Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/14/19
Area Forecast Discussion
National Weather Service Bismarck ND
1012 PM CDT Fri Sep 13 2019
.UPDATE...
Issued at 945 PM CDT Fri Sep 13 2019
Showers are trying to hold on over eastern Montana as they
approach the border. We did adjust pops modestly based on a blend
of Previous forecast, HRRR and HREF. This cut back a litte on
pops, especially south, but overall only minimal changes. Also
adjusted sky cover a little based on latest Satellite and short
term guidance.
UPDATE Issued at 622 PM CDT Fri Sep 13 2019
We bumped up pops a bit late evening into the overnight hours over
western ND. Showers and a few thunderstorms pushing across north
central ND at this time ahead of a shortwave trough. Short term
models bring this activity into northwest ND around midnight and
track it across the CWA through around 16 UTC Saturday. Best
chances remain across the northwest and north central, with
chances tapering the farther south you go into southwest and
south central ND. Kept a mention of isolated thunder through
around 11 UTC.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 225 PM CDT Fri Sep 13 2019
This afternoon, North Dakota sits between a stacked low pressure
system spinning over southwest Ontario and an upper level ridge
extending from central Saskatchewan through eastern Montana. 18Z
surface analysis places a high pressure ridge over western North
Dakota. Persistent cloud cover associated with the departing low
is finally decreasing early this afternoon as ridging continues to
build over the Northern Plains. This clearing will allow western
North Dakota to see temperatures reach near 70 before diurnal
heating ends for the day. Much of the rest of the area should see
temperatures reach the 60s.
Tonight into Saturday morning, a shortwave that is currently seen on
water vapor imagery near Glacier National Park is forecast to track
across the area. This will bring a chance of scattered showers and
perhaps a thunderstorm to parts of western and north central North
Dakota late tonight through mid morning Saturday. Behind the
shortwave, the rest of Saturday is shaping up to be very pleasant,
with clearing skies and highs in the 70s.
.LONG TERM...(Saturday night through Friday)
Issued at 225 PM CDT Fri Sep 13 2019
Warm and dry weather is expected Sunday into Tuesday as a strong
upper level ridge builds over the central CONUS. Should see highs in
the 80s for most areas these days. Monday looks to be warmest, when
a few +90 degree readings may be possible.
A strong upper level shortwave is forecast to move onto the Pacific
Northwest early Monday and track towards the Northern Plains by
Wednesday. This will bring chances for rain and cooler temperatures
back to the region beginning Tuesday evening. Models begin to
disagree on the synoptic pattern beyond mid week, but the general
trend seems to suggest a southwest flow pattern for the Northern
Plains, with longwave troughing over the western CONUS.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 945 PM CDT Fri Sep 13 2019
VFR conditions are forecast through the 00Z forecast period.
Showers and isolated thunderstorms along a cold front will move
into west ND around midnight and spread east across the forecast
area through mid-late morning Saturday. At this time we limited
shower activity to Williston, with a vcsh at KDIK and KMOT. Shower
activity remains mostly north of KBIS and KJMS so too much
uncertainty at this time. Kept the mention of thunder out of the
forecast for the time being as thunderstorm activity currently
over north central MT will likely wane as we move toward midnight.
Still some possibility for thunder at KISN but too much
uncertainty to include in the TAF at this time. Southerly surface
flow this evening will shift westerly behind the cold front
Saturday.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...Hollan
LONG TERM...Hollan
AVIATION...TWH
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
234 PM MDT Fri Sep 13 2019
.SYNOPSIS...
Scattered showers and thunderstorms, some with localized
torrential downpours, will continue to affect much of the region
this afternoon and evening, with the focus slowly shifting into
southwestern New Mexico. Thunderstorm chances will mainly be
focused near and west of the Continental Divide this weekend, but
will overspread the region again Monday and Tuesday as an upper
level trough moves into the west coast, and winds aloft shift to
the southwest again. Drier conditions will prevail mid-week.
&&
.DISCUSSION...
Surface obs show E to SE flow has pushed west of the Arizona
line, with 50s dewpoints having overspread the area over the past
few hours. Upper 50s to near 60 dewpoint remain in place generally
east of the Continental Divide. RAP analysis suggests MLCAPE
values of 800-1000 J/Kg over the NM Bootheel and eastward along
the international border, with higher values up to 1500 J/Kg over
Far West Texas and the Otero Mesa. CIN values are weak and mostly
limited to the Gila Region where showers have so far been weaker.
However, with the mid-level ridge axis over the area, we are
lacking any focusing mechanism, and with an unstable and CIN-free
sounding, we`re basically seeing relatively small multicell storms
over both the higher terrain and the desert lowlands. Weak mid-
level flow is also resulting in nearly stationary storms with a
tendency to back-build.
High-res models have had a tough time indicating any sort of
consistent evolution of convection for this afternoon and evening,
likely due to the lack of forcing and small horizontal scale of
the showers/storms. Some earlier runs suggested thunderstorms
would slowly increase in coverage and eventually converge on SW
New Mexico this evening, roughly on the leading edge of the deeper
low level moisture (mid/upper-50s dewpoints).
Basically kept broad-brushed scattered PoPs in through the
afternoon and evening, slightly favoring SW New Mexico tonight.
Both the NAM and GFS have consistently developed a convectively-
induced mid-level low over the northern Sierra Madres by Saturday
morning, and carry this feature northwards along the western edge
of the subtropical ridge, pulling the deepest subtropical moisture
into far SW New Mexico and southern Arizona, while drier and
slightly warmer air aloft tries to seep into areas east of the Rio
Grande. We will likely still see a few isolated storms in the
eastern lowlands tomorrow, but the better coverage of storms will
be over the Gila and Bootheel Regions.
This pattern looks to continue into Sunday, as the mid-level
disturbance moves northwards towards the Four Corners, and a sharp
upper level trough moves into the West Coast. This trough will
cause mid-level winds to veer more to the southwest, spreading
monsoonal moisture to the east Monday and Tuesday. The west coast
trough looks to take a more northerly route, limiting wind shear
and upper level forcing with the trough passage on Tuesday
(diminishing the risk of isolated severe thunderstorms). Drier
air aloft will push in from the west on Wednesday, diminishing the
threat of precip through at least Thursday.
&&
.AVIATION...Valid 14/00Z-15/00Z...
P6SM FEW-SCT070-090 SCT-BKN200-250 through period. Expect scattered
storms with VRB25G40KT 1-3SM TSRA BKN030-040 across area through 06Z
then becoming more isolated through 18Z. Storms expected to
increase in coverage again, mainly mountains and west of divide
after 18Z. Winds east to southeast at 5-15KTS.
&&
.FIRE WEATHER...
Moisture has returned to the area with scattered showers and
thunderstorms expected through this evening and continuing into
early next week as a Pacific trough moves over the Rockies. The
best precipitation chances after today will be focused in the
mountains and west of the Rio Grande, but isolated storms will
continue to affect the eastern lowlands. Temperatures will be
near to slightly below normal for most of the period with minimum
relative humidities remaining above 25-30 percent most days over
the lowlands and 30-40 percent in the mountains. Winds through
the weekend will be east to southeast at 5-15 mph, but gusty near
thunderstorms. Vent rates through the weekend will range from
fair to very good.
&&
.PRELIMINARY POINT TEMPS/POPS...
El Paso 68 87 67 87 / 30 20 10 10
Sierra Blanca 62 85 59 82 / 30 10 0 0
Las Cruces 65 85 61 84 / 40 20 20 20
Alamogordo 64 86 62 86 / 40 30 20 20
Cloudcroft 50 65 45 64 / 50 60 30 40
Truth or Consequences 64 84 63 84 / 50 30 30 30
Silver City 59 79 58 77 / 60 50 40 40
Deming 65 84 62 84 / 60 30 30 30
Lordsburg 65 87 62 83 / 50 40 40 40
West El Paso Metro 69 86 67 87 / 30 20 20 10
Dell City 65 88 62 87 / 30 10 0 0
Fort Hancock 69 89 67 89 / 20 10 0 0
Loma Linda 62 81 62 81 / 30 20 0 10
Fabens 68 88 67 87 / 20 10 10 10
Santa Teresa 67 85 64 85 / 30 20 20 10
White Sands HQ 66 84 65 85 / 40 20 20 20
Jornada Range 64 84 61 85 / 50 20 20 20
Hatch 65 84 61 85 / 50 30 30 20
Columbus 67 86 64 85 / 40 20 30 20
Orogrande 65 86 62 85 / 30 20 10 10
Mayhill 54 74 50 73 / 60 40 20 20
Mescalero 54 74 49 74 / 50 50 30 40
Timberon 53 72 48 72 / 50 40 10 20
Winston 54 78 50 77 / 50 50 40 40
Hillsboro 60 82 59 82 / 50 50 40 40
Spaceport 62 84 59 84 / 50 30 30 20
Lake Roberts 54 79 51 77 / 50 60 40 40
Hurley 60 80 57 79 / 50 40 40 40
Cliff 60 87 56 85 / 50 50 30 40
Mule Creek 61 85 59 79 / 50 60 40 50
Faywood 61 81 59 80 / 60 40 40 40
Animas 65 88 61 84 / 60 40 50 40
Hachita 64 86 61 83 / 50 30 40 30
Antelope Wells 63 85 61 84 / 50 50 50 50
Cloverdale 62 82 60 79 / 50 50 50 50
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
NM...None.
TX...None.
&&
$$
25-Hardiman / 26-Grzywacz
Area Forecast Discussion
National Weather Service Grand Rapids MI
1119 PM EDT Fri Sep 13 2019
LATEST UPDATE...
Update
.SYNOPSIS...
Issued at 313 PM EDT Fri Sep 13 2019
- Storms exiting this evening
- Chance for showers and thunderstorms Sunday
- Dry with seasonal temperatures in the 70s most of next week
&&
.UPDATE...
Issued at 1119 PM EDT Fri Sep 13 2019
I have increased the chance for rain and thunderstorms for late
Saturday night into Sunday based on the latest Hi Res model runs.
Both the NAM and HRRR 36 hour run from 00z show a 30 to 50 knot
low level jet aimed as Southwest Michigan Sunday morning. This is
aided by a digging 80 to 90 knot 300 mb jet on the back side of
digging northern stream wave. All of these features support good
moisture transport into Southwest Michigan during the early
morning hours of Sunday. There is thin cape early and EL levels
rise to near 42000 ft by afternoon Sunday. It seems to me there is
an excellent chance of elevated thunderstorms with locally heavy
rain west of US-131 and south of I-96. During the day there is
enough instability for scattered thunderstorms.
&&
.DISCUSSION...(This evening through next Friday)
Issued at 313 PM EDT Fri Sep 13 2019
-- Storms exiting this evening --
Strong to severe convection has initiated along a northeast to
southwest line located just southeast of Jackson County. This
effectively removes our chances for thunder and have updated the
forecast accordingly.
-- Chance for showers and thunderstorms Sunday --
Showers and thunderstorms will be possible from midnight Saturday
night into early Sunday night. Precipitation amounts should not be
heavy and overall chances for measurable precipitation are only in
the 30% range at this time which is not substantially different from
the previous forecast. It is possible rain chances could increase as
we get closer to the event.
Forecast reasoning: Synoptic conditions do not favor significant
rain due to surface high pressure between us and the Gulf of Mexico
limiting moisture return. The upper forcing is characterized by a
minor upper trough in northwest flow aloft. It is not uncommon for
models to sharpen these features as we get closer to the event, so
we could see a more refined time window and an uptick in PoPs with
subsequent forecast updates. A sharper trough would also boost
thunder chances due to stronger mid-level cooling / height falls.
-- Dry with seasonal temperatures in the 70s most of next week --
Confidence is fairly high for dry conditions Monday through
Wednesday. There will be a gradual warmup with highs possibly
reaching the low 80s towards the latter half of the week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 728 PM EDT Fri Sep 13 2019
With the passage of the cold front had cleared out low clouds this
afternoon. However as typical of a deeply occluded storm system
(which is what has come through this area) there is an area of
MVFR/VFR cigs low clouds in the coldest air trailing the system.
The MVFR cigs are over northern WI and likely will stay north of
our TAF sites tonight, but I do believe VFR cigs are likely. The
low clouds should move out by mid morning Saturday resulting in
mostly clear skies.
Winds will slowly diminish this evening and should be more in the
5 to 15 knot range tomorrow.
&&
.MARINE...
Issued at 313 PM EDT Fri Sep 13 2019
Latest guidance suggests Small Craft Advisory conditions will cease
by mid-morning Saturday. However will leave the current afternoon
expiration time alone for now to see if this trend in the forecast
guidance continues.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory until 5 PM EDT Saturday for LMZ845>849.
&&
$$
UPDATE...WDM
SYNOPSIS...TJT
DISCUSSION...TJT
AVIATION...WDM
MARINE...TJT
Area Forecast Discussion
National Weather Service Jacksonville FL
942 PM EDT Fri Sep 13 2019
.UPDATE...A band of fast moving showers approaching the St Johns
CO coast in the next hour will bring brief downpours and gusty
winds. High-res HRRR indicates more bands of showers moving ashore
the coast overnite so will be keep pops going for coastal areas.
Brief downpours and storms possible.
&&
.AVIATION...Ocnl MVFR from shra at the Taf sites til around 03Z-
04Z. Otherwise prevailing VFR with spotty light showers possible
tonight. Gusty NE winds at SGJ...CRG...and SSI.
&&
.MARINE...Moderate ENE winds will continue between high pressure
north of the waters and TD Nine over the Bahamas. Winds will
increase and waves will build through Sunday as this system moves
north and then northeast into early next week. Advisory conditions
expected over all the waters this weekend and may need a Tropical
Storm Watch for the ne Fl waters. Local mariners should monitor
the latest official forecasts from the National Hurricane Center.
Coastal Impacts: Minor coastal flooding possible this weekend at
the east coast beaches and along the St. Johns River due to high
astronomical tides and increasing onshore winds.
Rip Currents: High risk of rip currents today through the weekend
due to persistent onshore winds and rough surf.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 72 89 73 86 / 0 10 10 50
SSI 78 87 76 84 / 10 20 50 60
JAX 76 87 75 86 / 20 50 50 60
SGJ 77 86 75 86 / 30 80 60 60
GNV 74 87 74 88 / 10 40 30 60
OCF 74 88 74 89 / 10 60 30 50
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through Sunday evening for Coastal Duval-
Coastal Flagler-Coastal Nassau-Coastal St. Johns.
GA...None.
AM...Small Craft Advisory until 8 PM EDT Monday for Waters from
Altamaha Sound GA to Fernandina Beach FL from 20 to 60 NM-
Waters from Fernandina Beach to St. Augustine FL from 20 to
60 NM-Waters from St. Augustine to Flagler Beach FL from 20
to 60 NM.
Small Craft Advisory until 8 PM EDT Sunday for Coastal waters
from Fernandina Beach to St. Augustine FL out 20 NM-Coastal
waters from St. Augustine to Flagler Beach FL out 20 NM.
Small Craft Advisory from 8 AM Saturday to 8 PM EDT Sunday for
Coastal waters from Altamaha Sound to Fernandina Beach FL
out 20 NM.
&&
$$
PP/LS/TH
Area Forecast Discussion
National Weather Service Phoenix AZ
434 PM MST Fri Sep 13 2019
.UPDATE...Updated aviation discussion.
&&
.SYNOPSIS...
Conditions will continue to moisten through Saturday with chances
for strong to severe thunderstorms increasing markedly across
south-central Arizona. The threat for storms will continue Sunday,
but will mainly be relegated to eastern Arizona. A low pressure
system moving into the Great Basin early next week will allow for
mostly slight chances of showers and thunderstorms on Monday and
Tuesday before drier and somewhat cooler air overspreads the Desert
Southwest.
&&
.DISCUSSION...
Western extension of the southern CONUS ridge remains sprawled
across the Desert Southwest. In the lower levels, conditions are
exceptionally dry with dewpoints in the 30s, though with the ridge
axis lifting northward, low-level mixing ratios will increase
steadily to around 10 g/kg through tomorrow. Latest runs of the HRRR
indicate that isolated showers will remain relegated to southeastern
Arizona this afternoon. Biggest weather impact will instead be the
above normal temperatures, however highs will fall well short of
daily records.
Focus will shift to an increased threat of monsoon hazards Saturday
as the models suggest ingredients will come together to produce
strong to severe storms across portions of the area. Latest
streamline analysis depicts an upper low near the northern Baja
Peninsula, which will drift eastward into northern Sonora, yielding
widespread jet-forced ascent across eastern Arizona. Convection will
ensue across southeastern Arizona, which the models suggest
will induce an organized inverted trough/vort max across eastern
Arizona. This will consequently increase the easterly component to
the steering flow off the higher terrain. Local/regional CAMS
indicate that additional storms in the lower deserts are expected
to initiate, given the abundant MUCAPE > 1000 J/kg. Although model
soundings indicate inhibition (due to a mid-level warm layer) will be
present to some degree, it is expected to erode during the afternoon
and should be overcome by any downslope-propagating outflow boundary.
Latest HREF > 40 dbz paintball and max surface winds suggest the
most intense cells Saturday will be capable of producing strong to
severe winds, microbursts and frequent lightning. Although PWATs are
not projected to be off the chart by any means, heavy rain and
subsequent flash flooding cannot be ruled out, particularly across
the urban areas of the Valley. Forecast PoPS were increased above the
latest NBM guidance and are some of the highest we`ve seen so far
this Monsoon season. SPC has also placed much of the forecast area
into a Marginal Risk for severe storms, however this could be
upgraded as the situation evolves.
A more distinct low pressure system (as depicted in both the
operational GFS and ECMWF) will likely emerge across eastern Arizona
Sunday, again resulting in favorable conditions for thunderstorms.
However, the southwesterly flow will generally focus activity across
eastern Arizona, though there will be a discernible risk of flash
flooding across portions of the Gila County, where PWATS remain
anomalously high. Further west in the lower deserts, rain coverage
will likely not be quite as widespread, given the environment will
be more subsident behind the departing low pressure system.
&&
.PREVIOUS DISCUSSION...
The track of the Pacific trough for early next week now looks to
be even farther north with the low center tracking across northern
Nevada into southern Idaho. We will still fall under cyclonic
flow aloft early next week and there should be enough lingering
low level moisture for some showers and thunderstorms mainly on
Monday and mostly over the high terrain north and east of Phoenix.
Slight chance PoPs are still in for the south-central Arizona
lower deserts, but it seems likely most of the activity will be
over the more favored upslope foothills areas just north and east
of Phoenix. Drying aloft will increase into Tuesday, ending rain
chances across the lower deserts, but there may still be some
isolated showers and possibly a few thunderstorms over the
eastern Arizona high terrain. Temperatures will lower back to near
normal readings beginning Sunday with highs sticking around the
century mark across the deserts through the middle of next week.
&&
.AVIATION...Updated at 2345Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Dry, tranquil conditions expected at the terminals this evening
with thunderstorms mostly remaining across southeast Arizona. As a
result of this activity, a weak southeasterly outflow may reach
the terminals after 04Z but speeds should remain light. Westerly
winds will transition later tonight to the southeast. Going into
Saturday afternoon, winds look to maintain a southeasterly
component with no typical diurnal switch to the west during the
afternoon. Tomorrow afternoon/evening looks to be an active period
where south-central Arizona will experience increasing
thunderstorm activity. The main threats with these storms will be
strong, gusty winds along with lightning. Maintained VCTS in the
TAF after 23Z at KIWA and 00Z at KPHX, with gusts up to 30 kt
possible. Areas of blowing dust may also affect area terminals,
with visibilities perhaps down to 5 SM at KIWA. Otherwise, FEW-
SCT mid and high level clouds are expected through late tomorrow
afternoon with bases generally remaining aoa 10 kft, before
thicker cloud cover with bases down to 8 kft possible with
increased thunderstorm activity.
Southeast California/Southwest Arizona including KIPL and KBLH:
No significant aviation concerns expected through the period as
light winds and VFR conditions prevail. Wind speeds through the
next 24 hours look to remain below 8 kts becoming light and
variable at times. Otherwise, FEW-SCT high clouds will be possible
through the TAF period.
Aviation Discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday:
A series of low pressure systems will move through the
Pacific Northwest and Great Basin next week. Conditions will remain
sufficiently moist ahead of the first system for a chance of
showers, mainly north and east of Phoenix Monday and Tuesday.
Otherwise, these storm systems will reinforce the westerly flow,
which will result in a gradual drying trend and near normal
temperatures.
&&
.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Hirsch
PREVIOUS DISCUSSION...Kuhlman
AVIATION...Rogers/Smith
FIRE WEATHER...Hirsch