Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/02/17
Area Forecast Discussion
National Weather Service Albany NY
1034 PM EDT Tue Aug 1 2017
.SYNOPSIS...
Warm and humid conditions will prevail through remainder of the
week. Scattered showers and thunderstorms expected Wednesday.
There will be better chances for showers and thunderstorms
Thursday through Saturday as a slow moving low pressure system
approaches and moves across the region.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
As o 1030 PM EDT, only minor changes need this evening to
account for the cooler temperatures across the higher terrain.
Also added heavy rain wording for tomorrow afternoon across the
Mid-Hudson Valley, Taconics, Litchfield Hills and Berkshires to
account for high PW values and slow storm movement. Otherwise,
forecast remains on track for tonight. Sent updates to NDFD and
web servers.
Prev Disc...
Isolated showers and thunderstorms continue early
this evening, mainly across the eastern Catskills. These storms
should dissipate with the loss of daytime heating within the
next hour. In terms of the forecast, updated the sky cover and
hourly temps to reflect recent trends and sent updates to NDFD
and web servers.
Prev Disc...
On going isolated showers and thunderstorms occurring mainly
south of I-90 will weaken and dissipate with the loss of the
heating. The HRRR has this occurring by 01Z-02Z/Wednesday.
Tonight will be a bit warmer/muggier than last night with lows
mainly in the 60s with some 50s across the southern Adirondacks.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
The area will remain in a very warm and humid air mass with a
cold front on the approach from the Great Lakes region. Heights
aloft will remain fairly steady across the Northeast through
Thursday. A vigorous short wave will dive southeastward out of
central Canada and over the Great Lakes region deepening the
longwave trough with an upper level developing over the western
Great Lakes region. Scattered convection is expected across the
local area mainly during the afternoon into the evening hours.
The activity will wane off at night with loss of heating and
decreased instability. Storms will be capable of some heavy
downpours with precipitable water values increasing to around
1.5 inches and mean flow remaining weak resulting in slow
moving storms.
Highs will continue to be in the upper 70s to mid 80s however
dew points will climb into the mid to upper 60s. Muggy nights
with lows in the 60s.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
There will be a very good chance for thunderstorms through the end
of the week, followed by a brief dry reprieve Saturday night and
Sunday, and a chance for rain during the early part of the work
week. A cold front slides through from the west Friday night.
High pressure builds in slowly behind it, just in time to
salvage the latter half of the weekend. But a system moving out
of the northern Rockies will track roughly east across the Lower
Great Lakes region. This low will be along a quasi-stationary
front along which weak waves could evolve beyond the extended
period.
Friday will be the mildest day...with highs ranging from the mid 70s
to mid 80s. Saturday`s highs will range from only the lower 60s in
the Adirondack high peaks...to around 80 degrees in the Mid-Hudson
Valley, where highs will roughly be throughout the remainder of
the period. Lows Friday night will be in the upper 50s to upper
60s range. Saturday and Sunday night lows will range mainly
from around 50 degrees to the upper 50s...with lows rebounding a
few degrees for Monday night. Normal early August highs at
Albany are in the lower 80s...with the lows in the lower 60s.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
A few isolated showers remain across the eastern Catskills but
should dissipate within the hour. Generally VFR conditions
should prevail through the TAF period. Patchy fog may form again
later tonight, especially in any areas which receive isolated
showers/thunderstorms earlier this afternoon. Best chance for
dense morning fog is at KGFL and KPSF.
Additional isolated to scattered showers and thunderstorms will
again be possible tomorrow afternoon but with limited aerial
coverage, did not include them in the TAFs at this time.
Winds are forecast to be light and variable this evening
through tonight. South to southwest winds at 5-10 knots are
expected on Wednesday.
Outlook...
Wednesday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Thursday: Moderate Operational Impact. Chance of SHRA...TSRA.
Thursday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Friday: Moderate Operational Impact. Chance of SHRA...TSRA.
Friday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Saturday: Moderate Operational Impact. Chance of SHRA...TSRA.
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: No Operational Impact. NO SIG WX.
&&
.FIRE WEATHER...
Warm and humid conditions will prevail through remainder of the
week. Scattered showers and thunderstorms expected Wednesday.
There will be better chances for showers and thunderstorms
Thursday through Saturday as a slow moving low pressure system
approaches and moves across the region.
Minimum relative humidity values are forecast to be generally
45 to 55 percent both Wednesday afternoon and in the 50s
Thursday afternoon, with a recovery to 90 to near 100 percent
at night, with areas of dew formation likely.
Winds will generally be light and variable today and tonight,
and from the southwest at less than 10 mph Wednesday and
southerly Thursday generally 10 mph and less.
Winds will be stronger, and variable in direction in and near
any thunderstorms.
&&
.HYDROLOGY...
Warm and humid conditions will prevail through remainder of the
week. Scattered showers and thunderstorms expected Wednesday.
There will be better chances for showers and thunderstorms
Thursday through Saturday as a slow moving low pressure system
approaches and moves across the region.
For details on specific area rivers and lakes, including
observed and forecast river stages and lake elevations, please
visit the Advanced Hydrologic Prediction Service /AHPS/ graphs
on our website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...IAA
NEAR TERM...IAA/JVM
SHORT TERM...IAA
LONG TERM...ELH
AVIATION...SND/JVM
FIRE WEATHER...IAA
HYDROLOGY...IAA
Area Forecast Discussion
National Weather Service Bismarck ND
1051 PM CDT Tue Aug 1 2017
.UPDATE...
Issued at 1045 PM CDT Tue Aug 1 2017
Given the strength of the upper level wave and QPF signals in the
18-00 UTC global guidance, backed up by CAMs through the 01 UTC
HRRR/RAP, trended towards the higher edge of QPF guidance for
Wednesday.
UPDATE Issued at 715 PM CDT Tue Aug 1 2017
Very little change with this update for the evening outside of
observed trends through 23 UTC blended to the 18 UTC global models
and rapidly updating suites through the 22 UTC HRRR for
precipitation evolution late tonight through Wednesday evening.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 233 PM CDT Tue Aug 1 2017
The short term will focus on the start of precipitation in what
will be the first significant rainfall for the region in quite a
while.
Late Tuesday afternoon a cold but nearly stationary frontal
boundary was draped east-west across northern South Dakota. A
shortwave trough topping a west coast ridge at h500 will dig
southeast into the northern plains tonight. Global models agree
the advancing shortwave will set up a strong return flow at h850
and bring moisture northward over the frontal boundary into North
Dakota. This will lead to widespread showers and scattered
thunderstorms. Average QPF from the models suggests the best
rainfall will be from northwest through central into southeast
North dakota where rainfall amounts of a half an inch to an inch
are possible by Wednesday night. Lesser amounts southwest. The
ensemble situational table continues to show an anomalously high
surface pressure across Alberta/Saskatchewan and into western
North Dakota. This supports the cool forecast high temperatures
for wednesday and Thursday.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 233 PM CDT Tue Aug 1 2017
The extended period is dominated by northwest flow aloft which
will keep temperatures generally cool through the period. The
coolest day will be Thursday followed by a general warming trend
through the weekend. The next chance precipitation will be
Saturday with the next shortwave. After Saturday generally dry
weather with near normal Temperatures.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1045 PM CDT Tue Aug 1 2017
Rain showers with embedded thunderstorms will increase across
western and north central North Dakota late tonight, and will
continue to increase west and central Wednesday morning and into
the early afternoon. Precipitation will decrease from west to east
late in the afternoon and through the evening. MVFR/IFR
conditions will develop in precipitation on Wednesday.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...PA
SHORT TERM...WAA
LONG TERM...WAA
AVIATION...PA
Area Forecast Discussion
National Weather Service Dodge City KS
605 PM CDT Tue Aug 1 2017
...Updated Aviation Discussion...
.SHORT TERM...(This evening through Wednesday)
Issued at 107 PM CDT Tue Aug 1 2017
Although a northwest flow aloft will intensify somewhat this evening
as a +70kt jet core transitions down the front of a building ridge
out west, a weak shear profile, a weak and disorganized flow in
the lower levels, and a lack of heating due to a prevailing cloud
deck will limit precip chances across the region tonight through
Wednesday afternoon. Clearing skies with surface dewpoints holding
in the lower to mid 60s(F) for the most part will allow lows to fall
well into the 60s(F) tonight. For Wednesday, a weak surface high is
projected to sink southward across the Central Plains as weak lee side
troughing slowly develops across eastern Colorado. This will bring
about a light southeast flow to western Kansas, tapping into slightly
warmer air to our south. Look for highs pushing the lower 90s(F)
Wednesday afternoon.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 222 PM CDT Tue Aug 1 2017
Thunderstorm chances return Wednesday night as medium range models
indicate an upper level shortwave trough digging southeast across
the Dakotas into the Upper Midwest, sending an attendant cold front
southward into western Kansas overnight. Meanwhile, a prevailing
southeast upslope flow will help draw moisture into the region
reinforcing surface dewpoints up into the 60s(F) and increasing
instability ahead of the frontal boundary. Sufficient forcing
provided by the frontal boundary will set the stage for possible
thunderstorm development late Wednesday night into early Thursday.
The focus for thunderstorm chances shifts southward with the
advancement of the frontal boundary, placing the best chances for
precip closer to the Oklahoma border Thursday afternoon/evening.
Surface high pressure will fill in across the Central Plains Friday,
returning a southeast upslope flow to the Western High Plains and
the potential for diurnally driven thunderstorms off the higher
terrain of eastern Colorado as low/mid level lapse rates steepen
Friday afternoon. A few storms could drift eastward into extreme
western Kansas Friday night. Thunderstorm chances continue into
Saturday as yet another cold front is projected to push across the
region early in the weekend.
Cooler air filtering into western Kansas in wake of a frontal
passage Wednesday night will drop high temperatures to well below
normal levels Thursday afternoon. Expect highs only up into the
70s(F) across west central Kansas with the 80s(F) still possible
toward south central Kansas. Similar highs can be expected Friday
with a small warm up likely Saturday as a southerly flow sets back up
across western Kansas in wake of a departing surface high.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 604 PM CDT Tue Aug 1 2017
A few weakening thunderstorms will be possible near the Garden
City area over the next few hours. Model soundings and surface
observations indicated that the cloud bases with these storms
will be at or above 4000ft AGL. Once these few storms dissipate
the skies are expected to clear and with a light east to
southeasterly winds there will be a chance for some early morning
fog. NAM and RAP models soundings both suggesting area most
favorable for fog development will be around Dodge City and
Liberal but the depth of this near surface moist layer is not very
deep. At this time dense fog is not expected only some MVFR
visibilities possible between 09z and 15z Wednesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 62 90 64 81 / 10 0 20 30
GCK 62 88 62 78 / 20 0 30 30
EHA 62 88 62 80 / 40 0 20 30
LBL 62 90 63 81 / 20 0 20 30
HYS 63 89 64 79 / 10 0 20 20
P28 65 91 67 86 / 10 0 0 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JJohnson
LONG TERM...JJohnson
AVIATION...Burgert
Area Forecast Discussion
National Weather Service Houston/Galveston TX
1009 PM CDT Tue Aug 1 2017
.DISCUSSION...
Radar imagery shows a void of echoes across SE Texas as convection
has dissipated from this evening. The 00Z upper air data shows a
jet streak at 300mb over the Texas panhandle with the main
anticyclone over Mexico. GOES 16 water vapor imagery and derived
upper level winds confirm this. GOES 16 derived precipitable water
imagery shows a large area of PW greater than 2 inches across SE
Texas and extending into the Gulf. The 00Z LCH and CRP soundings
are on either side of this moisture plume see in the GOES 16
imagery. This plume seems to be on the south side of a frontal
boundary, perhaps the old frontal boundary that pushed through
over the weekend.
From a pattern recognition standpoint, a lot of boxes get checked
for the potential of heavy rainfall. Aloft there will be an
approaching jet streak where the nose of the jet is pointed right
at SE Texas tomorrow afternoon. This is about the same time a
trough axis and height falls occur over the area along with
increased jet divergence and large scale ascent. If it was not for
the NW flow aloft, this pattern looks very much like a setup for
late spring. About the only thing missing is a strong LLJ in the
boundary layer. However there will be a lot of moisture for
thunderstorm development. Synoptic models show PW getting close
to 2.4 inches at time which would be pushing climo 99 percentile
for the area. There also looks to be several boundaries for storms
to form along. One boundary will be along the plume of higher PW
air along the Gulf coast. A second will be outflow pushing down
from the north so there may be some natural convergence due to the
boundaries pushing together. It looks like there could be a
couple areas that could see heavy rainfall based on the location
of boundaries but the exact location will largely depend upon
mesoscale evolution. For now areas from College Station to
Crockett along the northern boundary could see heavy rainfall, and
then down along the coast anywhere SW of Houston to E of Houston.
Several models like the 00Z HRRR, 00Z NAM, 18Z Tx Tech WRF, 21Z
HRRR ensemble, 00Z HRRR-TL, NCAR ensemble, and 18Z GFS show
similar precipitation patterns consistent with the boundary
locations. Ensemble guidance shows areas of greater than 50
percent chance of 3 inches of rain in a 6 hour period. It is also
worth noting that none of them show any probability of 6 inches of
rain in a 6 hour period. It seems that 1 to 3 inches of rain
looks like a good range and likely cause street flooding and rapid
rises on bayous. The concern is that given the synoptic set up,
there could be the possibility of higher rainfall amounts in a
short period of time. Given the FFG of 4 to 6 inches in 3 hours,
most areas can handle this much precipitation except for the urban
areas. For now a FF watch is not needed, but this could be
revised tomorrow depending upon how storms evolve.
For now the changes to the forecast include increasing PoPs a bit
along the coast and to the north where boundaries are expected to
be located. Forecast will leave wording for locally heavy rainfall
as this should be the primary threat.
Overpeck
&&
.PREV DISCUSSION... /ISSUED 637 PM CDT Tue Aug 1 2017/
AVIATION...
First portion of the forecast looks generally on track, with VFR
conditions across the area and winds slowly coming down through
the evening. Big picture for the back half also appears good, but
uncertainty about the details - including the potential for
heavier rain - remains at this time.
As an upper disturbance swings into Southeast Texas, feel there`s
enough confidence to start bringing in TEMPOs for rain/storms at
the northern sites. The question comes closer to the coast, as
convergence in winds seen today over Colorado/Austin/Wharton
counties will set up and become the dominant feature for our
Houston and coastal TAF sites. While the blanket VCs seem
reasonable, whether the northern feature or the coastal feature
become dominant may impact the timing of when the best coverage of
storms is possible farther south by several hours. For now, both
scenarios seem plausible, so will punt on probs/tempos for this
cycle, and look for more clarity with the evening model runs.
It does seem likely that around 00Z, most of the rain will be
ending or at least moving east of the TAF sites. For most, this is
the end of period so I don`t explicitly forecast this at this time,
but does show up in the extended portion of the IAH TAF.
Luchs
PREV DISCUSSION... /ISSUED 358 PM CDT Tue Aug 1 2017/
DISCUSSION...
Gulf moisture nosing back into the region this afternoon had
allowed for a few showers to develop along and south/east of the
Highway 59 corridor, but most of the region has remained dry
today. However, recent dryness will quickly change to a relatively
wet pattern for Southeast Texas for early August as an
approaching disturbance from the Southern Plains reaches the
region later tonight into Wednesday.
Most shower activity is expected to dissipate with loss of
daytime heating this evening, but another round of rain will
approach the region from the north and northwest tonight into
early Wednesday morning as the upper level disturbance arrives.
Additionally, afternoon surface analysis shows several distinctive
surface convergence zones or boundaries located across the
northwest Gulf. Height falls on the order of 2-4 decameters
tonight may result in enough of a surface reflection/trough to
draw one or both of these boundaries inland... but several
questions still exist on when, which one(s), or how far inland
they will travel but will need to monitor areas along and
south/east of Highway 59 based on consensus from 12Z guidance.
Convergence along these features should result in continued
shower development across the waters overnight with coverage
gradually spreading into the coastal counties along any one of
these boundaries. As the upper disturbance passes across the
region on Wednesday, additional showers and thunderstorms may
focus along whatever boundaries move inland. With forecast
soundings showing precipitable water values rising into the
2.2-2.4 inch range (near the 99th percentile for August), locally
heavy rain will be possible with any shower or thunderstorm that
develops tomorrow. Luckily, recent July rainfall deficits of
anywhere from 1-3 inches below normal should help mitigate against
any widespread threat... but a splitting (albeit weak) 250-300 MB
jet over the region during the day should be enough to support
high rain rates and this may result in minor flooding issues in
urbanized areas.
The main energy from the upper disturbance looks to clear the
region Wednesday night into Thursday morning with subsidence
behind this feature expected to result in a temporary decrease in
rain chances during the overnight hours. However, a secondary
shot of energy moving across the region during the day Thursday
should result in the development of another round of scattered
showers and thunderstorms into Thursday night before this energy
clears the region.
Northwest flow aloft will persist across the region through the
end of the work week and into the weekend, with rain chances
highest over the coastal waters at night and inland during the
day. Any smaller disturbance translating across the region during
this time in the flow aloft would certainly result in an
enhancement to coverage, but pinpointing any of those features (or
timing) at this point out is incredibly difficult. One such
disturbance may send a cold front into Texas by Friday, but with
the disturbance quickly pulling east across the Great Lakes the
front appears to lose too much of its upper level support to make
it into the region.
Temperatures over the next few days should remain near to below
seasonal normals due to rain and cloud cover, with highs in the
upper 80s to mid 90s and lows in the 70s to low 80s.
Huffman
MARINE...
A weak trough of low pressure over the western Gulf and high
pressure over the eastern Gulf will maintain a light east wind
through Wednesday. Low pressure will develop in West Texas
Wednesday night into Thursday and surface winds will veer to the
south-southeast by Thursday and persist for the rest of the week.
A series of upper level disturbances will bring unsettled weather
to the coastal waters through next weekend. Winds and seas will be
higher in and near scattered showers and thunderstorms. The
pressure gradient will tighten over the weekend and slightly
stronger onshore winds will be possible on Saturday night into
Sunday. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 74 89 73 92 75 / 10 70 30 30 20
Houston (IAH) 76 87 74 89 76 / 30 60 40 50 30
Galveston (GLS) 79 87 78 87 79 / 50 60 50 50 40
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
Discussion...39
Area Forecast Discussion
National Weather Service Medford OR
836 PM PDT Tue Aug 1 2017
.SHORT TERM...High temperatures records were set today in many
locations, including:
* 110 at Medford which broke the old record of 104 set in 2015
* 102 at Roseburg which broke the old record of 99 set in 2015
* 107 at Montague which broke the old record of 103 set in 2015
* 99 at Klamath Falls, which broke the old record of 97 set in
2015
Also, two locations tied old records for high temperatures today
including:
* 100 at Alturas, which ties the old record of 100 set in 1908
* 74 at North Bend, which ties the old record set in 1940.
Additional very hot temperatures are expected Wednesday with the
heat continuing through the end of the week. Temperatures tomorrow
are expected to exceed 110 in the Rogue Valley with a high of 114
expected at Medford. This will near the all time high at Medford,
which is recorded at 115 degrees. Other west side valleys are
also expected to see highs in the 110 to 115 range. Valleys east
of the Cascades are expected to see temperatures near or slightly
above 100.
This heat brings dangerous conditions to most inland areas due to
the hot conditions over a prolonged period. Overnight lows are
only expected to briefly dip into the upper 60s to mid 70s
tonight and early Wednesday morning before conditions heat up
again. These hot temperatures will continue Thursday and slightly
lower but still hot on Friday. Excessive heat warnings and heat
advisories are out for the area. Please see the NPWMFR for the
latest details.
Otherwise, the second concern with be the slight risk for
thunderstorms over central and eastern portions of the area
tomorrow. This slight risk continues in portions of Siskiyou
County on Thursday then expands slightly into the Southern Oregon
Cascades and Siskiyou and possibly into the east side mountains
in Modoc and Lake counties on Friday and Saturday. Sunday and
Monday, the thunderstorm chances increase further across the area
as a trough moves into the area from the southwest.
Also of note with this pattern, gusty winds are expected with the
dry hot weather during the afternoon and evening on Wednesday and
Thursday. Overall, the combination of heat, gusty winds and
unstable conditions will bring heightened fire weather concerns
over the next two days. For additional details, please see the
fire weather discussion below.
&&
.AVIATION...02/00Z TAF CYCLE...Gusty north winds will persist along
the coast north of Cape Blanco early this evening. KOTH is expected
to come down to LIFR again late tonight into early Wednesday
morning. Elsewhere VFR continues but KMFR visibility may decrease to
close to MVFR around midnight overnight into Wednesday morning due
to smoke from nearby wildfires. /DW
&&
.MARINE...Updated 230 PM PDT Tuesday August 1 2017...Gusty north
winds and steep to very steep seas will persist through this evening
then steep seas will linger into Thursday with winds gradually
weakening late Tonight into early Saturday. A surge of southerly
winds and fog is expected to make its way up the coast Wednesday
into Thursday. After a period of relatively calm winds and seas into
Friday, the thermal trough is expected to redevelop with north winds
and steep seas returning on Saturday. Gales are then possible early
next week. -DW
&&
.PREV DISCUSSION... /Issued 255 PM PDT Tue Aug 1 2017/
SHORT TERM...A strong ridge of high pressure will bring very hot
temperature to most of the forecast area. This is still on track
with forecast high temperatures in the 110-115 possible in the
Rogue Valley. One factor that can keep the area from reaching the
forecast high is the blanket of smoke from wildfires. Wednesday
will be the hottest day with T850 around 27C but Thursday will
only be a few degrees lower. Highs are expected to remain in the
100-105 for the west side valleys at least through the end of the
week.
On Wednesday night the thermal trough will start to shift inland
and wind reversal is expected at the coast. After several days of
northerly winds, winds at the coast are expected to turn southerly
and this could also lead to stratus surge with areas of night time
fog along the coast.
With very hot temperatures, it will not take much to reach
convective temperatures. However moisture is limited and patchy so
we expect convective clouds to develop into towering cumulus but
there may not be enough energy to continue to cloud growth into
thunderstorm clouds, except for favored terrain like the Cascades
and Warners. This morning`s GFS run keeps most of the mid level
moisture bottled up in northern California with limited moisture
into the Cascades. Timing of individual storm development is tough
at this point but there is small chance of thunderstorm
development each day from the Cascades east and Siskiyou south.
Actual forecast location may change from day to day depending on
model instability and moisture field.
LONG TERM (Saturday through Tuesday)...The trend in this period
is for a slight weakening of the ridge. Key word here is slight as
temperatures will still be quite warm across our forecast area.
Saturday may be close to Friday but the GFS is trying to bring
more moisture up to the OR-CA border, then spread into the Klamath
and Lakeview area Tuesday and Wednesday. We have trended toward
more TS coverage and chances from the weekend into next week. /FB
FIRE WEATHER...Updated 240 PM Tuesday 1 August, 2017...Very hot and
dry conditions will continue away from the coast for most of the
week with near record breaking heat Tuesday through Thursday. The
magnitude of the heat on each of these days is expected to be the
hottest in the last 25 years. This will be of high concern for crews
involved in firefighting efforts and it is highly recommended they
stay hydrated and take steps to avoid heat exhaustion or even heat
stroke. Even crews in the higher elevations will not be immune to
the heat with afternoon temperatures expected to be in the 90s with
little relief at night.
The thermal trough is expected to hover west of the Cascades the
next few days resulting in at least Haines 5 conditions with Haines
6 more than likely over the fires. Red Flag warnings are in effect
for this. Also, the Fire Weather Watches have been upgraded to Red
Flag Warnings for Wednesday through Thursday for gusty winds and low
relative humidity for much of the West Side. Wind gusts aren`t
expected to be especially strong, but could exceed 20 mph for a
couple of hours each afternoon/evening. Even in areas not covered
by warnings, high Haines and very hot and dry conditions can be
expected through at least Thursday.
The latest HRRR model shows isolated cells developing this afternoon
and evening, mainly from the Medicine Lake/Modoc areas north to
Winter Rim and then east across Lake County. Even so, since the air
aloft is so dry, prolonged convection is doubtful.
Practically no thunderstorms are expected Wednesday into Thursday,
but a slight chances persists, mainly in portions of northern
California and perhaps up the Cascades/over the East Side. Models
are showing an increase in the diurnal winds (gusts of 20-25
mph) over the East Side during this time frame. While not expected
to reach Red Flag criteria, any increase in winds could be
problematic for the ongoing wildfires, especially the July complex
in Modoc.
Models have also backed off on the timing of short waves lifting
northward into our region late this week, so we have lowered
thunderstorm probabilities on Friday. A weakness in the upper
pattern offshore should move toward the California Coast this
weekend allowing flow to become more southerly and also increasing
short wave activity. As a result, thunderstorms should become
increasingly likely. -Spilde
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Heat Advisory until 8 PM PDT Friday for ORZ021-027>030.
Excessive Heat Warning until 8 PM PDT Friday for ORZ021-023>029.
Excessive Heat Warning until 11 PM PDT Wednesday for ORZ022.
Red Flag Warning until 9 PM PDT this evening for ORZ619-623.
Red Flag Warning until 9 PM PDT this evening for ORZ616-620.
Red Flag Warning from noon to 9 PM PDT Wednesday for ORZ616.
Heat Advisory until 8 PM PDT Friday for ORZ023.
Red Flag Warning from noon Wednesday to 9 PM PDT Thursday for
ORZ617-622.
Red Flag Warning from noon Wednesday to 9 PM PDT Thursday for
ORZ623.
CA...Heat Advisory until 8 PM PDT Friday for CAZ082>085.
Excessive Heat Warning until 8 PM PDT Friday for CAZ080>085.
Pacific Coastal Waters...Small Craft Advisory until 11 AM PDT Thursday for
PZZ350-356-370-376.
Hazardous Seas Warning until 5 PM PDT Wednesday for
PZZ356-370-376.
$$
CC
Area Forecast Discussion
National Weather Service Omaha/Valley NE
652 PM CDT Tue Aug 1 2017
.SHORT TERM...(Tonight through Friday)
Issued at 300 PM CDT Tue Aug 1 2017
The main short term concerns are thunderstorm chances from tonight
into Thursday morning.
Water vapor loop early this afternoon showed a couple of shortwave
troughs dropping southeast. One was up over western MT and that
may come into play for tomorrow. Another was dropping toward our
area from SD. Storms currently tracking east/southeast should
affect at least the northern and central parts of the area this
evening, possible down to around Interstate 80. Storms could
produce gusty winds early this evening, but the overall chances
for organized severe weather are low. The RAP model seems to hang
onto showers and storms tonight a little too long. As for lows, we
expect values from around 60 to the mid 60s.
On Wednesday, thunderstorm chances will be increasing during the
day especially in northeast NE. Experimental HRRR is faster with
development compared to most of the parameterized models (NAM,
GFS, ECMWF) and it seemed too fast. We will have likely POPs in
parts of northeast NE by late afternoon. Storms could approach
severe limits mainly in the evening and produce locally heavy rain
across the northern parts of the forecast area. Would not be
surprised to see some rain amounts over an inch across our
northern zones. Ahead of the front, temperatures should rise into
the 80s Wednesday.
Rain/thunderstorm chances continue into Thursday morning, but
heaviest activity should move out of the area by sunrise. This
will be a cooler airmass, with highs mainly in the lower and mid
70s. The coolest morning this week is expected to be Friday, when
temperatures bottom out in the upper 40s and lower 50s.
.LONG TERM...(Friday night through Tuesday)
Issued at 300 PM CDT Tue Aug 1 2017
At the start of this period a moderately strong mid level trough
will be moving toward the western Great Lakes region with a ridge
from northwest Mexico to off the coast of the Pacific Northwest.
Like yesterday, we look for that ridge to weaken, with an overall
slight decrease in 500 mb heights across the northern and central
parts of the Plains into early next week. Look for highs 75 to 80
Saturday and Sunday then 80 to 85 Monday and Tuesday, with lows
in the mid 50s to lower 60s.
As mentioned yesterday, a cooler than normal pattern is expected
to continue into the 8 to 14 day period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 641 PM CDT Tue Aug 1 2017
A broken thunderstorms is pushing southward with a cold front in
the area. The storms are hit and miss along the front. The CAMS
are about 2hrs too slow with the storms and show a weakening
trend/a decrease in coverage as they head toward KOMA and KLNK.
Just showers linger early on at KOFK...however at KOMA/LNK due to
the hit and miss nature of the thunderstorms will not include
thunder...but mention rain in the TAF and amend as needed. An
outflow boundary produced 35 to 40kts wind gusts in northeast
Nebraska...however should weaken. Will mention some wind gusts
generally 15 to 25kt range. Outside of the showers/storms...winds
will become light and variable.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
SHORT TERM...Miller
LONG TERM...Miller
AVIATION...Zapotocny
Area Forecast Discussion
National Weather Service Norman OK
715 PM CDT Tue Aug 1 2017
.DISCUSSION...
00Z TAFs.
&&
.AVIATION...
Rainfall is moving out of the area, although some light rain may
linger an hour or so at KSPS. Conditions are mostly VFR early this
evening with a few patches of MVFR ceilings. HRRR and RAP show
some potential of shower re-development along the Red River that
could affect KSPS and perhaps KLAW overnight, but the probability
is too low for a TEMPO group.
With light winds expected and the recent rains today, there is the
potential of some fog developing Wednesday morning. The best model
signal is in northwest and west central Oklahoma /KGAG KWWR KCSM
KHBR/ but is certainly possible throughout the area. Have put some
reduction in visibilities in most TAFs, and some patches of IFR
visibility will be possible. Again, uncertainty is enough to
preclude a TEMPO with IFR conditions, but it will definitely be
worth watching trends through the evening and into the morning.
&&
.PREV DISCUSSION... /issued 237 PM CDT Tue Aug 1 2017/
DISCUSSION...
Several locations across Oklahoma and western north Texas have
received rainfall today. A tenth to a quarter inch has been
common, but a band of heavier rainfall amounts is seen in the
Oklahoma mesonet totals from near Woodward east-southeast to
Guthrie where locally 1-1.25" has fallen. Rain occurred in an
anomalously moist environment. A PWAT of 1.80 inches was observed
on KOUN 12z sounding, and 1.98 inches on Lamont 12z sounding. Very
weak mid-level lapse rates and lack of diabatic heating today
have resulted in negligible instability and so no thunder has
occurred.
A dry subsident layer behind a mid-upper level wave is clearly
evident in all three water vapor bands of GOES-R experimental
imagery pushing southward into northern Oklahoma. This signals the
end of this rain event. Latest radar mosaic shows rain oriented in
a band near and south of I-40 as of mid-afternoon and this will
continue to push southeast through the evening. Lingering rain
showers will be possible near the Red River through early
tomorrow.
Model forecast soundings show very weak instability during peak
heating tomorrow. This may be enough to support isolated
convective showers from mid-afternoon through early evening,
generally southeast of a line from near Shawnee to Wichita Falls.
A fairly potent shortwave trough evolves into a closed low as it
moves southeast into the Midwest states by late Thursday. This
will send a cold front south into the area that will bring cooler
temperatures on Friday (around 10 degrees below normal for early
August). Low probabilities of precipitation were retained late
Thursday into Friday as ascent from the aforementioned wave and
frontal convergence impact the area.
Better rain chances are expected Saturday night lasting into early
next week as another shortwave trough moves across the northern
Plains while the upper flow pattern deamplifies some. Medium range
model guidance indicates a respectable moisture surge northward
into the area ahead of a period of ascent that should favor fairly
good chances of convection--possibly in the from of periodic MCS
activity during that period. Given the typical uncertainties of
multiple days of convection this time of year, we haven`t yet
tried to identify a period of higher probabilities from Saturday
night through Monday. Once we have a better handle on how this
pattern will evolve we may be able to better refine the forecast
and separate out a period with higher probabilities than
currently indicated.
BRB
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 65 89 68 90 / 10 10 10 30
Hobart OK 64 90 69 91 / 10 10 10 30
Wichita Falls TX 68 90 70 94 / 40 10 10 10
Gage OK 63 90 66 85 / 10 10 10 30
Ponca City OK 66 89 68 88 / 10 10 10 30
Durant OK 69 87 70 92 / 60 20 20 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
Area Forecast Discussion
National Weather Service Shreveport LA
1017 PM CDT Tue Aug 1 2017
.DISCUSSION...
We have updated our hourly temps/td/and RH, but no changes to
overnight lows. Radar is still active in many places and no
changes to the forecast are needed with coverage likely to
increase overnight as the cool pool sinks deeper into the
ArkLaTex. Our VAD wind profiler is showing good moisture flow in
the lower levels feeding this subtle overrunning with W/NW flow
aloft. /24/
&&
.PREV DISCUSSION... /issued 635 PM CDT Tue Aug 1 2017/
AVIATION...
For the 02/00Z terminal forecast, VFR categories across all sites
tonight to become MVFR around 02/07Z-02/12Z with lowering
ceilings and increased convection. -TSRA conditions expected
across most locations from 02/09-02/15Z with gradual improvement
through the afternoon. Otherwise, surface winds will be light and
variable overnight and southeast around 5 to 10 knots on
Wednesday. /05/
PREV DISCUSSION... /issued 548 PM CDT Tue Aug 1 2017/
UPDATE...
Expand pops a bit farther South across I-20.
DISCUSSION...
Several outflow boundaries can be seen milling about on our 88D
radar across Deep E TX and Toledo Bend country over to near
Alexandria. A couple of hours of heating yet will allow for more
showers and an Isolated Thunderstorms. Weather to the well North
is sinking in this way with a cool pool or sorts under favorable NW
flow. The monster cap on this mornings sounding has long gone
with mid afternoon development in the Shreveport and Bossier
metro area is still in progress on outflow from Carthage to
Mansfield and Jonesboro. We will soon send out the zones once
again to remove some zones with a late afternoon mention. HRRR
looking at a wet start to the day for many. /24/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 73 84 72 90 / 40 50 30 30
MLU 71 86 70 90 / 30 40 20 40
DEQ 69 85 68 89 / 30 50 20 10
TXK 69 82 70 89 / 40 50 20 20
ELD 70 83 69 89 / 30 40 20 30
TYR 73 83 71 89 / 40 60 30 20
GGG 72 84 71 89 / 40 60 30 30
LFK 73 85 71 91 / 30 50 30 40
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
24/05
Area Forecast Discussion
National Weather Service San Angelo TX
634 PM CDT Tue Aug 1 2017
.AVIATION...
/00Z TAFS/
Look for VFR conditions to continue for the next 24 hours.
Thunderstorms remain in the forecast for tomorrow, mainly during
the afternoon.
&&
.PREV DISCUSSION... /issued 341 PM CDT Tue Aug 1 2017/
SHORT TERM...
(Tonight and Wednesday)
Area of showers and storms continues to drift east across the
eastern portions of West Central Texas this afternoon. This is the
remnant of the larger complex of storms that moved across the
Permian Basin overnight. Abundant cloud cover has limited
instability somewhat, and have seen mainly light to moderate
rainfall so far. Trying to pin down the exact placement of
convection tonight continues to be a difficult process, with so much
of this being mesoscale driven. We will continue with northwest flow
aloft, with an upper level trough axis moving through the area
tonight. Suspect that we will see a bit of a lull in the convection
this evening, with rain chances picking up ahead of the upper level
trough axis tonight. This would mean that the best rain chances
will likely be across about the southeast half of the area for
tonight and Wednesday. Latest HRRR model falls in line with this as
well, with convection redeveloping later this evening and spreading
across the Concho valley and Heartland.
Temperatures will again be mild tonight, with a little rain cooled
air mass allowing many locations to drop into the 60s. Lots of
clouds again tomorrow will again limit heating and keep most areas
in the 80s. The northern Big Country may actually be the warmest
area tomorrow, with a little more sunshine.
LONG TERM...
(Wednesday night through Tuesday)
There is a lull in showers and thunderstorm activity Wednesday
night into Thursday night, as a shortwave in NW flow aloft moves
southeast of the region. There could an isolated shower or
thunderstorm south of I-10 Wednesday night before the upper
shortwave moves into South Texas, and an isolated shower or
thunderstorm in the Big Country Thursday night (mainly towards
morning) as another upper shortwave approaches from the Panhandle.
Friday into Saturday, shower and thunderstorm chances increase as
weak upper shortwaves moves through. Storm chances then continue
Sunday into Tuesday with the upper flow becoming weakly zonal
along with a weak upper trough over the region. Main threat from
Sunday night and on...is the potential for locally heavy
rainfall...as GFS precipitable water increase to nearly 2 inches
across the region. In addition, storms will be slow moving storms
due to weak winds aloft. GFS and EC models have rainfall amounts
of 2 to 4 inches across the CWA with locally higher amounts. Main
concern will be flooding.
While the models suggest heavy rainfall next week, with most of
the rainfall on days 6 and 7, confidence in the heavy rainfall and
its location is still in the low range. However, good agreement
between some of the model rainfall algorithms does increase the
potential.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 69 88 69 93 / 40 40 5 5
San Angelo 69 86 67 93 / 40 50 10 10
Junction 70 85 68 93 / 40 60 20 20
Brownwood 69 85 68 93 / 40 60 20 10
Sweetwater 68 86 68 91 / 30 30 5 5
Ozona 70 85 67 91 / 40 60 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$