fri cold FROPA during the afternoon could be accompanied by more
scattered tstm activity, with this feature becoming nearly
stationary to the south. Thus, any activity on Sat should be focused
more south of the forecast area possibly clipping part of SE ND and
WC MN. Most of Sun looks drier before the next front approaches
during the eve or at night. Ridging will try to build early next
week, but we`ll have to watch the extent to which encroaching jet
stream energy can dampen its effects.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 712 PM CDT Wed Jun 27 2018
VFR conditions are expected at the terminals through the next 24
hrs. A few showers or perhaps a thunderstorm may develop late
tonight/early tomorrow near FAR, but did not include in this TAF
set due to high uncertainty. Otherwise, strong/severe
thunderstorms are possible late Thursday afternoon...and likely
Thursday night.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Knutsvig
SHORT TERM...DJR
LONG TERM...WJB
AVIATION...Knutsvig
Area Forecast Discussion
National Weather Service Hastings NE
838 PM CDT Wed Jun 27 2018
.UPDATE...
Issued at 834 PM CDT Wed Jun 27 2018
Updated forecast to include the potential for fog tonight given
the low level moisture in place, and fairly light winds with the
warm front located across northern Kansas. Uncertainty exists on
how widespread or dense fog may be with varying cloud cover toward
morning and will need to monitor.
UPDATE Issued at 807 PM CDT Wed Jun 27 2018
Temperatures have been slow to drop off this evening and heat
index values are still near 105 degrees this hour across north
central Kansas. As we lose daytime heating with sunset,
temperatures will continue to cool and the heat advisory which was
in effect today has been allowed to expire. The heat will ramp up
again Thursday afternoon with heat indices again forecast near 107
degrees and a Heat Advisory is in effect Thursday for the high
heat indices.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 319 PM CDT Wed Jun 27 2018
Cumulus development has lead to scattered-broken skies for parts
of central Nebraska. This may keep temperatures down just a bit
for some locations in Nebraska, but it appears that the heat
advisory is still on-track for our Kansas counties.
This evening, the HRRR shows development of a few air-mass
thunderstorms, but its placement is suspect...as it develops the
storms in the areas that are currently cloud-free. Other models
don`t really support this, so I believe the area will stay dry
until later overnight.
Late tonight, models continue to indicate the potential for a few
thunderstorms as a subtle wave tracks across Nebraska. For PoPs,
I used a blend of the SREF/HREF ensembles, which keeps the highest
probabilities generally along and south of Interstate 80 in
Nebraska. Shear is pretty minimal, so severe weather is unlikely.
Lingering cloud cover from overnight convection introduces a
little uncertainty into the temperature forecast for tomorrow.
Right now, I think we will still see enough sun and warm-air
advection for temperatures to reach the 90s generally north of
Highway 136 in Nebraska and the 100s for areas to the south.
Models also indicate very deep mixing and southerly winds gusting
over 30 MPH in our warmest areas (far southern NE and northern
KS). This will serve to mix out dewpoints a bit, ultimately
reducing the heat index slightly in these areas. Nevertheless, it
will be hotter across most of the area tomorrow, so it makes sense
to issue a heat advisory for the areas that will get closest to a
105 degree heat index.
Gusty winds continue Thursday night, which will keep low
temperatures from falling much lower than the low 70s. Friday may
approach heat advisory criteria once again in eastern portions of
the forecast area. That said, dewpoints will be even lower, so we
will wait and see how much our dewpoints mix out over the area on
Thursday.
Chances for thunderstorms move into northwestern portions of the
forecast area Friday evening as an approaching upper trough
deepens over the Rockies. An isolated strong storm is possible,
but the best threat for severe storms appears to be over northern
and western Nebraska.
.LONG TERM...(Saturday through Wednesday)
Issued at 319 PM CDT Wed Jun 27 2018
The approaching trough will push a cold front into the area on
Saturday, which, depending on how convection plays out Friday
night, will move through the area during the day on Saturday. This
will bring us our best chances for rain and thunderstorms over
the next week. Convective details are always shaky 3-4 days in
advance, but increased deep-layer shear would support at least
some threat for severe weather.
The passage of the cold front will bring a temporary reprieve
from the heat Saturday into early next week, but the upper level
ridge is expected to strengthen overhead by the middle of next
week...likely leading to another heatwave. The model consensus
continues to show low PoPs Sunday through Tuesday as we remain in
zonal to southwesterly flow aloft. That said, predictability is
relatively low as there isn`t much of a consistent signal amongst
the models at this point.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday)
Issued at 602 PM CDT Wed Jun 27 2018
Overall looking for mainly VFR conditions for the TAF period, but
that being said, a warm frontal boundary will gradually lift
north from Kansas into southern Nebraska tonight. Moisture pooling
along the front combined with a light easterly wind component may
lead to patchy fog for a few hours tonight/early Thursday. Short
term models are rather hit or miss on whether or not convection
will develop tonight with models trending north of the terminals
attm. Do to low confidence in precip, the aviation forecast
remains dry. Forecast soundings indicate deep mixing by mid day
Thursday with potential for wind gusts over 25kts.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...Heat Advisory from 1 PM to 8 PM CDT Thursday for NEZ064-076-077-
083>087.
KS...Heat Advisory from 1 PM to 8 PM CDT Thursday for KSZ005>007-
017>019.
&&
$$
UPDATE...Fay
SHORT TERM...Mangels
LONG TERM...Mangels
AVIATION...Fay
Area Forecast Discussion
National Weather Service Goodland KS
548 PM MDT Wed Jun 27 2018
.SHORT TERM...(This evening through Thursday)
Issued at 248 PM MDT Wed Jun 27 2018
Upslope flow over Colorado will assist in the development of isolated
thunderstorms this afternoon along the Front Range and the Palmer
Divide. Some of these storms may survive long enough to move into
our far northwest counties this evening producing strong wind
gusts. Warm temperatures aloft will likely limit coverage this
evening. The HRRR continues to develop some thunderstorms further
east along the weak cold front, however confidence is not high
since the latest run for Composite Reflectivity shows a storm
near Colby in 15 minutes but currently the CWA is void of clouds.
The main issue for the next two days will be temperatures. This
afternoon, east to southeast winds brought in higher dewpoints to
Norton, Graham and Sheridan counties resulting in a dramatic rise
in Heat Indices over 105F. Temperatures Thursday will be 5-10
degrees higher than today, but the highest dewpoints will have
shifted into Nebraska, and forecast Heat Indices tomorrow will be
98-104F.
.LONG TERM...(Thursday night through Wednesday)
Issued at 100 PM MDT Wed Jun 27 2018
The upper-level ridge that has been responsible for high
temperatures during the week will give way to a longwave trough and
several associated shortwave troughs late this week. This will
increase shower and thunderstorm chances and decrease high
temperatures into the upper 80s for the Central High Plains area
through the weekend and early next week. A weak cold front passing
through the Tri-State Region Friday evening will provide the
greatest chance for thunderstorms. However, strong upper-level winds
will provide enough forcing for ascent and southerly low-level winds
will bring increasing low-level moisture which will modestly
modulate instability enough to keep showers and thunderstorms in the
forecast at least through Monday. Even as upper-level ridging builds
back up Tuesday onwards and high temperatures climb back into the
mid 90s across the CWA, a few stray afternoon showers and isolated
thunderstorms cannot be ruled out heading into the middle of next
week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 542 PM MDT Wed Jun 27 2018
VFR conditions are expected at GLD and MCK through the 00Z TAF
period. Skies will be mostly clear with light northeast winds this
evening transitioning to a southerly direction by 18Z and possibly
increasing after 12Z with some gustiness possible as the lee
trough along the front range begins to reintensify resulting in a
stronger pressure gradient and stronger winds across the central
high plains region.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DLF
LONG TERM...JRP
AVIATION...LOCKHART
Area Forecast Discussion
National Weather Service Green Bay WI
1038 PM CDT Wed Jun 27 2018
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Thursday
Issued at 248 PM CDT Wed Jun 27 2018
Overall no significant changes to the short term forecast through
Thursday.
Latest GOES16 visbible imagery indicates scattered to occasionally
broken SC/CU across much of the forecast area this afternoon.
Overall trend has been for clouds to thin in areal coverage a bit
which has allowed temperatures to climb into the 75 to 80 degree
range. Surface winds have recentluy turned easterly along the
lakeshore with temperatures there closer to 70. still a fair
amount of low-level moisture with surface Tds mainly in the 60s.
The majority of the short-range guidance insists on developing a
few showers across the far north or northeast Wisconsin late this
afternoon into early evening. Easterly onshore flow has finally
developed over the eastern Oconto and Marinette counties with
mainly westerly winds further inland. This will allow for a period
of boundary layer convergence across the northeast portion of the
forecast area into the early evening. Although MLCAPEs in this
part of the state are generally less than 250 J/kg, RAP suggests a
gradual increase in instablity in this region toward evening,
thus it is not inconceievable to still see a shower pop-up north
of Green Bay and east of highway 55. Will therefore maintain
slight chance POPS in that region until early evening.
Otherwise, partly cloudy skies will be the rule overnight with
lows generally in the upper 50s to lower 60s. Could be some patchy
fog also developing after 06Z Thursday given light winds under
mainly partly cloudy skies.
Looks like a nice day on Thursday as upper heights continue to
build over the state and weak surface high pressure moves across
the region. saw no good reason to deviate from the CONSSHORT blend
with highs generally in the lower to middle 80s.
.LONG TERM...Thursday Night Through Wednesday
Issued at 248 PM CDT Wed Jun 27 2018
Mean flow headed into the weekend to generally consist of a large
upper ridge over the eastern Pacific, an upper trough over the
Rockies and another upper ridge over the eastern CONUS. This
pattern will bring hot, humid, unsettled weather into northeast WI
as prevailing southwest winds aloft pull plenty of gulf moisture
northward. By the end of the weekend into early next week, the
upper trough is forecast to broaden and extend from the Pacific NW
to the eastern Great Lakes. This change will allow temperatures to
cool a bit with less humidity. Models then suggest that upper
ridging would rebuild over the central CONUS toward the middle of
next week with another uptick in temperatures.
Concerns continue as to whether any convection may develop between
the 8H warm front lifting north of WI and a surface warm front
approaching WI from the south. While instability will be
plentiful, the atmosphere appears to be capped (plenty of CIN/warm
7H temperatures), thus it may prove difficult for storms to
develop. However, this does not rule out elevated thunderstorms
and this potential does exist, thus have opted to go with a small
chance of showers/storms across north-central and parts of central
WI after midnight. Min temperatures to range from the lower 60s
north/near Lake MI, middle to upper 60s for central/east-central
WI. This small chance of showers/storms would continue into Friday
morning as the surface warm front lifts northeast through WI. Once
the front clears WI, look for a hot/humid afternoon as 8H
temperatures climb into the +23 to +28C range. This would take max
temperatures into the lower to middle 90s away from Lake MI with a
few locations over central WI possibly reaching the upper 90s. Add
in dew points in the lower to middle 70s and we will be looking at
heat indices > 100 degrees over central/east-central WI. Assuming
these values hold, a Heat Advisory would eventually be needed.
Warm/muggy conditions are expected for Friday night as any
convection to be located north (warm front) or west (cold front).
Min temperatures to only be in the lower to middle 70s over most
of northeast WI (perhaps upper 60s right along Lake MI). The cold
front is progged to push across the Upper MS Valley on Saturday.
Instability will build over WI during the day with a weakening cap
during the afternoon. Strongest shear is forecast to be located
along the frontal boundary, thus any strong to severe storms would
appear to hold off until Saturday evening. Based on latest model
timing, will bring an increasing pop to central WI Saturday
afternoon. Max temperatures for Saturday will be hot, although not
as high as Friday as clouds to increase during peak heating. Look
for readings in the middle 80s north/near Lake MI, upper 80s to
lower 90s south.
The cold front pushes into WI Saturday night, accompanied by a
trailing, but weakening shortwave trough. Even though instability
will diminish a bit post-sunset, shear will increase and allow
some thunderstorms to become strong to severe. Damaging winds
would be the primary threat, although large hail is also possible,
especially during the evening hours. Locally heavy rainfall is
also possible as PW values approach 2" and this could lead to
localized flooding. Showers/storms to persist into Sunday morning,
especially over eastern WI until the cold front exits the area.
Skies should then begin to clear from west to east Sunday
afternoon as weak high pressure begins to move into the region.
Max temperatures Sunday to cool post-frontal with readings in the
upper 70s to around 80 degrees north/near Lake MI, mainly lower
80s south.
Sunday night to be quiet and cooler as the high pressure passes to
our south. By Monday, northeast WI best back into a south-
southwest flow aloft as the high pressure to be located over the
eastern Great Lakes. Models begin to differ with regards to the
movement of another cold front. The GFS is much faster than either
the ECMWF or GEM, so prefer the latter solution for now. Max
temperatures on Monday to range from around 80 degrees near Lake
MI, lower to middle 80s elsewhere.
Toward the middle of next week, the mean flow is forecast to turn
from near zonal across the CONUS, to a western U.S. upper trough/
central U.S. upper ridge. This scenario would keep most convection
to our west and allow for another shot of very warm/humid air to
overspread WI. The GFS remains at odds with other models with a
frontal boundary locked in place over the region). Have followed
the consensus solution for now which brings mainly slight chance
wording for both Tuesday and Wednesday. Temperatures should be
above normal with max temperatures in the middle to upper 80s
(away from Lake MI).
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1038 PM CDT Wed Jun 27 2018
VFR flight conditions expected through Thursday
evening, with the possible exception of a few hours of MVFR or
IFR ground fog between 09 and 12z Thursday morning.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....ESB
LONG TERM......AK
AVIATION.......RDM
Area Forecast Discussion
National Weather Service Jacksonville FL
217 PM EDT Wed Jun 27 2018
.Near term.../through Friday/...
The region will be between high pressure to the South and a trough
of low pressure to the North this period. This will result in a
continued light West/Southwest low level flow. Each afternoon,
diurnal instability will lead to the development of convection. In
this pattern the East coast sea breeze will be able to push inland,
but likely not much further than I95, while the Gulf sea breeze
should be able to push well into NE FL. These sea breezes will help
to support development and direct movement of the convective
activity this afternoon. In addition, the proximity of the troughing
will aid in convective potential over inland GA as well. Near term
model depicting energy pushing South from this boundary through the
evening continuing convective potential through around midnight.
Temperatures are expected to trend above normal this period, with
heat indices rising into the 100 to around 105 range each
afternoon.
&&
.Short Term.../Friday night through Sunday/...
High pressure will be East of the region this period, resulting in a
mostly light Southerly low level flow. This flow should provide
additional moisture for convection. Convection will be initiated
each afternoon by diurnal instability, with ample moisture
available. The convection will be aided by sea breeze boundaries
near the coasts. In general expect a higher than normal coverage in
afternoon/evening storms this period. Most convective activity will
dissipate in the evening hours, but given the expected increased
coverage, could see a few storms linger past midnight.
Highs will trend near normal this period, with heat indices peaking
each afternoon near to slightly above 100.
&&
.Long Term.../Sunday night through Wednesday/...
Surface high pressure ridge will build from the East to the
Northeast this period. The prevailing low level flow will be from
the South, with input from the both the East coast and Gulf sea
breezes. Convection will initiate each afternoon and evening due to
diurnal instability with additional focus on sea breeze boundaries.
Convection will largely dissipate during the evenings, with partial
overnight clearing.
Near to slightly above normal temperatures are expected this period,
with afternoon heat indices around 100 to a little above.
&&
.Marine...
Surface high pressure will be South of area waters with troughing to
the North through Friday. The high will then be to the East through
the weekend, and toward the Northeast early next week. The potential
for thunderstorms will exist through this period.
&&
Sea breeze front convergence over north Florida and southeast Georgia
has been somewhat capped with a few cells blowing though the cap
near KGNV and over the Ocala National Forest area. Ceilings near
CBs are running in the 3 to 5 kft range and expect that to
continue this afternoon into this evening with convection in tempo
groups for all fields between 18 and 24 utc. We then take a bit
of a breather after the loss of diurnal heating as a squall line
forms in central Georgia and drops southward. Both the HRRR and
ARW models have this feature even though NAM20 doesn`t model it
well. Looking for that line to drop through KSSI between 02-06
utc, the JAX metro fields between 04 and 08 utc and Gainesville
between 06 to 09 utc. As the line will be bowing as it comes
through the area looking for strong potential wind gusts of 25 to
40 kts at all fields but pulled it back to 15 to 30 kts at KGNV as
the line begins to break up.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 75 94 75 95 / 30 40 50 50
SSI 78 92 78 92 / 20 40 20 30
JAX 76 94 76 95 / 20 60 30 50
SGJ 77 93 75 92 / 20 20 20 40
GNV 75 93 75 93 / 30 60 10 60
OCF 74 90 75 92 / 30 70 20 40
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&
$$
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1105 PM EDT Wed Jun 27 2018
.UPDATE...
Issued at 1105 PM EDT WED JUN 27 2018
NAM forecast soundings suggest that thunder will continue to be a
possibility as the cold front sinks south through the area
overnight, and a slight chance of thunder has been expanded to
follow the front.
UPDATE Issued at 952 PM EDT WED JUN 27 2018
Only minor changes were made to blend evening obs into the night`s
forecast.
UPDATE Issued at 620 PM EDT WED JUN 27 2018
Cooler and more stable air over eastern KY prevented more
significant convection today. With peak heating passed,
substantial development is unlikely in most areas for the time
being. There are some showers and thunderstorms upstream of our
southwest counties, and that area stands the greatest chance at
precip in the next hour or two. Mesoscale models still suggest a
bit of activity along the cold front which will be dropping in
from the north during the night, and a bit higher POP (no higher
than chance category) has been continued to be used with this
feature.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 315 PM EDT WED JUN 27 2018
The latest scans of the WSR-88D radar shows numerous to scattered
showers and thunderstorms moving across portions of eastern
Kentucky this afternoon. In general this activity has been weaker
and lesser rain rates given the lack of better instability and
moisture in place this afternoon. However, in coordination with
WFO LMK will keep the FFA up through 8 PM to deal with any
minor/isolated flood threats. The HRRR has been showing a
stronger band of storms moving through the Lake Cumberland region
at times this afternoon, but the latest radar trends shows this
developed further west where instability and moisture was
greatest. This will likely move southeast of eastern Kentucky as
it follows the better instability and moisture across Tennessee.
Most of the shower and thunderstorm activity will wane through
the evening, but a slight uptick is possible as a cold front
pushes across the region through the night into early Thursday.
This will push south and upper level wave will push east giving
way to clearing skies through the day on Thursday. The bad news is
the front will provide little in the way of relieve from the warm
weather, with highs topping out in the mid to upper 80s Thursday
afternoon. Given the clearing skies and potential for cooler
valley temperatures expect the possibility for mainly river valley
fog on Thursday night into Friday morning.
.LONG TERM...(Friday through Wednesday)
Issued at 315 PM EDT WED JUN 27 2018
Strong ridge will build in on Friday and Saturday, allowing heat
and humidity to build over the region. The area should stay capped
on Friday and Saturday with heights at their peak. However, as the
ridge breaks down a bit by Sunday into next week, afternoon shower
and storm chances will begin to enter the picture. Lack of shear
should limit severe threat and keep activity in the pulse up and
down mode. Warm and humid conditions will continue right into the
4th of July. Heat index values still look on target to reach
around 100 Saturday into next week and will continue to highlight
in the HWO.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
ISSUED AT 922 PM EDT WED JUN 27 2018
As the period started, there were pockets of MVFR conditions (mainly
near I-64), with generally VFR conditions elsewhere. Most
precipitation had tapered off.
A cold front will drop south through the region during the night.
Scattered showers and thunderstorms are expected along the front.
A deterioration to largely IFR is forecast with the arrival and
passage of the front. A few showers/thunderstorms could linger
into Thursday near the TN and VA borders, but most locations will
be dry during the day. Conditions are expected to improve to VFR
early in the afternoon.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...DJ
LONG TERM...KAS
AVIATION...HAL
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
952 PM CDT Wed Jun 27 2018
.UPDATE...
Issued at 945 PM CDT Wed Jun 27 2018
Main issue for tonight remains the thunderstorm threat which would
extend into Thursday morning. A quasi-stationary boundary
stretches from north-central KS across west-central and south-
central MO and into southern IL late this evening. Evening
soundings from SGF and TOP show very steep mid level lapse rates
of 7.5-9.0 degC/km which is contributing to a reservoir of bigtime
MUCAPE of 5000+ J/KG roughly along and south of the boundary. We
are beginning to see an increase in clouds in the 4000-5000 foot
layer stretching from NW MO thru central MO into southern IL
within a region of 850 mb moisture convergence and WAA associated
with an anticyclonically curved branch of the stronger flow.
The previous guidance and various runs of the operational and
experimental HRRR continue to support the expectation that
thunderstorms will develop/blossom within this region of lift from
north central thru central and into east central MO during the
overnight hours and move southeastward. Deep layer shear of 30-40
kts along with the aforementioned lapse rate and MUCAPE values
would support a severe threat, primarily large hail, however
storm mergers and merging cold pools would also support a damaging
wind threat. The longvity of storms into Thursday morning is a bit
in question, but I would think at this time at least until 15-16z.
Glass
&&
.SHORT TERM... (Through Late Thursday Afternoon)
Issued at 328 PM CDT Wed Jun 27 2018
Main focus for tonight will be on possibility of convection late
tonight into the day on Thursday. Guidance generally agrees that
retreating warm front will be the focus for at least scattered
thunderstorm activity in response to low-level warm/moist advection.
While there is a general agreement in this scenario, as always the
specifics are more difficult to pin down. Some CAMs including the
NAMNest develop convection earlier and further west/southwest while
the HRRRX and low-res NAM delay the onset, with convection more
focused closer to the Mississippi River. Went with a blend of these
two camps and added likely PoPs for late tonight toward dusk roughly
along a KMYJ>>KCPS line.
Atmosphere is expected to be very unstable tonight, and with
sufficient deep-layer shear (~30 knots), at least somewhat organized
convection seems possible. Very steep midlevel lapse rates within
the hail growth zone suggests hail will be the main threat at least
with the initial storms. If cold pools amalgamate, a
south/southeastward propagating cluster(s) of storms would be
capable of producing damaging wind gusts as well.
Convective trends are more uncertain during the day on Thursday.
Best guess is for overnight activity to continue into the early
morning hours moving southeast along the boundary. As the low-level
jet weakens, may see a lull or a complete lack of activity by mid-
late morning. Additional storms would then be possible in the
afternoon in close proximity to the retreating warm front along the
eastern edge of the cap. Another possible scenario is for an outflow
boundary from the morning storms to initiate scattered activity,
though this may be more focused to the south/southeast of the CWA if
this indeed occurs.
High temperatures on Thursday are certainly a challenge with quite a
bit of uncertainty, especially along/east of the Mississippi River.
With frontal boundary in the vicinity and the possibility of
convection and debris clouds, many areas may escape the first day of
this upcoming heat wave. Further to the west, portions of central
Missouri look like they should reach into the mid 90s for highs with
peak heat index readings around 105-108F.
Gosselin
.LONG TERM... (Thursday Night through Next Wednesday)
Issued at 328 PM CDT Wed Jun 27 2018
(Thursday Night - Saturday)
Unlike Thursday, have a higher confidence in high temperatures and
peak heat index readings across much of the area on Friday.
Mid/upper level ridge axis should be located across the
Mississippi Valley on Thursday before slowly moving eastward with
time. Some slight uncertainty on Saturday as ridge moves into the
Ohio Valley with slightly cooler 850-hPa temperatures advecting in
from the south with a weaker cap in place for diurnal convection.
Slightly deeper mixing however is progged for Saturday compared
to Friday along with lower surface dewpoints. Therefore expect
highs on Saturday to be near persistence with heat index values
each afternoon generally in the 100-110 range.
Going heat headlines largely looked good, but did add remaining
counties in Illinois for intensity due to the 105+ heat index
values expected both on Friday and Saturday afternoon.
(Sunday - Next Wednesday)
Little to no change in the general upper-air pattern across the
CONUS through the middle of next week. Mid/upper level ridging is
forecast to extend further westward and nearly reach the west coast.
Hot/humid weather should continue through the end of the forecast
period (and perhaps beyond) with isolated diurnal thunderstorm
activity possible each day/evening due to weak capping. Some short-
term relief however still appears likely in the Sunday/Monday time
frame as a cold front attempts to move through the CWA. Temperatures
are expected to drop back into the low 90s on Sunday and Monday, but
with dewpoints in the 70s, peak heat index values still may be above
100 degrees in some locations. Did not elect to extend the heat
advisory in time at this point because of uncertainties with the
timing of the cold front and potential for thunderstorms and
convective debris clouds, but advisories may need to be extended if
confidence in 100+ heat index values rises.
.
Gosselin
&&
.AVIATION... (For the 00z TAFs through 00z Thursday Evening)
Issued at 639 PM CDT Wed Jun 27 2018
Tranquil conditions are expected across the region through mid
evening. During the late evening and overnight hours we should see
scattered thunderstorms develop in a northwest-southeast axis
across central and eastern MO, with this axis shifting both south
and east with time during the early morning hours on Thursday.
Some of the storms could be rather strong and contain hail,
however pinning down the exact location and a direct terminal
impact is difficult at this time. Current thinking is that the
threat of thunderstorms will diminish across the region from mid-
late Thursday morning. Outside of any thunderstorms, VFR flight
conditions should prevail.
SPECIFICS FOR KSTL:
Tranquil conditions are expected for the terminal through this
evening. During the overnight hours we should see scattered
thunderstorms develop in a northwest-southeast axis and these are
expected to impact KSTL. Some of the storms could be rather
strong and contain hail, however I have been conservative at this
time in the TAF due to uncertainty in exact location of the
strongest storms. Current thinking is that the threat of
thunderstorms will diminish by mid morning on Thursday. Outside
of any thunderstorms, VFR flight conditions should prevail.
Glass
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Heat Advisory from 11 AM Thursday to 10 PM CDT Saturday for
Audrain MO-Boone MO-Callaway MO-Cole MO-Crawford MO-
Franklin MO-Gasconade MO-Iron MO-Jefferson MO-Knox MO-Lewis
MO-Lincoln MO-Madison MO-Marion MO-Moniteau MO-Monroe MO-
Montgomery MO-Osage MO-Pike MO-Ralls MO-Reynolds MO-Saint
Charles MO-Saint Francois MO-Saint Louis City MO-Saint
Louis MO-Sainte Genevieve MO-Shelby MO-Warren MO-Washington
MO.
IL...Heat Advisory from 11 AM Thursday to 10 PM CDT Saturday for
Adams IL-Brown IL-Calhoun IL-Clinton IL-Greene IL-Jersey IL-
Macoupin IL-Madison IL-Monroe IL-Pike IL-Randolph IL-Saint
Clair IL-Washington IL.
Heat Advisory from 11 AM Friday to 10 PM CDT Saturday for Bond
IL-Fayette IL-Marion IL-Montgomery IL.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1041 PM EDT Wed Jun 27 2018
.SYNOPSIS...
A weak front and area of low pressure near the coast will
weaken and move northeast tonight. A cold front will approach
from the west Thursday, move into the area Thursday night and
then stall late week into the weekend. High pressure will pass
to the north over the weekend.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
As of 1030 PM...Adjusted POPs for next few hours to just slight
chance for coastal plains except chance for SW sections. Did
leave 20% in for all zones overnight with latest HRRR and NAM
still indicating possible isolated activity with shortwave
overnight. Rest of forecast on track.
/Previous discussion/
As of 230 PM Wed...Latest sfc analysis shows weak frontal
boundary near the southern portion of the forecast area this
afternoon, with weak low off the NC coast. Front is expected to
wash out overnight with surface low weakening as well.
Latest radar imagery shows some scattered showers across Eastern
NC this afternoon, with best coverage still near the Albemarle
Sound region. The bulk of the precip remains well to the west
over Eastern TN and Western NC. Challenging precip forecast for
the rest of this afternoon into tonight, with models depicting
a variety of solutions. Could see a slight increase in coverage
this afternoon and early evening, but remaining widely
scattered. Latest mesoanalysis shows SB CAPE values around 2000
J/kg with less than 20 kt bulk shear. Think any threat for the
next several hours will be the potential for heavy downpours
with PWATs still around 2 inches. Most guidance keeps the area
mostly dry overnight, with the GFS still brining in the best
chance for showers. Shortwave energy expected to increase
overnight, which could be enough to support scattered showers
and a few storms. Though most models show the precip well west
weakening moving across Central NC and dissipating before
reaching our area tonight. Will keep sc pops, though not
expecting much coverage. Mild with overnight lows in the low to
mid 70s.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
As of 230 PM Wednesday...A cold front will approach from the WNW
Thu, with bulk of upper level energy remaining north of the
area. Typical summertime type day expected...hot and humid with
isolated to widely scattered showers. Will continue slight
chance pops in the morning, with slightly increasing chances in
the afternoon. Instability looks slightly more impressive,
though little shear expected, and PWATs also drop to less than 2
inches. Low level thickness values and SSW flow support temps
above normal, with highs in the low to mid 90s inland and upper
80s to low 90s along the coast. Hot temps combined with
dewpoints in the 70s, some areas along Hwy 17 could see heat
index values around 105 degrees during the afternoon. A Heat
Advisory may be needed for a few counties.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
As of 230 PM Wed...Unsettled pattern continues into Thu night.
An approaching upper level shortwave with several embedded vort
waves will pass through Thu night, with scattered showers and
thunderstorms. Latest surface wind forecast from GFS/ECMWF
seems to suggest the front will stall and dissipate along the
south coast rather than continuing moving off the coast to the
southeast. Time sections show support for this, with no drying
out of the boundary layer seen. Will taper off PoPs in the NW
counties Fri evening, then continue slight chance to chance PoPs
SW of a line from Manteo to New Bern to Jacksonville from late
Thu night through the day Friday. Lingering moisture in the SW
half of the forecast area Sat through Sun with several vort
centers passing through so kept slight chance to chance PoPs in
the forecast for mainly diurnal convection. The typical
summertime pattern redevelops Monday into Tue with the mid-state
surface trof and offshore high and mainly diurnal convection.
Highs through the period will be in the lower to mid 90s inland
with mid 80s along the Outer Banks. Overnight lows will be in
the lower to mid 70s, with mid to upper 70s along the Outer
Banks.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Short Term /through 00Z Friday/...
As of 745 PM Wednesday...VFR expected to prevail most of TAF
period with return of SSW flow in warm sector conditions. Brief
sub-VFR possible in scattered showers over western sections this
evening and in scattered TSTMs same area Thu afternoon. Cloud
cover and light SSW winds expected to limit fog overnight but
cannot rule out brief period of MVFR VSBYs mainly 10Z-12Z.
Long Term /Thursday night through Monday/...
As of 3 am Wed...Sub- VFR Thu night and Sat-Sun in scattered
thunderstorms. Mostly dry/VFR Fri. Surface winds SW around 10
kts Thu, light and variable Fri, E to SE around 5 kts Sat and
Sun.
&&
.MARINE...
Short Term /through Thursday/...
As of 1030 PM Wednesday...no changes to winds/seas with update.
/Previous discussion/
As of 230 PM Wed...Latest obs show variable winds across the
waters, generally NE to SE 5-15 kt north of Lookout and N/NW
5-10 kt south. Seas still slow to subside across the northern
waters this afternoon, still 3-5 ft. Allowed SCA to expire at
17z. Weak low expected to dissipate overnight as boundary to the
south washes out. Winds become more uniform and S/SW 5-15 kt
this evening and overnight. A cold front will approach the
waters from the WNW Thu. Increasing SW winds through the day,
10-15 kt in the morning increasing to 15-20 kt in the afternoon.
Seas 2 to 4 feet early, building to 3 to 5 feet in the
afternoon, highest south of Oregon Inlet.
Long Term /Thursday night through Monday/...
As of 310 am Tue...Winds go southwest Thu night. A weak front
will pass through Friday with high pressure passing to the north
this weekend. Seas north of Ocracoke will average 3-5 feet
through Thu night and 2-3 Fri and Sat. Seas south of Ocracoke
will average 2-4 through the period.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...None.
&&
$$
SYNOPSIS...CTC/JBM/CQD
NEAR TERM...JBM/CQD
SHORT TERM...CQD
LONG TERM...HSA
AVIATION...JBM/CQD/HSA
MARINE...JBM/CQD/HSA
Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
742 PM CDT Wed Jun 27 2018
.SHORT TERM...(This evening through Thursday)
Issued at 320 PM CDT Wed Jun 27 2018
Main concern near term is convective potential to the northwest
during the evening and then again into Thursday.
Latest SPC mesoanalysis shows a narrow corridor of cape over 1000
J/kg over the northwest cwa. The HRRR continue to generate some
isolated convection into that region of the area though about
00z. Covergence is weak along surface boundary and believe little
in the way of development should occur. We will hold onto the
slight chance PoP through the rest of the afternoon. Clouds do
appear more cumuliform over the area so we should see erosion
this evening. Along with light winds and higher dewpoints we
should see some fog develop later tonight. THis may linger into
early Thursday morning. Still a question as to how widespread it
will be and will mention patchy/areas of fog late mainly to the
east.
Some instability return into the day Thursday with various HIRES
models develop some isolated convection developing mainly Thursday
afternoon. This lifts north and weakens by evening. We will hold
onto the slight chance PoP for this possibility as well.
Temperatures should warm through the 80s.
.LONG TERM...(Thursday night through Wednesday)
Issued at 320 PM CDT Wed Jun 27 2018
Heat...heavy rain and severe weather threats return mainly Friday
through Saturday.
Models in general agreement with MCS development over North
Dakota Thursday night and traveling into northern MN late. This
may affect mainly the northern fringe of central MN zones. Mid
level warming is quite impressive with the GFS driving +14c to
+16c 700 mb temperatures ahead of the surface cold front and upper
trough into Friday. This should limit overall convective
potential into Friday evening. High temperatures should warm
through the mid 90s ahead of the front. The ground remains very
moist so it may be difficult to attain the century mark. With
forecast dewpoints in the low to mid 70s, heat indices will likely
exceed 105F in a few locations Friday afternoon. Confidence level
for heat headlines continues to increase and will likely be
issued with the next forecast package.
The severe weather threat will remain Friday night with high CAPE
values forecast and increasing shear as the upper trough
approaches. Both the GFS and ECMWF trend a short wave into the
area Friday night and will likely be strong enough to erode the
mid level cap. Timing could be tricky however, and trends of
clouds and any convective outflow will modulate overall severe
weather threat through Saturday. Does appear the front may have
slowed some and is progged only into central MN by Saturday
morning. This should allow for redevelopment of convection into
the afternoon, barring significant MCS earlier.
Along with severe weather, heavy rain will also be a good
likelihood with PW`s 2-3 standard deviations above normal with
the system. Will have to continue to monitor flood potential
through the weekend. The front should exit the area Sunday which
could linger into Monday. Blended guidance continues to trend
rather wet into next week. The models to diverge on timing of
western trough movement into Wednesday however. The cwa will
remain near the surface front/baroclinic zone which should stall
south over Iowa into next week. It will lift back north again into
midweek and should focus increasing convective threat into at
least the first half of the week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 742 PM CDT Wed Jun 27 2018
VFR this evening. Some patchy fog may develop east of I-35 tonight
where winds will be light with clear skies persisting for most of
the night. Some showers or storms may build toward western MN late
tonight, but confidence and coverage are low enough to keep them
from the TAFs for now.
KMSP...No additional concerns.
/OUTLOOK FOR KMSP/
FRI...VFR. TSRA possible overnight. Wind SW 15G30kts.
SAT...MVFR possible. Occasional TSRA. Wind WSW 5-10kts.
SUN...VFR. Wind light.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&
$$
SHORT TERM...DWE
LONG TERM...
AVIATION...BORGHOFF
Area Forecast Discussion
National Weather Service Mount Holly NJ
955 PM EDT Wed Jun 27 2018
.SYNOPSIS...
Low pressure moving from Lake Ontario to the Saint Lawrence Valley
will lift a warm front through the area tonight followed by a cold
front on Thursday. Meanwhile, high pressure over the Ohio Valley
assumes a position off the east coast this weekend into the middle
of next week. During this time frame, a warm front moves through
the region on Saturday, followed by an approaching cold front on
Wednesday.
&&
.NEAR TERM /THROUGH THURSDAY/...
Main adjustment with this update was to increase PoPs across NJ
from about the I-195 corridor north. The showers and
thunderstorms to our west are coming together as discussed. The
HRRR has been more progressive the last few hours with the
precipitation as it moves through the forecast area. Expect the
heaviest showers and isolated thunderstorms between 07z and
12z.
Previous discussion...
Mid afternoon surface analysis shows a 1005 mb low over lower
MI. The attendant warm front extends to the southeast into WV
and VA while a trailing cold front extends to the southwest
across the Midwest states. Meanwhile, an upper trough was
evident on satellite imagery over the Great Lakes region. The
low is expected to track eastward across the eastern Great Lakes
tonight and into western New York by early morning while the
upper trough tracks to the east- southeast into PA.
Enhanced southerly flow ahead of the surface low and low-level
trough will continue to advect moisture and warmer air downstream
into the region. This setup will yield cloudy skies and several
rounds of precipitation (although there are currently some breaks in
the dense overcast cloud cover across eastern MD this afternoon).
Showers thus far today have been isolated in coverage, very light in
intensity and confined to locations along and west of I-95. Expect
this activity to gradually ramp up in intensity and coverage during
the early to mid evening but still remain confined to western zones.
Some of the showers this evening may contain heavy downpours across
Berks County, the Lehigh Valley and southern Poconos as elevated
instability arrives in concert with a plume of high low-level theta-
e air.
There may be a brief lull in the precip late this evening before the
main show arrives overnight. CAMs have been in decent agreement with
convection organizing over central PA/MD this evening and moving
into our far western zones in eastern PA after midnight. This
activity will be aided by forcing for ascent downstream of the
approaching mid-level trough and isentropic lift induced by an
impressive 40-50 kt southwesterly low-level jet.
The main concern is for locally heavy rainfall across our far
western zones in eastern PA late tonight with PWATs increase to
around 2" and increasing elevated instability through the night.
Additionally, there is a signal in the models for backbuilding
storms with Corfidi vectors become light for a brief period late
tonight. QPF output from the HRRR and RAP in particular has been
rather persistent for the last several runs in showing a mesoscale
band of heavy rainfall amounts of 2-3"+ across Berks County, the
Lehigh Valley and southern Poconos. A Flash Flood Watch was
considered but ultimately uncertainty was rather high and there is
concern that both rapid refresh models are a bit overdone with the
earlier convective rainfall late this afternoon and early this
evening (which has yet to materialize).
The lesser concern is severe weather in our far western zones of
eastern PA and northeastern MD mainly overnight when instability and
kinematic parameters are maximized. Forecast hodographs are
impressive, especially overnight owing to the strong veering flow in
the low-levels. There is a potential for rotating updrafts though
the risk of tornadoes is highly conditional on convection being
rooted close to the boundary layer (not currently expected).
&&
.SHORT TERM / THURSDAY THROUGH 6 AM THURSDAY/...
Low pressure will pass to our north across Upstate NY and New
England tomorrow while the system`s cold front progresses eastward
through the region.
Leftover showers across northeastern PA and northern NJ around
daybreak should exit the area by mid morning. A lull in the precip
is likely for the remainder of the morning. Breaks in the clouds
that are expected to develop will allow for pockets of strong
heating and boundary-layer destabilization during peak heating
hours. Accordingly, expect showers and storms to initiate in the
early afternoon. CAMs indicate convection will be rather scattered
in nature despite convergence (albeit modest) along the cold front
could provide a focus for convection. This activity is expected to
move east toward the coastal plain by late afternoon.
Forecast highs range from the upper 70s in the southern Poconos to
around 90F in the urban I-95 corridor and interior Delmarva.
&&
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
Summary...
The main weathermaker will be a deep layer ridge becoming
established across the eastern seaboard, leading to above
normal heat and humidity, beginning on Friday with the
potential to last into the middle of next week. The heat
will be punctuated by showers and thunderstorms beginning
Monday through the Fourth of July.
Heat...
The majority of the guidance has signaled this event over the
last several days. The upper-level jet moves well north into
eastern Canada, while positive 500 hPa height anomalies ~210
meters move across the US-Canadian border, and 850 hPa temps
approach 4C above average centered on Saturday thru Monday.
There is the potential for maximum temperatures at or above
90 degrees beginning Friday and lasting through Tuesday. In
particular, confidence is increasing for highs in the mid
90s Saturday and Sunday, based on mixing to 5-6 kFT per
model soundings, as well as the upper jet placement well to
the north, which will limit debris clouds from convection
around the periphery of the upper-level ridge.
Regarding Heat Index, the question is afternoon dew points,
taking into account the boundary layer mixing of dryer air
aloft to the surface. It looks as though there will be a
tendency for drying on Friday and Saturday afternoons,
based on the position of the surface trough and resultant
wind field, which should hold apparent temperatures close
to high temperatures (low-mid 90s). For Sunday, mixing of
dryer air to the surface appears more limited, which should
result in higher apparent temperature values.
In terms of potential headlines, it`s too early to say for
sure beyond 72 hours (Saturday and Sunday). There is some
potential for advisory level heat in the I-95 urban corridor
on Saturday. There is also the potential for warning level
heat in the I-95 urban corridor on at least Sunday. For the
remainder of eastern PA and NJ outside of the I-95 urban
corridor, there is the potential for advisory level heat on
Sunday. The timing of convection with an approaching cold
front on Monday will determine whether or not critical heat
thresholds will be reached, e.g., convection earlier than
the climatological norm would suppress heat index values.
Looking ahead beyond the Fourth of July for planning
purposes, both the GFS and Euro Ensembles indicate the
heat building back into the area late next week into
next weekend. The CPC 6-10 outlook indicates a high
probability of above average temperatures into next
weekend.
Precipitation...
With deep layer ridging across the region through Sunday,
large scale subsidence through the column will promote dry
weather, albeit with increasing uncomfortable humidity.
The approach of a shortwave and attendant cold front will
lead to an increase in forcing, moisture, and instability
on Monday, with the chance for showers and thunderstorms.
As mentioned previously, the timing is still in question.
This front is expected to stall in the vicinity of the
region Tuesday and perhaps into the Fourth of July, so
additional showers and thunderstorms are likely during
this period, with a return to temperatures closer to
seasonal norms by the Fourth.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.
Tonight...MVFR CIGs at RDG-ABE-ILG this afternoon should expand N/E
toward the Phila terminals between 22Z and 01Z this evening. Any
SHRA this evening should be light except potentially in vicinity of
RDG. Low-end MVFR conditions are forecast overnight tonight with
lowering CIGs and restrictions in periods of moderate SHRA. The
greatest risk for heavy SHRA and TSRA with IFR restrictions will be
at RDG and ABE between 05Z and 09Z. There is also a potential for
LLWS conditions primarily over western terminals late this evening
and overnight with a SW low-level jet strengthening to 40-50 kt in
the lowest 2 kft AGL.
Thursday...MVFR CIGs should gradually improve to VFR during the mid
to late morning. Additional showers and storms may develop during
the afternoon but coverage should be much more scattered than
tonight. SW winds shift to W and then NW behind a cold front.
Outlook...
Thursday night through Tuesday...Predominantly VFR conditions.
For Monday, showers and thunderstorms could lead to brief MVFR/
IFR restrictions.
&&
.MARINE...
Based on current trends and the increase in seas within
Wavewatch, we decided to issue a SCA for hazardous seas from
Sandy Hook down to Little Egg.
Previous discussion...
A breezy S wind 10-20 kt will continue into tonight. Despite
stronger winds of 30-35 kt only a few hundred feet above the
surface, poor mixing over the cooler waters will continue to limit
the gust potential. Seas in our coastal waters are around 3 ft this
afternoon but will build to around 4-5 ft tonight and Thursday
morning. Held off a SCA for now given the marginal setup.
Outlook...
Sub-SCA conditions are expected Thursday night through
Sunday night. South-southwest winds may gust to up SCA
level closer to the coastline on Monday afternoon and
evening, but forecast confidence at this time range is
low.
RIP CURRENTS...
Through this evening...A moderate risk for the development of
dangerous rip currents is in effect for both the DE and NJ
beaches. Contributing factors include an onshore southeasterly
wind with gusts to 25 mph, the full moon tomorrow (greater tidal
amplitude accentuating water flow through sand bars), and the
lower end of the tide cycle centered around 8 PM.
Thursday...A moderate risk is outlooked for the NJ beaches
and a low risk for the DE Beaches. In addition to the full
moon, the wind will be more onshore along the NJ beaches
(south-southeast), which will elevate the risk. Meanwhile,
the wind will be more parallel to the DE beaches, leading
to a comparatively lower risk.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory for hazardous seas from 4 AM to 6 PM EDT
Thursday for ANZ450-451.
&&
$$
Synopsis...LF
Near Term...Klein/Kruzdlo
Short Term...Klein
Long Term...LF
Aviation...Klein/LF
Marine...Klein/Kruzdlo/LF
Area Forecast Discussion
National Weather Service Blacksburg VA
1130 PM EDT Wed Jun 27 2018
.SYNOPSIS...
Low pressure moves across the Great Lakes and pushes a cold
front across the Mid Atlantic states on Thursday. High pressure
will follow for Friday through Tuesday with above normal
temperatures.
&&
.NEAR TERM /THROUGH THURSDAY/...
As of 1127 PM EDT Wednesday...
Forecast area in a lull of activity at the moment, with warm
front now northeast across northern VA into the Delmarva. Cold
front stretched from near CLE-IND-STL.
Area of deep moisture convergence ahead of the front will be
pushing into our mountains by dawn, with increased chance of
showers. Otherwise, expect either mostly cloudy skies west, to
increasing clouds east. Patchy fog also expected, mainly in the
mountains.
Previous discussion from early evening...
Watching one cell over Bedford County showing rotation with a
couple of sources reporting a wall cloud but no funnels/tornado.
0-1km SRH is around 100-150, and LCL is 750 m AGL. No damage
reports yet.
Forecast update to cut pops back to more isolated to scattered
more along the latest HRRR and radar trends. Just a few showers
over the Blue Ridge along Wilkes/Watauga, otherwise pretty quiet
apart from that one storm southeast of the town of Bedford.
Previous discussion from early afternoon...
The warm front will continue lifting north as the cold front
approaches tonight. The cold front will move east across the region
Thursday. High pressure off the East coast this afternoon will move
further out into the Atlantic ocean tonight. The morning cool wedge
has lifted and winds have shifted south to southwest this afternoon.
Rich cloud cover has slowed the temperature climb this afternoon.
However with more heating, scattered showers and thunderstorms will
develop and spread east across our region this afternoon into this
evening.
There is enough shear and potential low level enhancement
along the warm front this afternoon into this evening to increase
severe thunderstorm potential. The Day One SPC Convective outlook
has the entire forecast area in a marginal risk. There is a slight
risk of severe thunderstorms to our northeast in Pennsylvania and
Maryland and to our southwest in Tennessee and North Carolina. The
primary threat will be for damaging winds.
Hires model having a hard time placing convection this afternoon. It
seems like the Namnest was doing best at this time. but this
could change next few hours after destabilization of the
atmosphere. The HRRR and Highresw-arw increase convection and
coverage around 20z this afternoon. We will need to watch
thunderstorms that form closer to the front and upper shortwave
trough for later into this evening. With the loss of solar
heating, much of the convection will diminish this evening.
Allowed for some scattered showers in the west overnight. Low
temperatures tonight will range from around 60 in the mountains
to near 70 degrees in the piedmont.
On Thursday, a large subtropical upper ridge will build over the
East with a trough digging into the west. Isolated to widely
scattered convection is possible in the west across the higher
terrain. High temperatures Thursday will warm into the mid 70s in
the mountains to around 90- degrees in the piedmont.
Confidence for above average for sequence of weather changes but
average to below average on the timing.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 215 PM EDT Wednesday...
Thursday night will be a period of transition from the region being
on the back side of a departing upper trough, and an upper ridge
starting to move into the region from the west. A the surface, highs
pressure also will be nosing into the area. The surface high will
settle over the area by Friday night, all while the upper ridge
continues to strengthen and shift east to over the Ohio and
Tennessee Valleys. On Saturday, the upper ridge is forecast to be
overhead.
The result of this transition will be a drier and warmer forecast
through this portion of the forecast. The only precipitation during
this time frame is forecast to be some isolated showers over the
Northern Mountains of North Carolina on Friday afternoon while there
still is some residual low level moisture, low level flow is
upslope/southeast into this region, and the capping inversion of the
approaching upper ridge is not yet at its strongest.
By Saturday, temperatures are forecast to average five to ten
degrees above normal. Heat Index values across parts of the Piedmont
will be in the low 100s.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 1230 PM EDT Wednesday...
Saturday night into Sunday, the axis of the strong upper ridge that
spent the day Saturday over the region, will start to shift eastward
in response to an approaching shortwave trough across the Upper
Mississippi Valley. The result will be a gradual weakening of the
subsidence inversion, and the start of low level southerly flow into
at least the western sections of the area. This transition will
allow for slightly better chances of diurnal convection across the
mountains Sunday afternoon.
This trend continues Sunday night into Monday. The center of the
upper ridge will be farther east, the approaching shortwave and its
dynamics will be closer, and an even better moist southerly flow
will establish itself across the area, not only western sections.
However, the western parts of the CWA are still expected to have the
best coverage.
Monday night through Wednesday, we expect the shortwave trough to
cross into New England while its associated weak cold front moves
into our region and then stalls. Synoptic steering flow is expected
to become extremely weak across the mid-Atlantic and southeast U.S.
with the Jet Stream becoming zonal near the U.S./Canadian border.
This scenario will keep our region within an area of good low level
moisture with a weak boundary wobbling across the region, its
location influenced greatest by daily outflow boundaries from
organized convection. Better than scattered coverage is expected
both Tuesday and Wednesday afternoon with limited coverage during
other times of the day.
Temperatures during this portion of the forecast will start the
period around five to ten degrees above normal. By Wednesday,
temperatures will average only a few degrees above normal. Heat
index values in the low 100s are still forecast both Sunday and
Monday afternoons.
Forecast confidence during this portion of the forecast is moderate
to high Saturday night through Monday and moderate on Tuesday and
Wednesday.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
As of 714 PM EDT Wednesday...
Aside from storm affecting LYH at the moment, all sites should
be rainfree most of the rest of the period. Could see a cell pop
up near DAN/ROA in the next hour or two but forecast confidence
is medium and based on the HRRR trying to form something.
Most indications are that VFR cigs/vsbys will be around this
evening, then possible low cigs maybe for at BLF/LWB/BCB late.
Northwest flow arrives Thursday to scour out any low clouds with
VFR the rest of the period.
Cannot rule out isolated MVFR showers in the west Thursday.
Medium confidence in ceilings,visibilities and winds during the
period.
.Extended Aviation Discussion...
High pressure will persist over the area for the rest of the
week. Mainly VFR weather is expected each day, but with some
localized early morning patchy MVFR valley fog, and perhaps MVFR
conditions in/near isolated thunderstorms that may fire across
the mountains during the afternoon hours late in the weekend
into Monday.
&&
.EQUIPMENT...
As of 810 PM EDT Tuesday...
The NOAA weather radio transmitter in Hinton, West Virginia that
is WXM72 and broadcasting at a frequency of 162.425 MHz remains
off the air, and will likely remain so through the weekend and
into early next week. Parts are on order to repair the
transmitter, but there is no known time of restoration. We
apologize for any inconvenience.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...AMS/KK
NEAR TERM...KK/WP
SHORT TERM...DS
LONG TERM...DS
AVIATION...AMS/KK/WP
EQUIPMENT...WERT
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
804 PM EDT Wed Jun 27 2018
.UPDATE...
Weak westerly flow allowed the west coast sea breeze to push
the majority of the convection east of the forecast area by
the mid afternoon, but a few isolated showers and storms are
lingering over the Nature Coast counties and into the Tampa
Bay area early this evening. The HRRR is indicating that
storms could still build back into southwest Florida along
outflow boundaries between now and 03z, but generally rain
free conditions will then be expected through the rest of
the overnight hours.
Some minor forecast adjustments were made to rain chances
over Southwest Florida through the next several hours
indicating the possibility of storms pushing back towards
the coast. Otherwise, no significant changes were needed for
the evening update.
.AVIATION...
A few scattered showers and thunderstorms are still
lingering over the interior, and could drift back towards
the Gulf coast causing brief flight category disruptions
through around 03z. VFR conditions should then hold
overnight. Thunderstorms will develop again near the coast
during the late morning, and will continue to develop and
shift inland through the afternoon and early evening.
.MARINE...
A ridge of high pressure will hold over the southern Gulf of
Mexico through the next few days with continued westerly
flow. Morning showers will develop over the eastern Gulf and
will generally move inland by the early afternoon. The ridge
will lift into the northeastern Gulf this weekend, with
lighter and more variable flow, and more scattered
thunderstorms. Winds and seas will stay below headline
criteria outside of thunderstorms.
&&
.Preliminary Point Temps/PoPs...
TPA 79 88 79 90 / 20 50 10 50
FMY 77 92 77 91 / 30 20 30 50
GIF 75 91 76 93 / 40 50 20 60
SRQ 80 89 79 89 / 10 30 20 40
BKV 76 89 76 91 / 40 50 30 50
SPG 79 90 79 91 / 20 40 10 40
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...Beach Hazards Statement through Thursday evening for
Coastal Lee-Coastal Sarasota.
Gulf waters...None.
&&
$$
UPDATE/AVIATION/MARINE...18/Fleming
UPPER AIR...42/Norman
DECISION SUPPORT...24/Hubbard
Area Forecast Discussion
National Weather Service Tucson AZ
848 PM MST Wed Jun 27 2018
.SYNOPSIS...A slow moisture increase will bring an increasing
chance of thunderstorms over the next few days, favoring border
areas and mountain locations. As this happens, temperatures will
fall back to average late June levels over the weekend.
&&
.DISCUSSION...Moisture is slowly increasing from the south with
storms developing farther north in far northern Sonora earlier
today. Some organization evident in east central and southern
Sonora once again, with a major complex in southwest Chihuahua
sending deep outflows into Sonora as well. For us, we`re seeing
some mid level moisture increase from the south evident on
satellite imagery. Also note a 15kt southerly flow about 3k feet
deep at Yuma with the surface dewpoint up to 60. The HRRR
continues the lower level trend in a broader area overnight in
response to earlier convection and shallow surge activity. This
slow moistening trend will continue over the next 48 hours with
more storms developing near the international border Thursday
afternoon and evening. Early looks at thermodynamic trends in the
HRRR and ensemble HREF are showing a jump in convective potential
just south of the border and into Santa Cruz and southwest Cochise
counties tomorrow afternoon. We put out a small update earlier to
bump thunderstorm chances up in and around the Santa Rita and
Huachuca mountains for later tomorrow afternoon and early evening.
Storm chances are still on track to increase Friday and Saturday
as outlined in the previous discussion below.
&&
.AVIATION...Valid through 29/06Z.
SCT-BKN clouds at 14k-20k ft AGL south and southeast of KTUS
overnight. ISOLD -TSRA near border areas including KOLS and KDUG
after 28/19Z. Winds diminishing to less than 10 kts and terrain
driven overnight. Gusty W-NW winds return Thursday afternoon.
Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Southerly flow will begin to pull moisture into
our area Thursday allowing for a slight chance of thunderstorms
near the International Border in Santa Cruz and Cochise Counties.
Chances will expand to include the Tucson vicinity and eastward
Friday evening into Saturday. Thunderstorm chances then become
more focused across locations east and south of Tucson and the
White Mountains Sunday and into early next week. 20-foot winds
will generally remain below 15 mph, except for in and around
thunderstorms where gusty outflow winds may occur.
&&
.PREV DISCUSSION...Visible imagery this afternoon showed moderate
cumulus clouds over the Huachuca and Chiricahua mountains of
Santa Cruz county. Cameras near Sierra Vista showed some virga
coming out of the cloud bases over the Huachucas. Can`t rule out a
quick dry thunderstorm over the above mentioned mountains until
early this evening. Otherwise moisture still slowly seeing in from
the south with values this afternoon ranging from 0.40" north of
Tucson to 0.90" near the International border. Looking south of
the border across Sonora Mexico, the leading edge of 1"+ of PW was
within 100 miles of Nogales. The 500 mb high over west-central
New Mexico this afternoon with east-southeast mid- level flow over
the area. The well defined inverted trof that was over the
Mexican state of Coahuila yesterday has washed out and hard to
find on water vapor. Models suggest that it has moved west and is
over eastern Chihuahua and Durango.
Moisture increase still on track over the next several days with
the focus of thunderstorms Thursday being across southern Cochise
county. Both GFS and ECMWF continue to be polar opposites on
Friday and its been that way all week. GFS still indicating a very
active late Friday afternoon into evening with possible MCS
developing over Cochise county, while the ECMWF continues to be
on the dry side. The high-res UofA WRF runs of the NAM/GFS showing
scattered activity across Cochise county Friday afternoon with
thunderstorm outflows pushing as far west as Tucson and east into
the New Mexico boot. Added blowing dust to the forecast for
Friday. Some lingering activity continuing into the overnight
hours Friday with weak upper level trof to our west.
Moisture starts to decrease a bit on Saturday with further drying
occurring Sunday into early next week. So isolated to scattered
storms Saturday east and south of Tucson and then much less area
coverage Sunday into early next week with best chances along the
International border and along the AZ/NM state line.
Temperatures remaining on the hot side tomorrow then cooling off
Friday into the weekend. With less moisture around next week high
temperatures warming back up to several degrees above normal.
Looking toward the end of next week, with is outside the current
7-day forecast package, with a anonymously strong upper high
building across the Rockies, it could get quite hot across the
area at the end of next week.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Meyer/G/L
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