Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/10/20
Area Forecast Discussion
National Weather Service Houston/Galveston TX
918 PM CST Thu Jan 9 2020
.DISCUSSION...
The evening update has already been sent and will be awaiting the
00z model suite. Primary change was to lower POPs during the
daytime hours on Friday across the SE 2/3 of the area and pared
back timing of the mention of possible severe until the late
afternoon hours. Most model fcst soundings show a warm nose
around 700mb persisting for much of the day. And with lack of a
focusing mechanism etc, wouldn`t expect much more than iso/sct
shra. Probably could have gone even lower, but didn`t want to make
drastic changes between forecast packages. Will let the midnight
shift re-evaluate coverage & any potential for iso severe cells
during the day Fri as they get a look at the full picture.
Expect a line of tstms to develop to our west and move across
southeast Texas in the 7pm-3am timeframe. Texas Tech WRF & the 00z
HRRR show a slightly faster movement...generally clearing the
area and to the east by midnight-2am. Still have a concern whether
the cap around 700mb erodes across the far southern part of the
area, but should definitely weaken with the approach of the upper
trof. But regardless, even forward momentum of the precipitation
itself could aid in some of 50-65kt just above the surface mixing
down to produce some damaging winds. Otherwise, helicity/shear
parameters still look quite impressive and the other hazards
(wind/tornado/hail) that have been well advertised remain in
play Fri night. 47
&&
.PREV DISCUSSION... /ISSUED 633 PM CST Thu Jan 9 2020/
AVIATION [00Z TAF Issuance]...
Even with breezy conditions persisting tonight, BKN/OVC MVFR cloud
decks will likely prevail across much of SE TX. The patchy showers
should be moving out to the north, but given the strong WAA, would
not be too surprised if -DZ/-RA showed up in the obs overnight. At
the coast, sea fog should persist...with visibilities not expected
to crater completely given the strong onshore winds. As for tomor-
row, models have been trending with the idea that most of the POPs
will be with the front/trof axis itself. One of the big issues may
be the wind shear pattern setting up tomorrow afternoon/evening as
the low-level jet strengthens further. The mention of TS/VCTS will
likely be needed for most sites with the 06Z TAF package. 41
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 67 76 45 54 35 / 40 60 100 10 0
Houston (IAH) 68 76 54 60 38 / 20 40 90 10 10
Galveston (GLS) 66 72 57 63 48 / 10 30 90 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through Friday evening for the following
zones: Brazoria Islands...Galveston Island and Bolivar
Peninsula...Matagorda Islands.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION from 6 AM CST Friday through
Friday evening for the following zones: Galveston Bay...
Matagorda Bay.
Small Craft Advisory from 9 AM Friday to midnight CST Friday
night for the following zones: Coastal waters from Freeport
to Matagorda Ship Channel TX out 20 NM...Coastal waters
from High Island to Freeport TX out 20 NM.
SMALL CRAFT SHOULD EXERCISE CAUTION through Friday morning for
the following zones: Coastal waters from Freeport to
Matagorda Ship Channel TX out 20 NM...Coastal waters from
High Island to Freeport TX out 20 NM.
Small Craft Advisory until 9 AM CST Friday for the following
zones: Waters from Freeport to Matagorda Ship Channel TX
from 20 to 60 NM...Waters from High Island to Freeport TX
from 20 to 60 NM.
Gale Warning from 9 AM Friday to midnight CST Friday night for
the following zones: Waters from Freeport to Matagorda Ship
Channel TX from 20 to 60 NM...Waters from High Island to
Freeport TX from 20 to 60 NM.
&&
$$
Area Forecast Discussion
National Weather Service Wichita KS
540 PM CST Thu Jan 9 2020
.SHORT TERM...(This evening through Sunday night)
Issued at 229 PM CST Thu Jan 9 2020
Forecast highlights:
*Severe weather and heavy rain threat Friday southeast Kansas.
*Wintry precipitation Friday afternoon-evening central Kansas.
*Wintry precipitation and possible heavier snow eastern/southeast
Kansas late Friday night-Saturday.
Continued moisture advection from the south tonight will allow for
low clouds to expand across much of southeast Kansas overnight. Low-
level lift coupled with the deepening saturation should support
patchy drizzle.
Large-scale ascent will increase dramatically across the region from
the southwest Friday, as potent shortwave energy ejects east onto
the southern/central plains, interacting with a sharpening/deepening
stalled frontal zone across the region. Increasing moisture,
instability and lift should support a round of numerous
showers/thunderstorms spreading northeast across the region by late
morning Friday. This scenario is supported by the hi-res model
suite. This convective activity is expected to spread
north/northwest into portions of central KS where the colder air
resides, supporting the potential for convective sleet/snow for a
time Friday afternoon and evening. If especially the NAM/RAP/HRRR
solutions verify, a winter weather advisory may be needed for
snow/sleet accumulations of 1-3 inches across central KS along with
strong north winds. Evening/night shift will need to monitor trends.
Next focus is severe potential southeast Kansas Friday afternoon.
The RAP and NAM especially develop/sustain a fairly healthy warm
sector south of the stationary front, with unseasonably rich
boundary layer dewpoints coupled with modest mid-level lapse rates
producing 500-1000 J/kg MUCAPE. While a messy storm mode will likely
ensue by midday given veer/back vertical wind profile, strong lift,
and boundary mostly parallel to mid/upper flow, strength of deep
layer shear coupled with marginal instability could support a few
strong to severe storms over southeast KS. Main threats will likely
be QLCS damaging wind gusts and to a lesser extent marginally severe
hail. Of note...given the strong low and deep layer shear vectors
and low LCLs, cannot completely rule out a tornado, especially if
impressive RAP/NAM progged low-level CAPE values verify. Stay tuned.
-ADK
Fri night into Sat...Any destabilization across southeast KS will be
on the wane rather quickly by the early evening hours on Friday as
the cold front ushers in much colder air during the early evening
hours. Any lingering precipitation in the wake of the front will
transition to a wintry mix and then snow as the cold air rapidly
deepens in the wake of the front but we should see a lull in the
activity during the evening hours Friday night. Large-scale
forcing for ascent will be on the increase after 07-10Z on Sat
and into Sat morning as the mid/upper trough emerges from the
Rockies. A transient period of coupled forcing will be most likely
during the morning hours on Sat, especially along and east of the
Kansas Turnpike where the higher snow accumulations of 4-6 inches
(locally higher) are anticipated. There could be a 4-6 hour
duration of enhanced lift within the TROWAL airstream on Saturday
morning where higher snowfall rates are anticipated. Due to the
combination of wind/snow and light wintry mixed precipitation a
winter storm watch will be issued for a chunk of south central KS
and all of southeast KS. Highs on Sat will hover in the upper 20s
for most locations.
Large-scale forcing for subsidence will rapidly overspread the
region in the wake of the trough late Sat afternoon/early Sat
evening as shortwave ridging returns to the central CONUS. Another
progressive shortwave trough will sweep across the area on Sunday
with limited impacts on sensible weather. Below normal temperatures
area anticipated across the area on Sun with highs struggling to
climb out of the 30s. A heavy snowpack will likely result in even
lower temperatures.
-MWM
.LONG TERM...(Monday through Thursday)
Issued at 229 PM CST Thu Jan 9 2020
A progressive mid/upper flow regime is anticipated through the
period resulting in dry weather conditions and seasonable
temperatures early in the week. Another blast of Canadian air is
progged to arrive on Wednesday driving temperatures well below
normal once again. Highs toward the end of the period may struggle
to climb out of the 20s although dry weather is expected to
prevail through the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 524 PM CST Thu Jan 9 2020
The wind and LLWS conditions have moved off to the east. Clouds
are starting to encroach on the region. VFR conditions currently
rules the region but MVFR ceilings are expected to slowly move
into the region and affect all terminals. IFR ceilings will also
eventually replace the MVFR toward morning tomorrow. During the
day tomorrow, rain and some thunderstorm possibilities will be
become prevalent. The thunderstorm threat will primarily affect
the CNU terminal but ICT and HUT have a chance for an isolated
thunderstorm. Much colder air will be pushing into the region
during the day Friday. This will cause the rain to change over to
sleet and snow toward the end of the TAF period. For this TAF
period, this will primarily affect the RSL, GBD and SLN
terminals. HUT and ICT may see some mix wintry precipitation
toward the end of the TAF period.
Metzger
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 43 45 16 28 / 10 90 60 90
Hutchinson 36 37 13 29 / 10 90 50 50
Newton 39 39 14 26 / 10 90 60 90
ElDorado 45 47 16 26 / 20 90 70 100
Winfield-KWLD 51 55 17 28 / 20 90 70 100
Russell 30 30 9 29 / 0 80 40 10
Great Bend 31 31 9 30 / 0 80 40 10
Salina 33 33 12 28 / 0 80 50 40
McPherson 35 35 11 27 / 10 80 50 50
Coffeyville 56 62 20 29 / 50 100 90 100
Chanute 53 56 19 26 / 50 100 90 100
Iola 51 54 19 26 / 50 100 90 100
Parsons-KPPF 54 60 20 28 / 50 100 90 100
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from Friday evening through Saturday
afternoon for KSZ052-053-068>072-083-091>096-098>100.
&&
$$
SHORT TERM...ADK-MWM
LONG TERM...MWM
AVIATION...ELM
Area Forecast Discussion
National Weather Service Lincoln IL
703 PM CST Thu Jan 9 2020
.SYNOPSIS...
Issued at 703 PM CST Thu Jan 9 2020
A slow-moving storm system will bring heavy rain to central
Illinois over the next 48 hours...with many locations picking up 3
to 4 inches of rain. As colder air gradually filters into the
region, freezing rain and snow will develop west of the I-55
corridor...particularly on Saturday. Snow accumulations of 3 to 7
inches will be possible west of the Illinois River by Saturday
night.
&&
.UPDATE...
Issued at 703 PM CST Thu Jan 9 2020
01z/7pm surface analysis shows a slow-moving cold front extending
from eastern Iowa southwestward to Oklahoma. Widespread showers
and a few thunderstorms have developed in advance of the front
from southwest Illinois into the Ozarks. Based on radar trends and
the last few runs of the HRRR, it appears these showers will
primarily impact locations east of I-55 tonight. Further northwest,
the HRRR and 18z NAM both hint at widely scattered showers
developing immediately along the front as it pushes into the
Illinois River Valley after midnight. Given clear trends, have
delayed and significantly lowered PoPs across the N/NW KILX CWA.
Think the Peoria area will remain dry until after midnight, then
only scattered light showers will occur. The steadiest/heaviest
rain with a few embedded thunderstorms will set up along/southeast
of a Champaign to Taylorville line where categorical PoPs are
warranted.
&&
.SHORT TERM...(This evening through Friday)
ISSUED AT 340 PM CST Thu Jan 9 2020
Will continue the wind advisory for the rest of this afternoon
til 6 pm for areas along and north of I-72, as south winds of
20-32 mph still gusting 35 to 45 mph. Winds will gradually
diminish after sunset and may be able to cancel the wind advisory
a little early. Strong south winds brought mild low to mid 50s
over the CWA, with 3 pm temps ranging from 47 in Champaign to 58
in Macomb. A broken band of mainly light rain showers lingered
over areas along and east of a Champaign to Litchfield line,
though more widely scattered se of I-70. Cloudy skies prevailed
over central/se IL with ceilings gradually lowering during the
day, still in VFR category, though approaching MVFR in sw CWA.
Mid afternoon surface map shows 1004 mb low pressure over west
central WI with its cold front thru central IA into nw MO and se
KS. Strong warm air advection over IL along with some increasing
moisture. A tongue of moisture had worked its way into sw and
eastern IL with precipitable water values of 0.75 to 1 inch east
of I-55 this afternoon with a strong 50-60 kt sw 850 mb jet.
Latest CAMs continue to show increasing rain showers over central
and se IL during tonight, especially se of the IL river where
precipitable water values reach 1-1.25 inches by late tonight.
Rain chances look less nw of the IL tonight and Fri morning
especially far nw CWA. Continued isolated thunderstorms late
evening and overnight from I-72 south. Milder lows tonight in the
upper 40s to around 50F, except cooler lower 40s over Knox and
Stark counties where a cold front moves into late tonight.
Low pressure deepening over the Red River valley along the eastern
TX/OK border by late Fri afternoon while the cold front slowly
moves se across the IL river valley and approaches I-55 Friday
afternoon. Expect rain showers and isolated thunderstorms to ramp
up again during Friday afternoon and Fri evening from sw to ne
along with moderate to heavy rains arriving. Highs Fri to contrast
form the mid to upper 40s nw of the IL river, to the upper 50s and
lower 60s over central and se CWA. Surface low pressure deepens as
it tracks into ne AR by dawn Sat and into NW Indiana by 6 pm Sat.
Widespread moderate to heavy rains Friday night and Sat morning
especially east of the IL river with 3-4 inches expected and
locally higher amounts with thunderstorms. Heavy rainfall is aided
by strong lift with favorable position of upper level jet. Continued
Flood Watch for all but far nw 3 counties from Fri afternoon thru
noon Sat, except thru 3 pm Sat in eastern IL. The rain is
expected to mix with and change to freezing rain and sleet nw of
the IL river during overnight Fri night especially late and
continue Sat morning. The freezing rain and sleet to mix with and
then change to snow over Knox and Stark counties Sat morning, and
then over rest of IL river valley late Sat afternoon. Highs Sat
contrast from near freezing over Knox and Stark counties, to the
upper 50s to mid 60s in southeast IL.
Much colder air arriving during Sat evening across rest of
central IL changes rain to snow with deformation zone over area
Sat evening and expect best snow accumulations late Sat afternoon
and Sat evening from I-55 nw. Between 3-7 inches of snow possible
nw of the IL river with a tenth to quarter inch of ice too,
highest over Knox and Stark counties. Issued a winter storm watch
for areas nw of the IL river from midnight Fri night thru midnight
Sat night. Some blowing and drifting snow could develop too during
Sat evening over nw CWA as winds stay strong and temperatures drop
below freezing. Much of light snow diminishes ne of CWA overnight
Sat night, with lows Sat night in the mid teens nw of the IL river
to upper 20s to near 30F in southeast IL.
Dry and seasonably cool weather arrives on Sunday with lighter
winds as high pressure settles in by Sunday night. Lows Sunday
night range from lower 20s nw of IL river to the lower 30s in
southeast IL. A northern stream system could bring a few light
snow showers or flurries to areas nw of the IL river Sunday night
mainly in the evening hours. Otherwise dry Monday and Mon evening
across the area with temps modifying. Highs Sunday in the lower
30s northern/nw CWA and lower 40s in southeast IL. Highs Mon range
from upper 30s over northern CWA to 45-50F in southeast IL.
Still some differences with models with wx systems during mid week
and stayed close to model consensus. This shows small pops
overnight Mon night and Tue morning and again Wed and Wed night.
Milder Tue with highs in the 40s in central IL and low to mid 50s
in southeast IL. Colder air starts moving into central IL on Wed
and across the area Wed night and Thu as we return to more winter
like temperatures as stronger Canadian high pressure settles into
the Midwest late Wed night and Thu.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 340 PM CST Thu Jan 9 2020
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 538 PM CST Thu Jan 9 2020
Strong S/SW winds gusting 20-30kt will persist for the next couple
of hours before gradually diminishing by mid to late evening. As a
frontal boundary pushes into the Illinois River Valley, winds will
become light/variable at KPIA toward dawn Friday...while winds
decrease to 12kt or less further east at the remaining terminals.
Ceilings will steadily lower this evening, with MVFR conditions
expected across the board after 02z. Current radar imagery shows
numerous showers well upstream across the southern half of
Missouri. These showers will track northeastward and primarily
impact locations east of the Illinois River from late evening
through Friday morning. After that, a lull in precip appears
likely before the next wave of heavier rain arrives by Friday
evening.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
Flood Watch from Friday afternoon through Saturday afternoon for
ILZ045-046-055>057-062-063-066>068-071>073.
Flood Watch from Friday afternoon through Saturday morning for
ILZ029-031-036>038-040>044-047>054-061.
Winter Storm Watch from late Friday night through Saturday
evening for ILZ027>030-036-040.
&&
$$
UPDATE...Barnes
SYNOPSIS...Barnes
SHORT TERM...07
LONG TERM...07
AVIATION...Barnes
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
916 PM EST Thu Jan 9 2020
.SYNOPSIS...
High pressure to the north will slide offshore later tonight
and Friday. An unsettled pattern is then likely for this weekend
and into early next week as a cold front approaches and lingers
near or over the area.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
As of 910 PM Thu...High res mdls show the coastal trof pushing
onshore over much of the coast after midnight. Only change was
to increase temps a bit after 06z central and srn cst as temps
jump with SSE flow.
Prev disc...Some shallow moisture will creep toward the coast
tonight as an inverted trough sets up just off the coast. The
latest HRRR and 3km NAM continues to indicate light rain showers
or sprinkles approaching the coast overnight, but left dry for
all but OBX zones as continued quite dry in the bndry layer. Low
temperatures fairly mild with increasing cirrus shield invading
from the west, and combined with slowly rising TD`s overnight,
expecting mid/upr 30s interior with 40s coast. Temps near coast
will likely experience lows pre midnight, with steady or slowly
rising trend towards daybreak.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
As of 330 PM Thu...Big warming trend commences on Fri as High
pres migrates offshore and Mid Atlantic ridge begins to build
towards the SE CONUS, while shortwave trough deepens across the
Plains states. Low level flow will veer srly and ocnl sct/bkn
strato cu will be present. Despite the clouds, it will be well
above climo with highs 65-70 most locales.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
As of 3 AM Thurs...High pressure will be offshore Friday and
into Saturday. Unsettled weather is expected Sat night through
early to mid next week as a cold front approaches then stalls
nearby or across the area. Near record to record highs are
expected this weekend.
Saturday...Eastern NC will be between two systems; to the east,
high pressure extending into the region, and to the west, a low
pressure system will take shape over the OH Valley with a cold
front extending southward into the Deep South. Expect an
increase in southerly flow over the area providing strong WAA.
Highs will climb well into the 70s inland, near 70 beaches,
approaching or exceeding records, depending on cloud cover. See
CLIMATE section for more information. Should see most rainfall
hold off until Sat night, though not expecting a lot of rain as
most of the energy gets shunted north and west of E NC, and
amounts less than a quarter inch or so. Continued the mention of
slight chc thunder overnight as TD`s max out in the 60s, so
overnight lows extremely warm into the 60s.
Sunday into Wednesday...The low pressure system will lift into
the Great Lakes region/Central Canada, while the associated cold
front will move into the area on Sunday, shall nearby or across
the area, before pushing through Wednesday (maybe). The latest
models are having timing difference in when the front will push
through. Overall, the front is then expected to be more or less
orientated east/west across the area Monday into mid week, with
continued rain chances. Maintained the likely pops on Monday and
Tuesday, with a 30-40% Wednesday, as there is enough consensus
between the forecast models and their respective ensembles that
this period will be quite unsettled.
Temperatures will continue to be well above average, at least
+20 degrees F, for this period, with highs generally around 70
and lows in the 50s to near 60, depending on cloud cover and
rain coverage.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Short Term /through 18Z Friday/...
As of 610 PM Thursday...High pres to the N will grad slide
offshore with a weak coastal trof moving onshore tonight.
Expect VFR to cont to dominate with mainly some high clouds. As
the low lvl flow turns SE in wake of coastal trof could see
some patchy lower SCU develop but confidence in cvrg is low so
just kept sct in tafs. As moisture conts to increase Fri some
bkn SCU cigs poss but think will be mainly in VFR range.
Long Term /Friday night through Monday/...
As of 315 AM Wed...VFR conditions prevail through Saturday
afternoon as a cold front approaches the area and eventually
stall over the area, leading to periods of sub-VFR conditions
late weekend through early next week.
&&
.MARINE...
Short Term /Today and Tonight/...
As of 910 PM Thu...Strongest winds now over far srn outer wtrs
and shld grad weaken as coastal front pushes toward the coast
overnight.
Prev disc....N/NE winds are currently 15 knots. Seas are
generally 3-5 feet. As high pressure builds south and east from
the Great Lakes to the mid Atlantic tonight, winds will shift to
E and diminish to 5 to 15 kts. Seas will drop from 3-5 feet to
2-4 feet on all waters by tonight and remain through Fri. Winds
veer srly though remain light Fri.
Long Term /Friday night through Monday/...
As of 315 AM Thurs...High pressure will extend over the coastal
waters from the western Atlantic with winds becoming southerly,
and increasing to 15-20 kts by Friday night ahead of an
approaching front. Winds gradient will tighter further more
Saturday night peaking S to SW 25-30 kts through early Sun
morning, with seas building to 8-12 ft. SCA and Gale headlines
will likely be needed this weekend, with SCA seas lingering into
early next week.
&&
.CLIMATE...
Record High temps for 01/11 (Saturday)
LOCATION TEMP/YEAR
New Bern 77/1974 (KEWN ASOS)
Cape Hatteras 70/2014 (KHSE ASOS)
Greenville 78/1930 (COOP - Not KPGV AWOS)
Morehead City 69/2017 (COOP - Not KMRH ASOS)
Kinston 76/1916 (COOP - Not KISO AWOS)
Jacksonville 81/1974 (KNCA ASOS)
Record High temps for 01/12 (Sunday)
LOCATION TEMP/YEAR
New Bern 76/2013 (KEWN ASOS)
Cape Hatteras 71/1995 (KHSE ASOS)
Greenville 79/2005 (COOP - Not KPGV AWOS)
Morehead City 72/2005 (COOP - Not KMRH ASOS)
Kinston 79/1907 (COOP - Not KISO AWOS)
Jacksonville 77/2013 (KNCA ASOS)
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...None.
&&
$$
SYNOPSIS...MHX
NEAR TERM...RF/TL
SHORT TERM...TL
LONG TERM...BM
AVIATION...RF/BM
MARINE...RF/TL/BM
CLIMATE...MHX
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
549 PM CST Thu Jan 9 2020
.UPDATE...
Issued at 526 PM CST Thu Jan 9 2020
Updated to include 00z aviation discussion below.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 200 PM CST Thu Jan 9 2020
Most of the measurable precipitation occurred east of Eau Claire
and Ladysmith today as moisture depth was not deep enough to
saturate over southern/central Mn. As the main upper wave moves
across the region this afternoon, any chances of precipitation
will end. Winds will become northwest tonight with a low stratus
deck of clouds, possibly mixed with flurries at times, moving
across central Minnesota. Otherwise, skies will be clear as
temperatures drop back into the single digits and teens.
Temperatures in west central/central Minnesota will be close to
zero toward morning, and any wind above 10 mph will create wind
chill values around -20F. I will highlight wind chill values in
the HWO this afternoon, but not anticipating any advisory based on
wind chill values holding above -25F. The next storm system will
rapidly increase the cloud cover late tonight, and into Friday.
Most of the moisture will be limited to mid/upper levels, but the
latest RAP has deeper moisture developing Friday afternoon. As the
next approaching short wave moves across the Northern Plains,
there could be some light snow/flurries development in west
central/southwest Minnesota. However, the much drier air advecting
southward behind today`s system will likely limit any boundary
layer moisture. I did introduce flurries/light snow in the far
southwest/south central Mn, but even this area will be hard to see
anything accumulate. Friday night will see mostly clear skies
with high pressure dominating the Upper Midwest.
.LONG TERM...(Saturday through Thursday)
Issued at 200 PM CST Thu Jan 9 2020
Longer term trends continue the progressive flow pattern aloft.
Timing and strength of embedded short waves will determine
overall chances for mainly light snows and influx of colder air.
Initially, models have been lifting the overall occluded surface
system a bit farther to the west with each model run. Still
appears better moisture and forcing will remain east of the area.
Will hold onto the chance PoPs to the far east for now just in
case further westward shift occurs.
Then, GFS and ECMWF continue to lift short waves northeast
affecting the area possible Sunday/Sunday night and again
Tuesday/Tuesday night. The Sunday system looks weak and if
anything did generate it should remain on the light side. The GFS
is consistent with lifting a stronger wave over the area Monday
night/Tuesday time frame. Depending on moisture available, this
could be an advisory type event.
The models diverge then into the end of the week, with the GFS
continuing to drive the 1048mb ridge southeast across the area
Thursday/Friday time frame following the arctic front Wednesday.
The ECMWF lifts the Wednesday wave through but holds the arctic
air farther north until the western CONUS trough reloads. It
brings in modestly cold air in for the following weekend. The GFS
has been consistent overall in timing of overall pattern, so will
follow more in line with it this forecast at this point. This
would bring in bitter cold air Wednesday night and lingering
through Thursday night. Wind chills will need to be monitored
closely if this trend continues.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 526 PM CST Thu Jan 9 2020
All sites to start out as VFR but the concern is a bank of MVFR
clouds over western MN, steadily pressing east. Models are not
handling these clouds well at all so have tried to use timing
tools to bring the clouds into and out of the terminals this
evening through the overnight hours. Will keep watch on trends and
issued AMDs as necessary. By late morning Friday, ceilings are
expected to be VFR between 070-100 followed by another round of
mid-level ceilings in the afternoon hours. No precipitation
expected. Winds will remain from the NW throughout this TAF
duration, speeds around 10kt though some gustiness can be expected
in the afternoon.
KMSP...Will look for MVFR ceilings to move into the MSP area later
this evening and am expecting them to hold in place through the
Friday morning push. Some ceilings below 1700ft are likely but
the cloud bases are not uniform through the incoming cloud deck,
ranging from 009-025. After daybreak, improved conditions can be
expected with mid-level ceilings throughout the day.
/OUTLOOK FOR KMSP/
Sat...Mainly VFR. Chc -SN. Wind N-NE 5 kts.
Sun...Mainly VFR. Chc -SN. Wind SE 5 kts.
Mon...VFR. Wind SSE 5 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&
$$
UPDATE...JPC
SHORT TERM...JLT
LONG TERM...DWE
AVIATION...JPC
Area Forecast Discussion
National Weather Service Phoenix AZ
450 PM MST Thu Jan 9 2020
.UPDATE...aviation discussion.
&&
.SYNOPSIS...
A low pressure system will move through the region the rest of
today and exit during the day Friday. It will bring an opportunity
for rain and higher terrain snow, mainly east of the Lower
Colorado River Valley. There will be a very slight chance of
thunderstorms. The primary time frame for shower activity
will be tonight. Anticipate breezy to windy conditions at times
through Friday over southeast California and southwest Arizona.
Over the weekend, conditions will be dry with below normal
temperatures. In fact, some of the colder desert locations will
get close to freezing. Anticipate a modest warming trend during
the first half of next week.
&&
.DISCUSSION...
The upper trough, currently centered over the southern Sierra
Nevada mountains, continues to move southeastward. Windy
conditions have developed over Imperial County. The Wind Advisory
for the southwest corner of the County remains in effect until
03Z. East of there, into the Imperial Valley, there will be windy
conditions but anticipate it to be too brief/marginal to expand
the Advisory. Earlier cloud cover from lee cirrus and upper level
diffluence effects has thinned as it shifts eastward. Cloudiness
will redevelop as the QG forcing moves through this afternoon and
evening. With the trajectory being largely overland, there isn`t a
lot of moist advection with this system. However, with the
dynamical forcing and fairly cold nature (500mb temps dipping
below -25C), there will be an opportunity for precip - albeit not
a lot. Ensemble mean QPF from various sources generally shows QPF
favoring our eastern areas (south- central AZ) with lower
elevations below one tenth and higher terrain in the 1-2 tenths
range. Main window of opportunity continues to be tonight. As for
metro Phoenix specifically, hi- res models have vacillated on
tracking showers to the south over southwest Maricopa and Pinal
Counties (as opposed to greater Phoenix area). Earlier, there were
several runs of the HRRR depicting shower activity over the metro
and now it seems to have backed off. The converse is true of the
HREF and NAMNest. Model CAPE is not very impressive, but HREF and
SREF trended upward slightly. And subjectively, it`s not uncommon
to get some sort of convection with Wintertime systems despite the
meager model CAPE. So, introduced slight chance of thunderstorms
for south- central AZ (better chances over Pinal County than
northern Maricopa). If something formed, would anticipate it to be
isolated and weak. The system exits during the day Friday.
Saturday through Thursday the large scale pattern remains largely
unchanged with troughing over the western CONUS and ridging
offshore as part of a Rex pattern. EPS and GEFS depict a system
brushing northeast Arizona Saturday to reinforce cool air. Early
next week, the troughing weakens a little bit for a modest warming
trend. By midweek, the EPS and GEFS differ for our area with the
EPS suggesting a system at least brushing the Desert Southwest
and even bringing some very minor precip whereas the GEFS
suggests continued warming. The NBM is leaning a bit toward the
EPS and has some very low end PoPs Wednesday and Thursday - but
slight chances will be very isolated and limited to higher
terrain. No real temperature drop though.
&&
.AVIATION...Updated at 2350Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
The two main aviation concerns during the first part of the TAF
period will be low ceilings and elevated westerly winds. Ceilings
look to drop close to 5 kft by 1Z though can`t rule out ceilings
getting down to 3-4 kft temporarily as vicinity showers move
through the metro. Any terminal will have a chance of seeing a
shower move directly overhead primarily between 1-6Z. This would
also be the time frame where`d we see the possibility for lower
ceilings and thus have decided to include a tempo group to
demonstrate the potential for lower ceilings in isolated showers.
A very small chance for an isolated thunderstorm will exist early
this evening but chances remain too low to make mention in the
TAFs. Winds will be predominantly out of the west with speeds
around 10-12 kts, but showers moving through may result in some
variability in direction. Sometime around 6Z, we expect west winds
to decrease to aob 6 kts, lingering vicinity showers to exit to
the east/southeast, and ceilings to improve.
There is also the possibility for patchy fog development sometime
between 10Z and 16Z. This is all going to depend on how quickly
we are able to clear out and how quickly wind speeds diminish.
Have opted out of including mention in this TAF package, but have
kept lower ceilings lingering into tomorrow morning.
Southeast California/Southwest Arizona including KIPL and KBLH:
Westerly winds at KIPL will continue to gust to around 30 kts
through around 03-04Z, and then diminish below 10 kts for the
remainder of the TAF period. At KBLH, winds will favor a
northwesterly component with speeds generally remaining aob 12kts
through early tomorrow morning. It then appears that breezy north-
northwesterly winds with gusts close to 20-25 kts will develop
tomorrow afternoon at KBLH.
Expect cloud decks around 5-7 kft through around 3-4Z as a
weather system moves through. Mostly clear conditions are expected
to prevail thereafter with a few high clouds passing through
tomorrow afternoon.
&&
.FIRE WEATHER...
Saturday through Wednesday:
A cool, but mostly dry regime will continue through the first part
of next week. Temperatures will remain below seasonal normals for
the period. Fairly dry conditions will be seen through early next
week with minimal humidities mostly ranging from 20 to 30 percent
over the lower deserts. Winds will generally be light for much
of the period with only occasional afternoon breezes.
&&
.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory until 7 PM PST this evening for CAZ562.
&&
$$
DISCUSSION...AJ
AVIATION...Hernandez
FIRE WEATHER...Kuhlman
For frequently asked questions about the Area Forecast Discussion
visit...
http://weather.gov/saltlakecity/general/afd_faqs.php