Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/05/17
Area Forecast Discussion
National Weather Service Albuquerque NM
601 PM MDT Tue Jul 4 2017
.AVIATION...
00Z TAF CYCLE
Through 03-6Z, the main impact to TAF locations will be a combination
of convective activity and outflows for KTCC/KROW/KLVS with gusty
gap winds developing at KABQ/KAEG this evening. The strongest
convection over the Eastern Plains is expected to move out of the
forecast area by 02Z, with lingering showers and isolated TSRA
through the evening hours. In the Rio Grande Valley, gap winds should
begin at KSAF by 01Z and at KABQ/KAEG about 03-04Z. Winds are
expected to gust up to about 30kts, although gusts at KABQ to 35kts
cannot be ruled out. Winds should begin to diminish about 08Z.
In the latter end of the TAF period, the main axis of convection will
shift westward to the Rio Grande Valley. Some showers may start on
the higher terrain as early at 18Z, so VCSH is included at KLVS and
TAF locations in the Middle RGV.
54/Fontenot
&&
.PREV DISCUSSION...330 PM MDT Tue Jul 4 2017...
.SYNOPSIS...
High pressure aloft strengthening west of New Mexico this Independence
Day will continue to build as it shifts eastward through mid-week.
The center of the upper high will likely remain in the vicinity of
the Four Corners region Wednesday through Saturday. Strong daytime
heating combined with residual moisture will support daily rounds of
mainly afternoon and early evening thunderstorms favoring the
mountains and western half of the state. Daytime temperatures will
remain well above average but trend closer to seasonal average late
week.
&&
.DISCUSSION...
Severe storms have impacted portions of central and/or eastern New
Mexico every day since June 22nd and another bout of isolated severe
storms expected through mid-evening across the far east.
Axis of 500mb ridge oriented NW to SE from west-central UT to near
the southwest corner of NM. Water vapor imagery showing the next
ripple/mid-level thermal trough in the northwest flow translating
southeast from the Colorado Front Range with region of enhanced
upper-level divergence from Raton Mesa toward northern EC plains.
Latest HRRR suggests a couple of loosely organized convective
clusters rolling across the NE and EC plains between 4-8pm before
exiting into TX. Will trend PoP/wx trends toward this timing and
provide some enhanced detail given Independence Day festivities.
Other area of concern will be across the the WC/SW high terrain
where high-based drier shower/t-storm activity could produce
localized strong winds.
Going into Wednesday, appears two distinct mid-level height centers
will continue within the large-scale Four Corners ridge: one
vicinity of the NM/AZ line southwest of Gallup and another to become
the dominant one over southwest CO. Overall, storm coverage should
continue to trend downward as compared to today with further limited
potential for severe storms in the east as mid- to upper level
steering flow veers and becomes more north to south. Diurnally-
driven convection over/near higher terrain will tend to favor
central/western areas late in the day and evening. Will again watch
for isolated high-based late day virga bombs. Otherwise, very warm
to hot temperatures will be several degrees hotter in the west and
only slightly cooler in the east.
The GFS now trending closer to dreaded the -5C isotherm at 500mb
near the NM/CO line north of Taos by Thursday PM, while the NAM is a
shade cooler. This strengthening subsidence inversion may hinder deep
moist convection more than currently expected. Otherwise, Thursday
should play out very similar to Wednesday if not slightly hotter with
even fewer storms especially NC areas. The Four Corners high will
remain in place Friday into early next week. However, models similar
showing the high contracting and shifting a bit farther west during
this period. At the same time, atmospheric moisture content trends
upward and any slight mid- level cooling would prove very favorable
and support a general uptick in storm coverage late week into the
weekend. Steering flow will again favor central/western areas and
perhaps we are on the verge of losing the influence of westerlies.
KJ
&&
.FIRE WEATHER...
In a pattern typical for early July, high pressure is becoming the
dominant upper level feature with occasional moisture intrusions from
the east projected to continue. Currently, high pressure has nudged
a bit farther northwest, separating into two centroids, one northwest
and one southeast of the Four Corners. Storm coverage has stayed
very low for most areas due to the prevalent dry air in the boundary
layer, but a weak upper level short wave coupled with a surface wind
shift has induced some stronger, wetter storms in the northeastern to
east central plains. Temperature and humidity has mostly followed
persistence, staying close to yesterday`s readings. Outside of the
plains, storms have been predominantly defined by gusty outflow winds
rather than rain. Tonight as storms trend down in the east, an
easterly flow will beyond the central mountain chain through
Wednesday morning. Gusty east canyon winds are expected in central NM
tonight while low layer moisture advances west toward the Rio
Grande.
With the moisture seeping farther west tonight, thunderstorm chances
will increase along and east of the central mountain chain
Wednesday. High pressure aloft will likely consolidate north of the
Four Corners, but will still be broadly over the Rockies, steering
storm activity in NM on a north to south or northeast to southwest
trajectory. Temperatures will only see small drops in the eastern
half of the state Wednesday, and Haines values would decrease in the
eastern half where humidity will be slightly higher.
Into the remainder of the forecast period, the pattern will continue
to be defined by high pressure over the Rockies while low layer
moisture sloshes around the plains, and diffuse mid to upper level
subtropical moisture holds over the central to western zones of NM.
The absence of westerly flow will signify the onset of the monsoon
season, and storm coverage will begin to shift to the central and
western zones of NM. Temperatures appear seasonal through this time
and humidity will make a slow trend upward day-by day. Prevailing
winds will typically be from the east or south in many zones, with
local storm outflows being the primary wind concerns.
52
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
41
Area Forecast Discussion
National Weather Service Bismarck ND
944 PM CDT Tue Jul 4 2017
.UPDATE...
Issued at 933 PM CDT Tue Jul 4 2017
Lingering convection is pushing its way out of the southern James
River Valley. Strongest convection will move through Ypsilanti and
Montpelier in the next 15 to 30 minutes. Farther south over Dickey
and Lamoure counties, any convection that has developed has not
survived the stronger cap. Strongest instability remains over far
southeast ND and it`s possible something could still develop over
far eastern portions of these counties over the next hour, but it
would be short lived over Bismarck CWA and the probability also
decreases with increasing inhibition with loss of daytime heating.
Made some minor adjustments to pops and sky cover. Otherwise no
significant changes to the going forecast.
UPDATE Issued at 754 PM CDT Tue Jul 4 2017
Thunderstorms continue to track from south central ND into the
James River Valley. After the initial development near Bismarck
the northern portion of the area has remained severe as it tracked
through northern Burleigh into northern Kidder. The southern
portion of the broken line has had a hard time maintaining itself
as it moves in a more capped environment. Within the next half
hour, the entire line has diminished fairly quickly. Still can not
rule out a severe storm over the southern James River valley in
the next hour or two, but for the most part, the threat of severe
weather will continue to diminish.
Updated pops and sky cover based on latest radar and satellite
analysis.
UPDATE Issued at 534 PM CDT Tue Jul 4 2017
Thunderstorms have developed over south central ND and are moving
to the southeast. Strongest storms in the south central have
developed in a localized area of cape to the north of Bismarck.
Updated pops based on latest radar analysis.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 239 PM CDT Tue Jul 4 2017
Hot weather will continue through Wednesday, along with a chance
of thunderstorms.
Scattered, surface-based thunderstorms are expected to develop in
the 20 to 23 UTC time frame from Hettinger northeastward toward
the Bismarck/Mandan area. That area is favored for initiation on
the nose of the low-level thermal ridge, immediately ahead a pre-
frontal wind shift, and in advance of the weak mid-level impulse
implied by the area of enhanced cloudiness moving from southeast
MT into southwest ND as of 19 UTC. Pre-convective MLCAPE ranges
from 1000 J/kg at Hettinger, to 2000 J/kg at Bismarck, and 3000
J/kg at Jamestown. The degree of bouyancy, driven in part by steep
low- and mid-level lapse rates, coupled with weak, but veering
winds aloft will be sufficient for a few marginally-severe storms
with hail and gusty winds. However, overall, the risk will be kept
in check by weak deep-layer wind shear, with effective shear
magnitudes less than 25 kt. CAMs through the 17 UTC HRRR support
this scenario with maximum updraft helicity values generally less
than 50 m2/s2 as convection moving eastward, past the Missouri
River by 00 UTC, and exiting the James River valley by 06 UTC.
The weak cold front moving southward this afternoon is expected to
stall along the ND/SD border tonight, then return northeastward as
a warm front Wednesday afternoon. A strong thermal ridge will once
again flex its muscles eastward into western ND behind that front
with 850 mb temperatures of 26 to 28 C from Williston to Bismarck
and values around 30 C in southwest ND. Forecast soundings show an
impressively-deep well-mixed layer to almost 600 mb, all of which
supports highs around 100 F in western and south central ND. Note
that record highs are closer to 110 for July 5th, and thus should
be safe given currently-forecast thermal fields. The 12 UTC NAM
appears reasonable with its low-level dewpoint forecasts east of
the north-south oriented warm front given observed trends both
ahead of and behind that boundary today. Thus, we expect surface
dewpoints in the upper 50s to lower 60s F in central ND Wednesday
afternoon and evening in support of weakly-capped MLCAPE upwards
of 3000 J/kg. Models unanimously agree on significantly-stronger
winds aloft by then with 0-6-km wind shear around 45 kt along with
notable anvil-level flow. Forecast soundings from the 12 UTC NAM
are therefore strong matches to environments which have produced
significant hailstones over 2 inches in diameter. That being said,
this threat is conditional on convective initiation, which is not
a sure bet given weak mid-level height rises at 500 mb during peak
heating. We do, however, believe that high-based, initially-weak
convection could emanate from the intensely-heated air mass in
western ND by late afternoon, then intensify as it crosses the
warm frontal zone in central ND. Moreover, glancing influence from
a weak impulse crossing southern Canada could also aide convective
initiation in north central ND by Wednesday evening.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 239 PM CDT Tue Jul 4 2017
Above-normal temperatures and below-normal precipitation will be
the theme through the long term forecast period. Amplification of
the strong 500 mb ridge centered over the western U.S. late this
week will allow somewhat cooler northwest trajectories to develop
over our region, resulting in highs mainly in the 80s F Thursday
and Friday. However, global ensemble guidance continues to show
the ridge shifting back eastward beginning this weekend with yet
another period of potential 100 degree weather in the offing by
the early to middle part of next week, especially if the 00 and 12
UTC ECMWF runs have anything to say about it. It`s worth noting
that the vast majority of recent deterministic GFS cycles have
been on the far cold edge of 850 mb temperatures from its ensemble
and so its numbers may be negatively-influencing blended forecast
guidance. Finally, CIPS analog guidance also suggests a generally
dry period, as expected with only weak shortwave troughs rounding
the 500 mb ridge.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 933 PM CDT Tue Jul 4 2017
Scattered thunderstorms exiting the KJMS TAF site this hour.
Otherwise VFR conditions with no threat of thunder for the
remainder of the night. Variable winds generally under 10 Kts
tonight becoming southerly on Wednesday ahead of an advancing cold
front. Winds expected to shift northwest at KISN and KDIK
Wednesday afternoon.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...CJS
LONG TERM...CJS
AVIATION...TWH
Area Forecast Discussion
National Weather Service Sioux Falls SD
621 PM CDT Tue Jul 4 2017
.SHORT TERM...(This evening through Wednesday)
Issued at 428 PM CDT Tue Jul 4 2017
Relatively quiet weather has prevailed today, as the strong upper
trough over the Central Plains inhibited most of the moisture inflow
into the area. Visible satellite imagery shows Cu mid-level clouds
developing this afternoon, ahead of a weak cold front currently over
central SD. With weak dynamic forcing, moisture and capping,
prevailing today, have lowered PoP chances and probability for this
evening. HRRR, ESRL HRRR and the ARW are suggesting isolated
thunderstorms developing along and east of Highway 71 through around
01Z in response of a weak boundary over eastern NE/western Iowa.
Decided to go with isolated storms, and left 15 to 20 % across these
areas.
Tonight will remain mostly dry and warm, with southerly wind flow
prevailing through Wednesday. A cold front will be moving across
central SD into central Minnesota in the evening and overnight
hours. This will only bring isolated to scattered showers and
thunderstorms along and north of Highway 14, followed by activity
spreading eastward into our extreme northeast zones in southwest
Minnesota. Mild low temperatures in the upper 60s are expected
tonight.
A few lingering showers will be possible early Wednesday morning,
mainly over southwest Minnesota, before mostly sunny skies prevail.
It will be even warmer than today, with very warm 850 temperatures
from 20 to 25 C. Southerly surface winds, and dewpoints in the upper
50s and lower 60s along and west of the James River, could bring
highs in the upper 90s to near 100. Highs east of the James River
will generally stay in the upper 80s to lower 90s.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 428 PM CDT Tue Jul 4 2017
A fairly low probability for any convection Wednesday evening, but
still possible that a few boundaries from prior convection could
remain and fester, only under air aloft that is slightly warmer than
today. Main question heading into Wednesday night will be whether
convection which forms further north and west from the area toward
North Dakota will be able to make a more aggressive turn into
warming layer aloft to brush through southwest MN later in the night
and early morning. Not the strongest LLJ expected, and moisture is
somewhat limited, so no more than a most minor chance at this point
late night and very early morning.
On Thursday, the weak wave in northwest flow moving across northern
Minnesota will drive a frontal boundary southward. This front will
be moving southward into a very warm airmass aloft, and thus should
be largely inert until perhaps late day. Have already adjusted
expected highs to several degrees warmer than blend across many
areas south of I-90, but if temps heat closer to 100 degrees in the
lower Missouri River valley, could be close enough for frontal
forcing to crack the cap and initiate an isolated storm or two.
Plenty of potential instability, so would have to keep watch on
severe potential from very late afternoon into very early evening,
the window during which boundary will be moving across areas
southeast of a KSPW to KYKN line. In addition to the thunderstorm
concern, there will also be some heat index values that likely
eclipse 100 degrees from KSUX toward KSLB.
Friday and Saturday will be a pleasant day as weak high pressure
ridge settles across the area by late Friday and shifts east on
Saturday. Mixing would favor highs mainly in the 80s, but could see
some upper 70s in southwest MN on Friday, and some near 90 degree
readings in south central SD on Saturday. With drier conditions west
of the James River, should continue to work a larger diurnal range
into forecast until some better rainfall occurs.
Divergence in the longer range models is primarily a question of how
amplified the troughing into the Great Lakes will be through the
weekend, and how much a wave pushing into the western ridge will
flatten the flow. Subtle differences between the ECWMF and GFS
camps introduce 5-10 degree differences in mixing potential (EC
generally cooler side) and some timing/location differences in
subtle northwest flow waves which bring with each a minor chance for
thunderstorms. Deeper moisture does appear as if it will be a
challenge through the period, so while much of the temporal and
spatial domain will likely be dry, there is a threat for storms with
any stronger wave that does slide through. For now, confidence is
low on timing and have not pushed any past lower chance.
Temperatures are also likely to be near to a bit warmer than normal
given the drier conditions.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 620 PM CDT Tue Jul 4 2017
VFR should be the primary category through Wednesday. Thunderstorm
chances in this area will be isolated, and thus not prevalent
enough to put in any particular TAF site at this time.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
SHORT TERM...05
LONG TERM...Chapman
AVIATION...MJ
Area Forecast Discussion
National Weather Service Hastings NE
648 PM CDT Tue Jul 4 2017
.SHORT TERM...(This evening through Wednesday)
Issued at 324 PM CDT Tue Jul 4 2017
A few showers and isolated thunderstorms have developed just to the
east of the forecast area this afternoon. They are moving toward the
west, but are having a hard time holding together as they get closer
to the forecast area. Still have some low PoPs in the southeast in
case they do move into the area. To the west, there have been a few
showers, but these are struggling even more.
An upper level ridge along the eastern slopes of the Rockies will be
the main feature through the period. There is an upper low to the
east/southeast and a wave from the low moves through this afternoon
and evening. The latest runs of the HRRR have had some development
to the east, but has little to nothing in the west. Have kept a few
thunderstorms in the west, but do not expect as much there as in the
southeast.
Later tonight, as the temperatures fall off, the light winds and
moisture will again lead to some patchy fog. Most areas will
probably not have much, but there could be a little around the area.
On Wednesday, a surface high develops to the east. Expect south
winds and warming temperatures with a little more sunshine than
today.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 324 PM CDT Tue Jul 4 2017
The upper level ridge in the western CONUS continues through this
period. There are a few waves that move over the top of the ridge
and into the area, but most of them are fairly weak. The summer-time
pattern leads to mainly small chances on and off through the period.
There are a couple more notable waves that come though and bring a
little better chance for thunderstorms. The first of these comes
through Thursday afternoon and night. The NAM and GFS have a little
more precipitation than the ECMWF which ends during the evening.
There is a small chance that it may linger into Friday morning. The
next wave will be Friday afternoon and Friday night. This one is
more evident in the GFS and ECMWF than the NAM. Another wave is
possible Saturday afternoon but it is not as strong and should have
less chances.
For the period Sunday through Tuesday there are a few weak waves
with some sporadic chances for thunderstorms mostly during the
afternoon and evening time-frame.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday)
Issued at 627 PM CDT Tue Jul 4 2017
A persistent westward moving outflow boundary has continued its
trek across the area with gusty east and southeast winds occurring as
it passes through. A few thunderstorms have also developed along
it providing brief heavy downpours and gusty winds for some
areas. This activity has remained rather isolated and any
lingering thunderstorms should diminish as the sun sets this
evening.
As the boundary exits the area, generally expect light winds out
of the southeast at 5 to 10 kts overnight. Winds will then become
light and variable heading into the early morning hours. This
along with plenty of moisture across the area overnight could lead
to some patchy fog development. Uncertainty remains as to how
widespread this will be and it is possible this mainly impacts
low elevations areas and river valleys. Still have maintained a
mention of MVFR conditions for reduced visibilities for both TAF
sites between 9Z and 13Z.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...JCB
LONG TERM...JCB
AVIATION...Petr
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1042 PM EDT Tue Jul 4 2017
.SYNOPSIS...
Broad high pressure will remain centered over the western Atlantic
while a slow moving, weak cold front lingers over the region through
midweek. A second cold front will push through the area this weekend
with somewhat drier and cooler air briefly settling in behind it.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 1035 PM EDT: Recent HRRR runs performed quite well in
depicting scattered convection redeveloping along the northern Blue
Ridge this evening as instability bounced back, but all CAMs agree
in diminishing the activity just as quickly by Midnight or shortly
thereafter as profiles stabilize. Anticipate mountain valley fog and
low clouds morning once again, with patchy early morning fog also
possible in areas that received heavy rain today.
Expect Wednesday to be nearly the same, with boundaries developing
near edge of convective debris and outflows playing a role in
forming new precip starting by midday. Temps will also be similar to
this past afternoon.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 230 PM EDT: In the early part of this forecast cycle the upper
low in Missouri will be opening up and lifting northeast. Meanwhile,
this will allow the Bermuda High to re-adjust its position with H5
heights rising across our forecast area (FA) from Wednesday night
into Thursday. This is particularly the case across parts of NE
Georgia and upstate South Carolina.
We will allow showers and thunderstorms to diminish or end Wednesday
night, except in the western North Carolina mountains, where upslope
could linger showers through the night.
The signals for showers and thunderstorms Thursday appear to be
better established for western North Carolina, where another in a
series of upper level pockets of energy ripples through the region.
This is coincident with a moist and unstable airmass, and a multi-
convergent surface pattern. As a result we have POPS reaching likely
in the NC mountains with chance POPS flared out to the east and
south. Our southern FA may nearly be capped, therefore slight chance
should work their.
The question mark is really for Thursday night and Friday. All of
the models are bringing an upper level trough, and some semblance of
a wind shift feature, into our area Thursday night and Friday. H85
wind fields increase to 30-30 knots with the a couple of the models.
Our call on this one is to refocus the shower and thunderstorm
potential Thursday night in our upslope areas, and then bring a
chance of showers and storms through the FA Friday. Confidence in
the latter half of the forecast is below average.
We have went on the warm side of the temperature guidance in those
areas with less thunderstorm potential Thursday and Friday, and near
normal elsewhere. Heat indices in our south and east FA Thursday
could reach into the upper 90s.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 205 PM EDT Tuesday: the extended fcst picks up at 00z on
Saturday with a broad upper trof digging south over the Eastern
CONUS with steep upper ridging in place over the west. This pattern
is expected to remain in place thru most of the period with heights
starting to rise again by early next week as the trof begins to
deamplify and lift northward. At the sfc, a reinforcing cold front
will move thru the fcst area on Saturday with a continental high
briefly sliding over the region in the front`s wake. This could
provide a brief period of fair wx on Sunday. According to the GFS,
the high weakens and slides offshore on Monday with moist SLY low
lvl flow returning to the region for the remainder of the period.
The 00z ECMWF is still slower to move the high offshore and is
therefore slower to return SLY flow to the area. For the sensible
fcst, I kept a blend of the model solutions that keeps high-end
chance PoPs on Sat and a slight chance PoP for Sunday. Monday and
Tues return to a more typical summertime afternoon/evening, diurnal
PoP regime. High temps should peak near climatology for Sat with
slightly cooler values for the rest of the period.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
At KCLT: All convection has diminished for the nighttime hours.
Expect mainly higher level VFR ceilings overnight. Abundant near
surface moisture is giving rise to some concern for low clouds or
fog overnight, but this is not really featured to any great extent
in the MOS or model profiles. Will thus hint in that direction with
some FEW to SCT005 to 010 level clouds during the early morning
hours. Winds should remain light from the southwest. A few low end
afternoon gusts will be possible Wed. but they should be brief.
Enough scattered thunderstorm coverage should develop to warrant a
PROB30 group at this point for the bulk of the late day hours.
Elsewhere: Redeveloping showers and thunderstorms across the
northern mountains and northern Blue Ridge should remain north and
west of KAVL and KHKY before diminishing shortly after mindnight.
Will hit the usual suspects of KAVL and KHKY with fog/low cloud
restrictions overnight, and also add some brief MVFR fog at KAND
given the late day rainfall. Otherwise, expect light SW winds,
picking up a bit through the day on Wednesday with additional
scattered thunderstorms developing around the region from 18Z to 00Z.
Outlook: Moist and unsettled weather will continue through the late
week. Thunderstorms may become more numerous Thursday into Friday as
an upper wave passes followed by a cold front. Nocturnal
restrictions can be expected in any locations receiving heavy
rainfall, and also in the mountain valleys. Some drying is indicated
this weekend.
Confidence Table...
02-08Z 08-14Z 14-20Z 20-00Z
KCLT High 100% High 93% High 100% High 100%
KGSP High 100% High 100% High 100% High 100%
KAVL High 100% Low 29% High 81% High 100%
KHKY High 98% High 90% High 100% High 100%
KGMU High 100% High 100% High 100% High 100%
KAND High 100% High 91% High 100% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...JPT
NEAR TERM...HG
SHORT TERM...TS
LONG TERM...JPT
AVIATION...HG
Area Forecast Discussion
National Weather Service Northern Indiana
733 PM EDT Tue Jul 4 2017
.SYNOPSIS...
Issued at 730 PM EDT Tue Jul 4 2017
Expecting most showers and storms to remain south and west of the
forecast area tonight providing a great night for festivities.
Temperatures will be able to fall back into the upper 50s to low
60s tonight as cooler and drier air comes into Southern Michigan,
NW Ohio and northeastern portions of northern Indiana. Dry air
remains around the region for Wednesday as well as only a late day
outside chance at a shower or storm and highs in the low to mid
80s. The next best chance for rain comes Thursday night and early
Friday as a cold front swings through. It`ll also bring cooler
temperatures for the coming weekend.
&&
.SHORT TERM...(This Evening through Wednesday)
Issued at 155 PM EDT Tue Jul 4 2017
Ill-defined pattern over our area currently as surface analysis
has high pressure centered across the central great lakes while
quasi- stationary boundary has slid a little further south toward
the OH valley. Latest RAP analysis indicating low level moisture
axis that has been focus for isolated/scattered convection over
the CWA also shifting a little further south...now along a line
from MIE to CMI. Surrounding radars showing convection beginning
to initiate along this boundary. HIRES guidance responding in kind
and now indicating better chances for continued convection this
afternoon now just south of our CWA. Will continue to monitor
afternoon trends but for now plan to stay with theme of current
forecast and keep small chance in far south through this evening
then dry forecast for tonight. Southern edge of great lakes high
is bringing drier air into the NE CWA as dewpoints have dropped
into the lower 50s this afternoon. This should continue spreading
southwest through the rest of the area tonight and allow for
comfortable overnight lows near 60. Upper level disturbance that
has been sitting over southern plains will begin to lift out and
shift eastward into the MO valley...but model trends continue to
show great lakes high will be dominant player for our weather and
keep forecast dry with near normal high temps.
&&
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 155 PM EDT Tue Jul 4 2017
Upper level disturbance will move eastward into the TN/OH valley
as upper ridge continues to build over the four corners. Surface
reflection in the form of frontal wave moving along quasi-
stationary boundary will combine to maintain low chance POPs in
southern CWA Thursday as main focus will be south of our area.
Northern stream wave will then drop down into the great lakes
region on Friday and bring surface cold front through the area.
Convection expected to initiate in the warm sector ahead of this
system Thursday afternoon in the upper MS valley and organize into
forward propagating MCS Thursday night. Depending on timing and
evolution of this system...may see some strong to severe storms
from this complex in NW CWA late Thursday night into the early
morning hours on Friday. Timing of cold front Friday not expected
to allow sufficient time for warm sector to recover and
destabilize before front pushes through which will lessen severe
potential for Friday except for possibly extreme SE CWA.
Seasonably cool Canadian airmass settles into the great lakes
region for the weekend providing very pleasant July weather with
less humid conditions and highs 75-80 and lows 55- 60. A couple
weak disturbances dropping down in NW flow pattern may generate a
few diurnal showers but meager -10 to -15C cold pool will keep
chances pretty limited. Temperatures will moderate back into the
80s beginning of next week as we get back into return flow on
backside of surface high.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 730 PM EDT Tue Jul 4 2017
Weak flow and a front remaining south across the area has been the
story for today. This will keep any storms that do fire ahead of
sunrise to the southwest of the terminals. Winds will also
continue to remain light and generally be out of the east for the
bulk of the period. Dry air moving in overnight will keep
terminals in VFR conditions into Wednesday.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...Roller
SHORT TERM...JAL
LONG TERM...JAL
AVIATION...Roller
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Area Forecast Discussion
National Weather Service Lake Charles LA
947 PM CDT Tue Jul 4 2017
.DISCUSSION...
A pleasant evening acrs much of southwest LA and southeast TX for
watching fireworks with nearly clear skies, temperatures in the
lower 80s and light south winds. Even Mother Nature is getting in
on the act just north of our central LA CWA border as a cluster of
showers and storms developed along a boundary just before sunset
and has persisted. This made for an interesting scene from our
office parking lot as fireworks around town were going off against
the backdrop of lightning from the distant storms.
Recent HRRR guidance indicates the storms acrs central LA will
diminish over the next couple of hours, and POPs are expected to
remain nil overnight. Made some minor tweaks to POP/WX grids from
00-06Z but none of these changes affected the current zone pkg.
24
&&
.PREV DISCUSSION... /issued 606 PM CDT Tue Jul 4 2017/
DISCUSSION...
00Z Taf issuance.
AVIATION...
South winds ~8-10 knots this evening expected to become variable
at 5 kts or less after 02z, picking up again after 14z Wed. VFR
expected through the period. Shower and isolated thunderstorm
chances 15-20% for Wednesday afternoon, not high enough to place
mention in terminals.
DML
PREV DISCUSSION... /issued 327 PM CDT Tue Jul 4 2017/
DISCUSSION...Happy 4th of July!!! Radar showing just a few
isolated showers left over the forecast area. Earlier scattered
activity over Acadiana was triggered by just slightly higher
moisture availability combined with low level convergence.
Interior southeast Texas showers were leftovers from earlier Texas
MCS. Will hold onto isolated showers through the remainder of the
afternoon. Not expecting any rains for the evening holiday
festivities, just the typical warm and humid conditions.
Little changes to the previous forecast. Continue to expect a
gradual uptick in pops through the week. This as low pressure now
advancing into west Missouri maintains a northeast track, while a
lingering southwest oriented trof gradually deepens and edges
southeast toward and eventually into the area. Scenario suggests a
weakening of dry high pressure aloft over the region that has
been providing effective capping. Moisture currently confined
predominantly to the lower levels will be increasing aloft. Hence
increasing rain chances. Otherwise look for persistent low level
southerlies to continue to keep the humidity in place. Afternoon
apparent temperatures will generally slip into a 100-105 range
during max heating.
For this evening...
8 PM...Temperature 84...Apparent Temperature 93...Light south
wind.
10 PM...Temperature 81...Apparent Temperature 87...Light south
wind.
MARINE...High pressure ridging across the northwest gulf will maintain
light southerlies and low seas.
23
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 75 92 75 92 / 20 20 10 30
LCH 78 90 77 90 / 10 20 10 30
LFT 76 90 76 90 / 10 20 10 40
BPT 77 90 77 90 / 10 20 10 30
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...None.
&&
$$
Area Forecast Discussion
National Weather Service Memphis TN
836 PM CDT Tue Jul 4 2017
.UPDATE...
Showers and thunderstorms continue over a good portion of the
Mid-South this evening. Although, the thunderstorms are now mainly
confined to an area near McNairy to Hardin County, Tennessee and
then a line stretching from near Olive Branch to just north of
Marks, Mississippi. The convection is putting a damper on holiday
festivities. Unfortunately, chances for off and on
showers/thunderstorms will continue into the early morning hours.
There will be some breaks between individual cells to possibly get
some fireworks off.
Another complex of storms may begin pushing into Eastern Arkansas
after sunrise. Will need to adjust POPS during the overnight hours
to account for this complex.
KRM
&&
.DISCUSSION... /issued 309 PM CDT Tue Jul 4 2017/
Quite a bit more convection on radar than we expected this time
yesterday. Summertime convection is especially difficult to
forecast as you are typically dealing with subtle
features/boundaries and its nearly always at least marginally
unstable. Anyway we should see the complex of storms approaching
East Arkansas to continue into and across the Midsouth over the
next several hours. The HRRR seems to have had a pretty good
Handel on the storms so far today and looks to be on track for the
approaching storms. However...it may be tracking the storms a bit
more to the Northeast than the radar is currently showing. Based
on its current track and speed this would take the line of storms
across the Mississippi River around 5-6 pm and likely approaching
the Tennessee River/Alabama state line around Sunset. It should
gradually weaken as it moves East into a less unstable airmass.
Short term guidance as well as the Storm Predictions day 1 outlook
also support a weakening trend. Hopefully it will move out of the
area quick enough to not interrupt any Independence day fireworks
displays.
Another round of showers and thunderstorms is expected to develop
after midnight...continuing through the day tomorrow. In fact, we
have enhanced rain chances in the forecast day and night across
all of the Midsouth through Thursday. A weak upper level low and
associated trough in place will result in steep lapse rates and
daytime heating will enhance instability. Dew points will remain
in the low 70s. The low will slowly fill and the trough will
gradually shift to the Northeast through Midweek. The threat of
strong or severe thunderstorms should decrease with time. High
temperatures will likely remain slightly below normal through
midweek.
By Friday surface high pressure will build in from the West and
strong Northwest flow will return to the Midsouth. High temperatures
will rebound a bit after midweek...to near 90 with near normal
temperatures, in the low 90s returning next weekend. Widespread
organized thunderstorms are not expected Friday through next
weekend. However, as temperatures turn warmer, afternoon pop-up
storms will become more likely.
30
&&
.AVIATION...
A slow moving disturbance over SW MO will bring a round of
convection to KMEM, KMKL and KJBR this evening followed by a
break later tonight then perhaps another round Wednesday morning.
Outside of convection conditions will be VFR with the potential
for MVFR stratus developing just after sunrise. Stratus will lift
by 15z or 16z with VFR conds returning. Light south winds
overnight outside storms will become SW on Wednesday with some
gusts above 15 kts at KMEM and KJBR in the afternoon.
SJM
&&
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Marquette MI
739 PM EDT Tue Jul 4 2017
.SHORT TERM...(This evening through Wednesday)
Issued at 415 PM EDT TUE JUL 4 2017
WV imagery and RAP analysis indicated a mid/upper level ridge over
the wrn CONUS with downstream wnw flow through the Great Lakes. A
weak shortwave trough over srn Manitoba supported an area of
shra/tsra into Ontario north of INL that was weakening as it moves
away from the srly flow of more unstable air through the ern Dakotas
and wrn MN. At the surface, high pressure over the central Great
Lakes continued to bring dry weather to Upper michigan with
prominent lake breezes and abundant inland diurnal cu.
Tonight, the high res models were in decent agreement that an area
of shra/tsra will develop this evening ahead of a weak trough into
from nrn Ontario into far nw MN. The tsra should move eastward
through nrn MN to wrn Lake Superior overnight, fueled by favorable
925-850 theta-e advection even with a modest 30 knot inflow. There
is more uncertainty by Wed morning as the MCS or shra/tsra weakens
away from the higher instability. MUCAPE values drop to around aob 1k
J/Kg farther east. Expect at least a chance for shra/tsra into
wrn Upper Michigan with the weakening system.
Even with leftover convective debris or mid/high clouds, expect
temps to recover by mid afternoon into the lower 80s inland. With
dewpoints into the mid 60s, expect SBCAPE values into the 1500-2500
J/Kg range. There will likely be enough of weak boundary or
shortwave moving through to help initiate convection. Although
models suggest that tsra chances will be greatest over the south,
sct tsra will be possible over most of the cwa. With modest 0-
6km shear of only around 30 knots, svr potential will be limited.
However, shear/instability will still be strong enough for isold
storms with strong winds or large hail.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 354 PM EDT TUE JUL 4 2017
Upper trough begins to amplify over the Upper Great Lakes by Thu and
remains amplified over the area into the weekend. Model consensus
timing indicates that a cold front will cross the western fcst area
Thu afternoon and then slide through the rest of the fcst area by
early overnight Thu night. NAM soundings indicate MLCAPEs
approaching 2000 j/kg ahead of the front into interior portions of
western Upper Mi. This instability combined with veering winds with
height and deep layer shear of 40-45 knots should lead to organized
storm development along and ahead of the front including supercells
and bowing line segments with large hail and damaging winds as
primary severe weather threats from late afternoon into the evening
hours. Not surprisingly, SPC day 3 convective outlook includes a
slight risk for severe storms across much of Upper Mi. Convection
will taper off or end by late evening west and the early overnight
east. After the warm (highs generally in the lower to mid 80s) and
humid conditions on Thu, temperatures will cool a little below
normal behind the front for Friday into Saturday with mainly dry
conditions expected.
Models still differ on timing of nw flow shortwave on backside of
trough and associated cold front for late weekend into early next
week. The ECMWF and CMC show similar timing with shortwave moving
down through Ontario Sat night pushing cold front across area late
Sat night into Sun with isolated to sct shra along the front and
drier cooler conditions behind the front late Sun into Tue. The 12z
GFS shows the cold front moving through Sun night and early Monday
and allows for a buildup of instability ahead of the front on Sun of
1000-2000 j/kg which subsequently leads to a higher coverage of
showers and t-storms late Sunday into Mon morning with the frontal
passage. Suspect the GFS instability is overdone as it quickly ramps
sfc dewpoints up into the mid to upper 60s on Sunday despite
soundings showing drier air which should mix to sfc to lower
dewpoints. GFS indicates drier cooler conditions Mon afternoon into
Tue behind the front. Given continued model uncertainty will likely
employ a model consensus approach with slight chc to low chc pops
from late Sat night into Mon until models can come into better
agreement on timing of frontal systems.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 739 PM EDT TUE JUL 4 2017
VFR conditions should prevail thru the fcst period at
KIWD/KCMX/KSAW. However, diminishing shra/tstms will likely approach
western Upper MI shortly after sunrise. If this pcpn, maintains some
intensity, MVFR or potentially brief IFR conditions could occur in
the morning at KIWD/KCMX. Only a VCSH mention was included for now.
Shra/tstms will likely develop in the aftn with the better chc
around KSAW. Conditions will likely drop out of VFR if any of the
terminals are affected.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 415 PM EDT TUE JUL 4 2017
Conditions across the lake should remain tranquil through the
forecast period with winds staying below 20 knots. However, there
may a conditional risk for strong wind gusts with any thunderstorms
moving into western Lake Superior late tonight.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...Voss
AVIATION...Rolfson
MARINE...JLB
Area Forecast Discussion
National Weather Service Norman OK
637 PM CDT Tue Jul 4 2017
.DISCUSSION...
The July 5-6, 2017 00 UTC TAF discussion follows:
&&
.AVIATION...
Scattered thunderstorms are expected to develop across north
Texas and adjacent parts of southern Oklahoma late this
evening/overnight. Highest confidence of showers/storms is south
of a line from KCSM/KHBR to KLAW. Opted not to include TSRA at
KOKC/KOUN, where the probability is lower. Gusty, variable winds
and reduced visibility will be possible within any thunderstorms.
Otherwise, light and somewhat variable winds will continue;
however, the predominant directions will be from the northeast,
east or southeast through period.
Mahale
&&
.PREV DISCUSSION... /issued 304 PM CDT Tue Jul 4 2017/
DISCUSSION...
High-based showers are moving southeast through central Oklahoma.
Much of this is virga, but there is some light rain reaching the
ground at times. The main weather for tonight though is likely
beginning to develop in the northwest Texas panhandle and
northeast New Mexico. There has been a consistent signal today in
the HRRR and other models of storms developing here, becoming a
complex and moving southeast through the southwestern portion of
the forecast area. The unclear thing about these storms is how far
north storms will be in the area. Additional showers and storms
are progged to develop along an east-west line across southern
Oklahoma and north Texas, although different CAM runs have placed
this development at various latitudes. Regardless, the highest
POPs tonight will be in the southern part of the area, and
generally later this evening.
The upper trough from Illinois into southwest Missouri or
northeast Oklahoma finally wanders farther east tomorrow and
leaves the area in northwest/northerly upper-level flow between
this exiting trough and the building ridge in the west. We
maintain some low POPs for the next couple of days before the
ridge builds in a little stronger. In the longer term, one big
difference in the models is the degree of the warming trend toward
early next week. GFS low-level temperatures increase the heat
significantly more than the ECMWF early next week, mainly in the
west. Brought high temperatures a little higher than the model
blend given the building ridge and the fact that it is July.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 69 88 69 91 / 50 30 10 0
Hobart OK 69 90 70 92 / 50 30 10 0
Wichita Falls TX 72 90 71 93 / 60 40 20 10
Gage OK 67 90 68 94 / 30 20 0 0
Ponca City OK 65 87 68 91 / 20 10 10 0
Durant OK 71 88 70 90 / 70 60 20 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
09/10/10
Area Forecast Discussion
National Weather Service Blacksburg VA
958 PM EDT Tue Jul 4 2017
.SYNOPSIS...
An upper level disturbance over the Tennessee Valley will move east
crossing our region tonight. A backdoor front over southern
Pennsylvania will drift south toward our area Wednesday before
lifting back north as a warm front Thursday. The combination of
todays upper level disturbance and additional waves of energy along
the front Wednesday and Thursday will result in an increasing threat
for showers and thunderstorms for the next several days.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 957 PM EDT Tuesday...Current radar mosaic reveals a
couple areas of showers: one is the large area of moderate rain
showers with embedded thunderstorms across much of the Central
VA Piedmont and Southside VA and into Rockingham and Caswell
Counties in NC. Atmosphere in this area is becoming more stable
due to persistent rain and a continued weakening trend expected
here through midnight. Also seeing increasing/deepening shower
development over western Wilkes/southern Alleghany Counties in
NC as well as further back into northeastern TN associated with
remnant MCV feature. SPC Mesoanalysis reflects axis of lingering
moderate instability into our NC counties - and is confirmed by
00z GS0 sounding. Past couple runs of the HRRR show this shower
activity brushing the NC foothills counties and making it into
the Triad through 05z. Possibility of some thunder given the
instability in this general corridor but thunder threat is
dwindling. Adjusted PoPs/Wx to better show these trends, but
maintained isolated showers for the overnight as near-term
guidance continues to point to unfocused, spotty shower coverage
pretty much anywhere.
Did increase lows up by a couple degrees now into the mid 60s to
lower 70s. It will no doubt be rather humid as well with similar
dewpoint readings. This should also lead to some patchy mist or
fog as well, preferentially in areas that received rainfall
today (Piedmont and Blue Ridge counties in VA and the NC
Piedmont/foothills).
Previous near-term discussion issued at 301 PM follows...
Happy 4th of July! Shortwave over the Tennessee Valley
associated with an area of showers and a few thunderstorms
across eastern Kentucky and eastern Tennessee will move east-
northeast this afternoon into tonight. Scattered showers and
thunderstorms will develop this afternoon into tonight in the
warm unstable air. The spc mesoanalysis at 18z showed SBCAPE
between 1000 and 2000 J/Kg are forecasted by modified 12z
soundings. SPC in the Day 1 convective outlook has placed
southern portions in a marginal risk for severe weather with
wind being the primary threat. Also, there is a threat for
localized heavy rainfall per forecast precipitable water values
near 1.75 and cloud layer mean wind from 250 degrees at 10 kts.
The diurnally driven thunderstorms should taper off around sunset,
however there will be a lingering threat for showers tonight per the
presence of the upper shortwave trough passing overhead. Considerable
cloudiness with the threat for showers will continue overnight
into Wednesday morning. With low level moisture and light winds,
added some patches of fog overnight. Low temperatures tonight
will range from the upper 50s in the mountains to around 70
degrees in the Piedmont.
The passage of several upper shortwaves will deepen and establish an
upper trough across the east by the end of week. High pressure over
New England wedges down the east side of the Appalachians and keeps
a frontal boundary across the region. This will trigger some
convection Wednesday afternoon into Wednesday evening. There is a
marginal threat for severe thunderstorms mainly south and west as
highlighted on Day Two convective outlook. The main threats will be
damaging winds and heavy downpours. High temperatures Wednesday will
range from the lower 70s in the mountains to the mid 80s in the
Piedmont.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 301 PM EDT Tuesday...
An upper level ridge in the western Atlantic will continue to block
and slow the progress of weather system tracking east of the
Mississippi Valley. This ridge will stretch westward across the Gulf
states reducing the influx of moisture into the region. However, high
moisture content will already be in place by the time the ridge
moves over the Gulf States.
Wednesday night, a surface reflection along the VA/NC border will
slowly move eastward. This reflection will keep some showers over
the area through the early morning hours. This system moves out to
sea on Thursday. A significant short waves and associated cold front
is forecast to move slowly across the Midwest Thursday and over the
southern Ohio Valley Thursday night. A second cold front will track
over the upper Midwest Thursday night and help push this short wave
across the mountains Friday morning and east of the piedmont during
the afternoon. This wave is able to pick up speed because the
blocking ridge is sinking southward Thursday night and Friday. Since
this wave is coming through during the morning, the severe weather
threat will be greatly reduced. However, the cold pool comes over
the area with a fair decent jet. Therefore, we can not rule out
gusty winds or hail for Friday. The mountains are less likely to see
severe storms Friday morning. The piedmont may see storms getting
stronger in the afternoon, but the max potential for severe chances
will be east across the coastal piedmont late Friday afternoon.
Close to normal temperatures are expected through Friday with low to
mid 80s west of the Blue Ridge and upper 80s to lower 90s east.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 240 PM EDT Tuesday...
The cold front that comes across Friday will take bulk of the
moisture and instabilities with it. Another front will slide across
the region on Saturday. With limited moisture, this second front may
produce a few hundredth of an inch of rain across the mountains,
mainly along western slopes. Showers will fade as they approach the
Blue Ridge then jump to a lee trough over the piedmont during the
afternoon. With good mixing and low instabilities, we will only
carry showers for this frontal passage. Cool and dry high pressure
will move over the region Sunday and Monday. The chance for
thunderstorms begin to increase on Tuesday.
Temperatures will fall a few degrees below normal following the
second frontal passage Saturday. Muggy conditions will also be
replaced with comfortable humidity levels with dew points falling
into the upper 50s to lower 60s over the weekend.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
As of 718 PM EDT Tuesday...
Generally VFR outside of any thunderstorms through a large part
of the overnight. Thunderstorm threat mainly from 00-03z, have
indicated VCSH for now and will amend as necessary for more
imminent impact to specific airports. Brief sub-VFR visibility
reduction and occasional/frequent CG lightning are the risks
from thunderstorms, along with erratic outflow gusts.
Approaching band of showers/embedded thunder now over northeast
TN mainly affects southern Blue Ridge/NC mountains after 04z.
Coverage of showers should diminish after 08z, with potential
for patchy fog particularly for airports that received rain.
Kept visibility in fog generally 1-4 SM. Outside of
thunderstorms, winds intially east to northeast 3-6 kts become
light to calm overnight.
Should see improvement in areas of patchy fog with VFR
conditions for the Wednesday morning hours. Potential again for
showers and thunderstorms in the afternoon with introduction of
VCSH at most terminals after 16z Wednesday. Light winds outside
of thunderstorms.
Extended Aviation Discussion...
Ceilings to lower to MVFR Wednesday evening as ongoing showers
interact with weak wedge building down from northern VA. Should
see return to VFR ceilings Thursday ahead of a potent shortwave
trough. While periods of VFR certainly expected at times,
potential for heavier showers/storms Thursday afternoon and
evening especially western terminals, and then again on Friday.
Generally VFR conditions for the upcoming weekend.
Late night and early morning fog can also be expected with
increasing probability through the week, especially given the
increasing potential for late day/evening rain at many TAF
sites.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...KK/PM
NEAR TERM...AL/KK
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...AL/JR
Area Forecast Discussion
National Weather Service Shreveport LA
935 PM CDT Tue Jul 4 2017
.DISCUSSION...
Mesolow movg mostly east of area, although small persistent
cluster of convection beyond sunset across southern portions of
northern LA. For this reason, will maintain isold pops areawide as
boundary may linger. further north, still expecting mcs
development overnight in nw flow aloft, although OK radar scope is
clear with all clusters in west TX and ne AR. Have only increased
pops to likely across extreme nw cwa and do not expect this
coverage until near daybreak. Current dewpoint trends and temps
suggest that overnight lows in lower to mid 70s should
prevail./07/
&&
.PREV DISCUSSION... /issued 831 PM CDT Tue Jul 4 2017/
AVIATION...
For the 05/00z TAFS vfr conditions prevailing... Terminals kmlu and
keld vcts will be possible over the next several hours before moving
away from these terminal sites by 05/03Z. Low clouds will filter in
from the west which will cause cigs across the region to drop to
mvfr by 05/09Z. Cigs will continue to decrease to mvfr to ifr
through the morning hours due to a warm moist air filtering in from
the Gulf of Mexico and a disturbance to the west. These low CIGS
will move from west to east starting with ktyr,klfk,kggg,ktxk around
05/10Z and move to kshv,kmlu,keld by 05/11Z. Vsby will fluctuate
from 5 to 6 sm through the overnight hours with most terminal sites
lifting to mvfr to vfr by 05/12Z with -shra/-tsra possible in east
Texas.
/21/
PREV DISCUSSION... /issued 356 PM CDT Tue Jul 4 2017/
DISCUSSION...
More upper 80s than low 90s, but skies are thinning with visible
showing rotating meso high overhead. This is bringing light NW
flow in over this morning`s outflow boundary and we have bumped
pops a bit the rest of this afternoon in NE LA for the most part.
A pre first period in the new zone forecast will introduce chance
and keep it going into the early evening for these zones.
The HRRR is a little better in it`s initialization and is showing
continued development toward sunset in the same general area. The
HRRR also shows the next nocturnal push developing right over NE
TX and SE OK along the Red and sinking South into Northwest LA on
its last available frame. So additional changes may develop there
on this evening`s update. The GFS had a good guess at 12Z and all
the models indicate another complex right in our neighborhood.
The overall chance is going up a bit a surface front nudges this
whole pattern slowly E across the area. This is only a 1018-1020mb
high so just slightly cooler, but drier a bit for Friday. Then
the boundary lifts back into the weekend bringing back good
coverage into mid month. That is good news for hanging on to
double digit highs and our rain deficit. /24/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 76 91 76 90 / 20 50 30 30
MLU 75 93 75 91 / 20 20 30 30
DEQ 72 87 70 90 / 60 60 30 30
TXK 74 88 72 89 / 40 60 30 30
ELD 73 88 74 90 / 30 40 30 30
TYR 76 90 74 91 / 20 60 30 20
GGG 76 90 74 90 / 20 50 30 30
LFK 76 94 75 93 / 20 20 20 30
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
Area Forecast Discussion
National Weather Service San Angelo TX
649 PM CDT Tue Jul 4 2017
.AVIATION...
/00Z TAFS/
Look for challenging flight weather for most of this forecast
period. Thunderstorms will continue for this evening, across
mainly the Big Country and Concho Valley. Plus, stratus and MVFR
ceilings will likely return late tonight at the Junction terminal.
Tomorrow afternoon, thunderstorms remain in the forecast for all
but the Sonora and Junction terminals.
&&
.PREV DISCUSSION... /issued 328 PM CDT Tue Jul 4 2017/
SHORT TERM...
(Tonight and Wednesday)
Scattered thunderstorms are starting to develop across portions of
the western Big Country and the northwest Concho Valley as of 3 PM
(20Z). Latest HRRR shows this activity expanding in coverage and
moving southeast through the remainder of the afternoon and into the
evening hours. Have expanded the PoPs farther southeast to cover
much of the area this evening, with the best chance north of a San
Angelo to Brownwood line. The HRRR and the TTU-WRF also show a
second area of showers and storms developing across the Panhandle
this afternoon, with this area of storms moving south into West
Central Texas later tonight. Overall, have increased rain chance for
much of West Central Texas tonight.
Chances for tomorrow are highly dependent on exactly what happens
tonight. Best chance will likely remain across the eastern counties,
where the convection moving in late tonight may well linger into the
morning hours. These storms should leave additional boundaries that
will again be a focus for additional convection tomorrow afternoon.
Just where these boundaries end up remain a question, so will keep
rain chances relatively low at the moment, although some areas may
well see higher rain chances needed tomorrow at some point.
Temperatures to remain near or a little above normal, with lows in
the lower 70s and highs in the low to mid 90s.
LONG TERM...
(Wednesday night through Tuesday)
Northwest flow aloft will continue this week, even as upper
ridging builds in from the west and northwest. Best chance of
storms (20-30 percent) will be Wednesday night and Thursday.
Storms will become even more isolated Friday and Saturday, with
the best potential over eastern and southern portions of West
Central Texas. Main storm threat will be strong gusty winds. Next
week, high pressure will suppress most shower and thunderstorm
development, although one can not rule out a storm given the
region will be on the eastern periphery of the upper ridge.
Highs will continue into the mid and upper 90s into next week
with lows in the lower to mid 70s.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 72 93 72 95 / 30 30 20 20
San Angelo 73 96 73 97 / 30 20 30 20
Junction 73 95 72 96 / 10 10 20 20
Brownwood 72 93 72 94 / 30 40 30 30
Sweetwater 73 93 71 94 / 30 20 20 10
Ozona 72 95 71 94 / 10 10 20 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$