Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/11/17
Area Forecast Discussion
National Weather Service Taunton MA
1028 PM EDT Mon Jul 10 2017
.SYNOPSIS...
An approaching cold front will trigger a couple round of scattered
showers and thunderstorms from early Tuesday morning through early
evening. This front lingers nearby Wednesday into Friday, resulting in
unsettled weather at times. Weak high pressure builds in for
Saturday, then another cold front is expected to move through the
area next Sunday or Sunday night.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Clouds moving over the region during the night, with radar
showing a few light showers, mostly to our west. The shortwave
driving these showers will move over New England toward 12Z
bringing a chance of showers moving in from the west a few hours
before that. The 01Z HRRR maps from SPC show a few light showers
moving in from PA toward midnight and crossing CT and
Western/Central Mass through 06Z/2AM. Somewhat stronger showers
than move into these western areas 2-4AM and across RI and
Eastern Mass 5-8AM. It is tricky to read too much into the
details of this output, except to expect a few showers during
the overnight hours moving in from the west and lingering
through the morning commute.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
***Scattered thunderstorms with localized heavy rainfall and an
isolated wind damage Tuesday morning into early Tuesday evening***
Tuesday morning...
The shortwave that was driving the current complex of showers and
thunderstorms over the eastern Great Lakes will track eastward
overnight. A developing modest low level jet coupled with ample
forcing from the shortwave and elevated instability will trigger
scattered showers and probably embedded thunderstorms after midnight
into Tuesday morning. While this activity is possible across most
locations, highest risk is north and west of a Boston to Providence
corridor and especially across western MA. This is where the
strongest forcing will likely reside.
Timing of the showers and embedded thunderstorm threat after
midnight into Tuesday morning remains uncertain, although models
have been trending faster. The main threat will any thunderstorms
through that time will be heavy rainfall and a brief localized urban
street flooding threat as Pwats climb to between 1.5 and 2 inches.
The overall severe weather threat is low through Tuesday morning, as
weak mid level lapse rates and limited surface instability. However,
we can not rule out an isolated strong to severe thunderstorm or two
given 0 to 6 km shear on the order of 35 knots and a decent
shortwave. In addition, 0 to 1 km helicity looks to be between 100
and 200 units. Most likely will not be an issue given elevated
nature of morning activity, but still need to keep a close eye on
the radar for the very low risk of some mesoscale intervention that
can sometimes make things go surface based earlier than expected.
Tuesday afternoon and early evening...
Probably will see some sort of break in the main activity for a time
Tuesday afternoon, but still may see a few showers/t-storms given
deep moisture and warm advection. Another shortwave will be
approaching from the west later in the day. This will probably
trigger additional scattered showers and thunderstorms that will
persist into early evening. Given Pwats close to 2 inches, heavy
rain and a brief localized urban street flooding threat will be a
concern.
There is an isolated strong to severe thunderstorm potential Tuesday
afternoon and early evening. This will depend on how quickly the
atmosphere can recover from the morning convection and timing of the
second shortwave. High temps may be able to recover into the lower
to middle 80s and it will be humid. As is often the case in our
region, weak mid level lapse rates will likely prevent a widespread
severe weather outbreak. 0 to 6 km shear is also rather marginal and
even diminishes a bit during the afternoon. Nonetheless, enough
instability may develop with MLCapes near or above 1000 J/KG for a
few strong to severe thunderstorms. The main threat would be locally
strong to damaging wind gusts, but hail can not be ruled out.
The bulk of the activity should wind down by the early evening hours
on Tuesday. However, frontal boundary stalling near the south coast
and low level jet persisting may allow some activity to last longer
in that region. Low temps mainly in the upper 60s to around 70.
Will have to watch for some patchy ground fog developing late in the
typically prone locations.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Highlights...
* Showers/t-storms possible at times Wed-Fri
* Warm and humid Wed/Thu then turning cooler Fri
* Mainly dry Sat but shower/t-storm risk returns next Sun
Overview...
Zonal flow dominates northern CONUS mid to late week with series of
fast moving shortwaves which will keep an unsettled pattern across
SNE. Mid level trof eventually amplifies a bit across the Gt Lakes
and New Eng next weekend as anomalous subtropical ridge builds
across the western CONUS. Will follow a blend of available guidance
to smooth the less predictable details.
Details...
Wednesday...
Cold front will be moving south across the region but there is
uncertainty with how far south the front gets before stalling. This
will affect how much drier air advects in from the north and the
extent of instability and resulting shower/t-storm activity if front
stalls further north across SNE. ECMWF keeps threat of showers/t-
storms across the region while GFS dries it out. We will have slight
chc PoPs during the day. Still humid near the south coast but
somewhat drier air may work into northern MA. Highs in the 80s. The
front is expected to lift back to the north Wed night and there may
be an MCS that develops across northern New Eng at the nose of the
low level jet. Some of the guidance has convection spilling into
northern MA late Wed night. Still much uncertainty.
Thursday into Friday...
Unsettled period expected. May be dealing with remnants of an MCS
across northern MA Thu morning, then front is expected to move back
south across the region with a period of showers/t-storms possible.
High PWAT airmass suggests potential for locally heavy rainfall. The
position and timing of the front is uncertain and its location will
be critical to temps and timing of showers/t-storms. Big temp bust
potential for Thu as slower timing means very warm but if front is
faster and further south temps will fall sharply. Warmest temps
across CT/RI and SE MA.
The front pushes south of New Eng Thu night into Fri, but SNE will
be on the leading edge of higher theta-e air with continued risk of
showers/t-storms, with greatest risk across SW half of New Eng.
Cooler Fri with E/NE flow expected and temps upper 60s to lower 70s
and it is possible all SNE remains in the 60s on Fri.
Saturday...
This potentially looks to be the driest day as weak high pres builds
south into the region with some drying of the column. Temps
likely still below normal with onshore winds.
Sunday and Monday...
Low confidence forecast at this time range with timing of shortwaves
and cold front. Another risk of showers/t-storms as the mid level
trof swings through but timing is uncertain.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Tuesday Night/...
Overnight...Moderate to high confidence. Mainly VFR. However, a
band of showers and isolated thunderstorms with brief heavy
rainfall may impact the region after 6z. Highest risk will be to
the north and west of a Boston to Providence corridor,
particularly in western MA. Lastly, will have to watch for some
low clouds/fog patches across the Cape and Islands but
confidence on whether they develop is low.
Tuesday...Moderate confidence. Scattered showers and embedded
thunderstorms are expected into early Tuesday evening with
locally heavy rainfall. Timing and areal coverage a bit
uncertain, but may come in two main rounds in the morning and
later in the afternoon/early evening. A few of the thunderstorms
may produce locally strong wind gusts. Outside of any showers
and embedded thunderstorms, mainly VFR conditions will probably
prevail but southwest wind gusts up to 25 knots.
Tuesday night...Moderate confidence. Most of the lingering
scattered showers and embedded thunderstorms should come to an
end early Tuesday evening, but may linger a bit longer near the
south coast. Otherwise mainly VFR, but will have to watch for
areas of patchy ground fog developing late that could result in
localized MVFR to IFR conditions.
KBOS Terminal...High confidence in TAF.
KBDL Terminal...High confidence in TAF.
Outlook /Wednesday through Saturday/...
Wednesday...Moderate confidence. Some early morning MVFR/IFR stratus
possible, otherwise mainly VFR. Low risk for a few showers/t-storms
with brief lower conditions.
Thursday and Friday...Low confidence. MVFR/IFR conditions possible
but timing and details uncertain. Showers/t-storms possible at times
both days.
Saturday...Moderate confidence. VFR/MVFR cigs.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Tuesday Night/...
Overnight...Moderate to high confidence. Weak pressure gradient
will keep winds/seas below small craft advisory thresholds.
Some fog may develop across our southern waters late, but
confidence in that is low.
Tuesday and Tuesday night...Moderate to high confidence. Modest low
level jet coupled with diurnal heating should result in southwest
wind gusts up to 25 knots developing by afternoon, especially near
shore. In addition, persistent southwest fetch should allow seas to
build to between 3 and 6 feet across our southern waters. Therefore,
have hoisted small craft headlines for all our waters on Tuesday.
Near shore 25 knot wind gusts should diminish Tuesday evening with
the loss of daytime heating. In addition, a few strong
thunderstorms with gusty winds are possible.
Outlook /Wednesday through Saturday/...Moderate confidence.
Wednesday...Light winds expected but 5 ft seas may linger over the
southern waters.
Thursday...Variable winds, becoming NE across eastern MA waters with
southerly winds south coastal waters, becoming easterly Thu night.
Seas may build to 5 ft over eastern MA waters late Thu/Thu night.
Sct showers/t-storms.
Friday...Easterly winds less than SCA with diminishing seas.
Saturday...Winds and seas below SCA.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 10 AM to 8 PM EDT Tuesday for
ANZ230>234-236-250-251.
Small Craft Advisory from 10 AM Tuesday to 8 AM EDT Wednesday
for ANZ235-237-254>256.
&&
$$
SYNOPSIS...KJC/Frank
NEAR TERM...WTB/KJC/Frank
SHORT TERM...Frank
LONG TERM...KJC
AVIATION...KJC/Frank
MARINE...WTB/KJC/Frank
Area Forecast Discussion
National Weather Service State College PA
1127 PM EDT Mon Jul 10 2017
.SYNOPSIS...
A dying cold front will approach from the Great Lakes this
evening, then stall out just north of Pennsylvania for the next
few days. This boundary is likely to push south of the region
by next weekend.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Radar showing a dwindling band of showers moving into the Susq
Valley late this evening ahead of shortwave moving over the
state. The back edge of remaining showers should be exiting the
eastern part of the forecast area around 05Z-06Z. However,
regional radar showing a new area of convection developing at
nose of low level jet over Ohio. This feature is progged by
near term models to overspread the area late tonight, with focus
of associated convection expected to be across the Laurel
Highlands and I-80 corridor per latest HRRR runs and 00Z NAM.
Will reintroduce the chance of thunder with this new batch of
convection late tonight, given the increasing forcing and
marginally unstable soundings.
Much higher humidity, along with cloud cover, will result in a
warmer night than recent ones, with min temps mostly between
65-70F.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/...
Focus for scattered showers Tuesday morning is likely to be
across the southern half of the forecast area associated with
passage of another weak shortwave. However, expect the best
chance of precip to come during the afternoon hours, as
brightening skies and resulting heating of high PWAT air mass
leads to development of more widespread diurnal convection. 18Z
GEFS and superblend continue to support POPs in the 50-60pct
range for most of central Pa.
The region remains within a marginal threat risk area for severe
weather Tue PM. Model soundings indicating moderate CAPEs but
fairly weak 0-6km unidirectional shear, suggesting the
potential for isolated large hail with the damaging wind gusts
originating from the strongest updrafts.
Dewpoints will be pushing 70F in most places Tuesday, likely
resulting in heat indices reaching as high as the mid 90s
across the Lower Susq Valley.
A ridge of a high pressure will briefly push the mugginess and
most of the convection south of the Mason/Dixon line late
Tuesday night through Wednesday morning, before the boundary
returns north into the CWA Wednesday afternoon and stays
situated near or right over our region through Thursday.
Convective development along this front and the potential for
one or more MCSs tracking in from the WNW will maintain a fairly
active weather period Wednesday afternoon/evening with the
potential for a few STG to SVR TSRA given the presence of the
sfc boundary and moderately strong mid level west-nwrly shear.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Guidance remains consistent in depicting the summertime pattern
evolution this period featuring strong upper level ridge
rebuilding over the Western U.S. with corresponding mean
troughing downstream over the Eastern U.S. The wavy front
pushing southeast from the Great Lakes will provide a focus for
thunderstorms with heavy rainfall Thursday-Friday. A trailing
front progressing from southern Canada may generate some
convection on Sunday. Above normal temperatures are likely ahead
of the front at the start of the period. As the pattern evolves
toward more troughing aloft, expect a gradual cooling trend
with near to slightly below normal temperatures during the
latter half of the period.
Dangerous heat conditions are possible Thursday afternoon with
fcst max heat index values around 100 degrees across portions of
the mid/lower Susquehanna Valley into far s-central PA. An area
of strong/severe storm potential could occur along/ahead of the
wavy front late this week given strong buoyancy and moderate
mid level flow between the ridge/trough pattern. However, model
detail differences render a low confidence/predictability in
severe storm risk at this time.
By next Monday, cool high pressure may make an eastward push
into the region, providing at least a temporary reprieve after
a warm and stormy week.
&&
.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
Band of showers now falling apart, updates done.
Small area of storms over far SW PA. Should stay south
of JST.
Low CIGS at BFD at times.
For Tuesday, went with VCSH. Most of the day should
be VFR.
.OUTLOOK...
Wed-Fri...Periods of localized sub-VFR in sct showers/Tstorms.
Sat...Improving conditions.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Fitzgerald
NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald/La Corte
LONG TERM...Gartner/Steinbugl
AVIATION...Martin
Area Forecast Discussion
National Weather Service Quad Cities IA IL
800 PM CDT Mon Jul 10 2017
.UPDATE...
Issued at 754 PM CDT Mon Jul 10 2017
Focus of marginal severe threat this evening has shifted far south
and possibly far east into Bureau/Putnam counties. Marginally
severe hail, isolated downburst winds and heavy rain are main
issues. Had a funnel cloud and possible brief tornado during
Roseville earlier, so cannot completely discount that threat as
well.
&&
.SYNOPSIS...
Issued at 305 PM CDT Mon Jul 10 2017
Heat Advisory in effect in the counties approximately to the south
of a Cedar Rapids to Quad Cities line through 7 PM this evening.
After widespread rainfall last night, the atmosphere has become very
humid with dewpoints rising into the middle to upper 70s. Expect
peak heat indices between the upper 90s to lower 100s.
&&
.SHORT TERM...(This Evening through Tuesday)
ISSUED AT 305 PM CDT Mon Jul 10 2017
Late this Afternoon through Tonight
Very humid conditions with dewpoints in the mid and even upper 70s
at some locations will be the main story. Threat for convection is
fairly low but continued the lower 20-30% PoPs roughly in the
counties along and south of I-80 to account for isolated activity.
However, latest thinking is that most locations will stay dry
overnight due to absence of low-level jet impinging into E Iowa/NW
Illinois.
Visible satellite shows a low-level cyclonic circulation within the
CU field moving into the NW forecast area. It appears the mid/upper
level cirrus streaming over the top are inhibiting more
substantial CU development. However, a few storms may form
downstream of this circulation in a localized zone of enhanced
ascent and low-level convergence. The past several runs of the
HRRR has developed a few storms mostly E/NE of the Quad Cities.
The Storm Prediction Center has a slight risk for severe storms
across Bureau and Putnam Counties which is in line with this
thinking. If a few storms form, the primary threats would be
damaging winds and large hail.
Tuesday
Shortwave or mid-level vorticity max currently analyzed over the
Central Rockies, is forecast to traverse the Plains and reach the
Upper Mississippi Valley by the late morning or early afternoon on
Tuesday. This is probably our next decent chance for scattered
showers and storms. It`s a return flow setup - there is a signal
for lower tropospheric isentropic lift and WAA, which could kick
off a broken band of convection that moves to the ENE. Models
indicate enough instability and shear for a few strong storms, but
do not see much of a potential for organized severe weather
through Tuesday afternoon. In fact, models are in pretty good
agreement breaking out the strongest convection to the north
across Minnesota and Wisconsin later Tuesday into Tuesday night on
the nose of the 850mb jet.
Heat Indices:
The highest dewpoints, in the mid 70s, are forecast to reside in the
counties along and south of highway 34 west of Galesburg, Illinois
for Tuesday afternoon. In this area, peak heat indices are forecast
in the upper 90s to around 100 F. If skies clear out for several
hours, it is likely values reach heat advisory criteria (~100 F).
Uttech
.LONG TERM...(Tuesday Night through Monday)
ISSUED AT 305 PM CDT Mon Jul 10 2017
A hot and humid air mas will continue to remain in place across
the region through the day Thursday. Wednesday looks to be the
hottest day of the period, as high temperatures will climb into
the upper 80s across the north, the middle 90s along and south of
Interstate 80. With forecast dewpoints expected to reach the lower
to middle 70s, this will produce afternoon humidity in the upper
50s and lower 60s, allowing heat index values to climb into the
upper 90s to lower 100s. A heat advisory is possible depending on
convective trends.
A better chance for showers and thunderstorms will come late
Wednesday through Thursday as an upper level shortwave and cool
front moves the middle Mississippi River Valley. Should storms
develop, an extremely moist atmosphere will allow for heavy
rainfall leading to localized flash flooding as the primary
threat. Other severe weather threats are low confidence at this
time.
Behind this front, weak high pressure will build south over Great
Lakes for Friday and Saturday, providing a temporary break from
the precipitation and higher humidity. High temperatures for
Friday are expected to climb into the lower and middle 80s, before
a return to the 90s for the weekend.
Past Sunday, models begin to diverge on possible solutions, with a
predominantly dry and high pressure filled ECMWF vs. a more potent
and shortwave aggressive GFS. Temperatures for the period are
forecast to remain in the middle to upper 80s, with dewpoints in the
lower to middle 60s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening)
ISSUED AT 754 PM CDT Mon Jul 10 2017
Evening storms have pushed south of KBRL, so low chances of
additional storms impacting TAF sites through the overnight. Fog
development is expected overnight with lingering low level
moisture and slackening winds, especially at KDBQ/KCID, where at
least 1-2SM visibilities are possible along with low stratus. A
warm front will lift north into the area Tuesday, with the best
chance of additional storms at KBRL/KMLI.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...RP Kinney
SYNOPSIS...Uttech
SHORT TERM...Uttech
LONG TERM...Speck
AVIATION...RP Kinney
Area Forecast Discussion...UPDATED
National Weather Service Gray ME
1035 PM EDT Mon Jul 10 2017
.SYNOPSIS...
A weak frontal boundary over northern New England will lift
north tonight. A cold front will approach from the northwest on
Tuesday and will push south through the region Tuesday night.
High pressure will build in from the northwest on Wednesday and
will shift east Wednesday night as low pressure moves in from
the west. Several waves of weak low pressure will pass south of
the region Thursday through Friday. A cold front will drop
southeast from Canada Saturday and will push east through the
area Saturday night.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Update...Radar to the west looks like it may have more bark than
bite at the moment. ASOS/AWOS sites across NY have shown mainly
trace to a couple hundredths precip out of the leftover
stratiform rain shield. This will continue to drift E thru the
night. Latest HRRR seems overly aggressive with QPF amounts in
the near term so far. However...a SWly LLJ is forecast to
approach late tonight/early Tue and will likely provide some
enhancement or redevelopment of rain/convection. This looks
fairly well covered with the likely PoP I have in thru mid
morning Tue across the Srn half of the forecast area.
Attention tonight will be on a well developed MCS in progress in
OH. CAPE axis trails off quickly to the E...and the strongest
part of the line...evident by lightning and cloud top temps...is
already starting to turn more Swd. The stratiform rain moving
off the NE of the complex is forecast by mesoscale models to get
into Srn zones late tonight...so I will continue to monitor its
progress. Also not seeing much in the way of marine fog at the
moment...so backed off this in the forecast. But skies are
mainly clear to the S where it would develop first...and it will
be a nice test run with new GOES-16 fog imagery.
Previous discussion...Remains of Midwest MCS will move east
tonight, bringing showers into the region later tonight. Models
have had a challenging time picking up on this feature. Have
upped pops for after midnight tonight. Prior to the clouds and
precipitation, patchy fog will form across the inland valleys.
There may be late night fog rolling in off the Gulf of Maine as
well.
Overnight lows will drop down into the upper 50s in the north,
with 60s elsewhere.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Timing and strength of the convection tomorrow will be dependent
on the amount of cloud cover and the exiting of the remains of
the MCS during the early morning hours. After plenty of
cloudiness and patchy fog early, subsidence after this passage
of the exiting complex should allow for some sunshine during the
day, allowing the atmosphere to destabilize ahead of an
approaching cold front. CAPE values increase during the day with
precipitable water values approaching 2 inches in some areas.
This may allow for a few storms to produce damaging wind gusts
and locally heavy rainfall. Freezing levels will be high so any
hail should be relatively small. SPC continues to keep the
forecast area in a marginal risk for severe weather tomorrow.
Most areas will be in the 70s for highs Tuesday, with lower 80s
over far southern areas away from the coast.
Showers and any remaining storms should diminish and weaken
around sunset tomorrow evening, with a few stray showers
continue for a good portion of the night over the far south.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
The long term outlook period will be featured with a fast
moving west to northwest flow aloft that will drive several
short waves through the flow into northern New England. This
will cause several bouts of convection, the first being Wed
night and Thu. Due to the fast flow aloft, this system will be
quick to exit, so by Thu night the system will have exited the
region. On Fri and again Sat the next few systems move rapidly
across the region spreading scattered showers back into the
region. Timing of the systems will be difficult, and combined
with some differences on model consensus, mean more of a broader
brush needed to be used for the chance of showers Fri and
through the weekend.
Temps will be comfortably mild Wed but cooler Thu and Fri. A
return to warmer temps expected for the weekend into next week
as warmer southwest flow develops.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Short Term...VFR conditions tonight. VFR Tuesday with areas of
MVFR/IFR ceilings/vsby in Thunderstorms.
Long Term...VFR Wed. Conditions becoming MVFR/IFR in showers
and scattered thunderstorms late Wed night and Thu. Conditions
improve to VFR Thu night into Fri although widely scattered
showers possible. Variable conditions to MVFR into the weekend
in scattered showers as another system approaches from the west.
&&
.MARINE...
Short Term...Seas and winds will reach SCA levels tonight over
the outer waters and all areas by Tuesday as a southerly
gradient increases.
Long Term...No flags.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory from 6 AM to 6 PM EDT Tuesday for ANZ151-
153.
Small Craft Advisory until 6 AM EDT Wednesday for ANZ150-152-
154.
&&
$$
NEAR TERM...Legro
Area Forecast Discussion
National Weather Service Lincoln IL
905 PM CDT Mon Jul 10 2017
.UPDATE...
Issued at 900 PM CDT Mon Jul 10 2017
Updated the forecast for handling convection trends tonight as
highest chances of showers/thunderstorms have shifted south of
I-74 with an MCS. Severe thunderstorm watch continues through 11
pm north of a Jacksonville to Springfield to Decatur to Tuscola
and Paris line. In addition to severe wx, heavy rains and frequent
lightning will also occur with these storms as they track se at
55 mph toward I-72. Still have unstable airmass over parts of
central IL especially where storms have not occurred yet, with
pockets of CAPE as high as 2-3k J/kg. Also have 30-40 kt bulk
shear over central and ne CWA (highest over northeast CWA). The
HRRR model shows convection shifting southeast toward I-70 toward
midnight as it weakens by that time, then convection is more
isolated over area overnight as airmass stabilizes. Muggy lows
overnight in the lower 70s look on track and no changes there.
&&
.SHORT TERM...(This evening through Tuesday)
ISSUED AT 318 PM CDT Mon Jul 10 2017
Clearing across central IL this afternoon is taking place as the
remnants of last night`s thunderstorm complex have moved east of the
area in to Indiana. Return of south-southwesterly winds have allowed
temperatures to rise into the upper 80s at most locations with a few
readings over 90 degrees, while dewpoints in the low to mid 70s are
predominant. Strong instability of 2000-3500 J/kg has built across
the area as a result, and sfc-6 km bulk shear 35-45 kt, combined
with an approaching shortwave and cold front from the north should
be able to initiate strong to potentially severe thunderstorms later
this afternoon especially in the I-74 corridor northward. This
activity should sink southward overnight, although weakening with
the upper level forcing moving east and instability decreasing. The
frontal boundary stalled out over central IL should keep a chance
for thunderstorms going over much of the area Tuesday. Southern
portions of the area may see highs over 90 with heat index around
100, but areas north of the front a less hot with upper 80s/upper
90s heat index.
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 318 PM CDT Mon Jul 10 2017
The warmest day of the week should be Wednesday as the frontal
boundary lifts well north of the area resulting in high temps in the
low to mid 90s across the area, with heat index around 100 with
perhaps a few spots of 105. Dry conditions look to occur much of the
day before chances of thunderstorms develop in the evening through
Thursday as a wave moving through the Great Lakes region pushing the
front back through central IL. SPC has a marginal risk for severe
thunderstorms from around I-74 northward with this feature. This
should also result in slightly cooler temperatures by Thursday. As
the front gradually shifts southward into the weekend, the focus for
thunderstorm chances should shift south of the area by Saturday
morning, and temperatures should remain slightly cooler with highs
mainly upper 80s into Monday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 658 PM CDT Mon Jul 10 2017
A band of thunderstorms north of a Rushville to Bloomington line
was tracking slowly south this evening and will affect the PIA and
BMI TAF sites in the immediate future with strong gusty winds and
hail. Still a question as to how far south these storms will get
later this evening as models suggest a gradual weakening of the
storms, but brief MVFR or IFR cigs possible with the stronger
cells will be possible. Outside any storms, we look for mainly
VFR conditions although there is the potential for some fog
by Tuesday morning in the areas that see the rainfall tonight.
We expect some cumulus to reform tomorrow with mainly scattered
coverage with bases of 3500 to 4500 feet expected. Winds tonight
will be light southwesterly and then west southwest winds expected
on Tuesday at 10 kts or less.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...07
SHORT TERM...37
LONG TERM...37
AVIATION...Smith
Area Forecast Discussion
National Weather Service Indianapolis IN
1149 PM EDT Mon Jul 10 2017
.UPDATE...
The AVIATION section has been updated below.
&&
.SYNOPSIS...
Issued at 327 PM EDT Mon Jul 10 2017
Upper waves and a few surface fronts will continue to bring chances
for rain to the area for much of the work week. High pressure will
bring dry conditions early next week. Hot and humid conditions
through the work week will give way to average conditions for the
weekend.
&&
.NEAR TERM.../Overnight/
Issued at 1030 PM EDT Mon Jul 10 2017
Current forecast looks on track. Storms over north central Indiana
should drop southeast over the area overnight. More storms could
also develop and central Illinois storms could hold together and
effect southwestern parts of the forecast area as well.
Previous discussion follows...
Issued at 327 PM EDT Mon Jul 10 2017
Scattered showers and thunderstorms have continued to develop in the
area with instability being fed into the area on decent 850mb winds.
The current round of showers and a few storms should move out of the
area in a couple of hours. Pop-up convection will still be possible
though as instability increases with decreasing clouds.
Late this afternoon and early this evening more convection will
develop to our north with some additional upper energy moving in and
a cold front to the north. This convection will sink south through
the area during the evening hours, before weakening as instability
wanes and with the cold front remaining to the north of the area.
Went likely PoPs across the north this evening with lower PoPs
south, diminishing to just chance or lower PoPs overnight as
convection weakens.
With the instability building upstream this afternoon, could still
see some severe storms later this afternoon and this evening. High
precipitable water values will make heavy rain/flooding an
additional threat.
The model blend looks ok for low temperatures.
&&
.SHORT TERM.../Tuesday through Thursday/
Issued at 327 PM EDT Mon Jul 10 2017
Models are close enough that the model blend initialization
was accepted for most items.
A leftover boundary from overnight convection should be across the
forecast area on Tuesday. This boundary plus still decent flow at
850mb will lead to the redevelopment of convection during the day as
instability builds once again. Will go high chance category to low
likely category PoPs across central parts of the area where boundary
is expected to be. Again heavy rain is a possibility with high
moisture content.
Chances for rain will diminish Tuesday night as the upper ridge to
our south begins to exert its influence into the area. On Wednesday,
enough of the ridge should be in control to go with a dry forecast.
However, isolated convection (with PoPs below the threshold for
mentioning) cannot be ruled out.
Rain chances return Wednesday night and Thursday as another upper
wave and surface front moves into the area.
Heat indices will be near 100 degrees at some locations by Wednesday
with high low level moisture content and the upper ridge nosing into
the area.
&&
.LONG TERM /Thursday Night through Monday/...
Issued at 309 PM EDT Mon Jul 10 2017
A gradual shift to a quieter weather pattern should take hold
through much of the extended as the upper ridge retrogrades into the
Intermountain West. This will enable the frontal boundary to finally
shift south of the Ohio Valley Friday with more widespread
convective threats ending as high pressure settles into the region
on Saturday.
Dry weather is expected to persist through much of the rest of the
period with the exception of a small threat for storms late Saturday
into Saturday night as an upper wave rapidly tracks through the
lower Great Lakes. While highs will remain in the 80s through the
extended...humidity levels will lower from the muggy conditions
expected for much of the work week.
Some hints in the long range data at the upper ridge expanding back
east into the Plains early next week...which conceivably would
thrust central Indiana back into a more active pattern with ridge
rider potential as the region sits on the edge of the heat dome.
&&
.AVIATION (Discussion for the 110600Z TAF Issiance)...
Issued at 1149 PM EDT Mon Jul 10 2017
The storms have been slow to develop and spread south this evening
compared to HRRR runs. Thus, will only go VCTS through 10z. Then,
should see more storms develop after 16z as another wave approaches
and the atmosphere becomes moderately to strongly unstable.
Good confidence that flying conditions should be mostly VFR away
from thunderstorms.
Winds will be southwest 10 knots or less but with high gusts
possible in thunderstorms.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50/MK
SHORT TERM...50
LONG TERM....Ryan
AVIATION...MK
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
949 PM EDT Mon Jul 10 2017
.UPDATE...
Issued at 949 PM EDT MON JUL 10 2017
Forecast is still in good shape with only minor adjustments needed
to make sure the near term grids were on track with current
observations. A few high clouds are continuing to move into
eastern KY from ongoing convective systems to our north and
northwest. Latest satellite trends are showing a rapid expansion
and cooling of cloud tops with the convective complex taking
shape across southern Illinois over the last hour. As this system
continues to track eastward overnight, these high clouds look like
they may be on track to move across portions of the CWA,
especially the northern half. Will continue to monitor this as it
may have an impact on temperatures in this area, however should
not pose any other threats. All updates were sent to NDFD/web,
with no major changes expected to impact the ongoing ZFP/HWO.
UPDATE Issued at 624 PM EDT MON JUL 10 2017
Forecast continues to be in good shape early this evening. Just
freshened up the near term grids for temps, dew points and winds
to make sure they were on track with current observations. No
updates to the forecast package will be needed at this time.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 415 PM EDT MON JUL 10 2017
19z sfc analysis shows high pressure off to the southeast of
Kentucky with enough of an influence to keep skies mostly sunny
today for the bulk of the area. On satellite, a small to moderate
cu field is diminishing in the face of thin and higher clouds
arriving as blow off from the storms well off to the northwest.
Temperatures are running in the mid 80s through the area as they
top out while dewpoints are in the mid to upper 60s making for a
warm and humid afternoon. Winds have been occasionally gusty out
of the southwest across the Bluegrass counties and near Lake
Cumberland.
The models remain in good agreement aloft through the short term
portion of the forecast. They all depict a strengthening ridge
through the Southern Plains and across into the Tennessee Valley.
This will help push the eastern trough out of Kentucky while
leaving the west to east track of energy impulses nearby and just
to the north of the state through Wednesday morning. Given the
good model agreement will favor a blended solution but lean
heaviest on the higher resolution HRRR and NAM12 given the small
scale nature of the features affecting the forecast.
Sensible weather will likely entail a quiet and mild night with
partly cloudy to mostly clear skies and some patchy valley fog by
dawn. Still expect a small ridge to valley temperature split
tonight on the order of 3 to 5 degrees. The caveat is that the
models are right and any convection stays well north of the area -
this will have to be monitored through thr night. Tuesday will be
a repeat of today with temperatures and humidity a notch higher.
We will even have a repeat of concerns about convection tracking
east just north of the CWA for late tonight into Tuesday. We will
need to watch out for any outflow boundaries that could trigger
some convection in the northern tip of the JKL CWA despite the
rising heights aloft. For this have carried small chance PoPs
north of Interstate 64. Tuesday night into Wednesday morning will
be quite similar to tonight but with less concern for any
convective intrusions.
Again used the CONSShort as the starting point for all the grids
with adjustments tonight and Tuesday night for a small ridge and
valley temperature distinction. Also, tweaked the blended
guidance PoP grids to allow for more of a lingering threat of
convection through the day Tuesday in the north.
.LONG TERM...(Wednesday through Monday)
Issued at 415 PM EDT MON JUL 10 2017
The models are in good agreement with a stagnant long wave
pattern to rule across the CONUS initially, with ridging in
place from the mid-Atlantic to the Desert Southwest. A little
more amplification then takes place towards the weekend, as
passing short wave energy along the Great Lakes and New England,
eventually re-establishes a trough in the eastern CONUS by the
weekend.
Heat and humidity will be the main weather story for eastern
Kentucky to start out, as highs on Wednesday look to be in the low
90s, with dew points on the rise. Capping from the nearby ridge
axis should keep a lid on convection. As the ridge breaks down
through Friday, rain and storm chances will be on the increase.
The highest chances will occur on Friday, as a cold front moves
through the area, with some modest upper level support
accompanying it.
The lingering trough and moisture still in place will allow for
chance POPs into Saturday, before some temporary dry weather
ensues Saturday evening. Another weaker cold front and modest
pocket of short wave energy will pass through the area on Sunday,
maintaining the threat of at least a few storms. Dry weather then
returns for Monday, as the trough axis works east of the area.
Highs will gradually cool to the mid 80s by Friday, thanks to
increasing cloud cover and storm chances; however, the humidity
will continue to be very high, as lows average around the 70
degree mark each night. A more noticeable change in humidity will
occur by the end of the week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 732 PM EDT MON JUL 10 2017
Expect VFR conditions through the period as sfc high pressure
will remain just to the SE. A series of passing mid level waves
just to the north of Kentucky will bring some high clouds
throughout the overnight. Otherwise, the only other concern will
be the moisture return into the south where some patchy valley fog
could develop late tonight. However, not expecting impacts to
make it into the TAF sites. Light winds are forecast out of the
southwest through the overnight and into the day tomorrow.
However, still can`t rule out a brief period of wind shear late
tonight/just before daybreak in northern KY (potentially including
KSYM) at 2k feet from the southwest at 35 kts. Have kept this in
the KSYM TAF as a result. Tomorrow, a few fair weather VFR CU
clouds may appear during the afternoon, but otherwise mostly clear
conditions and light SW winds will persist.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...GREIF
LONG TERM...GEOGERIAN
AVIATION...JMW
Area Forecast Discussion
National Weather Service Louisville KY
616 PM EDT Mon Jul 10 2017
...Updated Aviation Discussion...
.Short Term...(This evening through Tuesday night)
Issued at 245 PM EDT Mon Jul 10 2017
Surface analysis this afternoon shows low pressure over Iowa with
broad southwesterly flow ahead of it across the mid-Mississippi and
lower Ohio River Valleys. A weak surface trough associated with an
earlier complex of storms lies across central Indiana. This
southwest flow has pushed dewpoints up into the 60s to lower 70s
across southwest Indiana while temperatures are running in the mid
to upper 80s.
For the remainder of this afternoon and evening, the main forecast
challenge is whether any storms will brush parts of southern
Indiana. As of mid afternoon, recent HRRR and RAP soundings show a
mid-level capping inversion holding in place, keeping a lid on storm
development across our area. While to the north, the cap is weaker
and diurnally driven convection has blossomed across central
Indiana. Forecast soundings across southern Indiana show this cap
weakening some which might allow an isolated shower or storm to
develop through early evening, so have introduced 10-15 percent
chances across our far northern areas.
Otherwise, the remainder of the area will stay warm and dry with
breezy southwesterly flow. Readings will be slow to fall and overall
a very mild and somewhat muggy night is on tap. Plan on lows in the
lower to middle 70s, warmest in the urban centers.
For tomorrow, the latest guidance suggests outflow or effective
boundaries will be draped east/west across central Indiana, a bit
further south compared to today. With maximum daytime heating and a
passing shortwave to the north, another complex of storms may
initiate over central Indiana and drop east/southeast into parts of
southern Indiana. Will continue to show 20-30 percent chances,
mainly north of the Ohio River during the day. It will be another
seasonably warm day with highs in the upper 80s to lower 90s. Lows
Tuesday night are expected to fall into the 70s.
.Long Term...(Wednesday through Monday)
Issued at 255 PM EDT Mon Jul 10 2017
Broad upper level ridging across the southern US is likely to
suppress convection across central Kentucky and most of southern
Indiana Wednesday and Wednesday night. Plan on very warm high
temperatures in the upper 80s to lower 90s and morning lows in the
70s.
By Thursday into Friday the upper ridge breaks down somewhat and
more northwesterly flow sets up across the Great Lakes, bringing a
better chance for showers and thunderstorms across portions of the
area. A more pronounced shortwave trough is forecast to drop through
on Friday which will enhance thunderstorm coverage across the lower
Ohio Valley. A few stronger showers and storms could be possible
during this time frame.
10.12z models then show high pressure building back into the area
from the Great Lakes next weekend, bringing lower humidity with near
normal temperatures.
&&
.Aviation...(00Z TAF Issuance)
Issued at 613 PM EDT Mon Jul 10 2017
VFR conditions are expected through the TAF period. Weak LLJ will
develop overnight but should be below LLWS criteria for mention in
TAF. Southwesterly winds will pick up again tomorrow morning and
afternoon and could be gusty at times.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Short Term...ZT
Long Term...ZT
Aviation...DM
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
958 PM CDT Mon Jul 10 2017
.MESOSCALE DISCUSSION...
958 PM CDT
Isolated strong/severe thunderstorms are currently approaching
the southwest Chicago suburbs at 945 pm. This small cluster of
storms may be somewhat elevated, within a region of warm/moist
isentropically forced ascent provided by 25-30 kt westerly low
level jet. SPC RAP mesoanalysis depicts roughly 2000 J/kg MUCAPE
axis across this region, and 35-40 kts of effective bulk shear,
sufficient for producing organized updrafts. Trends over the past
hour or so have indicated some healthy cores aloft at times with
this cluster of storms (ping pong ball size hail in Peru IL), and
currently noting wind signature with 45+ kt inbounds per MDW TDWR
and LOT 88-D data. Magnitude of wind at the surface is of some
question as these storms may be rooted slightly above the boundary
layer, though warm/moist low levels and analyzed DCAPE pocket of
1000-1500 J/kg in ahead of storms suggests that some severe
threat persists. Based on these trends have elected to hold onto
current watch counties at this time. Overall though, will likely
see a gradual decrease in intensity with time further east.
Ratzer
&&
.SHORT TERM...
200 PM CDT
Through tonight...
Meso discussion to follow closer to initiation...
We get into lighter north winds once the surface low spreads
along the southern CWA tonight. With some clearing expected and no
real dry advection occurring, it appears some fog and or stratus
will form overnight into the early morning hours on Tuesday. Will
need to hang onto some pops overnight as the boundary does not
clear the area and some weak energy slides southeast across it,
though most of the activity will shift south before daybreak.
MTF/KMD
&&
.LONG TERM...
224 PM CDT
Tuesday night through Monday...
Active weather looks to continue into Thursday as a low amplitude
upper flow remains in place with a number of waves rippling through
it. A surface frontal boundary will be just south of the area
Tuesday morning with high pressure settling in early but then
shifting to the east into the afternoon. Low pressure will be across
the plains with a southerly low level flow trying to become re-
established across the area. Warm and humid conditions will
continue. Upper level energy which is currently across the northern
Rockies and is helping to break down the ridging over the plains
will cross the local area later Tuesday. This will likely generate
scattered showers and thunderstorms which will work east across the
area through the evening. Instability is not notably strong and
forecast soundings do show some inhibition. Severe threat is on the
low end but cannot rule out something isolated. Best chances will be
across the south closer to the boundary where instability will also
be greater.
Surface low pressure will better organize across the northern plains
Wednesday. The upper flow will become a bit more cyclonic with
another shortwave expected to cross the region. The surface low will
move eastward across central Lake Michigan and work in conjunction
with the upper flow to generate convection. Much stronger low level
southwesterly flow will have developed over the area by Wednesday
afternoon resulting in a push of warmer and much more unstable air.
This should result in quite a bit of instability as well as
precipitable water values pushing 2 inches. The combination of
instability and forcing point to a decent severe potential. Tough to
pin down any specifics at this time frame given several rounds of
convection locally and nearby between now and then but will need to
keep an eye on a potentially greater severe threat. Also have some
initial heavy rain concerns as the surface low will pass north of
the area allowing its attendant surface boundary to stretch out
parallel to the westerly mean flow which may lead to training
storms. Temp-wise, should see highs in the lower 90s for most areas
combining with mid 70s dewpoints leading to heat index values in the
97 to 103 or so range.
The boundary will hang up to the south on Thursday with the active
upper flow continuing so storm chances will linger, especially south
where instability will likely be greatest. Should see a range in
temps as well with highs near 80 north and in the upper 80s south.
The upper flow buckles to the east into Friday with broad ringing
developing to the west. Surface high pressure is expected to settle
into the local area leading to a quiet period and a modest break in
the warm and humid conditions. The northwest flow aloft may become
somewhat active as we have seen on several occasions in recent weeks
so may see several windows for isolated to scattered showers and
storms over the weekend.
MDB
&&
.AVIATION...
For the 00Z TAFs...
638 pm...Main forecast concern this period is potential for low
clouds and fog overnight into Tuesday morning.
A boundary is moving south toward mdw and gyy and will shift winds
northerly shortly. Winds will eventually become light northeast
this evening and then possibly light/variable overnight into
Tuesday morning. A weak gradient will likely lead to light east/
northeast winds for the Chicago terminals Tuesday with the
potential for a lake breeze. Further west...including at rfd winds
may remain light for much of the day with a west/southwest
direction by mid/late afternoon.
Other than a few showers in the next hour or two...the rest of
tonight into Tuesday afternoon looks dry for the terminals.
Additional thunderstorm development is possible Tuesday afternoon
into Tuesday evening...likely well south of the terminals but
confidence decreases by late Tuesday night with the possibility of
thunderstorms developing over the terminals by early Wednesday
morning...but this would be beyond the end of this forecast.
With the light winds and moist low levels...some fog is expected
overnight and as a weak surface low moves across the area...some
low cloud development is also expected. Confidence on specifics is
still rather low but some period of ifr cigs/vis are possible
overnight through sunrise. cms
&&
.MARINE...
224 PM CDT
Low pressure will move from eastern Iowa to southern Lake Michigan
this evening before weakening as it continues east. The associated
frontal boundary will push south of the lake this evening before re-
developing across northern Lake Michigan Tuesday night as low
pressure moves across central and northern Wisconsin. This low will
push the front back south down the lake later Wednesday into
Thursday. High pressure will spread across the lake Friday keeping
northerly winds in place. An active pattern returns for the weekend
bringing a series of lows across the lake which will result in winds
oscillating between northerly and southerly with the passage of
associated frontal boundaries.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
National Weather Service Lubbock TX
629 PM CDT Mon Jul 10 2017
.AVIATION...
VFR conditions continue through this forecast. Low level jet
intensifies overnight enough to add LLWS to KCDS TAF. Otherwise,
gusty south winds on tap for Tuesday afternoon.
&&
.PREV DISCUSSION... /issued 227 PM CDT Mon Jul 10 2017/
DISCUSSION...
Anti-cyclonic motion was quite evident on visible satellite today.
RAP analysis showed our forecast area to barely be under the
southeast edge of the high. Low and mid-level dry air was
encroaching from the east via water vapor imagery. Near the state
line, a cu field was developing, as well as across the TX Panhandle.
Though one or two random showers may pop up across the forecast area
this afternoon or evening, the vast majority will stay dry.
Models show a wobbling ridge starting Tuesday, and that trend
continues for most of the week. We never end up squarely under the
high, which means highs will only reach a few degrees above normal,
at the most. A weak wave will pass westward to our south in Mexico
over the course of Wednesday and Thursday. Models show the moisture
with this wave making it as far north as the southern Permian Basin,
but the strength of the ridge will be too much to allow it to pass
northward into our area. Temperatures on Tuesday and Wednesday
should be fairly similar to Monday, varying by a degree or so, as
thickness will be roughly the same. By Thursday, thicknesses fall,
so Thursday temps should be slightly cooler.
For the weekend, a slight disturbance may develop in the flow about
the high over Colorado. May is the word of focus as the models have
yet to agree on this feature. Moisture return by the weekend looks
to be meager to the slight end of modest at best. We also return to
northeast flow, which tends to hose our thunderstorm chances. With
all of these negating factors, have chosen to keep PoPs out of this
forecast package for the weekend. This will certainly be something
to watch over the coming days as models hone in on the finer
details.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
74/74/24
Area Forecast Discussion
National Weather Service Spokane WA
445 PM PDT Mon Jul 10 2017
.SYNOPSIS...
Breezy and dry conditions will raise wildfire concerns in central
Washington through this evening. There will be a slight chance of
thunderstorms along the Canadian border through the evening as
well. Winds will decrease on Tuesday with near average
temperatures. Look for another round of hot and dry weather for
late next week and the weekend.
&&
.DISCUSSION...
Tonight: Scattered showers and thunderstorms are expected to
develop in the 3 PM to 5 PM time frame over the high terrain
Ferry, Stevens, Pend Orielle, Boundary, and northern Okanogan
counties. Growing cumulus over the mountains suggest that our
convective temperature has been reached. RAP analysis as of 2 PM,
suggests 400 J/KG to as much as 1000 J/KG of surface based CAPE
along the Canadian border in the vicinity of a surface low
pressure trough. Shear profiles are weak. Cells will likely form
over mountain ridges and weaken as they move off the high terrain
with a cell motion of northeast at 15 to 20 mph. Brief heavy rain,
gusts up to 30 mph, and cloud to ground lightning will accompany
the strongest cells through 9 PM. There may be enough mid-level
instability through the night to produce ongoing, high-based
showers into the early morning hours around Laurier, Northport,
Porthill, and Bonners Ferry.
Gusty west or northwest winds will raise wildfire concerns for the
remainder of the afternoon into this evening along the East Slopes
of the Cascades, the Waterville Plateau, and the Moses Lake area.
On-shore flow will produce our typical late day "gap winds" as
marine air spills over the Cascades. Gusts as high as 25 to 30 mph
are expected around Wenatchee, Chelan, Vantage and portions of the
Waterville Plateau through mid evening. Further east, winds in the
Spokane, Coeur d`Alene, Pullman, and Colville areas will subside
prior at or around sunset.
Tuesday and Wednesday: The weather Tuesday and Wednesday will be
relatively quiet and dry. Today`s weak shortwave will exit the
region by Tuesday morning leaving the region in a dry westerly
flow for Tuesday afternoon. High temperatures on Tuesday will be
about average with most lowland areas in the 80s. Readings will
rebound into the mid 80s and low 90s on Wednesday as a hot high
pressure ridge rebounds over the Northern Rockies. /GKoch
Thursday through Monday: Synoptic weather pattern shows a strong
upper level ridge near the 4 corners region and a low pressure
system in the gulf of Alaska. This will provide southwest flow
into our region and keep us quite warm. the 12Z model runs have
come in similar to the 00Z runs of yesterday evening, which is
trending quite a bit cooler than what was forecasted in
yesterday`s afternoon forecast package. Have continued the trend
of lowering daytime high temperatures...about another 2-5 degrees
cooler for Fri-Sun. Around 100 is possible for the deep Basin and
Snake river valley with 90s for all other valley locations. Mostly
clear skies are expected through the week. Saturday we may start
to see an increase in cirrus across extreme eastern WA and north
ID, but our forecast will remain dry. /Nisbet
&&
.AVIATION...
00Z TAFS: Breezy west winds will be the main focus for aviation.
Wenatchee will experience the strongest winds but occasional
gusts near 20 mph could impact all other terminals through 03z.
Winds slacken this evening then look to increase slightly again
overnight with the passage of a cold front. Look for a general
decreasing trend in winds Tue afternoon with most terminals
decreasing toward 10kts or less after 21z.
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 58 82 58 87 60 90 / 0 0 0 0 0 0
Coeur d`Alene 55 81 54 85 55 89 / 0 0 0 0 0 0
Pullman 54 81 48 86 56 89 / 0 0 0 0 0 0
Lewiston 60 88 59 94 63 97 / 0 0 0 0 0 0
Colville 54 86 53 90 53 91 / 20 0 0 0 0 0
Sandpoint 50 79 48 83 49 87 / 10 0 0 0 0 0
Kellogg 52 79 52 84 53 89 / 0 0 0 0 0 0
Moses Lake 55 88 56 92 57 94 / 0 0 0 0 0 0
Wenatchee 60 88 62 91 61 91 / 0 0 0 0 0 0
Omak 58 89 57 91 57 93 / 10 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Red Flag Warning until 9 PM PDT this evening for East Washington
Central Cascade Valleys (Zone 677)-East Washington Northern
Columbia Basin (Zone 673).
&&
$$
Area Forecast Discussion
National Weather Service Raleigh NC
941 PM EDT Mon Jul 10 2017
.SYNOPSIS...
A positively-tilted mid level shear axis stretching from the eastern
Carolinas to the lower MS Valley will become increasingly diffuse
through mid-week, as a sup-tropical ridge centered over the central
N. Atlantic expands west across the southeastern U.S. At the
surface, a trough will remain anchored in the lee of the central and
southern Appalachians.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 940 PM EDT Monday...
Earlier multi-cellular convection has propagated (along outflow) to
the southeast of the RAH CWFA, with now just a lingering canopy of
convective mid-high level blow-off streaming northeast across the
eastern half of NC, including all but the RAH nw Piedmont. There
does remain a lingering axis of weak instability centered over the
Piedmont, which will gradually lessen with further nocturnal
cooling; and satellite data indicates cumulus continues to bubble
from the SC upstate to the nw NC Piedmont, within/invof an
Appalachian-lee trough.
A few showers have tried to percolate within that area of cumulus in
recent hours, including over Durham and nrn Guilford counties within
the last couple of hours. However, the associated shallow cores
quickly collapsed (within a few volume scans of initial reflectivity
development), presumably as a result of tropospheric-deep dryness -
characterized by precipitable water values of a mere half to three
quarters of an inch centered over wrn NC- sampled by both the RNK
RAOB and Blended Total Precipitable Water data. As such, a dry night
is expected, aside from perhaps a very brief shower over the
Piedmont that may yet briefly percolate in the next few hours,
before instability further wanes.
Relatively abundant low level moisture, characterized by surface
dewpoints in the 70s over all but the nw Piedmont, where 60s reside,
will probably result in patches to areas of low stratus late tonight-
early Tue, centered from the Sandhills to the ne Piedmont. This idea
is supported by a common signal in both SREF and HRRR model data.
Persistence lows in the upper 60s to middle 70s.
&&
.SHORT TERM /Tuesday and Tuesday night/...
As of 200 PM Monday...
The big story for Tuesday will be the increase in temperatures as
the subtropical ridge takes over and thickness values climb to near
1440 meters. The surface frontal boundary will still be draped over
our southern tier and this will once again be the most likely area
for diurnal convection. An isolated severe thunderstorm cant be
ruled out in these areas but most of the activity should remain sub-
severe and as a result the SPC has the area in general thunder at
this time. With highs in the low 90s and some dewpoints in the low
70s heat indices should remain in the upper 90s but a few 100 degree
readings are possible. Low temperatures in the low 70s.
&&
.LONG TERM /Wednesday through Monday/...
As of 130 PM Monday...
The weather pattern for Wednesday and Thursday will feature high
pressure extending across the Carolinas from the western Atlantic
with ridging aloft. With limited forcing across our CWA, most of the
WDLY sct tstm activity should develop on the sea breeze to our east
and/or higher terrain to our west. But nevertheless, we can`t rule
out isolated showers/tstms across our area as outflows move into our
area. PoPs at or below climo during this time. The main story will
be the heat and humidity, with heat index values approaching 100
both afternoons.
On Friday, rain chances will increase as a short wave moves across
the Great Lakes and Ohio Valley region then across the Mid Atlantic
region by afternoon. Additional cloud cover should keep temps a few
degrees cooler than Wed/Thu, but with no substantial airmass change,
readings once again should climb into the 90s.
Over the weekend, another short wave within the longwave trough
developing over the East, will approach from the NW and it`s
attendant sfc cold front will subsequently stall out over the
Carolinas as the southern extent of the midlevel trough weakens and
its axis stalls over the East. At this point it appears that rain
chances will be at or above climo over the weekend and perhaps into
Monday. Clouds and rain will keep temps closer to normal.
&&
.AVIATION /00Z Tuesday through Saturday/...
As of 840 PM EDT Monday...
24 hour TAF period: VFR conditions are expected to continue this
evening. Some patchy sub-VFR conditions will be possible at
KFAY/KRWI (and possibly even KRDU) during the early morning hours of
Tuesday. Generally light and variable winds tonight will become
south to southwesterly Tuesday afternoon in the 6 to 10 kt range.
Isolated to widely scattered showers and storms are expected Tuesday
afternoon, with the greatest coverage expected across the
southeastern/far eastern reaches of central NC. Thus, have included
a prob30 at KFAY and KRWI for storms from 18Z Tuesday onward.
Outlook: Scattered convection across the southern counties will be
possible for the next several days but otherwise VFR conditions
should be prevalent through much of the period.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...Ellis
LONG TERM...np
AVIATION...BSD/Ellis
Area Forecast Discussion
National Weather Service Riverton WY
330 PM MDT Mon Jul 10 2017
.SHORT TERM...(Tonight through Thursday)
Issued at 130 MDT Mon Jul 10 2017
Afternoon convection will continue into the evening hours
tonight, with some strong storms possible, particularly across
northern WY and Sweetwater County. Wind gusts over 40 mph are
certainly possible along with small hail and brief heavy rain.
In advance of a shortwave trough moving through MT, Early
afternoon SB CAPE values across NW WY were above 2000 J/kg and LIs
in the -2 to -4C range. Interesting that the HRRR continues to
keep convection to the north in MT though. Thunderstorms and
showers should diminish by midnight as a weak dry slot pushes
through central WY from the west. A weak boundary appears to set
up tonight across the WY/MT border, and will continue Tuesday for
some weak showers and storms before pushing southward east of the
divide Tuesday evening. The mid-level moisture and instability
with the high pressure should remain more south into CO as well
for only a slight chance of convection across the southern half of
Sweetwater County.Some west wind with gusts over 20 mph should
push into west central WY Tuesday afternoon for mostly clear
skies. Wednesday should be the least active day this weak as drier
air with weak flow moves in from the west under a flattening ridge.
Still above normal temperatures and mostly clear skies. Thursday
continues the Wednesday trend with weak northerly flow, and only a
slight chance of mountain thunderstorms over southwest WY.
.LONG TERM...(Thursday night through Monday)
Issued at 130 MDT Mon Jul 10 2017
Persistence appears to be the pattern for the medium range
forecast today, as the upper level ridge axis over the Rockies
remains fairly stationary through the period. GFS and ECMWF are
suggesting a slight strengthening and northwest movement of the
upper level high over the southern portion of the UT/CO border.
Friday and Monday look to be the more active of the four days for
convective action during the afternoon and evenings with some
instability impacting the area, although mainly diurnal terrain-
initiated convection should dominate. Temperatures will continue
to be above normal with 90+F and around 60F east of the divide for
afternoon highs and morning lows. Winds appear to be fairly
light, although thunderstorm outflow is always a concern. Models
are suggesting some easterly flow from the plains at times for the
eastern portions of the forecast area. A slight transition to a
monsoon type flow from the Southwest US may develop Tuesday into
Wednesday next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 330 MDT Mon Jul 10 2017
Convection has developed across the area, and is expected to
continue through at least 03Z/Tue, as a shortwave trough moves
through MT, and the northern edge of a monsoon like patter affects
the southern part of the state. Wind gusts over 40 kts along with
small hail and brief heavy rain are possible with the storms. VFR
generally expected with MVFR possible under and around storms.
Strong storms could develop across the northern part of the area due
to more favorable conditions. Some showers could remain until just
after 06Z/Tue, with clearing expected overnight. Tuesday will see
breezy westerly flow push into the central area with gusts over 20
kts. Some showers and thunderstorms are possible along both the
northern and southern borders of the state. After 00z/Wed, a
northerly push is expected east of the divide with a slight chance
of showers.
&&
.FIRE WEATHER...
Issued AT 130 MDT Mon Jul 10 2017
Isolated to scattered thunderstorms will continue this afternoon
into the evening hours, and bring gusty outflow over 40 mph as
well as some small hail and brief heavy rain. The storminess
should continue through 9 pm, moving from west to east. The storms
may be stronger across northern WY then produce gusty NW wind
around Buffalo this evening. Tuesday through Thursday look to be
less active across the area in terms of showers and thunderstorms.
Conditions should dry out gradually as well with RHs dipping down
to the 13-16% range in some of the lower elevations. Tuesday looks
to be the breeziest of the three days as well with a westerly flow
with gusts over 20 mph pushing in from the west. A somewhat
moister boundary from MT will push down wast of the divide on
Wednesday. Thursday will continue with light flow and drying.
Temperatures are all expected to be above normal for the next few
days.
&&
.RIW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...McDonald
LONG TERM...McDonald
AVIATION...McDonald
FIRE WEATHER...McDonald
Area Forecast Discussion
National Weather Service Tucson AZ
226 PM MST Mon Jul 10 2017
.SYNOPSIS...Plenty of moisture for afternoon and evening
thunderstorms with a favorable pattern for storm development most
days this week. Some storms this afternoon and evening will
generate heavy rainfall, especially in the mountains. The increase
in moisture and rain chances will also result in more seasonable
temperature readings.
&&
.DISCUSSION...Deep moisture is in place with precipitable water
values around 1.4 to 1.5 inches on sounding and satellite
estimate data. Our weak flow this morning is giving way to a very
modest northerly flow which has enhanced outflow from the rim a
little more than earlier HRRR resolutions suggested. The main
concern is still heavy rain, especially in the mountains. FFW
earlier for Mt Graham and portions of the Frye fire area. Valleys
will still be at the mercy of outflows, and those outflows are
doing pretty well with several cell mergers and the Rim activity.
Good potential of better shower and thunderstorm coverage this
evening and even overnight as outflows try to merge over Pima and
Pinal counties. A strong complex developing in northern Sonora
just south of Nogales may end up playing a big part in that.
Beyond today and tonight, we will maintain enough moisture and a
favorable pattern for daily thunderstorm chances. Nothing special,
with mountains favored until later in the week when we will watch
an easterly wave currently developing on the southeast periphery
of the high move across central to northern Mexico. There`s going
to be a busy day or two as a result but timing is difficult. At
this point Wednesday night and Saturday night into Sunday are
looking interesting.
&&
.AVIATION...Valid thru 12/00Z.
Isolated to scattered -TSRA/-SHRA mainly E and S of KTUS this into
this evening with SCT-BKN clouds 7-11k ft AGL. MVFR conditions and
gusts near 40 kts possible with the stronger TSRA. Otherwise, VFR
conditions with SFC wind wly/nwly 8-14 kts. A few SHRA may persist
overnight with SCT SHRA/TSRA occurring again Tuesday
afternoon. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Scattered mainly afternoon and evening thunderstorms
will prevail this week, with better chances in the mountains. Expect
brief strong, gusty and erratic winds due to thunderstorm outflows.
Otherwise, 20-foot winds will generally be terrain driven at less
than 15 mph. Occasional gusts will occur during the afternoon hours
due to daytime heating. High temperatures will be close to seasonal
normals this week and increased moisture will help moderate relative
humidity levels.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Meyer/French
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion
National Weather Service Las Vegas NV
815 PM PDT Mon Jul 10 2017
.SYNOPSIS...Increasingly dry southwest flow will reduce thunderstorm
chances across the region Tuesday and Wednesday. A slight warming
trend is possible through the end of the week before another
possible push of monsoonal moisture surges northwest back over the
area, bringing with it another slight cool down and more
precipitation chances for the weekend.
&&
.NEAR TERM...800 PM to 200 AM.
OUTLOOK: Widespread thunderstorm activity is expected to diminish
with the loss of daytime heating this afternoon. The two main threat
areas are across southeast San Bernardino/southern Mohave counties
as well as southern Nye, Lincoln, and northeast Clark counties over
the next few hours. The overall threat of flash flooding is becoming
more isolated this evening, with outflow winds and lightning
becoming the main threats.
CURRENT ANALYSIS: Moderate-grade monsoon moisture remains across
nearly the entire forecast area this evening with 850-500mb mixing
ratios of 6-8 g/kg exist in all but San Bernardino County. Across
southern Nevada and northwest Arizona MLCAPE of 500+ J/kg exists,
with local maxima over Lincoln, southern Nye and northeast Clark
counties. Convection has worked over much of the atmosphere across
much of Clark and northern and central Mohave counties, resulting in
downward trends in those areas. The best lift is located over the
NNSS and is progressing east. This is where the bulk of the activity
is likely over the next 1-2 hours as the region of lift tracks into
Lincoln County. To the south, outflow was pushing south in a line
extending from Baker to Wikieup. Storms are primarily discrete,
forming small clusters on outflow boundaries. Storm motion has
increased to around 10-15 mph, which has resulted in a decreased
flash flood threat. DCAPE values are generally less than 1000 j/kg
leading to a primarily sub-severe wind threat, with a local maxima
near Lake Havasu City. If storms make it that far south (which is a
low probability outcome), they have a higher potential of producing
isolated severe wind gusts. -Wolcott-
&&
.SHORT TERM...through Wednesday morning.
An active afternoon for thunderstorms is underway over the forecast
area but a drying trend will lead to less thunderstorm coverage the
next couple days. The most extensive thunderstorms were developing
over central and northern Mohave County on the western periphery of
a well defined circulation lifting up over northwest Arizona.
Another hot spot is the McCullough range south of Las Vegas where
cells were developing and expanding then moving north into the
southern and southeast Vegas Valley. Also, thunderstorms were
developing under a deformation axis extending across Inyo county and
central Nevada, along with a jet entrance region over eastern
Nevada. These will be the areas to watch through the afternoon and
early evening. Storm movement will be generally toward the north-
northeast around 10 mph. There will be the potential for heavy rain
and possible flash flooding with a few storms. The HRRR indicates
thunderstorms will continue across Lincoln and northeast Mohave
Counties until a little after midnight.
A drying trend will develop Tuesday due to a broad weak trough
dropping down over northern California and northwest Nevada. This
will lead to increasingly dry southwest flow going into Wednesday.
Thunderstorm coverage will diminish Tuesday but isolated storms will
still be possible over the southern Sierra, Spring Mountains and
parts of Lincoln and Mohave counties. Temperatures will trend upward
slightly as dewpoints and cloud cover decrease.
&&
.LONG TERM...Wednesday through Monday.
Mid level high center will be suppressed to our southeast Wednesday
allowing for slightly drier air associated with Pacific Northwest
trough to penetrate in southeast California and southern Nevada.
This will bring a decrease in thunderstorm coverage to that area by
Thursday and Friday. Moisture never really gets scoured out of
Mohave County with low grade monsoon persisting with isolated
thunderstorms possible each day primarily over the higher terrain.
With the lack of significant low level moisture in place gusty winds
and lightning will be of concern.
Easterly flow increases across Arizona and into southern California
over the weekend as mid level high center circulation becomes
established over the Great Basin. Position of the high initially
looks to keep deeper monsoon moisture confined to southern Mohave
County, lower Colorado River valley and southern San Bernardino
County Saturday and Sunday. Models have been consistent showing a
well defined easterly wave moving across northwest Mexico over the
weekend. Outflow pushing north from large thunderstorm complexes
could quickly change the atmospheric parameters so something to keep
an eye on. Otherwise, as inverted trough pushes east off the Baja
Peninsula early next week a more favorable southeast flow develops
with moisture surging north in the rest of the Mojave Desert and
southern Great Basin.
&&
.AVIATION...For McCarran...Showers and thunderstorms have developed
south of Las Vegas and will continue to push into the southern
portions of the valley this afternoon. Some of these storms may
cause sudden and gusty wind shifts associated with thunderstorm
outflow. Will continue watching storm development and motion through
the afternoon and evening. As storms settle down later this evening,
winds will favor a southwest/west direction with speeds around 10-15
kts. Winds will become light and variable overnight and will begin
to favor an easterly component after sunrise. Otherwise, VFR
scattered clouds are expected through evening and overnight.
For the rest of southern Nevada, northwest Arizona and southeast
California...South to southwest winds around 10-20 kts are expected
to develop this afternoon and continue into the evening across the
Mojave Desert and southern Great Basin sites. There will be a lull
in the wind overnight before setting up again tomorrow in the late
morning/early afternoon. A few areas of thunderstorms are expected
this afternoon and evening, mainly across Clark, Mohave, Lincoln and
Inyo Counties. Thunderstorms may produce strong wind gust and sudden
changes in wind direction. Thunderstorm activity should begin to
decrease later this evening. Skies will be mostly scattered to
broken this evening, however VFR conditions are expected.
&&
.HYDROLOGY...Not at the magnitude of runoff in late June, but
creeks, streams and rivers in northern Inyo County continue to run
higher than normal and fast from snow melt. Some road closures
continue in the area. Bishop Creek Bypass and Big Pine Creek Bypass
continue to be utilized to minimize flows through Bishop and Big
Pine. Over the past week, streamflows on Independence Creek have
stabilized with peak flows comparable to 1969 and 1983. Isolated
thunderstorms over the mountains may aid snowmelt runoff and keep
some drainages elevated over the coming days as well. Remember,
never drive through flooded roadways or around barricades. Also,
pastureland or farmland adjacent to creeks, streams or rivers could
experience areas of standing water.
&&
.FIRE WEATHER...Isolated to scattered thunderstorms with the
potential for wetting rains will persist into the early evening then
dissipate late this evening and overnight. Humidity values and
thunderstorm coverage will decrease Tuesday and Wednesday as a dry
southwest flow aloft begins to develop over the region.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
SHORT TERM...Adair
LONG TERM/HYDROLOGY....Pierce
AVIATION...Boothe
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