Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/13/17
Area Forecast Discussion
National Weather Service Charleston SC
929 PM EST Sun Feb 12 2017
.SYNOPSIS...
A cold front will sweep through late tonight. Another cold front
will move through Wednesday night followed by high pressure into
next weekend.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
The forecast is on track. Approaching line of showers along the
front is quickly diminishing as it encounters downslope induced
subsidence. Made minor adjustments to sky cover to account for
current trends.
Lingering cloud cover will dissipate this evening, then briefly
increase again with the cold front. The front is quickly moving
across western North Carolina, the South Carolina Upstate and
northern Georgia early this evening and is delineated by a
pronounced, yet shallow line of convection. Expect this line to
dissipate as it moves east and encounters an increasingly
downslope/subsident environment that is in place across central
and eastern portions of South Carolina and Georgia.
Both the RAP and H3R do show a few sprinkles moving into
portions of Jenkins, Screven and Allendale counties just before
midnight, but no measurable rainfall is expected as the cold
front pushes offshore. A rain-free forecast will be maintained
with gridded pops 0-5%.
The downslope component is strongest north of a Hampton-
Beaufort line so skies may very well remain mostly clear to
partly cloudy until after the front pushes through. Farther
south, partly to mostly cloudy skies can be expected with
clearing conditions expected late. Lows from the upper 40s far
interior to the upper 50s along the Georgia coast seem
reasonable, although a non-diurnal temperature curve will occur.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
Dry high pressure will prevail Monday into Tuesday as a zonal flow
sets up aloft. Temps will feature a slow warming trend as the cold
advection shuts off and warm advection begins by late Tuesday. A
southern stream shortwave will push a surface low through our area
Wednesday, followed by a cold front late. PWATs rising to near 1.5"
could lead to brief bouts of locally heavy rainfall. Instability
ahead of the front is low, but shear is forecasted to be high. We
added thunderstorms to the forecast for Wednesday afternoon to
account for this. Focus will need to be on the location of the low
and how much instability is able to make it into our area.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
A brief period of at or below normal temps expected Thu into Fri
as cold high pressure settles over the area. An upper level
cutoff low over TX late week should lift out to the ENE Sat and
Sun, potentially bringing some showers to the area, and warmer
temps.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
VFR.
Extended Aviation Outlook: A cold front could bring brief MVFR
Wednesday and Wednesday evening.
&&
.MARINE...
Tonight: Offshore of Charleston County, winds were likely still
gusting to SCA levels closer to 20 NM offshore and the SCA was
initialized with expectations of a better surge after midnight
in the wake of cold front. All waters will see wind directions
shifting nw and n late with increasing surges in cold air
advection in tandem with improving low level lapse rates.
Advisories have been issued in a staggered fashion from north to
south to account for the increasing flow.
A brief period of advisory conditions will occur over the coastal
waters Monday morning with the main surge of cold air behind the
cold front. Another period of marginal advisory conditions is
possible on Wednesday, mainly the offshore waters, ahead of a cold
front and coastal low pressure system.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory from 5 AM to 11 AM EST Monday for AMZ352.
Small Craft Advisory from 1 AM to 3 PM EST Monday for AMZ374.
Small Craft Advisory until 11 AM EST Monday for AMZ350.
Small Craft Advisory from 7 AM to 11 AM EST Monday for AMZ354.
&&
$$
Area Forecast Discussion
National Weather Service Grand Forks ND
947 PM CST Sun Feb 12 2017
.UPDATE...
Issued at 944 PM CST Sun Feb 12 2017
Only changes to evening forecast are reduction of sky cover for
mostly clear, although some thin cirrus will be aloft tonight.
Latest CONSSHORT increased temps over northwest MN a deg or two,
and with SW winds around 10 mph in the region, concur with latest
guidance. No other changes needed.
UPDATE Issued at 643 PM CST Sun Feb 12 2017
Overall forecast is in good shape. Will blend in latest HRRR
guidance for hourly temps through remainder of the
evening...however MinT grid unchanged. Clear skies with lows
ranging from mid teens northeast to mid 20s across the south.
&&
.SHORT TERM...(This evening through Monday)
Issued at 311 PM CST Sun Feb 12 2017
Not looking at anything of much impact throughout the short term
period. Usually when there is some melting snow during the day
hours, it can result in some fog formation at night under the
right conditions. There was some melting today, but it does not
appear to be that substantial, so will not mention any fog
tonight. Otherwise, the traditional cold spots that have more snow
will stay cooler than areas with less snow. Looking for the west
winds to turn more to the south southwest tonight, then back to
the west on Monday. Monday should be a little warmer than today.
.LONG TERM...(Monday night through Sunday)
Issued at 311 PM CST Sun Feb 12 2017
The main theme in the extended period is above normal temperatures
with an overall mild and dry forecast.
On Monday night, a shortwave rushes through southern Manitoba and
northwest Minnesota, bringing very slight chances of flurries to the
Lake of the Woods area and increased cloud cover elsewhere. As
eastern North Dakota and northwest Minnesota remain in
northwest/northerly flow aloft and at the surface, temperatures will
remain relatively cool Tuesday through Wednesday with highs in the
middle 20s to middle 30s and lows in the single digits to upper
teens.
For Wednesday night through Saturday, the operational models and
GEFS ensemble are in good agreement that an unusually strong ridge
building in the West this week will work its way through the
Northern Plains. Adjusted in coordination with surrounding offices
to account for this anomalous pattern combined with strong warm air
advection, which will likely bring highs in the 40s for most
locations, and even 50s for some, in our area Thursday through
Saturday. This would be 15 to 25 degrees above normal for this time
of year. The latest CPC outlooks indicate that this warmer than
normal pattern will last well into next week. While some operational
models have a signal of precipitation chances developing somewhere
in the Plains early next week, the forecast looks dry for our area
until then.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 643 PM CST Sun Feb 12 2017
Clear skies tonight. A surface low will move across northern
Manitoba and sink into wrn Ontario late tomorrow afternoon. This
may result in some VFR cigs sinking into portions of northwest MN,
however they should remain north and east of TVF/BJI through the
00Z TAF period.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Speicher
SHORT TERM...Godon
LONG TERM...BP
AVIATION...Speicher
Area Forecast Discussion
National Weather Service Wilmington OH
1018 PM EST Sun Feb 12 2017
.SYNOPSIS...
Surface cold front has pushed through the area this afternoon
with clearing skies currently progressing off to the east. A
rather dry and quiet week is expected with fluctuating
temperatures as several fronts move through the area. The
coldest days are likely to be Wednesday and Thursday with highs
in the 30s. Other days will be more mild with highs in the 40s.
A few flurries or snow showers will be possible during the
middle of the week as a cold front pushes through.
&&
.NEAR TERM /THROUGH MONDAY/...
Mid level trof pivoting through the Great Lakes with northwest
flow across the Ohio Valley. Surface high pressure to nose into
the region overnight. Clouds have pushed off to the east leaving
clear skies. This trend will continue with low clouds acrs MI
pushing south into ILN/s northeast counties late tonight. Expect
lows in the upper 20s.
Previous Discussion...
Cold front is currently clearing the CWA this
afternoon with the clearing line in Clinton county. This
afternoon the 850 mb cold front will also push through with 850
mb temperatures falling to near 8 degrees C below zero. The
cooling 850 mb temperatures will help to steepen lapse rates and
allow elevated low level winds to mix down. Currently off to
our west and northwest wind gusts of 30 to 40 mph have been
observed which will likely translate across the area this
afternoon. GFS and NAM forecast soundings are showing about
these values with HRRR forecast soundings showing gusts
approaching 40 mph (via momentum transfer). This is probably on
the high end with gusts of 35 mph more likely (mainly across the
northern zones). Will leave mention of wind gusts in HWO and
have issued SPS across our northwestern zones.
Tonight surface high pressure over the midwest will slowly nudge
east helping to keep the pressure gradient elevated. The
tighter gradient will also act to help keep the PBL from
decoupling as quickly as normal so have left elevated wind gusts
in the forecast longer than normal. Low level flow over Lake
Michigan is quasi- parallel for some time Monday morning which
would support cloud development across the northeastern zones so
have gone above guidance for sky cover here.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
Monday afternoon low level flow will turn perpendicular to the
lake helping to clear skies with high pressure pushing in from
the west. 850 mb temperatures Monday are forecasted to be
around 5 degrees C below zero which would support high
temperatures around 40 degrees across the northern zones to the
mid 40s across the southern zones.
Monday night into Tuesday surface high pressure will begin to
loose cohesion just south of the region as the best ageostrophic
convergence collapses. An upper level low will then drop south
out of central Canada. During the day Tuesday the system will
still be far enough away to support mostly clear skies with an
uptick in high temperatures (approaching 50 degrees... esp.
across the south). Tuesday night into Wednesday morning the
upper level low will swing southeast into NY with a band of PV
trailing across the area. This will also push a surface cold
front through the area early Wednesday morning with a mostly dry
frontal passage expected. The GFS does support some light snow
along the front but forecast soundings reveal a moisture starved
profile with saturation only extending from around 900 to 800
mb. NAM forecast soundings show even drier soundings. Given the
lack of confidence this far out have left the mention of
precipitation out of the forecast for Wednesday morning as of
now.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
An amplified flow pattern will be in place across the CONUS by mid
week with ridging over the Rockies and a trough over the eastern
seaboard. Our region will be on the western edge of the trough for
Wednesday into Thursday. In the northerly to northwesterly flow,
several pieces of energy will drop down the back side of the trough,
especially through the day on Wednesday. However, moisture is fairly
limited and the better forcing will be off to our northeast. Will
therefore maintain a dry forecast but we may eventually need some
lower end pops across parts of central ohio on Wednesday. High
temperatures will be in the mid 30s to lower 40s both Wednesday and
Thursday.
Ridging will build east into the area through the end of the week
and remain in place across the region through the weekend. This will
result in dry conditions and a warming trend through the end of the
long term period. Highs by the weekend will be well into the 50s
with even some lower 60s possible across the south on Sunday.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Northwest flow aloft with secondary front observed on Satl/radar
pushing into central Ohio. This band of VFR clouds will clear
KCMH/KLCK in the next hour with clearing as surface high
pressure begins to nose into the region.
A tight pressure gradient has resulted in westerly wind gusts
up to 30 kts. As the high builds in overnight the winds will
slowly subside. Additional moisture will result in clouds over
central Ohio late tonight into early Monday. This may result in
a return to MVFR ceilings but have opted for VFR cigs around
3500 feet due to uncertainty.
Once the early clouds move out of central Ohio, eXpect mainly
clear skies for the remainder of Monday with only some increase
in high level clouds late in the day.
OUTLOOK...MVFR cigs may develop Wednesday into Thursday
particularly across central Ohio.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Haines
NEAR TERM...Haines/AR
SHORT TERM...Haines
LONG TERM...JGL
AVIATION...AR
Area Forecast Discussion
National Weather Service Northern Indiana
644 PM EST Sun Feb 12 2017
.SYNOPSIS...
Issued at 625 PM EST Sun Feb 12 2017
Strong pressure gradient will be decreasing overnight allowing for
gusty winds to decrease as well. High pressure moves in for Monday
with a mix of sun and clouds. Weather will be mainly dry with the
only chance for precipitation coming midweek as cooler air comes
into the area. Lows will be in the 20s with highs in the 40s
Monday and Tuesday before dropping into the 30s on Wednesday.
&&
.SHORT TERM...(This Evening through Tuesday)
Issued at 330 PM EST Sun Feb 12 2017
Forecast reasoning from morning update regarding wind potential
remains largely unchanged. CAA currently ramping up with increasing
mixing depths and corresponding sharp increase in wind gusts.
Upstream obs show 40+ kt peak winds across Chicago and MKE. Only real
question is whether or not to expand advisory southward. Peak winds
south of current advisory will likely flirt with criteria. However,
upstream obs are falling just short, which corresponds to latest
HRRR and RAP13 925mb winds which are maximized in our northern half.
May need an hour or two extension but given strongest winds only
expected to last a few more hours, will hold off on expansion and
just maintain SPS.
Winds will gradually relax overnight as high pressure from the
Central Plains slowly pushes eastward. Dry and generally pleasant
weather then expected through Tuesday as sprawling anticyclone
spreads across the Ohio and Tennessee Valleys. Incoming thermal
trough not particularly cold (925mb temps around -6C). MOS guidance
supports inherited forecast of mid 20s for overnight lows. Raw
guidance is a bit higher (upper 20s) but seems a bit too high with
at least some clearing overnight and lighter winds by early Monday.
Low level flow begins to back late Monday with increasing WAA.
Expect mostly sunny skies by afternoon and this will likely push
highs into the low 40s by late in the day. Similar and slightly
warmer conditions expected on Tuesday with continued westerly flow.
Shortwave approaches late in the day with some increased clouds but
highs should still reach mid 40s for most locations.
&&
.LONG TERM...(Tuesday Night through Sunday)
Issued at 330 PM EST Sun Feb 12 2017
Aforementioned shortwave crosses the Great Lakes Tuesday night. Best
PV advection is focused to our north with very dry profiles locally.
Our N/NE zones may get clipped with some light, lake-enhanced snow
showers but chances very low given stable environment and northern
displacement of better omega. 850mb temps do drop to around -14C on
Wednesday but strong subsidence/low inversion heights and lackluster
background moisture/instability will prevent a more vigorous lake
response. Maintained some low chance PoPs in our NW on Wed but not
expected any significant accumulations or impacts.
Ridge axis moves overhead early Thursday, cutting off any muted lake
effect precip. Main story for the rest of the week will be steadily
rising temps as high amplitude ridge builds over the Great Lakes.
Dry conditions expected with temps possibly making a run at 60F over
the weekend if sun prevails.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 625 PM EST Sun Feb 12 2017
A strong pressure gradient between a developing low pressure system
in the Northeast and an approaching high pressure system from the
Plains allows for strong winds that are being brought to the surface
with help from mixing from the day`s heating. As the high approaches
tonight, winds will decrease in intensity and turn more westerly.
Also, some lake effect BKN clouds could approach the terminals
overnight, but since there is low confidence on that, have left them
out.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Wind Advisory until 8 PM EST /7 PM CST/ this evening for
INZ003>009.
MI...Wind Advisory until 8 PM EST this evening for MIZ077>081.
OH...Wind Advisory until 8 PM EST this evening for OHZ001-002-004-005.
LM...Gale Warning until 1 AM EST Monday for LMZ043-046.
&&
$$
SYNOPSIS...Roller
SHORT TERM...AGD
LONG TERM...AGD
AVIATION...Roller
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Area Forecast Discussion
National Weather Service Jacksonville FL
824 PM EST Sun Feb 12 2017
.UPDATE...Cold front currently ATL-BHM will move steadily
SE...reaching GA-FL border toward dawn...and moving across ne FL
and coastal waters during the morning. Band of showers currently
along front forecast to fall apart after 06z...given lack of
dynamic lift and presence of subsidence inversion on 00z
soundings. Will just go with 10 pop interior se GA ahead of
front tonight. HRRR more suggestive of low cloudiness than fog
ahead of front...though some potential for patchy fog I-10
corridor southward...best chance of fog is in our srn counties.
Low temp forecast looks good with mid-upr 50s se GA...lwr 60s ne
FL.
&&
.AVIATION...Latest TAFs reflect potential for lower CIGS ahead of
cold front late tonight through early morning...clearing from N to
S during the morning. Winds become N to NE during the morning...
with occasional gusts 20-25 kts by late morning.
&&
.MARINE...No significant changes planned for next CWF issuance.
Offshore flow will continue through this evening ahead of
approaching surface cold front. Exercise caution conditions
expected over the outer waters late tonight as the gradient
increases ahead of the front...with winds shifting onshore to the
NE Monday and advisory conditions expected as high pressure builds
over north GA. Winds and seas relax Mon night into Tue as the
ridge builds quickly offshore of the Fl Atlantic coast. An area
of low pressure will approach from the Gulf of Mexico Wednesday
with an increase in offshore flow to near Advisory levels ahead of
the low. Offshore flow develops Thu as high pressure builds
across the Gulf Coast region.
Rip Currents: Low risk through tonight. Moderate risk of rip
currents on Monday.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 55 69 43 71 / 10 0 0 0
SSI 59 65 51 68 / 10 0 0 0
JAX 62 69 48 72 / 10 10 0 0
SGJ 63 69 54 72 / 10 10 0 0
GNV 62 74 49 73 / 10 10 0 10
OCF 59 76 51 75 / 10 10 10 10
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...Small Craft Advisory from 7 AM to 5 PM EST Monday for Coastal
waters from Altamaha Sound to Fernandina Beach FL out 20 NM-
Coastal waters from Fernandina Beach to St. Augustine FL
out 20 NM-Coastal waters from St. Augustine to Flagler
Beach FL out 20 NM-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.
&&
$$
Wolf/Shashy/Peterson
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
842 PM EST Sun Feb 12 2017
.SYNOPSIS...
Low pressure will rapidly strengthen near New England tonight
and Monday. High pressure will briefly return Tuesday. Another
cold front will pass through Wednesday. High pressure will
return for late in the week.
&&
.NEAR TERM /THROUGH MONDAY/...
Current surface analysis shows one low pressure center southeast
of Long Island and another east of Lake Ontario. The first cold
front has moved southeast of the area, although the airmass
change has been rather minimal, and so far winds have not been
exceptionally strong (most gusty where the "warm sector" was
today). The second front is currently moving through
southwestern PA with an associated line of convective showers
and embedded storms. While guidance has this line weakening east
of the mountains, the RAP and HRRR hold onto a broken line of
showers crossing the northeastern half of the area. Have
increased POPs to chance, but will need to monitor trends. If
the showers remain organized enough, they could continue to pose
a gusty wind threat.
For the rest of the night, the main story is the two systems in
the Northeast and Great Lakes. They will phase near New
England, resulting in one large and explosively deepening low
pressure which will result in very gusty winds across our
region. For the northern part of the area, the first strong wind
surge will occur with/behind the second cold front late this
evening. The main concern over the next couple of hours is if
the eastern segment of wind headlines will need to start earlier
than 11 PM. Besides the threat right along the front, winds may
not mix efficiently during the night, but any lull will not be
long enough or diminished enough to change headlines.
Upslope flow will also result in rain showers changing to snow
showers along the Allegheny Front. Right now, think that
accumulations will likely stay just below advisory levels, so
have not issued any winter weather headlines, but an inch or
two, perhaps an isolated total of 3, is certainly expected
overnight.
Right now, best wind surge across the metro may occur during
the morning Monday after the sun comes up, when winds aloft will
remain very strong (50-60 kts) and mixing increases with
insolation. As winds slowly diminish during the day, gusts
should start to drop off, but gusts to 40 knots or more are
still likely most of the day especially around the metros.
Otherwise, it should turn out mostly sunny as high pressure
slowly builds in, with cooler temperatures. Highs mostly in the
40s with colder readings in the mountains.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
High pressure continues building in from the west Monday night
and pushes past the region to our south on Tuesday, so winds
will steadily diminish. Low pressure will then start approaching
from both the southwest and Great Lakes, so clouds will start
to increase later Tuesday. Some showers of rain or snow may
spread into northwestern areas Tuesday night with the Great
Lakes system, while rain could try to push into southern areas.
Right now however, Tuesday night looks dry across most of the
region, with lows mostly in the 30s.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
A cold front associated with low pressure over northern New
England will move through the Mid-Atlantic Wednesday. Rain
showers are possible ahead of the front but will likely be
confined to the south. Cold air advection will move into the
region behind the front and snow showers will be possible across
the Allegheny Front and Potomac Highlands. Breezy and cool
conditions expected Thursday into Thursday night. High pressure
builds into the region briefly Thursday night and winds will
become southerly into Friday causing temperatures to turn mild
Friday-Saturday.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
Ceilings have lifted with the first front having pushed through
the area. However, winds are slow to increase, especially where
conditions were more stable today. That will change in the next
few hours as a second cold fronts crosses the area. TAFs still
show a gradual ramp up of winds to the morning, but it may be a
strong surge with the front (possibly accompanied by showers), a
lull, then a second surge after sunrise as mixing increases.
A few gusts to near 50 knots will be possible at most terminals
(CHO being the main exception where 35 knots is more likely),
but for the most part am expecting 35-45 knots. Winds diminish
Monday night with light winds Tuesday.
Ceiling and visibility flight restrictions not expected Wednesday-
Thursday.
&&
.MARINE...
Developing strong low pressure will bring Storm Force Winds to
much of the bay and Gales to the remainder of the waters tonight
and Monday. Winds are rather benign at the moment but will
rapidly increase as a second cold front arrives late evening or
just after midnight. If showers hold together, they may have the
gustiest winds. Am not seeing a gradient wind threat to expand
the Storm Warning, so if showers maintain organization, SMWs
would be required on the southern MD waters if 50 kt are
expected. Winds will begin to diminish Monday afternoon with
sub-SCA looking likely by Tuesday.
A cold front will cross the waters Wednesday leading to a wind
shift. SCA conditions are likely Wednesday-Thursday.
&&
.FIRE WEATHER...
RH may drop below 30% with sustained winds of 20-30 mph in the
central VA Piedmont and central/southern Shenandoah Valley on
Monday afternoon. However, fuel moisture is above 10% for most
of the area, precluding a fire weather threat.
&&
.TIDES/COASTAL FLOODING...
Strong northwest winds will develop behind a cold front late
this evening and these winds will persist through Monday. Tidal
blowout conditions are likely...especially late tonight and
Monday with anomalies around 1 to 2 feet below normal possible.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...High Wind Warning until 6 PM EST Monday for DCZ001.
MD...High Wind Warning until 3 PM EST Monday for MDZ501.
Wind Advisory until 3 PM EST Monday for MDZ003-502.
Wind Advisory until 6 PM EST Monday for MDZ016-017.
High Wind Warning until 6 PM EST Monday for MDZ004>006-011-013-
014-018-503>508.
VA...High Wind Warning until 3 PM EST Monday for VAZ025-026-503-504-
507-508.
Wind Advisory until 3 PM EST Monday for VAZ027>031.
Wind Advisory until 3 PM EST Monday for VAZ038>040-051-057.
Wind Advisory until 6 PM EST Monday for VAZ052-055-501-502.
High Wind Warning until 6 PM EST Monday for VAZ053-054-505-506.
WV...High Wind Warning until 3 PM EST Monday for WVZ501>503-505-506.
Wind Advisory until 3 PM EST Monday for WVZ050>053-055-504.
MARINE...Storm Warning until 6 PM EST Monday for ANZ530>533-535-538>541.
Gale Warning until 6 PM EST Monday for ANZ534-536-537-542-543.
&&
$$
SYNOPSIS...RCM
NEAR TERM...ADS/RCM
SHORT TERM...RCM
LONG TERM...HSK
AVIATION...ADS/HSK/RCM
MARINE...ADS/HSK/RCM
FIRE WEATHER...ADS
TIDES/COASTAL FLOODING...BJL/MM
Area Forecast Discussion
National Weather Service Norman OK
810 PM CST Sun Feb 12 2017
.UPDATE...
Removed mention of mixed precipitation from the forecast overnight
in northwestern Oklahoma.
&&
.DISCUSSION...
Based on observational trends across the region, from the Oklahoma
Mesonet and West Texas Mesonet, the forecast was running a few
degrees too cool over the next few hours. The latest RAP seems to
have a decent handle, but does keep temperatures a too warm across
Texoma and into north Texas, even with the building cloud cover
southward this evening. Therefore, increased temperatures a few
degrees overnight, resulting in warmer lows, not dipping below
freezing, but in a few locations and not for more than an hour.
Looking at wet bulb temperatures, the dew point forecast remains
on track, and even with the warmer temperatures overnight,
calculations would suggest two to three degrees below freezing is
possible. However, based on precipitation rates, or truly the
lack of precipitation through sunrise, there is virtually little
chance of any saturation that would result in these temperatures
being realized. Therefore, dropped any mention of mixed
precipitation types from the forecast through 13/12z in the
northwest and pulled back precip chances, confining them until
after midnight toward sunrise.
Kurtz
&&
.PREV DISCUSSION... /issued 519 PM CST Sun Feb 12 2017/
DISCUSSION...
Please see the 00Z aviation discussion below.
AVIATION...
Winds will slowly decrease after sunset. Expect at least high
clouds over most terminals through tonight, with low clouds
around 040-070 developing near sunrise. CIG heights will continue
to lower to MVFR heights after 18Z Mon. Rain and BR will likely be
introduced in the 06Z TAFs after 18Z Mon for a few of the
terminals once the timing of such can be more accurately assessed.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 41 53 36 46 / 10 30 90 70
Hobart OK 39 49 34 45 / 10 60 90 70
Wichita Falls TX 45 50 38 45 / 10 40 90 90
Gage OK 33 45 31 49 / 20 60 80 40
Ponca City OK 36 54 35 52 / 10 30 80 30
Durant OK 47 51 40 46 / 10 10 90 90
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
04/03
Area Forecast Discussion...CORRECTED
National Weather Service Phoenix AZ
248 PM MST Sun Feb 12 2017
.SYNOPSIS...
A low pressure system moving slowly across the Desert Southwest
and northwest Mexico will mean a chance of showers and a slight
chance of thunderstorms tonight tonight with decreasing chances
through Tuesday. Dry conditions return Wednesday through Thursday
along with above normal temperatures. Another system returns next
weekend for unsettled conditions.
&&
.DISCUSSION...
Rest of Today and Tonight...
Isolated to scattered weak echoes continue over our forecast
area. Surface dew points are in the mid 40s to mid 50s over the
lower elevations of south-central AZ into portions of southwest AZ
which is contributing to the CAPE in those areas. However, there
is CIN to deal with and thus, coverage of convective showers will
not be widespread but favoring areas outside of metro Phoenix.
SREF depicts 30-40 kts of effective shear over a large portion of
southern AZ and so there could be a pretty strong storm or two for
that area. More significant shower activity has developed over
southeast AZ (including some thunderstorms) where upper diffluence
has strengthened. There is also some increasing DivQ forcing
there as the upper low has started tracking east (centered over
the northern Gulf of California early this afternoon). In
addition, there is an area of lower level convergence over
southeast AZ extending into Gila County associated with the
remnant front that moved in yesterday along with a backdoor front
seeping in from New Mexico. Given these factors, expect showers
and isolated thunderstorms to expand into Gila County and eastern
portions of Pinal and Maricopa counties. In fact, the HRRR has
been depicting a batch of showers tracking northward through
eastern portions of metro Phoenix early this evening. Made some
earlier upward adjustments to PoPs, QPF accordingly.
Monday through Thursday...
The upper low moves into New Mexico Monday and into Texas on
Tuesday. Previous model runs have called for continued clearing
and drying Monday night into mid week as the upper low moved well
off to the east. However, latest runs have called for a vort
lobe/short wave to move around the back side of the exiting low,
providing sufficient lift and cooling aloft to kick off another
minor round of light showers over south central AZ over the
Tuesday/Tuesday night time frame. As such POPs have been raised
from Phoenix east and into the 10-20 percent ballpark. Latest MEX
MOS depicts this change with a POP of 25 percent in Phoenix
Tuesday night, and these slight chances are supported by NAEFS
POPs. It does appear that this lobe will push off to the southeast
of the area by early Wednesday leaving behind generally sunny
skies and allowing high temps to rise into the mid to upper 70s
over most of the lower deserts. Upper ridging will continue to
dominate the weather pattern into Thursday for continued dry
conditions along with well above seasonal normal high
temperatures.
Friday through Sunday...
Although GEFS spaghetti ensemble members become much more chaotic
with large discrepancies between the various members, it is becoming
very clear that a very wet and unsettled weather pattern will set up
across the western CONUS starting Friday and continuing through the
weekend. The upper ridge over the area will flatten and shift east
Friday ahead of the first strong system and we can expect a slight
chance of showers to develop across most of the lower deserts Friday
afternoon with a chance for light/moderate showers across the higher
terrain of Joshua Tree National Park. Scattered to numerous showers
will likely move across the area Saturday into Sunday and POPs have
been raised quite a bit area-wide. Latest MRA MOS for Phoenix calls
for a 100 percent chance of rain by Saturday night. Given the amount
of clouds/showers that will be present this weekend with the passing
weather systems, we can expect high temperatures to lower
significantly with many of the deserts likely to fall into the mid
to upper 60s Saturday. This will be an interesting weekend weather-
wise!
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA,and KSDL:
Showers and isolated thunderstorms are expected to develop late this
afternoon and this evening across the higher terrain east of
Phoenix. Latest hi-resolution guidance indicates that an abrupt wind
shift from the northwest to the east is also likely with this
activity around 02z. Although rain is not anticipated to persist
through the night at the Phoenix terminals, occasional showers
will bring brief heavy rain and ceilings down to 5-7k feet.
Southeast California/Southwest Arizona including KIPL and KBLH:
A low pressure system across the Desert Southwest will continue to
bring a breezy northerly flow to the area through this evening.
However, lower ceilings and precipitation will generally remain to
the east across Arizona.
Aviation Discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Tuesday through Saturday...
A lingering chance for showers on Tuesday will give way to drying
conditions through the middle of the week before a marked
increase in moisture and rain chances by Saturday. Temperatures
will remain slightly above normal through Friday before cooling to
below normal for the weekend. Winds through Thursday will be on
the light side with breezy conditions returning for Friday and
Saturday. Initial minimum afternoon humidities on Tuesday of 25
to 35% will decrease into the teens for Wednesday through Friday
and then increase back to 40% or above for Saturday.
&&
.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
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DISCUSSION...AJ/CB
AVIATION...Hirsch
FIRE WEATHER...Kuhlman
Area Forecast Discussion
National Weather Service Pueblo CO
325 PM MST Sun Feb 12 2017
.SHORT TERM...(This evening through Tuesday)
Issued at 325 PM MST Sun Feb 12 2017
Tonight an upper level low wl be moving eastward acrs nrn Mexico,
just south of AZ. Moisture and a weak disturbance from this system
are expected to moving northward into southern CO, bringing chances
for pcpn to the area. The most favored areas for pcpn tonight will
be across the southern third of the state. The models show the best
agreement over Las Animas and Baca counties, where they show between
about 1 and 3 inches of snow accumulation in the late night hours,
probably mostly on grassy areas. The models do not agree on what
will happen over the southwest CO mtns. The GFS and RAP show only
the potential for light snow accumulations, while the NAM has
several inches. There are some minor differences over the southern
Sangre De Cristo mtns.
Monday and Monday night, that upper level will track eastward along
the srn New Mexico border. The models agree on a band of pcpn acrs
the southeast CO plains Mon morning, but the location is a bit
different and thus the bullseyes of pcpn. The NAM remains more
heavy-handed over the souther mountains and over portions of the San
Luis Valley for Monday morning than the GFS. Other locations in the
forecast area could just see some spotty pcpn Mon morning. In the
afternoon hours, most of the mtn locations are forecast to see some
snow, with the NAM and GFS not agreeing on amounts. Once again the
NAM is showing much more than the GFS, mainly over the SW mtns and
southern Chaffee county. At the lower elevations, temps should
generally be warm enough for rain rather than snow. It is possible
that some of the southern mtns could see advisory level snow amounts
tonight through monday night, but with the models not in good
agreement, will hold off on issuing anything at this time.
With that upper low remaining to our south Mon night there wl still
be chances for pcpn, mainly over the southern quarter of the state,
with some additional light accumulations of snow in the mtns. The
upper low then track into TX on Tue and drier conditions and warmer
temps are expected over southern CO, along with some breezy
northerly winds over the eastern plains.
.LONG TERM...(Tuesday night through Sunday)
Issued at 325 PM MST Sun Feb 12 2017
Tuesday night-Thursday night...Generally warm and dry weather
remains in the forecast through this period, as northerly flow aloft
across the region Tuesday night gives way to more west to southwest
flow through the day Thursday, as upper level ridging building
across the Great Basin continues into the Rockies. At and above
seasonal temperatures looks to prevail across the area with highs in
60s to lower 70s across the lower elevations and mainly in the 30s
to 50s across the higher terrain. The warm and dry weather will
likely lead to elevated fire danger across the area, although winds
look to remain generally on the light side through Thursday.
Friday-Sunday...Increasing west to southwest flow aloft expected
through the day Friday, as a minor short wave ejects across the
Great Basin and through the Rockies, ahead of an eastern Pacific
system moving onshore across the West Coast. This first system looks
to bring a quick shot of snow to the higher elevations along the
ContDvd Friday and Friday night, with breezy and warm conditions
continuing across the rest of the area. Moderate to strong west to
southwest flow aloft continues across the region through the
weekend, as West Coast system moves across the Great Basin and
through the Rockies through the period. Models differ on timing and
strength of this passing system, though looks to bring good chances
of precipitation to areas over and near the ContDvd through the
weekend, with lesser chances of precipitation to eastern portions of
the area. This system does not look to have a lot of cold air
associated with it, so at or above seasonal temperatures looks to be
the rule through the upcoming weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 325 PM MST Sun Feb 12 2017
VFR conditions are expected at KCOS and KPUB tonight. Mon morning
there will be the possibility of some showers moving into the area,
especially at KPUB, which could bring some lower ceilings for a time.
KALS should have VFR conditions this evening, but forecast soundings
are showing low ceilings by late evening and then continuing thru
Mon morning, along with the chance for pcpn.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...28
LONG TERM...MW
AVIATION...28