Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/08/17
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
601 PM MDT Fri Jul 7 2017
.AVIATION...
00Z TAF CYCLE
Isolated convection will continue through 08/05Z. Favored area for
storms will be across nern NM where a more organized band will drop
south out of sern CO. Stronger storms will result in heavy rain/small
hail and MVFR cigs/vsbys. Storm coverage will increase somewhat
Saturday afternoon as moisture continues to seep in from the south
overnight.
33
&&
.PREV DISCUSSION...315 PM MDT Fri Jul 7 2017...
.SYNOPSIS...
Dry thunderstorms will be more popular west of the central valley
with better chances for wetting precipitation over the north central
mountains today. The upper high over the Four Corners will weaken and
begin to move east into the front range of the Rockies this weekend.
This will allow increased coverage of wetting precipitation over New
Mexico heading into next week. Temperatures will remain fairly
consistent with daytime highs near average, and overnight lows a bit
over average.
&&
.DISCUSSION...
Convective activity fired up a little earlier this morning over the
Sangre`s before noon, and convection is now active over the north-
central and western high terrain. Dropped PoPs a bit over the Gila
today to reflect drier mid-level air aloft there, reflected in the
GOES-16 low and mid-level WV imagery. The crop of cu there is also
quite pitiful for this time of afternoon. The NAM12 and HRRR latched
onto lingering convection into the NE plains overnight, and thus
increased PoPs there accordingly given lastnight`s activity.
Overall, no major changes to the forecast with this run. Models
continue to show the Four Corners high flattening as a trough moves
into the Pacific NW this weekend. Models are hinting at the chance
for isolated svr storms over the NE Saturday with SE sfc flow
meeting NW flow aloft. Gusty outflow winds and hail would be the main
threat.
The high continues to weaken and flatten into next week as it also
moves east, allowing increased monsoonal like flow to penetrate into
New Mexico. Subsequently, the coverage of precipitation looks to
increase, favoring mainly the higher terrain over western NM, for
early to middle of next week. More wetting precipitation can be
expected with next week`s storm activity compared with what we have
been seeing recently. The high begins to build again and move towards
the Great Basin by the end of next week, reducing precipitation
coverage a bit.
24
&&
.FIRE WEATHER...
Models have provided little change in the overall weather theme the
next several days. Upper high will meander around the greater Four
Corners area. Drifting somewhat to the northwest of the four corners
this weekend but then drifting back to the east during the earlier
half of next week due to a Pacific trough across the NW third of the
nation. Either way, moisture currently trapped within the high will
only increase and especially favor western and central areas in terms
of storm coverage. Wetting rain footprints associated with the cells
will also increase as the days progress. Gusty outflows and strong
downdrafts will be a concern during the next few days. Some of the
outflows will be able to travel over 50 miles.
Models are showing a persistent breezy SSW wind pattern across the
eastern plains as next week progresses. This is a known breezy
pattern and sometimes the models under forecast the speeds. Decided
to hedge speeds above blended model guidance by 2 to 3 mph across
the eastern third to account for this possibility.
50
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
24
Area Forecast Discussion
National Weather Service Wakefield VA
1039 PM EDT Fri Jul 7 2017
.SYNOPSIS...
A weak cold front will push off the coast this evening. Another
cold front will approach the Mid Atlantic from the northwest
late tonight into Saturday and slide through the region Saturday
evening. This front settles across the Carolinas Sunday as high
pressure builds in from the northwest.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Initial complex of storms that moved across the Ohio Valley
weakened north of the area with one shower making it into
Dorchester county with a nice outflow boundary showing on the
DOX radar. Outside of that shower, the region is very quiet
weatherwise with clear sky and light wind. That should continue
through most of the night, but will need to monitor the complex
of storms back in WV/KY that could impact the region toward
morning. However, like the first wave, this complex is already
showing signs of weakening and with the drier air that is in
place east of the mountains, seeing dew points in the low 60s
along the I-81 corridor, think this complex will receive the
same treatment as the first keeping most areas dry over night.
Temperatures in the lower to mid 70s should prevail overnight,
except for in the Piedmont where readings could drop into the
upper 60s.
Prev discussion...
Current wv imagery depicts an upper trough
digging across the Great Lakes with a ridge anchored over the
subtropical wrn Atlantic resulting in SW flow aloft across the
Mid-Atlantic. At the surface, a weakening cold front (mainly
comprised of a brief wind shift and a dewpoint gradient) is
pushing across the area and triggering iso showers/tstms across
the Peninsula and Tidewater as of 330pm. A few additional
showers/tstms may develop across NE NC but otherwise mainly dry
conditions are expected across the area through 6 pm.
Temperatures this aftn are generally in the mid/upper 80s, with
a few low 90s in far SE VA/NE NC and across the far NW piedmont
within the slightly drier airmass behind the front with better
mixing.
An MCS is currently racing sewd across the Ohio Valley. The
main impact from this system is expected to remain W of the
mountains in the presence of higher instability. However, the
past few runs of the HRRR suggest some convection could develop
along outflow to the lee of the mountains across nrn VA through
the Delmarva, so the nrn tier counties will have a 20-30% chc
for tstms this evening. 08/18z RAP suggests 0-6km shear
increases to ~35kt with steepening 850- 700mb lapse rates, so
any tstms could contain strong wind gusts.
The initial front will push offshore and wash-out overnight,
with the low-level flow becoming SW once again, and sky cover
becoming partly cloudy to mostly clear. Continued warm and humid
tonight with lows ranging from the upper 60s/around 70 W to the
low/mid 70s at the coast.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
A cold front over the Midwest this aftn will approach
from the NW Saturday. Downslope flow should prevail once again with
high temperatures rising into the low/mid 90s. Dewpoints should be
lower inland, low/mid 60s, but remain in the low 70s for inland SE
VA/NE NC where heat indices will reach around 100, and perhaps the
low 100s near the Albemarle Sound with locally higher dewpoints.
Downslpe flow will initially suppress convection through much of the
day Saturday. However, the RRQ of a 100kt jet over New England will
arrive later in the aftn along with a mid-level shortwave trough and
this should help trigger convection. PoPs range from 20-30% from the
Piedmont to the MD Ern Shore, mainly after 18z, with 30-50% across
SE VA/NE NC during the late aftn/evening in vicinity of higher
surface dewpoints and higher low-level theta-e. 0-6km bulk shear
reaches 30-40kt with the best instability, which could result in
some organized line segment or multicells capable of producing
strong wind gusts.
The upper trough spreads across the Ern Conus by Saturday
night/Sunday. There will be an airmass change behind the front
with drier air filtering in from the NW late Saturday night.
Lows Saturday night range from the low 60s NW to the low 70s SE,
followed by highs Sunday of 80-85F E, and mid/upper 80s well
inland, with aftn dewpoints ranging from the upper 50s NW to the
upper 60s SE. A 30-50% chc of showers/tstms will linger through
the early overnight hours across NE NC/far SE VA as the front
slowly pushes through, with a ~20% chc of sea-breeze convection
Sunday aftn for NE NC, but otherwise dry across the region
Saturday night/Sunday.
The subtropical ridge will gradually rebound Sunday night into
Monday as the trough lifts to the NE. The low-level flow will
gradually become southerly by Monday. Lows Sunday night range
from the mid 60s to around 70, followed by highs Monday in the
upper 80s to around 90, with dewpoints in the 60s. The current
forecast has PoPs below 15%, but very iso sea/bay breeze
convection is possible Monday aftn.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Washed out frontal boundary lifts north through the region
Monday night into Tuesday. Meanwhile, persistent upper level
troughing over the nern half of the country and high pressure
off the Southeast Coast will allow pulses of shortwave
energy/moisture to cross the area at times throughout the long
term forecast. Most recent trend is to dry things out more even
though afternoon/evening thunderstorms may be possible.
Temperatures will be above normal throughout the long term
period.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions across the CWA with only a few clouds. Some
showers and thunderstorms moving across Northern Va/DC area and
may affect the Maryland Eastern Shore by 01-02Z. Do not expect
this to be widespread and should be out of the region in a short
period of time. Another complex of thunderstorms approaching WV
at this time but models show it falling apart before reaching
our area. Winds will be mostly SW tonight less than 10 kts.
There could be some early morning fog/haze but should not be
significant.
A cold front pushes across the region Saturday, followed by
high pressure Sunday and Monday. Conditions should remain VFR
through the weekend.
&&
.MARINE...
Update...SCA flags cancelled for Currituck Sound. Wind gusts
have diminished below 20 knots.
Previous discussion...
Unsettled weather through Saturday will become more focused
over the srn waters Sunday/Monday...with periods of
afternoon/evening thunderstorms at times Tuesday into mid week.
Winds generally west 10-15kt late this afternoon and are
expected to diminish into this evening. Will need to keep a
close eye on a severe weather complex racing across Ohio. If it
holds together past the Appalachians, then thunderstorms with
strong wind gusts may be possible late this evening into the
early morning hours over the waters. Mariners should remain
aware of the potential for rapidly changing conditions during
this timeframe.
A cold front approaches from the northwest on Saturday and is
expected to slowly cross the waters late Saturday afternoon into
the evening. The front then stalls invof Carolina Coast Sunday
into Monday (slowly washing out during this time) and focusing
showers/storms over srn waters during this time. Winds generally
SW-W aob 15kt ahead of the front...becoming NW-N 10-15kt behind
the front. A period of cold air advection late Saturday night
into Sunday morning may result in a period of near-SCA
conditions for Ches Bay with waves up to 3ft during the
strongest winds. Otherwise, winds aob 15kt become NE-E Sunday
afternoon into Sunday night...then SE Monday...becoming S-SW
Tuesday/Wednesday as a lee trough develops with high pressure
off the Southeast Coast. Seas average 2-3ft (3-4ft possible nrn
waters Tuesday night into Wednesday morning). Waves generally
1-2ft Ches Bay (2-3ft at times south of New Point Comfort to the
mouth of the Bay).
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...None.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...AJZ/ESS
SHORT TERM...AJZ/SAM
LONG TERM...BMD
AVIATION...MRD/JEF
MARINE...BMD
Area Forecast Discussion
National Weather Service Bismarck ND
929 PM CDT Fri Jul 7 2017
.UPDATE...
Issued at 926 PM CDT Fri Jul 7 2017
High pressure extending from central Alberta/Saskatchewan
southeast through North Dakota will maintain mainly clear skies
and and dry weather over the region tonight and Saturday. The
current forcast looks good with no changes.
UPDATE Issued at 549 PM CDT Fri Jul 7 2017
Latest observations place surface low pressure across far
southwest North Dakota with a warm frontal boundary extending from
the low south through western South Dakota. Bowman radar shows
scattered showers along the warm front. The latest HRRR ensemble
forecast place isolated showers across northwest South Dakota with
just a slight chance in North Dakota over the next 2 hours. Based
on the latest radar do not think there will be any chance in North
Dakota. So far current forecast looking good with no changes.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 224 PM CDT Fri Jul 7 2017
The short term appears quiet and warm. High pressure will slide
off to the east Saturday and warm air advection will kick in
across western North Dakota. Temperatures in the 90s can be
expected for most of western and central North Dakota. Very dry
conditions across western North Dakota may lead to near critical
fire conditions across the west tomorrow, however, it appears
winds will remain rather light at this time.
.LONG TERM...(Saturday night through Friday)
Issued at 224 PM CDT Fri Jul 7 2017
Near critical fire conditions Sunday will highlight the long term.
Above normal temperatures are expected for the next week and
beyond as ridge maintains its position over the western United
States. Given dry soils and a well mixed boundary layer we leaned
on the warmer edge of the 12 UTC guidance. This means widespread
temperatures in the low to mid 90s are expected most days,
especially in western and south central ND. The hottest day of
the current forecast period may be Sunday when a weak mid-level
shortwave trough rounds the ridge and leads to additional
compressional warming and mixing across the Northern Plains. Critical
fire conditions are possible on Sunday as breezy conditions may
develop across southwest ND behind a surface pressure trough and
wind shift for at least a few hours Sunday afternoon.
Precipitation chances will generally be limited during the period,
but some chance of thunderstorms will exist Saturday night,
mainly across northern North Dakota. Another, somewhat greater
chance of storms may occur on Tuesday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 549 PM CDT Fri Jul 7 2017
At 6 pm CDT surface low pressure was tracking across the far
southwest portion of North Dakota. High pressure will remain over
teh Northern Plains. VFR conditions forecast through the 00Z TAF
period.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WAA
Area Forecast Discussion
National Weather Service Caribou ME
1106 PM EDT Fri Jul 7 2017
.SYNOPSIS...
A cold front will approach the area tonight from Quebec and
cross the region on Saturday. Another cold front will approach
on Sunday and stall over the region Sunday night into Monday.
&&
.NEAR TERM /THROUGH SATURDAY/...
1105 PM Update...
Adjusted the pops to align better w/the radar returns showing
heavy rainfall axis shifted across the nw areas. HRRR doing well
w/the handling of this rainfall. MRMS data showing up to 1.5
inches in the last 3 hrs across this area. Instability has
weakened considerably this evening. Some isolated flashes still
seen in the nw areas. So, kept isold tstms in through 2 AM.
Sounding data showed the llvls stabilizing further overnight.
Low pres seen on the latest sfc analysis moving across the Gulf
of Maine bringing the western edge of the rain shield to the
coast. Kept 30-40% pops for the coast overnight but things
should drop off by early morning.
The other factor is fog potential especially downeast w/some
breaks in the clouds. Kept fog in the fcst for the overnight
period.
Previous Discussion...
Activity will die out slowly after midnight, but patchy fog and
widespread low stratus appears likely to overspread CWA
overnight and persist into the morning.
Some burn-off of the fog and low stratus is expected in the
morning, with at least patchy sunshine providing for some
warming, especially for northward of Bangor. Given the ample
moisture, forcing from an approaching cold front, and increasing
shear, at least a marginal risk for severe storms is expected.
As a result, kept in the enhanced wording for the areas of
likely or higher POPs. The front will likely come through
sometime after 21z, with the severe risk dying down behind the
front.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
On Saturday evening, the cold front will be exiting the forecast
area and storms will be quickly winding down as the upper trough
weakens. Low clouds will move out with dry west winds. There`s
not a lot of cold air behind this front and highs on Sunday will
be warmer than Saturday for many locations...especially on the
coast due to offshore flow. However, it is a dry Canadian air
mass and humidity will be lower for Sunday...and much lower
towards northern Aroostook County. The mixing layer will be
quite deep and produce some wind gusts up to around 25
mph...mostly in northern zones. A weakening shortwave will
approach from the NW Sunday afternoon and evening. The
associated cold front is not expected to generate much
precipitation at this point. The only pops will be in the far
northwestern zones for light showers by late afternoon. Lows on
Sunday night will vary from the upper 40s in the Allagash on the
north side of the cold front. Upper 50s are forecast for Bangor
and the Down East region on the other side of the front. The
frontal boundary will stall Sunday night into Tuesday while a
succession of upper level shortwaves move from the NW. The exact
position where the front stalls in the forecast area remains
uncertain, but a shortwave arriving Monday afternoon will set
off scattered thunderstorms. The left rear entrance region to a
strong upper jet will be in the area to enhance any storms and
shear looks robust. The exact position where the front stalls
will determine where surface heating occurs and where the
thermal boundaries set up. For now will place the highest pops
for thunderstorms across central portions of the forecast area.
The differential heating and thermal boundaries currently look
like they`ll set up from south-central Piscataquis County
towards southern Aroostook County. This means highs around 80F
at Bangor, but only around 70F at Fort Kent.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
On Monday night, thunderstorms will taper off. The next
shortwave moving southeastward from Quebec on Tuesday looks even
more active with the potential for strong thunderstorms. There
will be a lot of shear, strong cold air advection aloft and warm
and humid air at the surface. Following this front, a dry and
cool Canadian air mass should provide fair weather Wednesday and
Thursday with very low humidity. A warm front will overrun this
dry air later Thursday. The area will be back in the humid air
Friday with the threat of another round of afternoon convection.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: Areas of MVFR to IFR conditions are expected in
shower and thunderstorm activity for HUL thru FVE through 04z;
otherwise VFR conditions are expected. However, fog and low
stratus will form around or after midnight and persist through
at least 12z. The fog is expected to burn off around that time,
but some low stratus may linger at some terminals into the
morning, keeping IFR conditions in place longer.
SHORT TERM: A lot of low level moisture will cause some IFR cigs
or vis Saturday night. Any low cigs will quickly be eradicated
Sunday morning and VFR is expected for all sites by mid-morning
Sunday and this condition will continue through Monday. The only
possible exception will be some patchy fog towards the coast
later Sunday night into Monday morning. Thunderstorms are a
threat Monday afternoon into the evening. IFR cigs and vis are
probable Tuesday night...followed by thunderstorms on Tuesday
afternoon.
&&
.MARINE...
NEAR TERM: Some rain continues offshore through at least
midnight, but as the rain clears out, areas of dense fog are
expected to cut visibility tonight. The fog may ease a bit Sat
morning, but may not fully clear until the afternoon.
SHORT TERM: Fog will gradually move away Saturday night. Some
patchy fog may return Sunday night briefly. Denser fog seems
probable to arrive Tuesday into Tuesday night. Continued to
apply reductions to model winds and seas with a persistent
inversion over the cold waters.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.
&&
$$
Near Term...Hewitt
Area Forecast Discussion
National Weather Service Dodge City KS
639 PM CDT Fri Jul 7 2017
...Updated Aviation Section...
.SHORT TERM...(This evening through Saturday)
Issued at 255 PM CDT Fri Jul 7 2017
A surface-850 mb frontal zone spreading southward later this
afternoon will allow for boundary layer moisture pooling just ahead
of it, mainly over south southern into west central counties. This
will be the favored area for isolated to a few strong to severe
storms in the 23-02Z timeframe. HRRR remains ambitious with
convective development this afternoon, while the morning runs of
WRF/NMM/ARW have backed off significantly from this surface based
development, while maintaining the solutions of all models for more
widespread convective development, aided by a shortwave exiting the
central Rockies very late evening and overnight.
Combination of post synoptic front and possible modified surface air
from convection could keep temperatures Saturday as much as 10
degrees cooler than this afternoon, although reality may only bring
about 5 degrees off. The thunderstorms risk appears similar late
Saturday with possibility of isolated widely scattered hail/wind
storm late day or evening with any minor vort max dropping though
the northwest flow.
.LONG TERM...(Saturday night through Friday)
Issued at 255 PM CDT Fri Jul 7 2017
Pattern adjusts by Sunday with strong southwest 850 mb downslope
surface flow over the entire area. This will bring an end to the 60s
dew points in the forecast area, although dew points may still be
in the 50s across south central Kansas counties. The drier air
will also mean hotter temperatures heading into midweek, with very
low chances for organized thunderstorms as the upper high across
the southwest states extends it`s influence into the central and
southern plains.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 635 PM CDT Fri Jul 7 2017
A stationary front will be the focus for widely scattered
thunderstorms through mid evening, mainly affecting GCK terminal
since it is closest to the surface front. Convection will be
slow-moving along this front. A more organized round of showers
and thunderstorms is expected late tonight, mainly after 06z, and
will carry 3 hours of VCTS at all terminals for this anticipated
activity.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 67 89 68 97 / 60 20 20 10
GCK 65 91 65 98 / 60 10 20 0
EHA 64 94 66 97 / 50 10 20 10
LBL 66 94 68 98 / 50 10 20 10
HYS 63 88 67 97 / 50 20 20 0
P28 70 88 70 96 / 70 30 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Umscheid
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1020 PM EDT Fri Jul 7 2017
.UPDATE...
Issued at 1020 PM EDT FRI JUL 7 2017
Storms are continuing to deteriorate with loss of daytime heating
late this evening. Still have a few SPS worthy cells, mainly from
gusty winds between 30 and 40mph. Otherwise, nothing severe is
expected. As such, went ahead and dropped our watch as of 10pm. A
new forecast package, including HWO, was issued to remove watch
wording. Also made some minor tweaks to the forecast to make sure
the latest observations for temps, dew points, and winds were
reflected in the near term forecast. So far Pops are actually
behaving quite well, but will continue to monitor as this line
slowly sinks south and will update timing as needed. All updates
have been published and sent to NDFD/web.
UPDATE Issued at 820 PM EDT FRI JUL 7 2017
Based on the latest radar trends with this defined line continuing
to drop southward, went ahead and updated pops through the first
part of the night to better reflect the expected trends. Also
incorporated some the HRRR data for the projected forecast as it
seems to be initializing well at this point. All changes have been
published and sent to NDFD/web. This shouldn`t cause much change
in the forecast package so do not need to reissue at this time.
UPDATE Issued at 742 PM EDT FRI JUL 7 2017
A fairly well defined line of showers and thunderstorms has formed
across southern Ohio and southern IN and is now quickly pushing
southward towards our northern CWA. Pops are actually timed out
quite well for the onset, but will have to monitor as it starts
moving across our area in case any timing updates need to be made.
Otherwise grids are in good shape. Just freshened up the near
term forecast for the temps, winds, and dew points to make sure it
was on track with the current observations. All changes have been
saved and sent to NDFD/web. Also a new forecast package and HWO
were sent out earlier to account for the Severe Thunderstorm Watch
issuance.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 334 PM EDT FRI JUL 7 2017
A cold front will pass southeast across the area tonight and
early Saturday morning. In advance of this front, multiple lines
of thunderstorms have formed well to our north and a plethora of
outflow boundaries are dropping south toward the Ohio River. These
boundaries are serving as a focus for additional storms forming
in advance of the established lines. Overall, have PoPs ramping up
quickly beginning about 6 pm north of I-64 and continuing to work
southward to about the Mountain Parkway by around 10 pm or so.
The greatest instability and severe weather threat will lie to the
north of the Mountain Parkway. South of the Parkway, dewpoints
drop off into the 60s. Plus, storms will be moving southward into
this area late in the evening, when instability is waning, so the
severe weather threat will diminish the further the storms move
south.
Fog and stratus will again plague the area late tonight into
Saturday morning. However, believe that stratus will dominate and
will only advertise patchy fog at the surface. Overnight lows will
only fall to around 70.
Drier air will slowly filter in behind the front on Saturday but
will leave in a small threat for a shower or storm right along the
TN and VA borders. The vast majority of the forecast area will be
dry, with plenty of sunshine by afternoon. Temps will warm into
the low 80s, and then tumble into the refreshing upper 50s to low
60s Saturday night.
.LONG TERM...(Saturday night through Thursday)
Issued at 335 PM EDT FRI JUL 7 2017
The models remain in good agreement aloft through the majority of
the extended portion of the forecast as they continue to evolve to
show more eastward progress to the persistent western ridge. As this
happens the broad eastern trough, extending south through the Great
Lakes, will start to retreat allowing heights to gradually rise
through mid week. This development will support a track for energy
packets to ride past to the north of Kentucky in northwest flow. The
model spread does increase through the week, though, so confidence
in any specific solution or wave track is lower than average.
Nevertheless, the rising heights should peak over the forecast area
on Thursday - stronger in the ECMWF than the GFS with the CMC in
between. Heights look to decline a bit over Kentucky to close out
the week as the model consensus shows the ridge retreating back to
the west and the eastern trough reinvigorated by energy pouring down
through the eastern Great Lakes. Given the model agreement through
mid weak, and greater uncertainty thereafter, will favor a blended
solution throughout.
Sensible weather will feature a good warm up for the week with humid
conditions in place. In this environment, periodic storms will be
possible - mainly driven by intrusions from any MCS activity to the
north. The ECMWF seems too aggressive with a sfc wave moving through
Kentucky later Thursday given the upper pattern so have discounted
it in favor of the GFS solution. The models are in better agreement
concerning convection for Friday as a boundary attempts to push
south through the state.
Similar to yesterday have made mainly terrain based adjustments to
the lows each night from the SuperBlend given the pattern and
favorable conditions for inversions to set up after sunset. Also
adjusted the PoPs to better capture the diurnal nature of the
showers and storm threat through the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 751 PM EDT FRI JUL 7 2017
While VFR conditions are currently in place across the TAF sites,
this will quickly change over the next few hours. A large line of
thunderstorms is quickly diving southward from southern IN and
southern OH, making its way across the northern portion of the
state. Tried to time out this line into the individual TAF sites,
though some modifications may need to be made to the southern TAF
sites as we see how fast it progresses through the state. SYM will be
the first affected, likely before 1Z. With this line expect a
quick drop in visibilities and CIGS, torrential rains,
gusty/strong winds, as well as potential for hail. The threats
will lesson significantly as it moves southward throughout the
evening, and may not cause as much impact by the time it reaches
KSME and KLOZ. In the wake of this initial line, expect another
couple of hours of steady rainfall, followed by lingering llvl
clouds and fog potential overnight. IFR conditions are possible
for late tonight, either by fog or by low ceilings. This will
slowly dissipate throughout tomorrow morning as high pressure
begins to move into the region. For the rest of the day tomorrow,
look for light winds and clearing conditions, with a sct fair
weather VFR CU deck expected by afternoon.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...ABE
LONG TERM...GREIF
AVIATION...JMW
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
622 PM CDT Fri Jul 7 2017
.SYNOPSIS...
Issued at 303 PM CDT Fri Jul 7 2017
H5 analysis this morning had a high pressure over the
four corners with a ridge extending north into the Yukon and central
Alaska. West of this feature, a closed low was present over the Gulf
of Alaska, while east of the ridge, a closed low was located off the
northern tip of Quebec. A trough of low pressure extended south into
the Great Lakes and Mid-Atlantic. On the northern periphery of the
high, a weak shortwave tracked across western and central Nebraska
this morning and brought isolated showers and thunderstorms to
portions of central Nebraska. Very little in the way of rain fell
with the showers this morning as they tracked to the southeast. A
second wave was located mid day across Montana and was approaching
sern Montana and the Black Hills. At the surface, a stationary front
was anchored across central Kansas and transitioned west into
Colorado where it turned north along the front ranges of Colorado
and Eastern Wyoming. Light easterly winds and much cooler
temperatures were present across western and north central Nebraska
this afternoon. Readings as of mid afternoon were in the 80s to
lower 90s.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 303 PM CDT Fri Jul 7 2017
Tonight through Saturday night: Thunderstorm chances
is the main forecast concern over the next 24 to 36 hours. for
tonight: The disturbance, currently over Montana, will continue to
slide to the southeast this evening. Based on the latest HRRR,
convection will initiate in the Black Hills, entering the northern
panhandle sometime around 00z this evening. Shear parameters remain
favorable for super cell thunderstorms with weak southeasterly and
easterly winds at the surface and northwesterly mid level winds.
With respect to the severe threat, it will be highly conditional on
whether or not convection can initiate over the black hills and nern
Wyoming over the next couple of hours. The HRRR does initiate it and
lift it sewd into the forecast area, but this is the only model
which does develop decent convection this evening. The NAM12, GFS,
and WARW initiate only a small amount of thunderstorms if any at
all. Right now, I do have a mention of thunderstorms in the western
and southwestern forecast area this evening which will suffice if
the HRRR were to verify. Will keep the mention in the 20 to 30
percent range as it should be isolated in coverage at best. For
Saturday, the short range solutions stall out a frontal boundary
from the northeast to the southwestern portion of the forecast area.
Moisture will pool along the boundary with SB CAPES reaching 2000-
3000 J/KG by mid afternoon Saturday. This is along and south of a
line from O`Neill to Imperial. Have introduced pops across the
forecast area Saturday afternoon into the evening hours INVOF the
front. The only place I feel confident in a dry forecast ATTM is in
the northwestern CWA. Elsewhere, have posted some 20 to 30 pops
during the late afternoon and early evening hours INVOF the front.
Shear will once again remain favorable for super cell thunderstorms,
so cannot rule out the threat for severe storms Saturday
afternoon/evening.
.LONG TERM...(Sunday through Friday)
Issued at 303 PM CDT Fri Jul 7 2017
Mid range (Sunday through Monday): On Sunday, a weak
frontal boundary, will once again set up across the forecast area
and serve as the focal point for thunderstorms. Both the NAM12 and
GFS solns, develop convection in the vicinity of the front Sunday
afternoon/evening. The main difference is location with the NAM12
favoring central and southern portions of the forecast area while
the GFS favors northern areas. With a compromise between the two
solutions, placed the front across the central CWA as well as the
highest pops, albeit slight chances. Deep layer wind shear is much
weaker on Sunday, so storms should be fairly weak and limited to the
late afternoon/early evening hours. On Monday, the frontal boundary
will lift north as a warm front. Very warm air will push into the
forecast area from the southwest. With the front north of the area,
temperatures will soar to the century mark across western and north
central Nebraska. The latest mex guidance has temps well above 100
degrees across the region Monday and this looks on track given where
the front is located.
Monday night through Friday: Hot temperatures will continue across
western and north central Nebraska into next week. Persistent
ridging aloft will remain entrenched across the intermountain west
and high plains well into the end of next week. There will be a
limited threat for thunderstorms during the peak heating times of
each day as weak shortwaves rotate around the northern periphery of
the closed low. Pops were limited mainly to the late afternoon and
evening hours in the outer periods, as little or no model agreement
exists for precipitation.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 622 PM CDT Fri Jul 7 2017
It is believed the convection across Wrn Neb will grow upscale
this evening and move south...generally tracking west of highway
83.
Other thunderstorms...currently across Wrn SD...will move south
through Wrn Neb tonight...also affecting areas west of highway
83...and exit Swrn Neb by 12z.
The forecast uses a blend of the HRRR and RAP models. The
thunderstorm coverage shown in those models was shifted west about
50 miles to line up with the ongoing thunderstorm activity.
Other storm activity...generally isolated...is expected across
Wrn/Ncntl Neb, 18z Saturday aftn-00z Saturday evening. The
experimental HRRR model was the basis for this forecast.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Buttler
AVIATION...CDC
Area Forecast Discussion
National Weather Service Louisville KY
809 PM EDT Fri Jul 7 2017
...Forecast Update...
Issued at 808 PM EDT Fri Jul 7 2017
Storms across Indiana and Ohio are congealing into a QLCS as they
drop to the south. Best theta-e ridging is to the west where new
cells have been sprouting above pool of 70-75 degree dew points
ahead of the advancing cold front.
Still plenty of surface instability and sufficient shear ahead of
the storms. However mid-level lapse rates are not very steep and
AMDAR soundings out of SDF show some possible capping. Radars show
that the storms are becoming outflow-dominated, and mesoanalysis
shows CIN beginning to increase as the sun sets. So while storms
are expected to continue their southward push into Kentucky,
severe chances should slowly start to diminish as the evening
progresses.
.Short Term (Now through Saturday Night)...
Issued at 220 PM EDT Fri Jul 7 2017
...Strong to Severe Storms More Likely Late This Afternoon and
Evening...
Still on track for strong to severe storms to come through at least
our northern zones, south central IN, north central KY, late this
afternoon to this evening. How fast the line pushes southward will
determine how far south that threat gets, as we start to lose
daytime heating. As of this writing, it still looks like 4-8 is the
prime period for southern IN, 6-10 for north central KY, and 10-2 AM
for south central KY.
Airmass ahead of these storms will have plenty of energy to give.
Latest RAP analysis has CAPEs around 3000 J/kg with Downdraft CAPES
in the 1500-2000 J/kg range...likely because of some mid-level dry
air ahead of the line. A timely special sounding from ILN, at 18Z
and ahead of the outflow boundary in OH, indicates 4000 CAPE, though
quite a bit of dry air, 1.2 inch precipitable water. Based on wind
shear, expect supercell structures still are possible as elements
within the lines of storms dropping down from the north, and cannot
rule out an isolated tornado, but the main threat will be damaging
wind gusts with some hail.
A little similar to last night, behind the rains we may have to deal
with some patches of fog. Unlike last night though, the cold front
may bring slightly more winds to keep us better mixed. We may have a
few pockets of dense fog, but do not think it will be as widespread
as this morning.
Northwest surface winds Saturday will bring in drier and cooler
weather. Still looking at temperatures below normal. With high
pressure right over us Saturday night, we should see temperatures
cool into the 50s in some locations.
.Long Term (Sunday through Friday)...
Issued at 220 PM EDT Fri Jul 7 2017
Nice weather will continue for Sunday, though after a cool start, we
should warmup to a little warmer than Saturday. A few models
continue to hint at some precip getting into southern IN late Sunday
afternoon, possibly as a result of a weak warm front lifting north
over the region or just as a result of instability in the warming
airmass. Superblend came in with dry pops for the day period and
slight chances in the north Sun. night.
Overall synoptic pattern for the next work week will have ridging
out west and northwest flow over the Midwest/Ohio Valley. Small
disturbances riding within this flow will determine our rain chances
through the week as well as temperatures. Models have a difficult
time resolving these systems, which can either pass by to our north
in the morning, but leave outflow boundaries for afternoon storms to
focus on, or blast the system through here, bringing morning storms
and drier but cloudy afternoons. Will continue the practice we`ve
had over the last few days of capping the blended model rain chances
in the chance range because of this uncertainty. One thing we have
some confidence in is we`ll be back to a humid pattern again, so any
days that do warm up significantly we could see heat indices get
into the mid/upper 90s.
&&
.Aviation (00Z TAF Update)...
Issued at 717 PM EDT Fri Jul 7 2017
Storms over Indiana will drop south and cross the SDF and LEX
airfields this evening. These storms may pack a wallop with strong
gusty winds, very heavy rain, and small hail. Things will calm down
behind the storms, with some patchy fog possibly developing toward
morning.
Quiet weather for the weekend.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........13
Short Term.....RJS
Long Term......RJS
Aviation.......13
Area Forecast Discussion
National Weather Service Miami FL
742 PM EDT Fri Jul 7 2017
.AVIATION...
VFR expected to prevail at all terminals through Saturday morning
with mainly light and variable winds. Southeasterly flow around
10 kt will resume late saturday morning, then another round of
thunderstorms will develop in the vicinity of the terminals. Best
chances of MVFR periods under heavy rain and low CIGS saturday
afternoon remain over APF.
.PREV DISCUSSION... /issued 703 PM EDT Fri Jul 7 2017/
UPDATE...
Right on schedule, the convection continues to diminish across
the peninsula. Winds will become light and variable overnight with
light southeast winds along the east coast. Short term models
indicate a few showers with possibly some embedded thunderstorms
developing during the late night over the Atlantic. These storms
may drift westward, towards the east coast metro. In the update,
upped PoPs in this region to account for the possible showers.
Otherwise, besides loading in the latest wind guidance, all other
variables appeared on track.
PREV DISCUSSION... /issued 422 PM EDT Fri Jul 7 2017/
DISCUSSION...
Latest IR imagery from this afternoon shows broad troughing over
the Ohio Valley and elongated upper level high pressure aloft
dominating South Florida. The MFL RAOB sounding from this morning
indicated a rather unstable atmosphere, due to slightly colder
than normal 500 mb temps. With over 3500 J/KG and no capping
inversion, the atmosphere was primed for active convection.
Scattered thunderstorms initiated along the sea breeze boundaries
during the early afternoon and have since been propagating
inland, following outflow boundary collisions. Short term models,
including the HRRR and Hi- Res WRF, show convection drifting back
towards the coasts, propagated by the outflow boundaries from
ongoing storms. By evening, with the loss of diurnal heating,
guidance diminishes this activity. Overnight, light east and
southeast flow will shift the threat of showers and thunderstorms
to over the Atlantic waters. A few of these showers may affect the
east coast metro region through mid morning, but not expecting
any widespread activity.
This weekend through mid next week: The aforementioned strong 500
mb high will edge slowly northeast towards Bermuda, generating a
more south southeast flow for South Florida. Deeper moisture will
be allowed to advect northward with GFS forecast PWAT values
rising to generally between 1.75"-2.00" on Saturday. A very
similar synoptic pattern will take shape from Sunday through mid
next week. Thus, expecting typical summerlike weather to ensue.
High pressure near Bermuda will create east or southeast flow
across the peninsula with mainly diurnally driven thunderstorms.
Most convection will form along the sea breeze, then push toward
the interior and Gulf coast during the afternoon. The main
threats with these storms will be frequent lightning, brief heavy
rain, and gusty/erratic wind gusts. During the nights, showers and
isolated thunderstorms will rumble over the Atlantic waters and
adjacent east coast metro region. Through the period, temperatures
will remain near average for this time of year. Maximums will be
near 90 with minimums from the mid 70s in the interior up to near
80 along the east coast.
MARINE...
Prevailing east-southeast winds around 10 knots will
continue across the South Florida waters into early next week as
high pressure remains to the north of the region. Both the Gulf
and Atlantic seabreezes are expected to develop each afternoon,
leading to locally higher winds near the coast. Isolated to
scattered showers and thunderstorms are possible each day, with
locally higher winds and seas as well as lightning near any
thunderstorms.
&&
.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach 77 90 77 90 / 30 40 30 40
Fort Lauderdale 80 91 79 90 / 30 40 30 30
Miami 79 91 78 91 / 30 40 30 40
Naples 76 90 75 89 / 20 50 40 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
GM...None.
&&
AVIATION...17/AR
Area Forecast Discussion
National Weather Service Marquette MI
730 PM EDT Fri Jul 7 2017
.SHORT TERM...(This evening through Saturday)
Issued at 406 PM EDT FRI JUL 7 2017
WV imagery and RAP analysis indicated an amplified pattern with a
prominent mid/upper level ridge from the sw CONUS into Alberta/BC
and a broad trough over the ne CONUS resulting in nw flow through
the nrn Great Lakes. A shortwave trough supported an area
of shra/tsra over nw WI that was diving quickly to the se. Heating
also great enough this afternoon to boost MLCAPE values above 500
J/Kg over the srn cwa so that isold shra/tsra also have developed
over srn Menominee county. Otherwise, stable air off of Lake
Superior has kept skies clear over the ern cwa while sct-bkn cu
dominated inland over the west.
Tonight, any shra/tsra that develop near the WI border late this
afternoon should diminish early this evening as the shrtwv slides
out of the area. The influx of much drier air, clearing skies and
diminishing winds will allow temps to drop into the upper 40s and
and lower 50s.
Saturday, another mid level shrtwv and cold front will drop toward
the nrn Great Lakes resulting in increasing wrly winds along with
moderate WAA. Sunshine and mixing to around 750 mb will push temps
into the upper 70s. High based afternoon cu will develop as
dewpoints remain aob 50F. Any chances for shra/tsra with the
front will arrive mainly after 00z over the far north near P59.
.LONG TERM...(Saturday night through Friday)
Issued at 347 PM EDT FRI JUL 7 2017
High amplitude ridging will remain in place for the Northern
Rockies, through at least Mon, allowing heat to build across the
Central/Southern Plains. Downstream of the ridge will be a
persistent trough over Hudson Bay, which will translate into a
cool/seasonal northwest flow for the Great Lakes region and
especially the Upper Peninsula of Michigan. Ensembles begin to
indicate good agreement that the ridge upstream will begin to
relax/flatten Tue, with the flow transitioning towards a quasi-
westerly orientation. This will allow surface temps to slowly return
to slightly above climo.
Operational solutions continue to indicate a frontal boundary
sliding southeast across the forecast area Sat eve/overnight, but
given the lack of a push behind the boundary, the front will get
hung-up and continue to keep a chance for precip around into Sun.
With cooler air aloft, any heating during the day Sun would likely
be warm enough to produce an isolated thunderstorm. Then weak
surface ridging will bring some drier air to the Upper Peninsula for
Mon, but this feature will be short-lived as the flow begins to
flatten and guidance progs a shortwave to arrive Wed/Thur.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 729 PM EDT FRI JUL 7 2017
Expect VFR conditions through the forecast period at all TAF sites.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 406 PM EDT FRI JUL 7 2017
Southwest winds will gust up to 25 knots over central Lake Superior
on Saturday. Otherwise, winds should remain tranquil through the
forecast period with winds staying below 20 knots.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...Beachler
AVIATION...Voss
MARINE...JLB
Area Forecast Discussion
National Weather Service Paducah KY
632 PM CDT Fri Jul 7 2017
.UPDATE...
Updated aviation section for 00z taf issuance
&&
.SHORT TERM...(Tonight through Sunday night)
Issued at 107 PM CDT Fri Jul 7 2017
Near term meso plot shows FA abounds in heat/moisture, with
surface dew points uniform in lower half of 70s. This heated and
moistened airmass is in place ahead of approaching cold front,
seen by wind shift extending across ncntl IL. Visible imagery
shows benign CU much of FA, but some agitation in CU field is
seen just along northern periphery. Radar mosaic depicts echoes
along/ahead of the front, as close as northwest IN, around
Lafayette, with its southwestward trail struggling to coalesce
into echo returns in IL. This is the area to watch for near term
development (next 1-3 hrs), per latest swomcd. HRRR has been
modeling convection nicely, and it breaks/brings development to
our northern counties around 22-23Z, then dives it southward
across much of remainder of FA thru 06z. Most action is sustained
in our northeast quad, per latest SWODY1. Increasing winds aloft,
and steepening mid level lapse rates, will mean wind/hail as the
primary strong to severe storm hazards, with ltg/heavy rain also
convective hazards. We have noted the HRRR trending a little later
for initial development, by 1-2 hours, since the beginning of the
shift, so that`s something we`ll adjust for in the grids as well.
After fropa, should see those drier dew points start to work in
tmrw, providing a welcomed respite to the early July heat/humidity.
Dew points should be falling into the low to mid 60s, and more or
less staying there, thru the remainder of the weekend. We think
Pops will likewise stay outside the confines of the FA, with Highs
in the 80s/Lows in the 60s.
.LONG TERM...(Monday through Thursday)
Issued at 323 PM CDT Fri Jul 7 2017
A southerly Gulf fetch will be in place for most of next week. This
will be conducive to gradually increasing surface dewpoints and
overnight lows, while highs should level off around 90 degrees,
though there were some model indications of possible higher temps.
Cloud and pcpn coverage may keep a lid on them however. Dewpoints in
the lower to middle 70s will cause heat indices to flirt with 100
mainly Wed and Thu.
The medium range models were in reasonable agreement depicting the
overall mid level flow pattern over the CONUS. However, by mid week,
the Canadian showed extensive deep moist convection across the PAH
forecast area, unlike the GFS/ECMWF, which were much drier. All the
models showed an initially somewhat amplified western ridge/eastern
trof pattern gradually flattening as the western ridge expanded
eastward. Meanwhile, a wavy west-east surface boundary is progged to
linger across the Midwest (just to the north of our area) during the
extended forecast period. This boundary will be the trigger for
shower and tstm development in the moist and unstable environment,
some being of the MCS variety, especially during the heating of the
day.
The model blend continues to show somewhat inconsistent "spotty"
pcpn chances from time to time through the period. Currently, it
appears that most of the pcpn will remain to the north of the PAH
forecast area until perhaps later in the week when some northern
stream shortwave energy begins to impinge on the broad mid level
ridge over us. Bottom line is, while pcpn may occur during the
extended period, the coverage and, to a lesser extent, the timing of
the pcpn is quite uncertain.
&&
.AVIATION...
Issued at 632 PM CDT Fri Jul 7 2017
A cold front was moving southeast into southern IL and southeast MO
as of 23z. A couple lines of cumulus clouds have formed along the
front, along with isolated intense thunderstorms. The front and its
associated lines of isolated convection will move across the taf
sites this evening. The tafs will be updated if storms appear
imminent, but coverage appears too isolated to warrant a tempo group
at this time.
Winds will become northwest behind the front by 06z. Some mid or
high clouds will follow behind the front, then mainly clear skies
are expected on Saturday.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
AVIATION...MY
Area Forecast Discussion
National Weather Service Pocatello ID
152 PM MDT Fri Jul 7 2017
.DISCUSSION...A ridge of high pressure anchored over the Great Basin
will continue to support above normal temperatures across the region
through Sunday. Embedded moisture will help to fuel isolated to
scattered mainly afternoon convection favoring the mountains each
day. By Sunday, a low pressure system moving into WRN Canada will
begin to break down the ridge as drier and increasingly stronger SW
winds spread into the region Monday and Tuesday. With the trough
passage will come slightly cooler temperatures and locally breezy
conditions. And although the models are showing enhanced convection
out ahead of the trough over the SE highlands Monday afternoon, the
placement of this activity will be highly dependent on the
progression and timing of the leading edge of the trough (so a bit
early yet to make any definitive calls on that timing issue). By mid-
week, the GFS is showing the ridge rebounding across the region with
unseasonably warm temperatures and a return to isolated mainly
afternoon convection favoring the mountains through weeks end.
Huston
&&
.AVIATION...Showers associated with a weak shortwave are pushing
east of Idaho Falls and into Driggs as of 11 am this morning. This
afternoon, we continue under the influence of the Southwestern
Monsoon and its associated moisture field. High confidence on
convective development in southeast Idaho, but less confidence in
where it will initiate. Including VCTS at all sites this afternoon
and evening. KBYI saw IFR vis in smoke this morning, and HRRR Smoke
forecast supports the idea of smoke/haze posing a potential problem
again tonight/tomorrow morning. Not enough confidence to drop vis
below VFR. Hinsberger
&&
.FIRE WEATHER...Hot temperatures continue under the dome of high
pressure over the West. The influence of the Southwest Monsoon will
stoke isolated afternoon and evening thunderstorms through Sunday.
As we head into Monday, an upper disturbance will move onshore while
a surface cold front appears to push through southeast Idaho Monday
afternoon. Models support the idea of mid-level drying behind the
cold front along with low surface RH. Some uncertainty remains on
the timing of the frontal passage, and how much convection will be
triggered by it. Thunderstorm coverage is still expected to be
isolated, but may increase along the cold front. Wind gusts of 25 to
30 mph are possible Monday and Tuesday afternoon in the Snake Plain
and Central Idaho Mountains in response to the tighter pressure
gradient. The greatest threat to potential Red Flag conditions in
those areas will be Monday and Tuesday due to the wind gusts and low
RH expected, though confidence is not strong enough to warrant
headlines just yet. Hinsberger
&&
.HYDROLOGY...Warm temperatures will continue across the region while
many of the rivers remain steady or fall. Significant backcountry
flood issues continue to impact roads, bridges, and trails in the
Sawtooth National Forest above 7500 feet MSL where district rangers
have requested that the Small Stream Areal Flood Warning continue.
Further south, along the Big Wood River, river levels remain well
below the established flood stage, however significant changes in
the river channel have left several homes along War Eagle Drive west
of Hailey and along Gimlet Road 4 miles south of Ketchum
experiencing ongoing flood issues. Emergency management officials
were in agreement that the flood advisory would be allowed to
expire. Huston/Wyatt
&&
.PIH WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Area Forecast Discussion
National Weather Service Phoenix AZ
448 PM MST Fri Jul 7 2017
.SYNOPSIS...
Increasing moisture will lead to a gradual cooling trend through
the weekend. Chances of thunderstorm activity will also increase
in central and eastern Arizona through the weekend. Moisture will
persist through next week continuing thunderstorm chances for the
mountains and deserts of Arizona.
&&
.DISCUSSION...
The Four Corners` version of the ring of fire is evident on
satellite, with convection and cooler clouds tracing out the
anticyclonic flow around the Monsoon high. Morning PSR sounding
registered a record 500 mb height of 595 dam. At the surface,
temperatures have soared with Phoenix already breaking the daily
record high of 115 degrees, set more than 100 years ago in 1905.
Latest consensus amongst the hi-res WRFs is for isolated to
scattered storms to affect the higher terrain north and east of
Phoenix this afternoon before dropping into the valley later this
evening. Although total precipitable water is only around the
50th percentile, a well-defined outflow boundary propagating out
of the northeast should help to provide the lift needed to
initiate isolated storms across the lower deserts. PoPs were
increased across mainly south-central Arizona, with higher weight
given to the latest SREF and NBM.
CAMs including the latest HRRR continue to suggest that areas
from Phoenix northward will see the greatest coverage of storms,
however just about anywhere within Maricopa and Pinal counties
stand to potentially see some impact. Trajectory is also less
than ideal for a dust storm, though areas of dust with reduced
visibilities, particularly over the Salt River Indian Community
cannot be ruled out.
&&
.PREVIOUS DISCUSSION...
Increasing Monsoon moisture will become more notable by Saturday,
as PW values during peak mixing should easily exceed 1 inch
across most of the lower deserts. The midlevel cyclone positioned
to the north will weaken, but still maintain general easterly flow
across Arizona/New Mexico. Timing of individual perturbations and
the potential for any debris cloudiness will affect the evolution
of thunderstorm development each day, but the atmosphere is
becoming primed in typical Monsoon-fashion for a more convectively
active period through next week. This will also bring a welcome
reprieve from the excessive heat, given the increased levels of
moisture and potential for more abundant cloudiness.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Showers and storms continue to build over the mountains north/east
of Phoenix. Some cells showing better structure over the
Superstition Mountains east of PHX. Not confident enough that any TS
will happen near/over any terminal to include mention at this time
but will monitor for updates. Still expecting outflow winds this
evening from the N/E, not an ideal location for dust. Will update
TAFs as timings change/confidence improves. BKN clouds will remain
overnight and more showers/storms expected tomorrow.
Southeast California/Southwest Arizona including KIPL and KBLH:
Westerly winds will quickly switch to breezy southerly winds during
the early morning hours Saturday as a surge of gulf moisture/air
pushes into the lower deserts. That flow will dominate through much
of the say Saturday. Small chance winds will produce some reductions
in visibility due to dust, especially in the Yuma area.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Sunday through Thursday:
An upswing in monsoon moisture levels from Sunday into early next
week to bring an increase in thunderstorm activity and chances for
wetting rains to the region, especially to the higher terrain north
and east of Phoenix. Along with the better chances for rainfall,
cooler temperatures can also be expected, with highs falling to near
normal values. Some decrease in convective activity is possible for
the middle of next week as slightly drier air moves into the region.
Minimum humidities to fall into the 15-30 percent range each day,
with fair-good overnight recoveries.
&&
.CLIMATE...
Record highs this week:
Date Phoenix Yuma
---- ------- ----
7/7 115 in 1905 117 in 1942
&&
.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Excessive Heat Warning until 8 PM MST /8 PM PDT/ this evening
for AZZ530>556-559>562.
Heat Advisory until 8 PM MST this evening for AZZ557-558-563.
CA...Excessive Heat Warning until 8 PM PDT this evening for CAZ561-
562-564>570.
&&
$$
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DISCUSSION...Hirsch
PREVIOUS DISCUSSION...Rogers
AVIATION...Iniguez
FIRE WEATHER...Percha
ClIMATE...Wilson
Area Forecast Discussion
National Weather Service Tulsa OK
931 PM CDT Fri Jul 7 2017
.DISCUSSION...
Isolated showers and thunderstorms continue to develop this
evening in the vicinity of a weak frontal boundary that is sagging
south into the area. The latest runs of the HRRR suggest that this
activity may fester much of the night near the boundary. Have
adjusted pops some based on observed and expected conditions
overnight, with the rest of the forecast looking good at this
time.
Update on the way.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&
$$
SHORT TERM...14
LONG TERM....05
PLATE
Area Forecast Discussion
National Weather Service Tucson AZ
245 PM MST Fri Jul 7 2017
.SYNOPSIS...Isolated showers and thunderstorms mainly north to west
of Tucson ending around midnight. The coverage of showers and
thunderstorms will increase starting Saturday, then scattered mainly
afternoon and evening thunderstorms will prevail during the upcoming
week.
&&
.DISCUSSION...An isolated shower developed around 2 pm MST near the
international border south of Sells. Other isolated showers were
developing at this time across the White Mountains. The 07/12Z Univ
of AZ WRF-NAM has the showers near the international border well
handled, while the 07/12 Univ of AZ WRF-GFS and several HRRR
solutions depict the White Mountain showers nicely.
At any rate, given the high-resolution model solutions, have
maintained isolated to scattered showers and thunderstorms this
evening from the White Mountains extending north-to-west of Tucson,
or into southern Pinal County and western/central Pima County. Dry
conditions will prevail this evening south-to-southeast of Tucson.
The bulk of any showers/tstms should end by midnight, but have
maintained a slight chance of showers/tstms late tonight across the
White Mountains. Various NWP solutions suggest fairly similar
coverage of showers/tstms to occur Saturday afternoon and evening
versus this afternoon/evening.
Thereafter, a fairly substantial increase in coverage of showers/
tstms should commence Sunday afternoon and evening, at least if the
07/12Z Univ of AZ WRF-NAM and WRF-GFS, the 07/12Z ECMWF, and to some
extent the 07/12Z GFS are close to reality. High pressure aloft is
progged to be centered near the Four Corners region, and increased
lower level moisture in combination with favorable steering flow
should promote generally scattered coverage of showers/tstms. Thus,
Sunday afternoon and evening should be the best period for showers/
tstms for much of the Tucson metro area so far this season.
Scattered mainly afternoon/evening showers and thunderstorms are
forecast to continue during much of the upcoming week. The best
chance of measurable rainfall on any given day will favor locales
east of Tucson, and lower precip chances occur west of Tucson.
However, the daily detail, or nightly detail for that matter, will
certainly be subject to revision with subsequent forecasts.
High temperatures Saturday will be about 5-8 degrees or so lower
from Tucson westward versus temps achieved this afternoon. Highs
Saturday east of Tucson will be just a couple of degrees lower
versus this afternoon. Daytime high temperatures Sunday into next
Friday will then average quite close to seasonal normals given the
increased moisture and precip chances.
&&
.AVIATION...Valid thru 09/00Z.
Isolated -TSRA/-SHRA from the White Mountains northeast of KSAD
extending north-to-west of KTUS into this evening. Most -TSRA/-SHRA
will dissipate by midnight. Isolated to scattered -TSRA/-SHRA will
occur Saturday afternoon. Otherwise, VFR conditions with surface
wind sely to nely 8-18 kts and gusts near 25 kts into Saturday
morning, then surface wind sly to sely 5-15 kts Saturday afternoon.
Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Expect isolated thunderstorms this evening from the
White Mountains northeast of Safford extending north-to-west of
Tucson. Dry conditions should prevail across Cochise County and also
likely dry conditions continuing for the Tucson metro area. However,
a slight chance of thunderstorms continues for the Catalina/Rincon
Mountains. The bulk of thunderstorms will end by midnight.
The coverage of showers and thunderstorms will increase starting
Saturday, then scattered mainly afternoon and evening thunderstorms
will occur during the upcoming week. The prospect of more
significant rains should also increase as the week progresses.
Expect brief strong, gusty and erratic winds due to thunderstorm
outflows. Daytime temperatures will also moderate closer to
seasonal normals next week.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning until 7 PM MST this evening for AZZ501-
502-504-505.
&&
$$
Francis
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