Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/23/17
Area Forecast Discussion
National Weather Service La Crosse WI
632 PM CDT Sat Jul 22 2017
.SHORT TERM...(Tonight through Sunday Night)
Issued at 124 PM CDT Sat Jul 22 2017
Water Vapor showing a mid-level circulation moving east along the
U.S./Canadian border. This will push a weak surface trough through
the area late this afternoon into this evening. Best forcing/p-v
advection with this mid-level feature swings across northern WI but
there will be enough surface convergence to trigger a scattered
storms further south into our area. RAP depicting 1000-2000J/kg
MUCAPE along with 20-25kt of 0-3km Bulk Shear. This looks to be
enough to support a few strong to possibly severe storms. Damaging
winds and a few larger hailstones would be the main threat.
Much needed drier/cooler air filters into the area Sunday as an area
of high pressure builds in from Canada. Plan on high temperatures in
the middle 70s to lower 80s with dew points in the upper 50s to
lower 60s.
.LONG TERM...(Monday through Saturday)
Issued at 124 PM CDT Sat Jul 22 2017
High pressure thankfully remains in control through monday,
providing another dry/pleasant day. Look for highs in the 70s with
dew points in the mainly in the 50s to lower 60s.
Shower and thunderstorms chances then return Tuesday, continuing
into Thursday as a mid-level trough and surface cold front slowly
make their way from the Northern Plains into the Upper Mississippi
River Valley. Too early to tell whether severe weather will be a
factor or not, but looks like later Tuesday afternoon into Tuesday
night could be a window of opportunity as the GFS and ECMWF both
show sufficient CAPE and shear. There is slight timing difference
between the two models, so details still need to be ironed out.
Otherwise, looks like seasonably warm conditions with a bit more
mugginess to the air as dew points start creeping up again.
Friday into Saturday look to be mainly dry as another Canadian highs
slides south into the region.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 632 PM CDT Sat Jul 22 2017
Isolated showers and thunderstorms will move across the TAF sites
early this evening. Then, high pressure builds in late tonight
into Sunday with VFR conditions expected.
&&
.HYDROLOGY...
Issued at 124 PM CDT Sat Jul 22 2017
Ongoing flooding across parts of northeast Iowa into
far southwest Wisconsin this afternoon. In particular, much of Clayton,
southern Fayette, and southern Grant Counties appear to be
hardest hit, with reports of 5-10 inches of rain falling. This
rainfall will take a while to work through the river systems, with the
biggest concerns focused along the Volga River and southern
reaches of the Turkey river, mainly south of Elkader.
Additionally, water continues to percolate down the Kickapoo
River, with the crest having just passed Gays Mills, and along the
Trempealeau River, with Dodge cresting earlier. High/flooding water
also remains along the La Crosse River. Flooding is expected to
continue for the next few days. Drier weather is on tap for Sunday
into Monday but then additional showers and storm chances are
expected to return Tuesday, lasting into Thursday.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...Wetenkamp
HYDROLOGY...DAS
Area Forecast Discussion
National Weather Service Denver/Boulder CO
801 PM MDT Sat Jul 22 2017
.UPDATE...
Issued at 754 PM MDT Sat Jul 22 2017
Tstm activity has ended over the CWA except for
a lone storm nr the CO-WY border. The HRRR and RAP
have been showing a trend for a few storms to dvlp
across nrn areas of the Urban Corridor between 9 pm
and 11 pm. If the storm nr the CO-WY border holds
together and moves south then there is some potential
for this happening so will leave in a slight chc of
storms thru midnight.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 230 PM MDT Sat Jul 22 2017
A ridge of high pressure aloft will be over the Great Basin with
a weak northwesterly flow aloft over the cwa. Two areas of showers
and tstms, one exiting eastern CO at this time, with another area
extending from northern Weld County into Park County. This area
is expected to weaken as it moves slowly east the rest of this
aftn and early evening. Additional showers may develop as outflow
boundaries get generated but overall pops will only be the 10-20
percent range. Overnight, the airmass will stabilize and dry out.
On Sunday, upper ridge with weak north/northwesterly flow aloft
over the area. Less cloud cover will lead to warmer temperatures
and will adjust them up by a degree or two. Best chance of showers
and thunderstorms will be late in the day and located in or near
the higher terrain, too stable for storms over the northeast
plains.
.LONG TERM...(Sunday night through Saturday)
Issued at 230 PM MDT Sat Jul 22 2017
The upper ridge axis will shift a bit eastward and flatten a bit
Sunday evening. Enough embedded moisture and instability in the
flow to keep a few showers and storms going over the mountains
into the evening hours, with a low chance of an isolated high
based storm drifting off the Front Range into the nearby plains
before dissipating.
On Monday, the latest model forecast show a flatter ridge
orientation over the Great Basin and Central Rockies. It will
certainly turn warmer again, with above normal temperatures and highs
likely pushing into the mid 90s on the plains. The more westerly
flow could allow a few late day thunderstorms to sneak out of the
mountains each day, but overall most of the storms will be confined
to the high country.
By late Tuesday and Wednesday, the medium range models still
suggest the next push of monsoonal moisture to arrive. The 700-500
mb specific humidity and Precipitable Water (PW) progs show this
well. We will continue to point to the better PoPs for Wednesday
into Thursday, but even then the best potential for more
meaningful rainfall would remain in the mountains. We should see
temperatures return to near normal levels during this period.
For Friday into next weekend, the upper level ridge may begin to
retrograde and amplify into the Great Basin. This would result in
drier northwest flow aloft. Temperatures at this time are
expected hold near normal values.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 754 PM MDT Sat Jul 22 2017
An outflow bndry has moved across the airport with sely winds
developing. Winds will continue sely for the next few hours and
then go more sly by 06z. Latest hi res data shows some potential
for isold storms between 10 pm and midnight. For now will keep any
mention of storms out of taf and see how things evolve the next
few hours.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...RPK
SHORT TERM...Cooper
LONG TERM...DB
AVIATION...Cooper
Area Forecast Discussion
National Weather Service Cheyenne WY
823 PM MDT Sat Jul 22 2017
.UPDATE...
Issued at 812 PM MDT Sat Jul 22 2017
Most of the late afternoon convection that developed over the high
plains has dissipated. A lone thunderstorm formed just south of
Cheyenne during the past 30 minutes. The 00Z HRRR tracks this cell
south of the CO border by 9 PM. Skies will become mostly clear
later this evening with light winds through the overnight.
&&
.SHORT TERM...(This evening through Monday)
Issued at 237 PM MDT Sat Jul 22 2017
Sfc trough is currently located from CYS to CDR with drier air to
the northwest and higher dewpoints to the southeast. Cumulus and
some storms are developing in the convergence along this trough.
Kept mainly 20-30 percent PoPs in the fcst from Laramie county
eastward into the southern Panhandle through the early evening.
The deep layer shear is better this aftn at around 30-35 kts,
thus cannot rule out an isolated stronger storm with small hail.
Any storm activity should drop wind down by late evening or move
into northern Colorado.
Heights aloft rise on Sunday with the midlvl ridge axis located near
the Laramie Range by the aftn. After slightly cooler temps today,
we will see around 5 degrees of warming at most locations. With the
subsidence aloft and PW values at a dry 0.5-0.75 inches, convection
should remain quite limited. The exception may be along the
southern Laramie Range where southeasterly sfc winds will result in
weak convergence. Monday will likely be the warmest day with highs
rising into the 90s for areas to the east of the Laramie Range.
Midlvl flow will remain westerly with low PW values across the CWA.
A weak shortwave trough moving into central WY by late aftn and
evening may promoted isolated storm develop over the Sierra Madre
and Snowy Ranges.
.LONG TERM...(Monday night through Saturday)
Issued at 237 PM MDT Sat Jul 22 2017
Medium range models are in good agreement with overall pattern
progression in retrograding the upper high west from the southern
plains towards the four corners. As this occurs, southwest flow
around the periphery of the upper high will be effective in
advecting monsoonal moisture into the intermountain west. Have
added thunderstorm chances to Tuesday as a southward moving sfc
front and mid-level shortwave energy moving thru. The sfc front
looks to stall southwest of the CWA on Wednesday, which should
focus convective chances mainly to areas in the hier terrain of
southeast WY. Afternoon thunderstorm chances continue on Thursday
as low-level convergence is centered on the Laramie Range. May
actually see a drier air mass work in for Friday and Saturday as
the upper high settles into the four corners allowing for drier
northwest flow into the region. Instability parameters look fairly
meager through much of the week, so wouldn`t expect to see much
widespread severe potential. The one exception may be Thursday,
where the GFS progs SBCAPE`s around 1500-2000 j/kg along with 40
knots of 0-6 km bulk shear. Much can change by then, but trends
bear watching. After one last warm day on Tuesday, afternoon
highs will generally cool into the 80s for Tue-Sat (exception
being 90s across lower elevations of the Panhandle).
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday afternoon)
Issued at 812 PM MDT Sat Jul 22 2017
VFR will prevail over all terminals through Sunday. Very low chance
of afternoon convection developing off the Laramie Range again
Sunday afternoon, but for now left the mention of thunder out of
KCYS and KSNY. Winds will be light and out of the south or southeast
tonight through Sunday.
&&
.FIRE WEATHER...
Issued at 237 PM MDT Sat Jul 22 2017
Minimal fire weather concerns through early next week. With warm
temperatures in place, minimum afternoon humidity values will drop
to 15-20 percent over portions of southeast Wyoming on Sunday and
Monday. The lowest humidity of 10-15 percent will be found across
lower elevations of Carbon county. Despite the dry airmass, winds
are expected to be relatively light so no critical fire weather
conditions are anticipated.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
UPDATE...MAJ
SHORT TERM...ZF
LONG TERM...CAH
AVIATION...DL
FIRE WEATHER...ZF
Area Forecast Discussion
National Weather Service Dodge City KS
856 PM CDT Sat Jul 22 2017
.UPDATE...
Issued at 856 PM CDT Sat Jul 22 2017
Cold front clearing Barber county through 930 pm after which it
will have cleared all of SW KS. Last of the spotty convection
diminishing between Meade and Ashland. Updrafts forced by the
frontal lift were extremely efficient rainfall producers, with
areas lucky enough to receive a storm picking up a quick 1-2
inches of rain. Some examples of this: SE Meade county, northern
Clark county, south central Ford county, near Ensign, near Hanston
in eastern Hodgeman county, near Otis in eastern Rush county. The
strongest storms impacted Trego county, where wind damage to power
lines was reported west of Wakeeney. Also, radar estimates 5-6
inches of rain in NE Trego county, north of Ogallah. The flash flood
warning issued earlier for Trego county has been cancelled. Also
expired the heat advisory as cooler NE winds arrive. Aligned pop
grids based on radar trends. Compelled to keep slight chance
showers/storms mentioned overnight, as HRRR and new 00z NAM both
indicate post-frontal activity developing after midnight.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 1233 PM CDT Sat Jul 22 2017
Precip chances return to western Kansas this evening as an upper
level shortwave trough slides southeast across the Upper Midwest,
sending an attendant frontal boundary further southward across
southwest and central Kansas. Although a weak flow aloft and a
lack of organized shear will prevail, enough instability will be
present to support the potential for isolated thunderstorms in a
band of increased convergence associated with the frontal boundary.
Even though the severe potential is minimal, the environment is
such that a few storms could become strong enough to produce small
hail and gusty winds in excess of 40 to 50 mph. Thunderstorm
chances shift southward closer to the Oklahoma border Sunday as
the frontal boundary pushes further south. With the weak frontal
boundary moving through tonight, look for lows down into the
60s(F) across west central Kansas to the 70s(F) in south central
Kansas. Temperatures will not be quite as hot tomorrow with highs
generally in the 90s(F) Sunday afternoon.
.LONG TERM...(Sunday night through Saturday)
Issued at 117 PM CDT Sat Jul 22 2017
Chances for significant precip dwindle early next week as upper
level ridging begins to rebuild across the South Plains and southern
portions of the Central Plains. Under a prevailing weak northwest
flow aloft, any thunderstorm chances are expected to be relegated
to more diurnally driven factors and should be fairly isolated in
nature within a southeast upslope flow setting up across the high
plains. In general, the better chance for storms looks to be
across eastern Colorado in vicinity of a developing lee side
trough each afternoon with storms then potentially drifting into
extreme western Kansas later in the evening time frame. A few
storms could be possible further east late Monday in conjunction
with a weak frontal boundary lifting back to the north across the
region. As for temperatures, a warming trend will take place
through at least Wednesday as low level southerlies set up under
ridging aloft. Highs are expected to push the century mark again
by Wednesday afternoon.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 600 PM CDT Sat Jul 22 2017
Cold front will progress southward across SW Kansas terminals this
evening, with surface winds becoming NE and averaging 15-25 kts.
Scattered thunderstorms along the frontal boundary are expected to
be most widespread near HYS early this evening, where a convective
TEMPO group was included. Otherwise, the odds of a thunderstorm
directly impacting an airport are low. Convective coverage will
decrease along the front after 06z as instability wanes. Frontal
boundary will continue to sag southward on Sunday, with the best
potential for further convection south of the airports. NE post-
frontal winds near 10 kts expected Sunday afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 69 93 68 94 / 20 20 20 20
GCK 68 90 67 94 / 20 20 10 10
EHA 63 89 67 92 / 30 40 30 20
LBL 68 94 68 94 / 20 30 30 20
HYS 69 92 69 95 / 60 20 10 10
P28 74 97 71 97 / 20 30 30 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Turner
SHORT TERM...JJohnson
LONG TERM...JJohnson
AVIATION...Turner
Area Forecast Discussion
National Weather Service Des Moines IA
638 PM CDT Sat Jul 22 2017
...Updated for 00z Aviation Discussion...
.SHORT TERM.../Tonight through Sunday/
Issued at 300 PM CDT Sat Jul 22 2017
Synopsis...
Giant ridge impacting the central to southern half of
the country continuing to propagate southward and slowly break down.
Meanwhile, 18z water vapor imagery shows two large-scale upper lows
positioned in Canada...one east of the Hudson Bay, and the other
over just off British Columbia. These lows complete the setup for
zonal flow across the northern third of the country.
Additionally, 18z water vapor imagery picking up on a smaller low
propagating along the Minnesota/Canada border. There is westward
tilt with this low, as a sfc reflection will be located just ahead
of the core of this upper low. Attendant to the sfc low is a
boundary oriented NE- SW and stretching into northern Iowa by 12z
Sun and SE Iowa near 21z Sun-00z Mon.
Saturday PM... Hi-Res models starting to come into agreement with
placement of the boundary...In fact, are handling location and
magnitude of boundary much better than Friday. 18z RAP sounding
analysis correctly had boundary south of KDSM and +15C to 750mb.
In short, best chance for initiation south and east of Iowa, and
have removed POPs for the remainder of this evening in Iowa. Hi-
res models picking up outflow from the above discussed low to
possibly clip our northeastern counties overnight, but severe
threat would be effectively nil if it manages to reach this far.
Sunday...
Timing of this boundary will impact max temps... a
slightly faster progression would imply cooler temps across the
central to southern portion of the CWA... slower progression would
imply warmer temps. With 850mb temps still expected to be in the
+20C to +22C range for Sunday along and south of I-80, still expect
highs in the upper 80s to mid 90s. Drier air being advected into
Iowa will keep dewpoints in the 60s...serving to keep heat index
values *only* in the low to mid 90s. The location of the above
boundary during peak heating would also have an impact for
thunderstorm potential. At this time, however, it appears the
boundary will be into northern Missouri, relegating the severe
weather potential to northern/NE Missouri.
.LONG TERM.../Sunday night through Saturday/
Issued at 300 PM CDT Sat Jul 22 2017
Monday through Wednesday...
Trough continues to dip east allowing for cooler and drier air to be
funneled in from the north. Comfortable highs and dewpoints will
persist into Monday. However, the building ridge behind the trough
will return us to southerly flow moving into Tuesday bringing with
it added moisture and heat. A surface boundary will move east
Tuesday into Wednesday bringing us the next chance for rain and
thunderstorms. Confidence is low at this time on the chances across
the state for rainfall. Sufficient instability and influence from
the upper level jet looks to be in place for Wednesday which
could support more storm chances across the area. Worley
Wednesday night through Saturday...
Surface front pushes through the state through Thursday morning,
continuing chances for storms across the far south Wednesday
night. On Thursday there is some model discontinuity as the Euro
stalls the front across southern Iowa keeping storm chances going
while the GFS has a stronger surface high build in and push the
quasi-stationary boundary further south...into Missouri. The
Canadian appears out to lunch so I did not consider in the range
of solutions. Beyond Thursday, a big ridge of high pressure builds
into the west and extends into the Upper Midwest for an extended
period of dry conditions. The GFS drops a ridge riding shortwave
across the northeast into the east and want to create some
spurious pop`s with that. It is the most robust of all the models
and appears overdone so for now, I discounted any pops northeast.
Otherwise temps will be generally in the mid 80`s with lows in the
60`s to lower 70`s which is about normal and humidities will be
tolerable.
&&
.AVIATION.../For the 00Z TAFS through 00Z Sunday evening/
Issued at 638 PM CDT Sat Jul 22 2017
Main concern this TAF period is possible fog development later
tonight. The factor that may limit fog is drier air that will
slowly work into the state tonight. Nearing 0z, dewpoints were at
least in the low 70s with dewpoints in the 60s upstream. Cross
sections show higher relative humidity after midnight, especially
over the eastern TAF sites. Not surprisingly, this is also where
forecast soundings show an inversion with saturation near the
surface. The blend of much of the short term, high res models have
the best signal for fog development across the eastern portion of
the forecast area, including KALO and KOTM. Will introduce fog
into these locations with MVFR visibilities, though patchy fog is
also possible farther west and will reevaluate at 6z TAF issuance.
Otherwise, VFR conditions will prevail at the TAF sites through
the period.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM CDT this evening for IAZ057-058-070.
Excessive Heat Warning until 8 PM CDT this evening for
IAZ059>062-071>075-081>086-092>097.
&&
$$
SHORT TERM...Kotenberg
LONG TERM...Worley/FAB
AVIATION...Ansorge
Area Forecast Discussion
National Weather Service Hastings NE
624 PM CDT Sat Jul 22 2017
.SHORT TERM...(This evening through Sunday)
Issued at 301 PM CDT Sat Jul 22 2017
Today should be the last day of the heat wave. I didn`t make any
changes to the heat advisory or heat warning. A weak upper-level
disturbance has continued to develop scattered showers and
thunderstorms over central Nebraska.
A weak cold front is located across northern Kansas, as evidenced
by a line of cumulus from Stockton to Beloit. Thunderstorms
should develop in this vicinity within the next few hours. Short-
term RAP soundings show 1000-2000J of CAPE and 30 kts of bulk
shear in this vicinity, so an isolated severe storm isn`t out of
the question. This activity should continue to gradually shift
south with the front tonight.
Sunday should remain dry and cooler as high pressure builds into
the area. Highs are expected to "only" be in the low 90s.
.LONG TERM...(Sunday night through Saturday)
Issued at 301 PM CDT Sat Jul 22 2017
Early next week, mostly dry weather is expected through Tuesday,
with daily high temperatures gradually rebounding back into the
middle and upper 90s.
Chances for thunderstorms return to the forecast Wednesday as a
large upper low tracks across Canada, pushing a front through the
Great Plains.
As has been the case several times this summer, this front looks
like it will stall out in our vicinity, giving us a potential for
isolated thunderstorms Thursday and even into Friday, primarily
across Kansas and far southern Nebraska. Right now, we`re only
looking at high temperatures in the upper 80s and low 90s through
this stretch.
Late Friday into Saturday, both the GFS and the ECMWF show the
western ridge amplifying a bit, which should limit precipitation
chances and potentially give us another round of heat as it shifts
eastward early into the following week.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday)
Issued at 622 PM CDT Sat Jul 22 2017
The north wind will die down after sunset and could even become
light and variable at times tonight. Overall the wind will remain
fairly light again tomorrow and will predominately be out of the
north or northeast. VFR conditions are expected with just some
high clouds around tonight and then mostly clear skies tomorrow.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Mangels
LONG TERM...Mangels
AVIATION...Wesely
Area Forecast Discussion
National Weather Service Green Bay WI
809 PM CDT Sat Jul 22 2017
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Sunday
Issued at 259 PM CDT Sat Jul 22 2017
Chance for, and strength of, thunderstorms late this afternoon and
tonight are the main concerns in the short term.
Fog from early this morning dissipated and low clouds were
gradually breaking up throughout the day. This allowed instability
to increase across the area during the late morning and afternoon.
Mesoanalysis as of 19Z had MUCAPE values generally in excess of
1000 J/kg range across the western part of the forecast area and
CIN values across north central Wisconsin were 25 J/kg or less.
Nothing had developed in the area or nearby as of 19Z, but there
was no shortage of boundaries, with a stationary front along the
Wisconsin/Illinois border, another across Lake Superior and Upper
Michigan, and a trough in eastern Minnesota. Wind directions
varied considerably across the area but speeds were light,
resulting in weak convergence at several locations. Dew points
were generally in the mid 60s to around 70.
Models were showing the surface low near the Minnesota/Manitoba
border passing north of the area and dragging a trough/cold front
through the state as a 500mb trough moves across Wisconsin with a
500mb low passing to the north of the state. These features
should be sufficient to get thunderstorms into the area later
today/tonight. Latest versions of the HRRR and RAP showed
development in northern Wisconsin around 23Z, just to the west of
the forecast area. Convection then moves into north central
Wisconsin with a line developing to the southwest as it makes its
way across the rest of the area during the late evening/nighttime
hours.
SPC day 1 convective outlook had most of the area in a slight
risk of severe with a marginal risk for Door County and the rest
of the lakeshore due to "robust speed shear."
Convection is forecast to exit the area overnight but there are
still some slight chance/low end chance PoPs in the far east and
north in cyclonic flow around the departing system.
.LONG TERM...Sunday Night Through Saturday
Issued at 259 PM CDT Sat Jul 22 2017
High pressure regimes will dominate much of the weather next week
with the exception of a frontal system with upper support from
Tuesday evening into Wednesday evening. Temperatures expected to
mostly be near seasonable levels.
Moist cyclonic flow with the departing deep upper trough or
nearly closed low may keep a few showers around Sunday evening
until daytime heating wanes. Clearing skies later Sunday night
with cooler overnight low temperatures in the 40s north to lower
and mid 50s central, may lead to fog formation by early Monday
morning. Otherwise a cool comfortable and drier air mass will
filter into the area for the start of new work week as a high
pressure system drifts into the western Great Lakes region.
Next chance for precipitation and possible strong to severe storms
during the Tuesday evening into wednesday evening time frame. A
strong short wave trough, near the Canadian Pacific coast line
this Saturday afternoon as per water vapor loop, is progged to
drop over the Great Lakes region late Tuesday into Wednesday. The
850 warm air return and possibly the start of the convection
begins to reach north central Wisconsin Tuesday afternoon and
evening. The short wave trough then drags a cold front across the
state on Wednesday, dropping the front south of the forecast area
later Wednesday evening.
Another high pressure system will then build into the area for
the remainder of the work week and perhaps remain settled over
the region into the start of next weekend.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 807 PM CDT Sat Jul 22 2017
An upper-level disturbance approaching the western Great Lakes
and associated cold front entering NW Wisconsin will continue to
generate isolated to widely scattered showers and thunderstorms
through the evening. The most concentrated activity is expected
to be generally over central and northeast sections of the
forecast area. This activity will gradually spread into the
eastcentral sections after about 02Z or 03Z. A few of the storms
this evening may contain small hail and wind gusts to 35kts.
Generally VFR conditions except brief MFVR conditions in widely
scattered thunderstorms. The preciptation should come to an end
shortly after 06Z or 07Z.
Some scattered IFR stratus and patchy fog may once again develop
after midnight especially over northern wiscosnin.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MG
LONG TERM......TDH
AVIATION.......ESB
Area Forecast Discussion
National Weather Service Gray ME
745 PM EDT Sat Jul 22 2017
.SYNOPSIS...
A cold front across the forecast area will exit into southern
New England tonight before stalling. High pressure will build by
to our north overnight through Sunday and provide some clearing
mainly to northern sections of New England. Low pressure will
approach from the southwest later Sunday night and for Monday
and will deliver cooler temperatures and the likelihood of rain.
Conditions will gradually improve by Tuesday night and
Wednesday as high pressure moves in.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
730 PM Update...
Cold front continues to drop slowly southward early this
evening. Band of showers ahead of this boundary has developed
across central New Hampshire. HRRR has a pretty good handle on
this activity which it gradually drops south into southern New
Hampshire by around midnight before shifting out of the
forecast area during the early morning hours. Have adjusted pops
and wx grids based on current radar trends. Aside from a few
tweaks to temps/tds...no other changes planned attm.
Previous discussion...
At 18z the cold front extended from mid coast Maine westward
through central New Hampshire and into upstate New York. This
boundary continues to inch southward and will provide a weak
focus for widely scattered convection through early evening. The
NWS Doppler Radar mosaic has showed some widely scattered
echoes over the past few hours and expect that to continue.
The boundary will finally settle into southern New england and
Long Island Sound by morning before stalling. Clearing should be
confined to northern areas...as the remainder of the region
remains on the northern periphery of the high and mid cloud
shield.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
On Sunday...the northeast synoptic flow between the surface
high over eastern Canada and the stalled front to our south will
gradually become more easterly. Much of the area will remain on
the northern periphery of the high cloud shield from the stalled
baroclinic zone and those clouds and the onshore flow will
limit highs to the mid 70s to lower 80s. It should be a dry day
with comfortable humidity levels.
Sunday night...thicker clouds will gradually spread north and
east in developing warm air advection ahead of approaching
shortwave impulse and associated surface reflection. showers
should gradually spread north and east in the predawn hours and
reach all but our far northern and eastern Maine zones by
morning.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
A temporary pattern shift will occur, with cooler and more raw
conditions developing for the beginning of the work week next
week. Some much needed rainfall may finally reach the coastline
which has missed out on much of the convection during the past
month or so do to cooling onshore breezes. Upslope conditions
may allow for locally heavy rainfall in the mountains.
Temperatures to begin the week well below normal with widespread
60s for daytime highs. Details are below.
A significant upper level trough for mid to late July swings
east and into New England on Monday. This will trigger
cyclogenesis along the south coast of Massachusetts during the
day. This will provide a cool and raw northeast flow over the
region. Low cloud cover will keep readings in the 60s over many
areas, especially near and along the coastline. Showers will
break out. The atmosphere will remain fairly stable at the
surface, but instability aloft may be sufficient for a few
embedded thunderstorms.
With high precipitable water values and the likelihood of
showers throughout the day, there may be some pockets of locally
heavy rainfall. As the showers and isolated storms continue
Monday night, the threat of the possibility of localized
flooding will be on the increase, mainly in favorable upslope
areas where persistent heavy showers are a possibility.
By Tuesday, the surface low will begin to exit to the east
towards the Canadian Maritimes near Halifax Nova Scotia. With a
wind shift, most of the showers will exit the region over
southern areas. However, the H7 and H5 low will remain over the
region, allowing an easterly upslope flow to continue over the
mountains. This will allow for additional showers across the
higher terrain during the day.
All areas finally begin to have drier air advect into the region
Wednesday as the upper level trough shifts to the east and a
ridge of high pressure builds into the region.
Yet another cold front will approach the region on Thursday,
before crossing off the coastline by Friday. This will add a few
more scattered showers and perhaps a thunderstorm during the
period.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Short Term /through Sunday Night/...VFR tonight and Sunday with
river valley stratus and fog psb late tonight. Areas of MVFR
developing aft 05z Mon in -shra.
Long Term...Monday will continue to lower into IFR conditions
as log pressure develops. There may be an embedded thunderstorm.
IFR conditions will likely persist throughout the night
especially along the coast Monday night. Conditions will
improve on Tuesday with mostly mountain shower activity and
increasing ceilings to the south. High pressure builds back in
for Wednesday.
&&
.MARINE...
Short Term /through Sunday Night/...NE flow will develop behind
a cold front tonight and could briefly approach small craft at
times in gusts outside the bays overnight into Sunday.
Long Term...A low will develop south of New England through
Monday. This will bring increasing easterly winds to the waters
with small craft conditions potentially during the day on
Monday. A strong low level jet may result in a few gusts over
SCA thresholds in regions of heavy showers. High pressure will
move in for Wednesday with subsiding winds and seas.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
Area Forecast Discussion
National Weather Service Indianapolis IN
918 PM EDT Sat Jul 22 2017
.UPDATE...
The NEAR TERM Section has been updated below.
&&
.SYNOPSIS...
Issued at 338 AM EDT Sat Jul 22 2017
Central Indiana will remain on the edge of a strong upper ridge
through tonight....maintaining hot and exceptionally humid
conditions. Chances for thunderstorms will continue until a frontal
boundary can push through the area overnight into early Sunday. A
secondary front may bring additional scattered storms on Sunday
evening before high pressure builds in with mainly dry weather and
seasonable temperatures for the early part of the week.
&&
.NEAR TERM /Rest of Tonight/...
Issued at 907 PM EDT Sat Jul 22 2017
Question of the evening is when and how much thunderstorm activity
will occur overnight. Latest mesoscale analysis shows an old
convective boundary that extends from southwest OH west through
Monroe county then southwest through Sullivan county. But, there
is also a slow moving front that will be moving towards western IL
that could result in developing more thunderstorms overnight.
MLCAPE of 4500 J/kg exists over central IL with 2500 J/kg
extending into the southwest counties. The HRRR has been
developing storms over IL much of the evening, but those have not
occurred at this time. So, will continue to forcast thunderstorms
overnight but it seems the probabilities may be a little lower
than earlier. Thunderstorms that do develop could produce frequent
lightning and heavy downpours and could possibly last towards
daybreak.
Warm and humid for one more day before high pressure can move into
parts of the area for a more comfortable Monday.
&&
.SHORT TERM /Tonight through Monday Night/...
Issued at 338 AM EDT Sat Jul 22 2017
Forecast challenges focus on precip chances...especially tonight and
again late Sunday and Sunday evening.
Convection will likely be ongoing this evening as development takes
place over northern counties and progresses southeast through the
evening and overnight ahead of the cold front. A surface wave along
the boundary...continued influence of a low level jet...BL shear
values around 30kts and a strongly unstable airmass all support a
threat for severe storms this evening gradually transitioning into
more of a heavy rain threat overnight. Highest pops will be employed
over the eastern half of the area where parameters will be just a
bit more favorable for more widespread convection. Precip water
values will remain above 2 inches and combined with freezing levels
near 15kft supporting warm rain processes...torrential rainfall and
flooding will continue to be concerns as the storms surge south
overnight.
Growing confidence that most if not all of the convection will be
out of the forecast area by 12Z Sunday with the front settling south
of the Ohio River. Much of the day Sunday should be dry with an
edge being taken off the humidity levels. A secondary front
associated with a sharp upper wave diving out of the western Great
Lakes may serve as a focal point for renewed convective development
to the northwest of the region Sunday afternoon...possibly spreading
into the northern half of the forecast area during the evening.
Steep mid level lapse rates in response to cooling aloft suggestive
that strongest storms may carry a damaging wind and large hail
threat. Will bring low chance pops back into the northern counties
Sunday evening as a result.
Convection will diminish overnight Sunday with high pressure
building south into the region on Monday with cooler and noticeably
less humid air. Likely to see diurnal cu develop on Monday before
skies become mostly clear Monday night.
Temps...it will remain very warm on Sunday with low level thermals
supporting highs from the mid 80s to around 90. Temps will fall back
into the lower and middle 80s Monday with cooler air aloft advecting
into the region. Lows will slide back into the 60s through the
period.
&&
.LONG TERM /Tuesday night through Saturday/...
Issued at 220 PM EDT Sat Jul 22 2017
The long term begins with central Indiana under the influence of
upper ridging, thus resulting in warming temperatures and dry
weather Tuesday night through early Wednesday night. By late
Wednesday night some model runs indicate the ridge could begin to be
suppressed as an upper wave travels through to the northwest and
thus bring a chance for thunderstorms back into the forecast on
Thursday. Friday currently looks like a cold front will move through
the area, and have chances for thunderstorms dropping off in its
wake. Result is thunderstorm chances Thursday through Friday with
dry conditions building in by Friday night. Long term temperatures
will peak on Wednesday with highs in the upper 80s to lower 90s
before dropping a couple degrees on Thursday due to cloud cover and
another degree or two for Friday with the cold front moving through.
Medium confidence in the return of storm chances late in the week,
and in cooler temperatures (low to mid 80s).
&&
.AVIATION /DISCUSSION FOR 23/0000Z TAF ISSUANCE/...
Issued at 645 PM EDT Sat Jul 22 2017
Complex situation this evening with several convective boundaries
across central parts of Indiana. One lies across southern parts
of Indiana from LUK - HUF, while another more frontal boundary
extends from near FWA - CMI. A cold front extends from south
central WI into northeast MO. It is the frontal boundary that is
expected to move slowly into IL tonight and trigger more storms
across central IL into west and central IN. Right now, central IN
is in a trough of instability with a small amount of convective
inhibition that is holding things back right now. So, we have VFR
for the time being. Will have to wait and see when the boundary
fires tonight and see if a MCS gets going later tonight into the
morning hours. If storms become widespread, would expect IFR near
the storms.
Confidence: Low on timing on thunderstorms. If develop they should
be widespread.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Ryan
NEAR TERM...DWM
SHORT TERM...Ryan
LONG TERM....CP
AVIATION...DWM
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
710 PM CDT Sat Jul 22 2017
.SHORT TERM...(This evening through Sunday)
Issued at 334 PM CDT Sat Jul 22 2017
The RAP, HRRR and HRRR exp are generating a diurnally driven area of
showers and thunderstorms across the Panhandle late this afternoon
which drifts into Wrn Neb this evening. POPs are limited to isolated
chances because the upper level forcing is weak.
Otherwise the ongoing area of showers and isolated thunderstorms
across ncntl Neb should move off east this evening. The
aforementioned models were the basis for this forecast.
The forecast is dry late tonight and Sunday a weak area of "cooler"
air moves into wrn/ncntl Neb. The temperature forecast tonight uses
blended bias corrected MET/MAV guidance for lows in the upper 50s to
around 60. Highs Sunday are a blend of guidance from the GFS, NAM
and ECM plus bias correction. This marked highs up a bit and picks
up on a "hot spot" around Valentine for highs in the mid 90s. The
area around Valentine has missed out on much of the rainfall this
summer.
.LONG TERM...(Sunday night through Saturday)
Issued at 334 PM CDT Sat Jul 22 2017
Heat wave conditions appear to set up Monday across Wrn Neb. Sfc low
pressure will be tucked up across Wrn SD and this would normally
focus the warmest h700mb temperatures and deeper mixing along and
west of highway 61. However, the drought has cured the Sandhills
and bias corrected model data suggests 90s to around 100 will focus
farther east, along highway 83.
Sfc low pressure moves into ern SD Tuesday fanning the warm air
advection throughout Wrn and Ncntl Neb. H700mb temperatures rise to
around 15C which could support 105F in some areas. The forecast is
more modest for now with highs in the 90s to low 100s as suggested
by the models.
A strong Pacific cold front moves through Wednesday and rain chances
are in place, 30-40 percent. Actually, the atmosphere may blow apart
across Nrn Neb Tuesday afternoon where CAPE values could be 3000-
5000 J/KG. The shear will be weak with h500mb winds around 20 kt.
Generally cool weather is indicated Thursday through Saturday with
mostly isolated rain chances. In the wake of the cold front
Wednesday, moisture appears to be piling up on Colorado Front Range
and Laramie range which could spark thunderstorm activity across
Swrn Neb and the Panhandle.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 704 PM CDT Sat Jul 22 2017
Isolated thunderstorms will continue over the Nebraska Panhandle
between KIEN and KSNY. Storms should dissipate with the heating of
the day. Skies will clear from northwest to southeast tonight as
surface high pressure builds in to western Nebraska. Winds will be
light and variable through Sunday.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Power
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1010 PM EDT Sat Jul 22 2017
.SYNOPSIS...
Offshore high pressure with an inland trough will be the
dominant weather features through the weekend producing hot and
humid conditions. A weak cold front will move into the region
early next week and become stationary.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 10 PM Saturday...Made only minor adjustments to the
forecast for a bit slower cooling this evening in the hourly
temperature trends and to drop the PoPs. Upper ridging continues
across the area with high pressure anchored offshore and weak
surface trough inland. It will be another warm humid
night...with lows only 76-80 degrees. Organized convection
currently remains well north of the area over the Mid- Atlantic
region. While a few models show a chance of some precipitation
later tonight, like the GFS, the majority of models including
HRRR and high res NMM and ARW keep the CWA dry with an MCS over
the Mid- Atlantic weakening as it moves SE tonight and
dissipating before reaching the forecast area.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH 6 PM SUNDAY/...
As of 315 PM Sat...Weak surface low will move through the Mid-
Atlantic and NE, while high pressure remains anchored off the SE
coast with troughing inland. Looks like one more oppressively
hot and humid day Sunday with heat index values 105-109 degrees.
Low level thickness values and 850mb temps around 20C support
highs in the mid/upper 90s inland and upper 80s/low 90s along
the coast. Will issue another heat advisory for all counties
except Outer Banks Hyde.
SPC has the northern half of the area outlooked in a Marginal
Risk, with a sliver of Slight Risk over the Albemarle Sound and
northern Outer Banks. Shear seems to be the limiting factor with
0-6 km bulk shear less than 15 kt. Forecast soundings show very
unstable atmosphere with MU CAPE values 4-5000 J/kg, LI values -8
to -11C. Expect generally pulse type storms, though if convection
were to become organized could see storms with strong winds
develop.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
As of 3 PM Saturday
The forecast remains in good shape with a trend
toward slightly "cooler" weather and increasing chances for rainfall
through much of the upcoming week.
Sunday night/Monday...The main players of the week will be a
disturbance now southeast of Winnipeg that will help to establish a
trof over the northeast US. This trof will help to push a frontal
boundary that is now over the Mid Atlantic toward our area Monday,
and this feature will impact us through much of the upcoming week.
The disturbance just mentioned will be making its way through
the Lower Great Lakes Sunday evening. This southward progression
will be just enough to push the shower/thunderstorm threat that
has remained well to our north the past few days, into our
area. SPC has expanded the marginal risk for severe storms
Sunday night into the norther half of our forecast area, with a
slight risk now just touching the very northern part of our
area. The end result will be an increasing trend in thunderstorm
chances from 30% Sunday evening, to near 60% Monday evening as
a cold front gets closer to our area. The best 0-6 KM bulk shear
values remain well to our north but strong instability could
support damaging wind threat either day. PWATs or precipitable
water values also high with locally heavy rain the other main
threat. With the increased cloud cover and rain threat, along
with slightly lower thickness values temps will be 2 to 4
degrees "cooler" than this weekend.
Tuesday/Wednesday...With a cold front near or over our area Tuesday,
this appears to be another day with a decent shot (60%) of
thunderstorms through most of the area. Model trends have been a
little slower and not as far south with the passage of the cold
front. This will keep the risk for storms around again Wednesday,
with the highest chances across the far south in closer proximity to
the front.
Thursday and beyond...While the trof in the northeast US lifts out
and heights build in that area, an elongated weakness in the
heights aloft will remain over the carolinas. At the same time
the remnants of the frontal boundary mentioned above will
remain, with a new front approaching by early next weekend. This
will result in daily chances for thunderstorms and near normal
late July highs of around 90 inland, and 80s along the coast.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
Short Term /through Sunday/...
As of 730 PM Saturday...Predominate VFR conditions expected
through the period outside of convection. Only a chance of an
isolated shower or thunderstorm this evening, mainly across the
northern area. Widely Scattered to Scatters thunderstorms will
be possible Sunday afternoon/evening.
Long Term /Sunday night through Thursday/...
As of 300 PM Sat...Cont mainly VFR Mon thru Thur however will
have better coverage of shra/tsra from time to time resulting in
a few pds of sub VFR. The best chance for this would be Monday
and Tuesday afternoon/evening. Weak front drops thru later Tue
and stalls over southern sections Wed...could see some lower
cigs assoc with the front and some late night fog.
&&
.MARINE...
Short Term /through Sunday/...
As of 10 PM Saturday...No changes with this update. Latest
observations continue to show SW winds 10-20 kt with gusts to 25
kt across the Pamlico Sound and central waters, and seas 2-4
feet. High pressure will continue offshore with troughing inland
through the period continuing the S to SW flow. Moderate S/SW
winds 15-25 kt will continue into Sunday, with seas building to
4-7 feet (south of Oregon Inlet). Brief period of frequent gusts
to 25 kt for the waters north of Oregon Inlet this evening,
with SCA continuing for the Pamlico Sound and coastal waters
south of Oregon Inlet into Sunday.
Long Term /Sunday night through Thursday/...
As of 300 PM Sat...SSW winds of 15 to 25 kts will continue
Sunday night thru Monday evening between offshore high pres and
front/trf to the W. These winds will lead to seas of mainly 4
to 6 feet outer central and srn wtrs. Small craft advisory
remains in effect thru Mon evening per ocnl gusts aoa 25 kts and
6 ft seas. Again preferred wave watch over NWPS with sustained
winds of 20-23 kts in a southwest flow more supportive of waves
up to 6 feet and not much higher.
As front gets closer later Mon night winds and seas will slowly
subside. The front will drop Thru nrn half of region later Tue
into Tue night then stall and weaken a bit Wed over srn tier.
Expect nrn wtrs will see a period of light onshore E to NE winds
behind front Tue night into Wed while srn tier will cont with
mainly S to SW winds but shld be light. Seas will subside to 2
to 3 feet all wtrs Wed. As the front lifts northward again over
the waters later Wednesday and Thursday, south to southwest
winds return and remain generally 5 to 10 kts. Seas remain 2 to
3 feet with such light winds over the waters.
&&
.CLIMATE...
Record Max Temps for 07/22 (Sat)
Location Temp/Year
New Bern 106/1952 (KEWN ASOS)
Cape Hatteras 92/1987 (KHSE ASOS)
Greenville 102/2011 (COOP - Not KPGV AWOS)
Morehead City 100/1987 (COOP - Not KMRH ASOS)
Kinston 105/1932 (COOP - Not KISO AWOS)
Jacksonville 99/2011 (KNCA AWOS)
Record Max Temps for 07/23 (Sun)
Location Temp/Year
New Bern 100/1952 (KEWN ASOS)
Cape Hatteras 92/1972 (KHSE ASOS)
Greenville 103/1932 (COOP - Not KPGV AWOS)
Morehead City 98/1987 (COOP - Not KMRH ASOS)
Kinston 103/2011 (COOP - Not KISO AWOS)
Jacksonville 97/1995 (KNCA AWOS)
Record Max Temps for 07/24 (Mon)
Location Temp/Year
New Bern 99/1952 (KEWN ASOS)
Cape Hatteras 90/2016 (KHSE ASOS)
Greenville 99/2011 (COOP - Not KPGV AWOS)
Morehead City 96/1999 (COOP - Not KMRH ASOS)
Kinston 101/1952 (COOP - Not KISO AWOS)
Jacksonville 97/1995 (KNCA AWOS)
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Heat Advisory from 11 AM to 7 PM EDT Sunday for NCZ029-044>047-
079>081-090>095-098-103.
Beach Hazards Statement from 8 AM EDT Sunday through Sunday
evening for NCZ095-098-103-104.
MARINE...Small Craft Advisory until 1 AM EDT Monday for AMZ135.
Small Craft Advisory until 2 AM EDT Sunday for AMZ150.
Small Craft Advisory until 2 AM EDT Tuesday for AMZ152-154.
Small Craft Advisory until 8 AM EDT Monday for AMZ156-158.
&&
$$
SYNOPSIS...CQD/HSA
NEAR TERM...RSB/CQD
SHORT TERM...CQD
LONG TERM...RF/EH
AVIATION...RSB/EH/CQD
MARINE...RSB/EH/CQD
CLIMATE...MHX
Area Forecast Discussion
National Weather Service Melbourne FL
944 PM EDT Sat Jul 22 2017
.UPDATE...
Tonight-Sunday...Once again, convection initiated rather early and
has already ended across the area. A weak mid level cyclonic
circulation is forecast to meander just to our north and keep weak a
westerly wind flow. This might be significant since the models are
showing this will blow considerable debris clouds into the area
through the night and into Sunday. The HRRR had been showing light
precip languishing over northern sections overnight but recently has
started to back off that solution. Will go with a dry forecast the
rest of the night over land.
Precipitable water on Sunday still looks to start off the day high,
around 2 inches. The convective evolution will likely be
complicated by the debris clouds though, probably delaying it some.
Forecast soundings show a dry layer below the debris clouds which
should keep the microburst potential elevated. The strongest
boundary interactions and highest POPs in this regime would be
expected over the east side of the peninsula.
&&
.AVIATION...A few patches of low clouds have occurred this
evening, but generally expect VFR to prevail through Sunday morning.
Daytime heating may be slightly delayed by some mid level debris
clouds. Generally expect convection to break out a little later than
today, so timing of the vicinity shower/storm mentioned in the
latest set of TAFs may need to be pushed back an hour or two.
&&
.MARINE...
Tonight/Sun...Surface high pressure ridge axis should begin to
lift northward from south Florida. This will continue a light south
to southwest flow and produce favorable boating conditions. Seas 1-
2 feet, occasionally 3 feet well offshore. Convective evolution on
Sunday afternoon is a bit more uncertain than recent days and the
chance for strong storms moving offshore looks to be a little later
in the day.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&
$$
Forecasts...Lascody
Impact Weather/Radar...Weitlich/Combs
Area Forecast Discussion
National Weather Service Mount Holly NJ
1104 PM EDT Sat Jul 22 2017
.SYNOPSIS...
A frontal boundary extended from the southern Great Lakes to
our region this afternoon. Low pressure will ride eastward along
the front and it should pass through our area tonight. Another
low is expected to follow on Monday. The second low is forecast
to pull the boundary southward and away from our region allowing
high pressure to build down from the northwest for the middle
part of the new week. A cold front from the northwest is
anticipated to arrive on Thursday night.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
It was an active late afternoon and early evening across much of
the area, mainly from Central NJ and Berks County on south to
the Delmarva where several areas of thunderstorms moved on
through. Activity initially developed in Central NJ along the
sea breeze while activity elsewhere developed from what was left
of any MCSs (Mesoscale Convective Systems) that moved east from
Central Pennsylvania and Central Maryland as well as Northern
Virginia. This activity has either moved offshore or weakened
altogether. Radar mainly shows light showers with embedded
moderate to heavier showers as of 9 PM across Central NJ and
Bucks County heading east. We cannot rule out any thunder here
given how unstable things are, but lightning detection has shown
a downward trend in activity across our area. The heavier
activity near Ocean City, Maryland and Chincoteague, Virginia
was heading offshore and should not bother southern Delaware
with just some light showers there.
The grids were revamped overnight based on the latest radar
trends initially for the first 3 hours. Afterwards, we leaned
towards the NAM 3 km, which seems to best have a handle of QPF
based on the look of satellite. All eyes now turn to the
convective complex that has impacted southwest PA and West
Virginia this evening. Most of the models, including the global
models at higher resolutions, and some of the higher resolution
short term models like the HRRR and RAP, take energy from this
complex and move it across Central PA toward Central and North
Jersey overnight. Given the 500 mb flow is west-northwest and
the 1000-500 mb thickness contours are also west to east
(basically zonal), I am not sold on this activity heading
further north. MCSs like to track parallel to the 1000-500 mb
thickness contours and thus I think the NAM 3 km is more likely
which would take it towards DC/central Maryland and then toward
the Delmarva and far South Jersey (Cape May/Atlantic/Cumberland
and maybe far southern Ocean Counties) overnight. As a result,
we updated the grids to reflect this thinking.
The heavy rain threat is greatest south of a line from
Wilmington to Atlantic City but may get as far north as
Philadelphia overnight if convection sneaks up that far. So we
kept in enhanced wording for heavy rains and gusty winds given
the complex now as we see things. Further north, it looks to
stable overnight for much thunder and north of Trenton and
Freehold/Asbury Park we yanked it.
Temperatures overnight will be mild as cloud cover increases
across the region. Fog may start to develop in some areas
towards late tonight/early morning, especially where heavy rain
has fallen. Lows will drop down into the low to mid 70s across
the region, with some mid to upper 60s across parts of the
southern Poconos and northwest New Jersey.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
Another slightly muggy day on tap for the region but
temperatures will not be quite as high as they have been
recently. Sky conditions will be pretty cloudy which should help
to keep the temps a bit lower. With a boundary across the
region it may be the tale of two cities (or parts of the
forecast area). Areas to the north of the boundary should remain
slightly cooler than those areas to the south of the boundary.
For now, anticipate that the boundary will remain just south of
or along the Mason-Dixon line. Areas to the north will remain in
the 80s, while areas to the south look likely to reach into the
lower 90s.
Low pressure is slated to travel along the boundary and another
round of showers and thunderstorms is expected, mainly during
the afternoon and evening hours. Once again the abundance of
moisture across the region will bring the threat for heavy rain
and we will need to monitor it closely, especially for those
areas that see heavy rain today. SPC continues the
slight/marginal risks across our forecast area for Sunday with
damaging winds being the greatest threat.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
Unsettled conditions are forecast to continue from Sunday night
into Monday night. The frontal boundary is expected to remain
in our region on Sunday night with another low expected to pass
through our area on Monday.
We are anticipating the likelihood of showers and thunderstorms
associated with another convective complex on Sunday night.
Precipitable water values should be in excess of 2 inches across
the central and southern parts of our forecast area. As a
result, we will mention the potential for heavy rain at that
time.
The chance of showers and thunderstorms will continue into
Monday and Monday night with the passage of the low. The low is
expected to begin pulling the front to our southeast and south
on Monday night.
The axis of a mid level short wave trough approaching from the
northwest is anticipated to pass overhead on Tuesday afternoon
and it will be followed by a shot of dry weather for the mid
week period.
A cold front is expected to approach from the northwest on
Thursday and it should pass through our region from Thursday
night into early Friday. We will mention a chance of showers and
thunderstorms with the front.
Dry weather is forecast to return for next weekend.
Temperatures are expected to be seasonable during the new week
with no excessive heat events in sight.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Tonight...Scattered showers will continue to impact mainly KABE
and to a lesser extent KRDG through 06Z, with the possibility of
an isolated TSRA. The other terminals have seen showers and
thunderstorms pass through and should remain quiet through 02Z
Sunday. Additional showers/storms may follow in the wake of
convection but confidence is lower as to timing and coverage.
The greatest threat overnight for SHRA/TSRA will be at ACY late
and possibly MIV and ILG with a lesser risk at PHL if activity
makes it that far northward. TAFs were adjusted to the latest
thinking.
MVFR/IFR ceilings and visibilities are likely to occur in the
wake of the convection and persist into the morning hours. Best
chances will be at those locations that see heavy rain.
There is potential for strong to severe storms today with gusty
to damaging downburst winds and torrential rainfall.
Patchy fog may form tonight especially in areas where any
heavier rain fell early. Visibility could drop to MVFR or lower
for a few periods.
Sunday...Fog/low clouds early should clear into the afternoon
but skies are expected to remain pretty overcast. VFR conditions
are expected to return late morning/early afternoon but
confidence is low that we see significant clearing through the
day. Another round of showers and thunderstorms is expected,
mainly during the afternoon/evening hours.
Winds...light southerly winds today will become more west to
southwest overnight and then will become more north to northeast
on Sunday morning. Winds speeds are expected to remain around
10 knots or less.
OUTLOOK...
Sunday night...MVFR and IFR conditions in showers and
thunderstorms. The rain may become heavy.
Monday...A chance of showers and thunderstorms with conditions
improving to VFR outside of any areas of rain.
Monday night...Conditions lowering to MVFR and possibly IFR. A
chance of showers and thunderstorms.
Tuesday...MVFR and IFR conditions in the morning improving to
VFR.
Tuesday night through Thursday...Mainly VFR.
&&
.MARINE...
Sub-small craft advisory conditions are expected to continue on
the area waters. Winds will generally be south to southwest
through this evening around 10 knots. Winds will become more
west tonight and then northerly into Sunday. Seas are 2 to 3
feet on the ocean today and will gradually rise to 3 to 4 feet
on Sunday. While seas are expected to remain below 5 feet, they
may near 5 feet on the outer waters late tonight into Sunday.
Showers and thunderstorms will impact the area waters through
tonight, with locally higher seas and gusty winds.
OUTLOOK...
Sunday night through Thursday...No marine headlines are
anticipated.
RIP CURRENTS...
A moderate risk for risk currents is expected to continue
through this evening. The underlying 10-12 second period
continues to show up on guidance and is impacting the rip
current risk. Additionally, with the new moon is occurring on
Sunday, and a moderate risk looks likely for New Jersey with a
low risk for Delaware for Sunday.
&&
.TIDES/COASTAL FLOODING...
There is Coastal Flood Advisory in effect for this evening`s
high tide along the New Jersey and Delaware coasts and along
Delaware Bay.
The surge at this morning`s high tide was about +0.4 to +0.6
feet. There will be an onshore component to the wind today and
it should bring the surge up around +0.6 to +0.7 feet by
evening.
The astronomical tides with the upcoming new moon are quite
high, as was the case with the new moon in both May and June. As
a result, the somewhat unimpressive surge values will likely
result in some minor flooding. If heavy rain occurs coincident
with the high tide, the potential for flooding will increase.
Conditions may be similar for Sunday evening`s high tide. An
onshore flow is anticipated for Sunday, especially in areas from
Atlantic City up to Sandy Hook.
&&
.CLIMATE...
ABE 1.29" today as of 03/23. Daily record is 1.54 set in 1938.
POR 1922.
ABE mo total as of 01z/23 is 6.46",20th wettest in the POR
dating back to 1922. July record 10.42" 1969.
&&
.EQUIPMENT...
Dew point readings at KDOV continue to measure too high
compared to surrounding locations and should be treated as
unrepresentative of the area.
Hibernia PA and Hamburg NJ transmitters are off the air (lost
Hibernia this evening around 0015z/23). Both have trouble
tickets. No known rts.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...Coastal Flood Advisory until midnight EDT tonight for
NJZ012>014-020>027.
DE...Coastal Flood Advisory until midnight EDT tonight for
DEZ002>004.
MD...None.
MARINE...None.
&&
$$
Synopsis...Iovino
Near Term...Meola/99
Short Term...Meola
Long Term...Iovino
Aviation...Iovino/Meola/99
Marine...Iovino/Meola
Tides/Coastal Flooding...
Climate...1104P
Equipment...
Area Forecast Discussion
National Weather Service Blacksburg VA
913 PM EDT Sat Jul 22 2017
.SYNOPSIS...
A cold front will cross overhead during tonight into Sunday,
which should spark showers and thunderstorms. This front should
pass south of our region by Monday. High pressure will arrive
to bring slightly cooler conditions by the middle of the week.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 910 PM EDT Saturday...
A short wave moving by to our north is helping the frontal
boundary sag a bit closer to the area early tonight. This will
allow convection along the front to brush the northern portion
of the region mainly along and north of the Interstate 66
corridor. However, the entire overnight period is rather muddy
as the remnants from waves of convection upstream move in our
direction and may be able to affect the area, while lingering
boundaries from earlier convection may be able to generate some
new activity in residual pools of instability. Believe the best
course of action is to play the POPs early from convection
dropping in from the north, then allow broader POPs in the west
later tonight.
Convective debris clouds will have an impact on overnight low
temperatures. Believe there will be enough cloudiness around to
keep us a degree or two above last night with low/mid 70s east
of the Blue Ridge and mid 60s/near 70 to the west.
Previous discussions...
745 PM EDT Saturday...
Activity associated with a wavy frontal boundary to our north
will remain very close to the boundary and gradually work its
way south during the night in a much weaker fashion.
Confidence in activity for tomorrow is still only in the chance
range, much of which will depend on how much cloud cover and
convection there is in the morning. Will not make any changes to
tomorrow`s pops for now. SPC still holding a SLIGHT RISK for
tomorrow.
330 PM EDT Saturday...
High resolution models hint at another round of convection
arriving west of I-77 by early Sunday morning. Cloud cover from
upstream convection could limit high temperatures from climbing
as high by Sunday afternoon compared to Saturday afternoon.
Still, it will be quite hot and humid, and the cold front may
reach the VA/NC border by the afternoon. This situation should
allow enough instability and lift for more scattered showers and
thunderstorms to develop in this area toward the evening.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 230 PM EDT Saturday...
For Sunday evening, weather forecast models are hinting at a line of
thunderstorms entering our far western Virginia/northern North
Carolina counties during late evening as an upper level disturbance
passes overhead. Believe any storms would diminish in intensity
quickly as they cross the ridges and move into downslope flow. Have
introduced a period of higher rain chances across the west for the
possibility of this system, however admit that confidence of the
occurrence/timing/location of any organized line of storms moving in
from the west is marginal. The coming overnight forecast shift will
have the benefit of an updated set of models to have a look at and
will make adjustments to these rain chances accordingly. Outside of
these storms, convection is expected to diminish after sunset with
the loss of daytime heating.
Widely scattered showers and thunderstorms can be expected for
Monday despite a cold front approaching from the northwest. Slightly
drier air and stronger northwest wind flow will help to inhibit
convective development, though those storms which do develop may
pulse up to strong/severe intensity for brief periods of time,
capable of producing localized damaging winds. The cold front will
enter the southeast West Virginia counties during late Monday
evening, and gradually loose momentum as it continue south across
our area.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 1230 PM EDT Saturday...
Looking to Tuesday, long-range weather models are indicating that
the cold front may not pass completely across our forecast region,
possibly stalling near the Virginia-North Carolina border as high
pressure shifts from the Great Lakes toward New England. Will hold
close to the previous forecast of a higher chance of spotty
afternoon showers/storms south of Highway 460...closer to the front.
Passage of high pressure off the coast on Wednesday will bring
cooler easterly windflow to the mid-Atlantic, resulting in likely
the coolest afternoon temperatures of the week. Upslope wind flow
will make for the best chances of shower/thunderstorm activity
across the mountains.
Winds will shift more southerly by Thursday, resulting in a return
of warmer temperatures and higher humidity, and greater coverage of
afternoon showers/storms, more so across the mountains. A cold front
will slowly make its way across the mid Atlantic on Friday and
Saturday, again resulting in scattered showers and thunderstorms
both days, a few of which may become severe for brief periods of
time.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
As of 750 PM EDT Saturday...
No convection left in the CWA at this time. Meso-high has built
across the area and left us with mainly just a high cirrus deck
from upstream convection. HRRR suggests little will happen until
after 08Z, when some showers/thunderstorms may begin to spread
back into the area from the west/northwest. Current
thunderstorms to our north extend along a wavy quasi-stationary
frontal boundary that will move little overnight. Southward push
of convection will be largely from cold pool outflow and
density. However, the overnight trends will determine how active
Sunday becomes in terms of convection. HRRR, as well as larger
synoptic-scale models, through tomorrow afternoon is not excited
about much convection in our CWA, largely in part because of
downslope westerly winds that develop in the morning in the wake
of potential MCV. We could see a situation where clouds and
early morning showers relocate to stronger convection in the
afternoon mostly across eastern/southern areas. For now, have
left VCTS/TS out of the TAFs until there is greater consensus
among the synoptic scale and short range models.
All this being said, generally looking at a VFR forecast through
the TAF valid period. Not expecting fog/low cloud development
tonight/early Sunday because of high temperatures today, large
T/Td spreads, and extensive mid/high clouds overnight from
upstream convection and possible convection later tonight.
Winds will be SW-WSW through the period at speeds of 4-6kts
overnight and 8-10kts after 14Z Sunday with low end gusts
possible at most sites.
Medium confidence in ceilings through the TAF valid period.
Medium to high confidence in visibilities through the TAF valid
period. High confidence in wind speed/direction through the TAF
valid period.
Aviation Extended Discussion...
The cold front currently to our north should be near the NC/VA
border by Monday. This leaves a baroclinic zone in or near the
area through much of the extended period. Additional upper-level
disturbances are progged in northwest flow to impact the area,
leaving an unsettled weather pattern in place. The most likely
areas to see convection, at least during the first part of the
week would be near the NC/VA border, mainly affecting KDAN.
Late/night early morning fog can be expected in the usual
locations, otherwise outside these concerns and scattered
convection, mainly in the south, look for mostly VFR cigs/vsbys.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...PW
NEAR TERM...MBS/RAB/PW
SHORT TERM...NF
LONG TERM...NF
AVIATION...RAB/PW
Area Forecast Discussion
National Weather Service Tucson AZ
904 PM MST Sat Jul 22 2017
.SYNOPSIS...Scattered to numerous afternoon and evening
thunderstorms will continue through Monday. Conditions for
thunderstorms will become less favorable by mid week, before
another upswing in activity late in the week.
&&
.DISCUSSION...Plenty of moisture and easily accessible
conditional instability combined with strong organized outflows to
generate a great day for rain across most of the area. Outflow
continues to push through southern areas, including Santa Cruz
county this evening. Expect mainly moderate showers with isolated
embedded thunder to continue for another hour or two down there.
For the early morning hours, we will see some shower activity in a
diminishing debris field, and watch for any outflows from late
night activity in New Mexico.
We may not see that until after sunrise however, with the HRRR
developing convection in the mid morning across NM border areas.
Slow development elsewhere, but the flow may be strong enough to
reset the atmosphere for areas hit hard today by late afternoon
and early evening tomorrow. We`ll have to see how much heating we
are able to manage.
Busy period may take a break around Tuesday and Wednesday as we
introduce a southwesterly component to our flow, a decrease in
moisture, and mid level warming with the high center shifting
around a bit. That won`t last long though.
&&
.AVIATION....AVIATION...Valid thru 24/06Z.
SCT SHRA/TSRA diminishing overnight. Otherwise VFR conditions
with cloud decks generally 5k- 10k ft AGL with BKN layers above,
and surface wind variable in direction mainly less than 12 kts.
SCT TSRA redeveloping after 23/17Z. Winds vicinity TSRA could
gust 40+ kts. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Scattered to numerous mainly afternoon and evening
thunderstorms will continue into Monday with locally heavy rain and
strong winds. Isolated to scattered showers and thunderstorms are
then expected Tuesday into next weekend. Temperatures will remain
below normal through Tuesday, with near normal readings the rest of
the week. 20-foot winds will remain below 15 mph with the exception
of strong outflow winds in the vicinity of thunderstorms.
&&
.PREV DISCUSSION...Activity got off to a quick start this morning
with first storm of the day popping up over the Chiricahua
mountains after 830 am which produced around 0.80" in less than an
hour. Mountain storms struggling to maintain themselves once they
move into lower elevations. With well above normal PW values in
place, between 1.60" and 1.85, heavy rain main threat this
afternoon into the evening hours, especially in the mountains.
Thus went ahead and hoisted a flash flood watch for areas east and
south of Tucson. The MCV mentioned in the morning discussion that
was near Glenwood NM in Catron county was over western Grant
county in NM and drifting south. For tonight scattered showers and
thunderstorms, more numerous east and south of Tucson. Tucson
will have to rely on outflow interactions for storms in the city.
Flow aloft becomes more E-SE later tonight as models move inverted
trof, which extended from NW NM to southern Sonora MX this morning.
Sunday has the potential to be rather gunked over for the bulk of
the day with showers around and embedded isolated thunderstorms.
High temperature forecast a challenge with MOS numbers rather cool
for July with lots of clouds around. At this time, the official
forecast high in Tucson for Sunday of 89 degrees would be the first
sub-90 high in July since 2010.
Monsoon train remains on the track next week, although there could a
slowdown day or two, while high temperatures warm back to late July
normal values.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Meyer
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