Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/08/18
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
506 PM MDT Sat Jul 7 2018
00Z TAF CYCLE
Upper high will continue to be centered over wrn CO with shower and
storm motion generally from northeast to southwest. Outflow
boundaries with gusts to around 45kt producing lcl MVFR vsbys in bldu may
also spark randomly moving storms. Lcl MVFR cigs/vsbys and small
hail in the stronger storms should be relatively brief along with any
related terrain obscurations. Short term models suggest there may be
lcl MVFR cigs around 06Z-08/15Z over the ern plains, and some
lingering precipitation over sern NM. Otherwise precipitation should
taper off aft 06Z.
.PREV DISCUSSION...302 PM MDT Sat Jul 7 2018...
Daily rounds of shower and thunderstorm activity is expected over the
next several days, however storm coverage will trend downward on
Monday and Tuesday. Given high atmospheric moisture content, some
storms will be efficient rainfall producers and may cause flash
flooding on burn scars. The rain and cloud cover will keep
temperatures at or below July normals.
As expected, showers and thunderstorms are more numerous this
afternoon as compared to yesterday afternoon. Steering flow is taking
these storms slowly to the southwest. The HRRR and RAP suggests that
a few storms may try to roll into the ABQ Metro area late this
afternoon or early this evening. Otherwise, should focus across
western NM after 00Z. Storms so far today have been capable of small
hail and torrential rains. This will persist into the evening, with
flooding over burn scars will be the biggest threat.
Storm coverage, motion and placement should be similar on Sunday,
perhaps slightly less along the east slopes of the central mountain
chain. PWATs will remain around an inch, so any storms that do
develop will continue to be efficient rainfall producers.
A downtick in storm coverage is expected Monday and Tuesday as some
drier and more stable mid level air shifts into the area from the
northeast. There will still be isolated to widely scattered storms
over the high terrain, but the southwest mountains will be the most
favored. Storm motion will be more toward due west. It should be
noted that even though storm coverage will be less overall, it only
takes one storm to cause a problem over a vulnerable area.
Storm coverage should gradually increase Wednesday through Friday,
particularly across central and western NM as the dominant upper
high shifts to the east. Daily rounds of thunderstorms are expected
with weak steering flow. Heavy rain and flooding will remain
Scattered showers and thunderstorms over NM today will continue
producing locally heavy rainfall and strong outflow winds. Storm
motion will be slow toward the southwest. The focus for storms will
shift into the northern and western higher terrain Sunday as drier
air aloft pushes into the eastern plains. Upper level high pressure
will strengthen over western Nebraska Monday and Tuesday and force a
more stable airmass with drier air aloft across NM. This will focus
moisture and instability over AZ early next week. There will still
be the threat for locally heavy rains from any storm since steering
flow will be very weak. Extended guidance is now in slightly better
agreement that the main monsoon moisture plume will focus over AZ
through as late as next Thursday before shifting back east over NM
by late week. This would trend humidity lower with temperatures
trending closer to normal.
18Z TAF CYCLE
Clouds building over the high terrain will develop into sct SHRA/TSRA
thru 20Z. Storm motions will be to the southwest around 10 kt. The
exception will be southeastern NM where TSRA are drifting to the
west. The coverage of TSRA will increase thru 22Z with a peak thru
02Z. Direct hits will be capable of strong outflow winds, frequent
lightning, and MVFR cigs/vsbys in heavy rainfall. The bulk of storm
activity will taper off thru 04Z however guidance is trending toward
SHRA/TSRA for much of the night around KROW.
Flash Flood Watch until midnight MDT tonight for the following
Area Forecast Discussion
National Weather Service Bismarck ND
955 PM CDT Sat Jul 7 2018
Issued at 955 PM CDT Sat Jul 7 2018
Once again, little change was made to the gridded forecast except
to blend observational trends and recent rapid-refresh guidance
into hourly elements through early Sunday morning. The latest
thinking on the severe-storm risk is contained in the mesoscale
discussion section from 934 PM CDT below.
Issued at 934 PM CDT Sat Jul 7 2018
The risk of severe weather is increasing over southwest and south
central ND, and is expected to peak in the 05 to 10 UTC window,
though the exact evolution of storms overnight remains somewhat
The 00 UTC Bismarck sounding sampled rich low-level moisture with
a mean lowest-100 mb mixing ratio around 15 g/kg surmounted by
steep midlevel lapse rates on the order of 8 C/km in the 700-500
mb layer, yielding strong potential instability. However, a warm
nose between 850 and 700 mb was sufficient to yield greater-than-
forecast inhibition for mean lowest-100 mb parcels as a result of
a somewhat shallower moist layer depth than models had expected.
This -- along with a continued weakening of the frontal zone in
central ND through the evening -- was likely sufficient to keep
earlier convective initiation at bay. As of mid evening, surface
observations show weakening wind fields and even a return to a
more southerly component across most of western and central ND
such that low-level moisture advection has resumed in most areas
in a magnitude greater than earlier modeled, as exemplified by a
return to 70 F dewpoints at Garrison. This implies that the sharp
northward gradient in instability and thus severe risk portrayed
by RAP-based analyses such as the SPC mesoscale analysis may be
less intense than suggested, which in turn may make it even more
difficult to narrow down the area of greatest severe risk through
the next several hours. However, continued advance of midlevel
cloud decks through central ND suggest that synoptic-scale ascent
may continue to weaken inhibition the next several hours atop the
rather broad area of strong to extreme bouyancy in place across
the area, and the area of intensifying convection in southeastern
MT is of particular interest, particularly since it is occurring
in a region of well-defined surface pressure falls, which is
further suggestive of a stronger impulse aloft that could assist
in sustaining convection east-northeast across southwest and into
south central ND overnight. Given MUCAPE of 3000-5000 J/kg and
effective-layer bulk wind differences on the order of 40 kt we
expect both severe hail and wind risks with this event. Based on
west-southwest deep-layer shear, mean wind, and anvil-level wind
vectors that are largely normal to the residual low- to midlevel
frontal zone that is broadly oriented in a northeast-southwest
fashion, which may favor at least some upscale growing clusters
and an attendant severe risk through the night, including some
potential for development of a forward-propagating complex.
UPDATE Issued at 810 PM CDT Sat Jul 7 2018
Quick update to allow the Heat Advisory to expire on schedule. A
few locations are still reaching headline criteria as of the top
of the hour, but heat indices will ever-so-slowly continue to ease
downward the next few hours, so we let the advisory expire.
UPDATE Issued at 650 PM CDT Sat Jul 7 2018
Little in the way of change was made with this update. Recent HRRR
and ESRL-HRRR cycles key on post-frontal thunderstorms developing
in the 04-06 UTC time frame roughly along and north of Interstate
94 from Dickinson toward Bismarck and Jamestown, but we are still
monitoring for the low probability of earlier development as some
earlier-day CAMs supported in south central ND. See the mesoscale
discussion section below for more technical details. Otherwise,
we chose to continue the Heat Advisory as-is for now, despite the
fact that heat indices in its western extent are below the 100 F
technical criteria for the headline, but we fully anticipate that
we will be able to let it expire at 01 UTC.
Issued at 555 PM CDT Sat Jul 7 2018
The near-term probability of convective initiation and an ensuing
severe-storm risk appears low -- but not negligible -- through 00
GOES-16 one-minute visible satellite imagery per mesoscale domain
sector number two has been showing persistent, but shallow cumulus
fields along a weak pre-frontal trough and the more well-defined
shift to west-northwest winds that marks a weak cool front across
east central ND the last few hours. The cumulus has at times shown
tendencies for increasing coverage, perhaps suggestive of regions
of enhanced meso-beta or meso-alpha-scale low-level ascent, but we
have yet to see any defined vertical growth to the cumulus fields.
The 22 UTC surface analysis revealed a relatively large corridor
of middle 70s F dewpoints in east central and eastern ND -- which
is contributing to MLCAPE on the order of 5000 J/kg and minimized
MLCIN centered on the Carrington region per RAP-based objective
analyses -- but it also showed veered surface winds in the frontal
zone, implying a lack of low-level convergence and ascent. Model-
derived soundings suggest that while MLCIN may be minimal over
parts of east central ND, a warm nose may still be centered in
the 760 mb layer, and veered southwest flow in the LFC to LCL
layer could be yielding detrimental parcel detrainment along the
frontal boundary, as well. Finally, the low-level thermal ridge
axis with surface temperatures of 95+ F -- which extends as far
north as Mobridge, SD -- does not intersect with the front or pre-
frontal wind shift across the local area (but does in northeast WY
where storms have developed already this afternoon). Taken
together, this suggests that the odds of convective initiation
through at least 00 UTC is low, but we will continue to monitor in
case isolated development occurs in the strong-extreme CAPE and
moderately-sheared environment that would likely yield intense
updrafts given initiation. More importantly, the midlevel cloud
decks streaming across western and into north central ND may
reflect greater ascent and related cooling aloft that could
eventually aide storm development in the immediate post-frontal
environment later this evening.
.SHORT TERM...(This evening through Sunday)
Issued at 109 PM CDT Sat Jul 7 2018
Scattered strong to severe thunderstorms are expected this evening
and through tonight. Uncertainty regarding timing and location of
convective initiation remains.
Current surface weather observations show a pressure trough along
a weak, slow-moving cold front located across western North
Dakota early this afternoon. This front will be the focus for
convective initiation later this evening. The latest CAM model
guidance shows rather drastic differences in the timing, location
and coverage of storm development. The 12z iteration of the
HiResW-NMM-East has convection initiation around 00z, the NAMNest
around 01z, and the HRRR around 05z.
With the 12z KBIS observed sounding showing a strong cap with
MUCIN over -350 J/kg and 850 mb temperatures around 27 degrees
Celsius, it is difficult to say when the most likely time for
convective initiation will be. There is little to no upper-level
forcing for this event, so initiation will depend almost solely on
the mesoscale forcing along the cold front.
When storms do finally form, some will likely become strong to
severe given the extreme instability with MUCAPE values in excess
of 4000 J/kg and bulk shear generally between 30 and 40 kts.
Storms will likely linger into Sunday morning across southeast
North Dakota as they slowly push eastward, with conditions drying
out across all of western and central North Dakota by the
.LONG TERM...(Sunday night through Saturday)
Issued at 109 PM CDT Sat Jul 7 2018
Heat builds back up early this work week, with an overall drier
pattern expected throughout the long term forecast.
The 12z iterations of the GFS/ECMWF show nearly zonal flow across
western and central North Dakota Sunday night, with a large upper
level ridge building in on Monday and peaking on Tuesday. Slight
chances for thunderstorms exist Monday night as a weak impulse
moves along the upper level ridge. Ridging will allow
temperatures to rise well into the 80s on Monday, and into the 90s
on Tuesday across western North Dakota and parts of central North
Dakota. Despite the hot temperatures, surface dew points look to
be too low to create heat index values over 100 degrees on
The latest suite of model guidance shows mainly dry weather across
western and central North Dakota Tuesday through Friday morning,
with above average temperatures. A weak impulse moves through
northern North Dakota Friday afternoon and evening, bringing with
it chances for showers and thunderstorms.
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 955 PM CDT Sat Jul 7 2018
Scattered strong to severe thunderstorms are expected across
southwest and south central ND through the James River valley
tonight. KDIK, KBIS, and KJMS could be impacted, but confidence
in storms impacting any given location remains low given the weak
nature of the front in place across the area. Thus, radar trends
will likely dictate amendments to TAFs as needed. Localized MVFR
to IFR conditions are possible in any storms that occur, but
otherwise VFR weather is generally expected for the 00 UTC TAF
cycle. The probability of storms will be relegated to the James
River valley region by Sunday.
Area Forecast Discussion
National Weather Service Flagstaff AZ
327 PM MST Sat Jul 7 2018
.SYNOPSIS...Scattered showers and thunderstorms activity is
expected overnight across northeast Arizona. Otherwise, the
monsoon weather pattern will persist over the region through next
week, with daily rounds of afternoon and evening thunderstorms.
The highest rain chances are currently expected on Monday and
Scattered to numerous thunderstorms have developed today across
western Arizona, with several reports of .50 to nearly an inch of
rainfall and a few reports of pea to marble sized hail.
For tonight through Monday afternoon...We have followed the HRRR
and UA WRF models closely for tonight. These models continue to
show high pressure aloft centered over Colorado with light east
and northeast flow into Arizona. QPF panels show rainfall tonight
across the northeast quarter of the state as a disturbance moves
from the 4 corners southwestward overnight.
Scattered storms are expected for Sunday and Monday. On Sunday,
covection likely to start first over the highest terrain of
Coconino County, while the eastern Mogollon rim and White
mountains should see a delayed start as this area may be
recovering from tonights disturbance.
From Monday night through Friday. Moisture increases with
potential for some dynamics as an inverted trough drifts through
southern Arizona Monday and Tuesday. This should be a much more
active period as improved moisture also arrives due to a shift in
the transport winds.
.AVIATION...For the 00z package...Expect isolated to scattered
-SHRA/-TSRA over northern Arizona through 12Z Sun due to a
disturbance moving from the Four Corners southwestward. An early
morning break in preciptation is expected through 17z, then
scattered storms redevelop over the higher terrain. MVFR conditions
with gusty outflow winds near any storms.
Otherwise VFR conditions expected away from thunderstorms, with
variable winds to 10 kts. Aviation discussion not updated for TAF
.FIRE WEATHER...Expect increased shower and thunderstorm activity
across northern Arizona through Monday. A disturbance moving from
the four Corners southwestward tonight should produce scattered
showers and storms tonight.
Tuesday through Thursday...The monsoon pattern continues across
northern Arizona for this period. Expect scattered to numerous
afternoon and evening showers and thunderstorms, with better chances
for widespread wetting rains each day.
For Northern Arizona weather information visit
Area Forecast Discussion
National Weather Service Hastings NE
800 PM CDT Sat Jul 7 2018
Issued at 800 PM CDT Sat Jul 7 2018
A few notes for this evening`s forecast/product update:
1) Although a rogue shower managed to pop up slightly outside our
far southern CWA in Ellis County KS a little earlier, unlike
yesterday evening, no daytime-heating-driven activity managed to
affect southern portions of our domain. Now that the sun is going
down and visible satellite clearly shows diurnal cumulus fading
away, any small chance of thunderstorms that once existed in our
southern zones has since ended, and have "cleaned up" our short-
term Hazardous Weather Outlook (HWOGID) as a result.
2) Although still several days away, decided to introduce a
mention of heat index values of 100 degrees or slightly higher to
our HWO for Wednesday-Friday afternoons, as this appears to be our
next chance of having at least "near-Advisory" heat levels, mainly
within our far southern/eastern zones. This also matches us better with
neighboring offices such as OAX/TOP/ICT/LBF, who already had a
heat index mention going in their respective HWO products.
3) The forecast for the rest of tonight appears to pretty much be
on "auto-pilot", with clear skies, virtually zero chance of
rain/storms, south-southeast breezes around 10 MPH-or-less, and
overnight lows eventually settling into mainly the upper-60s.
.SHORT TERM...(This evening through Sunday)
Issued at 302 PM CDT Sat Jul 7 2018
Just enough low-level moisture and lapse rates for me to throw in
some isolated pops mainly over north-central Kansas. We don`t have
the divergence aloft and well-defined instability axis as we did
yesterday, so I am not looking for a lot of activity here. Models
are not generally handling short-term convection well, but the
latest HRRR indicates the possibility of small pop-ups into mainly
our north central Kansas counties, and perhaps just into Nebraska,
mainly over the area of slightly more favorable low-level lapse
Persistent and intense upper ridge continues to expand east and will
provide a warm and dry forecast with lows tonight in mid to upper
60s and highs Sunday near 90 to the lower 90s. These temperatures
are a bit above normal, which is what one would normally expect with
an upper ridge as in this case. Flow will remain rather weak aloft
as the jet stream lies primarily in southern Canada near the US
.LONG TERM...(Sunday night through Saturday)
Issued at 302 PM CDT Sat Jul 7 2018
Flow remains weak for the long term as the upper ridge strengthens
its influence at the beginning of the long term period. Ensembles
indicate a potential weakness from a wave skirting the northern
periphery of the upper ridge, possibly flattening or breaking down
the previous amplification. This may possible allow the ridge to
turn a bit farther south, which could possible send it far enough
south to give us a small shot at rain/thunder by the end of the work
week. Given the strength of the upper high, this may be a bit of a
stretch, but appears to be the next possible chance of precip. With
the anomalously strong high, comes somewhat above normal
temperatures with highs in the 90s and lows in the 65-75 range.
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday)
Issued at 616 PM CDT Sat Jul 7 2018
Confidence is very high in continued VFR ceiling/visibility and
rain/storm-free weather with little if any cloud cover, and any
possible light haze around sunrise not expected to drop visibility
below 6SM. If anything, probably got a bit too detailed with wind
trends in the TAFs, but the bottom line is that a generally
southerly direction will prevail throughout, with sustained speeds
at-or-below 12KT most of the time, and the overall-strongest
speeds with gust potential around 20KT focusing between 18-22Z
Sunday afternoon. Any low level wind shear (LLWS) overnight
appears to be a bit marginal to formally include at this time
(shear magnitude only topping out around 25KT).
Area Forecast Discussion
National Weather Service Medford OR
804 PM PDT Sat Jul 7 2018
.UPDATE...Smoke continues to pour from the Klamathon Fire, filling
the Shasta Valley, and overspreading much of the region along and
east of the Cascades. Once daytime winds clam, overnight
inversions will allow the smoke to settle into area valleys once
again. Prevailing winds above the surface remain from the
southwest, while surface winds remain northerly. This means the
same areas that saw smoke this morning and today are likely to
see the same, if not more, tomorrow.
No updates were needed this evening, other than to refine
expected smoke coverage. For more information on the rest of the
forecast, see the previous discussion below.
.AVIATION...For the 08/00Z TAFs...Smoke from Klamathon Fire will
lower visibility across the Shasta Valley of northern California to
MVFR with IFR vis likely in valleys where smoke settles overnight.
With southwest steering winds, smoke has drifted into the southern
Oregon Cascades and the Klamath Basin and vis at LMT has gone down
to MVFR. Expect terrain and mountain obscuration in these areas.
HRRR smoke model shows condition remaining steady overnight as
northwest winds keep denser smoke and lower visibility in northern
Siskiyou County. However winds on Sunday are expected to shift to
southerly and the smoke model bring denser smoke and lower
visibility to LMT from late morning (18Z) through the remainder of
Sunday. We have gone with MVFR vis for LMT but occasional IFR vis
from smoke drifting in and out is possible Sunday.
For the coast, patchy MVFR cigs are likely to form again tonight,
mainly north of Cape Blanco, and in the Coquille and Umpqua Basins.
VFR conditions are expected elsewhere overnight and into Sunday. -FB
.MARINE...Updated 800 PM PDT Saturday 7 July 2018...Relatively calm
conditions will continue through the weekend. Seas will remain at or
below 5 feet through Monday and northerly winds will remain below
small craft advisory levels. Although the wind forecast for
this afternoon and evening has been decreased, areas south of Cape
Blanco and within 30 nm from shore may see a few wind gusts approach
small craft advisory levels. Near shore, some fog and low clouds may
develop tonight from Point Saint George north to Brookings or Gold
The thermal trough will redevelop Tuesday. Winds will steadily
increase next week, with small craft advisory winds and seas likely
developing Monday evening into Tuesday for areas south of Cape
Blanco. Then winds and seas increase further Tuesday evening and
Wednesday, possibly reaching gales. Gusty winds with steep to very
steep seas are possible north of Cape Blanco by mid week. -BS/BPN
.FIRE WEATHER...Updated 300 PM PDT Saturday, 07 July 2018...
Breezy southwest winds are ongoing east of the Cascades and the
eastern portions of northern California this evening. These
conditions will continue into tomorrow, but the airmass is expected
to dry out even more compared to today , Saturday. This drying will
result in some single digit RH values in northern California and
south central Oregon on Sunday. Given the drier airmass, we
believed another red flag warning was needed.
RH`s will trend higher on Monday with winds trending slightly lower
over the region. It appears the slightly higher RH`s will keep us
out of red flag warning criteria, but the winds Monday should be
similar to the winds on Sunday.
With this upcoming warm up, models are expecting a thermal trough
and offshore winds to build along the Curry County coastline. This
should bring lower RH`s to that region in addition to some breezy
winds for the middle of the week.
Temperatures are expected to push into the 90`s and 100`s next week
Wednesday into the weekend. We`ll also have the chance for
thunderstorms Thursday into the weekend as some monsoon moisture
comes out of the southwest. -Smith
.PREV DISCUSSION... /Issued 520 PM PDT Sat Jul 7 2018/
DISCUSSION...Dry and gusty weather continues into Sunday east of
the Cascades. Although an upper level trough begins to move into
the region Monday, heights remain relatively constant into
Tuesday when the axis of the trough moves through the region. A
weak front offshore washes out with the tail end of the frontal
precip brushing inland well north of the region. the result of
this trough passage will mostly be a slight cool down Monday that
remains into Tuesday, and north winds prevailing down into
California for both days. An upper ridge then builds behind the
exiting trough offshore with heights rising, a thermal trough
deepening on the coast bringing off shore flow across the east
side by Wednesday. This combination will bring temperatures to
triple digits by Thursday in the west side valleys south of the
Umpqua divide. On Thursday monsoonal moisture begins to move in
from the south and have added a slight chance of thunderstorms in
Northern California. The preceding southerly flow does not begin
until Wednesday night, so the confidence that it will happen is
not high. With a cut off low developing off shore of central
California, the monsoonal moisture continues to wrap into our area
Friday, bringing chances of thunderstorms into southern Oregon,
but have kept just slight chances at this time. Sven
OR...Red Flag Warning from noon to 9 PM PDT Sunday for ORZ624-625.
CA...Red Flag Warning from noon to 9 PM PDT Sunday for CAZ285.
Red Flag Warning until 9 PM PDT this evening for CAZ285.
Pacific Coastal Waters...None.
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1002 PM EDT Sat Jul 7 2018
Tropical Depression Three will meander off the southeast coast
for the next several days before moving off to the northeast by
midweek. A trough of low pressure and weak front will move into
the region mid to late week.
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
As of 950 PM Sat...Latest radar returns continue to show bands
of light rain showers coming ashore, while an isolate
thunderstorm is over the Gulf Stream this evening. Slightly
lowered PoPs based on current radar trends and latest HRRR
model. The best chances for rain will continue over the coastal
counties. No other changes to the public forecast.
Pre Dis...The sfc analysis is showing high pressure to the
north, while TD#3 is well to southeast of NC this evening, and
will continue to spin and remain nearly stationary overnight.
Occasional bands of rain showers will continue to rotate ashore
through tonight for coastal areas where chance to likely PoPs
are forecast through the night. The weak trough started to sink
down into the Coastal Plains this evening and precip has
dissipated over the inland area...therefore have made tweaks to
PoPs over the Coastal Plains. Breezy conditions will continue as
the gradient tightened between TD#3 and high pressure ridging
into the Carolinas from the NW. Lows tonight near climo in the
mid/upr 60s interior to low 70s coast.
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
As of 330 PM Sat...TD3 will remain well to the SE with best
moisture along the coast, though not as much covg as Sat and
therefore just advertising sct/iso pops for eastern 2/3 of the
FA, with dry conditions interior. It will continue breezy,
especially along the coast with tightened gradient between TD3
and high pres ridging into the Carolinas.
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
As of 330 AM Sat...Main feature through mid week will be TD 3,
which is forecast to slowly meander off the SE coast.
Sunday through Tuesday...TD 3 is forecast to strengthen and
slowly meander off the SE coast into Monday before finally
lifting NE Tuesday. Some uncertainty remains regarding the
intensity of the system and exact track, which will impact the
forecast specifics. It still looks like the system will remain
far enough east to keep the strongest winds well off the coast,
though a jog to the west and areas along the immediate coast
could see some stronger wind gusts develop. Most models keep the
system well offshore, though the NAM/HWRF/UKMET/CMC bring it
closer to the NC coast. At this time it still looks like the
main impacts from TD 3 will limited to areas along the immediate
coast. Expect an enhanced rip current threat this weekend into
early next week, as well as rough surf for the beaches. Some
ocean overwash and minor erosion will be possible for the Outer
Banks. Interested parties should continue to monitor this system
over the next few days.
Highs in the low to mid 80s Sunday, warming a few degrees Monday
and Tuesday. Could see isolated to scattered showers along the
coast in the outer rainbands, and will keep sc to low chance
Wednesday through Friday...TD is forecast to lift quickly NE
Tuesday night and Wed, along with any lingering impacts. Upper
trough moves into the area, and models try to show a weak front
pushing into the area Thursday. Increasing precip chances and
will keep sc to low chance pops. Temps near climo through the
period, in the upper 80s to low 90s. Models also trying to show
lingering Beryl lifting well offshore of the SE coast Thu and
Fri, which could lead to additional rip current concerns for the
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
Short Term /through 18Z Sunday/...
As of 715 PM Sat...High confidence of a mix of VFR and MVFR
conditions for the TAF period. Expect MVFR conditions to
persistent over the coastal TAF sites (KEWN/KOAJ) as there is
plenty of moisture over the area on the outer periphery of
Tropical Depression #3, while inland TAF sites (KPGV/KISO) will
see mainly VFR, but cannot rule out an occasional MVFR ceiling
to stream by overnight. Winds will remain gusty through tomorrow
as pressure gradient is tightened. Expect additional showers
over the coastal TAF sites tomorrow and MVFR ceilings
condition spreading to the inland TAF sites after 12z Sun.
Long Term /Sunday night through Wednesday/...
As of 330 AM Sat...Sub-VFR conditions could lingering into
early Sun, then improving to pred VFR through mid week.
Short Term /through Sunday/...
As of 950 PM Sat...A tight pressure gradient remains over the
portions of the coastal waters this evening as high pressure
from the north and TD#3 remains to the southeast of NC. This
resulted in persistent gusty winds up to 40kt mostly over the
Sounds, Alligator RVR and north of Cape Hatteras...therefore
have upgraded those zones to a Gale Warning until 4 am Sun. The
SCA for the rest of the coastal zones remain unchanged.
Pre Dis...Only change to the SCA was to add Neuse river to the
headline, and adjusted ending times of the SCA for the waters
per latest NWPS. Tightened gradient will persist between TD3
well off the NC coast and high pres riding in from the N and NW.
Winds will be a solid 20-30 kt with ocnl gusts to gale force,
with highest winds across the sounds and nrn waters. Trop
Depression Three to the SE and high pres to the N. Seas will
build to 6 to 9 feet for the northern waters, and therefore
issued high surf adv for areas north of Oregon Inlet. Seas
further south into the 4 to 7 ft range.
Long Term /Sunday night through Wednesday/...
As of 330 AM Sat...The main feature late weekend into early
next week will be TD 3, which is forecast to slowly meander off
the SE coast. Current NHC track shows TD strengthening, then
lingering off the SE coast into Monday before finally lifting NE
Tuesday. Some uncertainty remains regarding the intensity of
the system and exact track, which will impact the forecast
specifics. It still looks like the system will remain far enough
east to keep the strongest winds out of our waters, though a
slight jog to the west and coastal waters could see TS force
wind gusts. SCAs currently out for the waters and sounds
through early next week, and may need to be extended depending
on how the TD evolves. Gusty NE winds will continue Sunday,
15-25 kt, diminishing to 15-20 kt Mon. Seas will peak at 5-8 ft
north of Hatteras Sunday, and 4-7 ft south diminishing about a
foot or so Monday. Winds become more S/SW late Tue and Wed with
seas slowly subsiding.
NC...Beach Hazards Statement through Sunday evening for NCZ103.
High Surf Advisory until 8 PM EDT Sunday for NCZ103.
MARINE...Small Craft Advisory until midnight EDT Sunday night for
Gale Warning until 4 AM EDT Sunday for AMZ130-131-135-150-152.
Small Craft Advisory until 5 PM EDT Monday for AMZ154.
Small Craft Advisory until 7 AM EDT Monday for AMZ156-158.
Area Forecast Discussion
National Weather Service Nashville TN
833 PM CDT Sat Jul 7 2018
FOR EVENING DISCUSSION.
Latest radar imagery this evening shows widely scattered showers
and storms continued in an arc from our southern counties
northeastward into the Upper Cumberland. Have adjusted pops for
the evening based on radar. After midnight, HRRR suggests a few
showers will remain possible over southern zones so will keep a
slight chance pop going for there, but will go dry everywhere
else. Also added mention of patchy fog over the south and east
where today`s rainfall will likely lead to some fog formation
overnight. Otherwise, forecast appears to be on track with only
a few other minor tweaks.
00Z TAF DISCUSSION.
While cigs may dip into the 3kft to 5kft this evening as
diminishing showers and storms pass over CSV, BNA, and MQY, expect
mostly VFR conditions throughout tonight. Clouds will increase on
Sunday morning as winds turn out of the southeast. Afternoon
showers are expected again with the best coverage over areas west
of I-65. Included VCSH in the forecast for all sites after 18z.
Area Forecast Discussion
National Weather Service Tallahassee FL
959 PM EDT Sat Jul 7 2018
Modified PoPs somewhat across GA to account for line of weakening
showers/storms along I75. HRRR has whats left of it possibly
making it into the Albany area before dissipating so nudged chances
up in this area through 06Z. After 06Z best PoP chances move
offshore. Skies will be mostly cloudy overnight with lows in the
.PREV DISCUSSION [730 PM EDT]...
.NEAR TERM [Through Tonight]...
Scattered to numerous showers and thunderstorms are expected through
the early evening hours before gradually diminishing. Storms will
likely last the longest across the far northern portion of the
forecast area. There still appears to be the threat for a few
stronger storms to pulse up with gusty winds this afternoon and
evening, mainly across portions of southern Georgia and southeast
Alabama. Modifying the 12z KTAE sounding for afternoon T/Td of 90/73
yields SBCAPE values around 4000 j/kg. The mid level lapse rates are
fairly steep for this time of year with the observed 700-500 mb
lapse rate at 6.8 C/km. Overnight lows are expected to be in the low
to mid 70s.
.SHORT TERM [Sunday Through Monday Night]...
In the upper levels a ridge will be over the Southeast. At the
surface a weak pressure gradient will be over the region. A weak
stationary boundary will be over the region on Sunday and Monday.
Therefore showers and thunderstorms will be more widespread than a
typical summer day. Convective activity will not be confined to the
afternoon and evening hours. Although afternoon/evening will be the
most active times. Daytime POPs will be 50 to 70 percent. Nighttime
POPs will be 20 to 40 percent. Highs will be in the upper 80s and
lower 90s. Lows will be in the lower 70s.
.LONG TERM [Tuesday Through Saturday]...
In the upper levels a ridge will be over the Southeast until an
upper level low forms late in the week. At the surface a weak
pressure gradient will be over the region until a weak low forms
late in the week. Nighttime POPs will be 20 to 40 percent. Daytime
POPs will be 40 to 60 percent, possibly higher late in the week as
low pressure develops. Highs will be in the lower 90s. Lows will be
in the lower 70s.
.AVIATION [Through 00Z Monday]...
An overall decreasing trend is expected with thunderstorm activity
over the next several hours. Overnight, VFR conds should prevail
into the early morning hours. Diurnal CU will develop by mid
morning with bases 025-030. Thunderstorm development will occur by
late morning with scattered coverage across the Tri-State region
into the afternoon.
Light winds will be southerly through the weekend. Light winds will
be northerly early this week. Seas will be low around 1 to 2 feet.
Other than low dispersions Sunday, no fire weather conditions are
expected. Chances for wetting rains will remain high through much of
the next week.
The wet weather continues through this week. Local rivers are steady
and below action stage at this time. QPF is 1 to 2 inches over the
next week. Higher rain totals locally are possible. Ponding of water
on roadways and flooding of low lying areas is possible with heavier
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 71 90 73 92 74 / 30 70 30 50 20
Panama City 74 88 75 90 76 / 40 50 20 50 30
Dothan 72 88 72 90 73 / 40 60 30 60 30
Albany 73 90 74 91 74 / 60 60 40 60 20
Valdosta 71 90 73 90 73 / 40 70 40 60 20
Cross City 72 91 73 91 73 / 30 50 20 40 30
Apalachicola 75 87 75 89 77 / 40 40 20 40 20
Area Forecast Discussion
National Weather Service Tucson AZ
141 PM MST Sat Jul 7 2018
.SYNOPSIS...Deeper moisture will bring a significant upswing in
showers and thunderstorms this weekend into next week. Daytime
temperatures will be above normal this weekend then be generally
below normal next week.
.DISCUSSION...Not much change in thinking from this morning`s
discussion, with the upper high centered just north of the four
corners region over west central Colorado and the upper ridge
oriented from southwest to northeast across the desert southwest and
into the central high plains. The first cells developed today around
19Z and were along the Rim and over portions of central Pima County.
At this time just very isolated activity, although models continue
to show isolated to scattered activity as we work through the
remainder of afternoon and into the evening hours tonight. The 18Z
HRRR and the UofA AZ WRF-NAM/WRF-GFS all indicate the favored area
of development along the Rim, with this activity then pushing to the
southwest. A weak disturbance over far west central New Mexico (as
seen on the Goes-16 Mid Level Water Vapor Channel 9 (6.95um)) is
expected to enhance development as it works into the region later
The high center will remain quasi-stationary over the next 36-48
hours, as the upper ridge becomes more amplified across the western
United States. As this takes place, mid level flow will switch from
a east/northeast direction today to a east/southeast direction by
Monday. This subtle change in the flow pattern will allow for deeper
moisture to work into the area as model PW values near 1.5" on
Monday. The models all begin to ramp up activity on Sunday, but
especially so in the Monday through Wednesday time frame. At this
time have scattered pops in the valleys for Sunday, with scattered
to numerous pops in the mountains. SPC has highlighted a good chunk
of the forecast area on Sunday as Marginal Risk, with isolated
severe thunderstorms possible and the main threat being strong wind
gusts. Expect high end scattered valley pops Monday through
Wednesday, with numerous showers and thunderstorms in the mountains.
Deterministic model guidance numbers are indicating that the
convective activity early to mid next week will occur during the
late afternoon and especially the evening/late night hours.
By late next week, expect a typical monsoon forecast with scattered
afternoon and evening showers and thunderstorms, mainly from Tucson
eastward. Daytime temperatures will be a couple of degrees above
normal through Sunday, before lowering to below normal values most
of next week due to deeper moisture and increased cloud cover.
.AVIATION...Valid through 09/00Z.
Isolated to scattered -TSRA/-SHRA with strong gusty outflows
possible this afternoon/evening as well as Sunday morning/afternoon.
Due to the isolated nature of the storms today, have not included
-TSRA/-SHRA in the TAFs, however ammendments may be needed later in
the day. This afternoon and evening expect SCT to locally BKN clouds
at 8k-12k ft AGL with SCT-BKN layer above 20k ft AGL. Ceilings could
be MVFR near any storms. Outside of thunderstorm winds, SFC winds
will be out of the east/southeast at 8-15 kts with some afternoon
gusts. Aviation discussion not updated for TAF amendments.
.FIRE WEATHER...Moisture will continue to increase resulting in
significant increases in Min and Max RH values and thunderstorm
coverage. From Sunday onward we are expecting more numerous
thunderstorms and showers across the entire area including
occasional rounds of nighttime storms. Mainly for the first few
days, the rain cores will be smaller with dry lightning around the
periphery of the storms. Typical storm motion will be toward the
west or southwest. 20 ft surface winds will generally be 15 mph or
less from an easterly direction through midweek, and thereafter
follow a more typical diurnal pattern. In the vicinity of
thunderstorms expect strong and variable winds.
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson