Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/06/16
Area Forecast Discussion
National Weather Service Wakefield VA
1100 PM EDT Wed Oct 5 2016
.SYNOPSIS...
High pressure remains over the region through Friday, with a coastal
trough along the Southeast coast. Hurricane Matthew is forecast to
lift along the Southeast coast through the weekend. Cool high
pressure builds in from the northwest early next week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
A surface ridge remains over the local area this evening as ~1026mb
high pressure remains centered off the Northeast coast. The
result is ongoing onshore flow. Winds have decoupled inland, but
still gusty near the coast. Mostly cloudy to cloudy conditions
persists with a marine layer over the local area. Aloft, latest
RAP depicts a vorticity maxima over the southeast forecast area
with a 300mb speed max exiting the Mid-Atlantic coast. Based on
previous radar trends and the NAM12 300K surfaces, have opted for
slight chance POPs across the southeast half of the forecast area
overnight for light rain/drizzle due to aforementioned forcing and
moist low levels. Some patchy fog is possible inland. Generally
mostly cloudy to cloudy conditions prevail. Wide range of
temperatures expected across the region tonight, with lows ranging
from the low 50`s northwest to mid 60`s southeast.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
Thursday begins with the region beginning to feel the effects of
Matthew, even though is it just getting toward the FL coast by
late in the day. The coastal trough will begin to slide toward the
coast and as it does the easterly flow will pull Atlantic moisture
into the area with overrunning showers developing. Initially,
will see that light rain across NE NC and gradually will see it
expand northward into Virginia. The NAM is a bit more aggressive
and further north than the GFS on Thursday with the rain, but both
models are similar by Friday on the north and westward spread of
the moisture. Have generally blended the guidance on the northern
extent on Thursday while continuing to increase pops area wide on
Friday for light rain. For temperatures on Thursday through
Friday, the cloud cover will be the difficulty as the humid air
mass will keep readings high over night Thursday while the highs
each day will be limited by the clouds. The MOS guidance looks a
touch too warm on Friday so have kept readings in the mid to upper
70s.
From Friday night on,the conditions will depend on the timing of
Matthew for how much rain and how far to the north the hurricane
goes. The GFS is the slowest of the guidance and the NAM is much
faster. The official NHC forecast is closer to the slower GFS and
further south. So have kept the pcpn amounts to less than an inch.
through Saturday evening. The chances for rain should gradually
increase across the south and moisture continues to advect into
the area. Overnight lows should be a touch warmer, especially
across the southern half of the area as the low level moisture and
clouds make radiative conditions poor.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Refer to the National Hurricane Center for official forecasts on
Hurricane Matthew heading into the weekend. Outside of that
system...a cold front will be approaching from the NW Sat
morning...then push SE across the FA through Sat night. Moisture
will be drawn nwd as cold front presses SE resulting in a mostly
cloudy...cool day w/ SCT-likely shras. Winds will remain from the
NE (and be a bit gusty at the coast). Large sfc hi pres will be
building across the Midwest and Great Lakes regions Sat into
Sun...and in combination w/ the (expected) tropical cyclone to the
S of the FA...gusty N winds (to 20-25 mph inland...25-35 mph near
the coast) will usher in drier and cooler air (to end the
weekend). 12z/05 ECWMF a bit slower w/ the drying on Sun...have
kept at least CHC PoPs across SE 1/3rd of FA (Sun morning). Zonal
flo aloft and sfc hi pres will be in control Mon-Wed providing
dry/near seasonable conditions.
Highs Sat in the u60s-l70s. Lows Sat night in the m50s W to the
l60s at the coast. Highs Sun mainly from 65-70F. Lows Sun night in
the u40s NW to the u50s SE. A gradual warming trend Mon-Wed.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
A strong surface high pressure over New England has allowed for a
continued onshore low-level flow and mainly VFR/MVFR ceilings over
the region. NE winds will continue to gust in excess of 20 knots at
times through the TAF period, mainly near the coast. Similar to last
night, cannot rule out the chance for some patchy drizzle across the
area during the first half of the night.
Guidance has been showing the possibility of stratus development for
the second half of the night. Brought IFR conditions into RIC and
SBY due to the potential for lower ceilings and fog. Have MVFR for
low ceilings at remaining TAF sites as fog potential should be more
limited near the coast. Conditions return to mainly VFR on Thursday.
Outlook: Mainly VFR conditions should linger into Friday. There is a
chance for showers beginning on Saturday as Hurricane Matthew moves
closer to the Mid Atlantic coast. Winds will continue to remain
gusty out of the east and northeast at times through Monday,
especially near the coast.
&&
.MARINE...
Weak lo pres invof stationary front off the Carolina coast in
combination w/ sfc hi pres invof the nrn Mid Atlantic-New England
has been kicking up NE winds/seas...highest from near the mouth of
the Ches Bay to E of the nrn NC Outer Banks. Seas to about 8-9 ft
ongoing along w/ winds to 25-30 kt (mainly on the ocean)
continuing there. Still will have SCA for all the waters...except
on most of the VA rivers tonight into Thu. Lower of winds/seas-
waves expected as pres gradient between the stationary front and
sfc hi pres (to the NNE) weakens from (late) Thu-Sat. Continuing
SCAs for the mouth of the Ches Bay and on the ocean waters through
22z/08.
Refer to the National Hurricane Center for official forecasts on
Hurricane Matthew heading into the weekend. Outside of that
system...a cold front will be approaching from the NW Sat
morning...then push SE across the waters late Sat-Sat night.
Winds will remain from the NE (and become a bit gusty on Sat)
ahead of the cold front. Large sfc hi pres will be building
across the Midwest and Great Lakes regions Sat into Sun...and in
combination w/ the (expected) tropical cyclone to the S of the
FA...a period of strong/gusty mainly N winds (to 20-30 kt N...25
to 35 kt S) expected by Sun morning...continuing until late in
the day. May need gales for about a 6-12 hour period (late Sat
night/Sun morning?). SCA conditions likely to continue early next
week (esp on the ocean) before hi pres sufficiently builds over
the waters (allowing maritime conditions to slowly improve).
&&
.TIDES/COASTAL FLOODING...
As of 20Z this afternoon, tidal departures average around +2.0
feet across the lower Bay/James River/Southern coastal sites,
and around +1.5 feet across the mid-upper Bay and coastal sites
along the VA/MD eastern shore. Looking at currents data from sites
in the lower Bay, significant water is piling up in the entire Bay
(incoming tides are far stronger than outgoing tides).
With this in mind, have added more of the ESTOFS surge guidance to
the forecast (especially in the mid-upper Bay where ETSS is verifying
far too low). Thus, expect the current tidal departure values to
persist for at least the next few tide cycles and have raised or
extended Coastal Flood Advisories to cover the entire Bay as well as
all of the main Rivers. For the coast, water levels still expected
to fall shy of minor flooding criteria across the N, while some
additional minor flooding will be possible from Northampton Co on
south and have raised an advisory for these areas for the high
tide late Thu morning/early aftn.
Conditions are expected to improve a bit Friday and the latest track
of Matthew suggests the potential for any additional coastal flooding
late Sat-Sunday may occur due to the pressure gradient between Matthew
and high pressure to the north though details are uncertain.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...Coastal Flood Advisory until 11 PM EDT Thursday for MDZ021>023.
NC...High Surf Advisory until 6 AM EDT Thursday for NCZ102.
Coastal Flood Advisory from 8 AM to 4 PM EDT Thursday for
NCZ102.
VA...Coastal Flood Advisory until 8 PM EDT Thursday for VAZ075>078-
084>086-089-090-093-096-522-524.
Coastal Flood Advisory until 4 PM EDT Thursday for VAZ095-097-
523-525.
High Surf Advisory until 6 AM EDT Thursday for VAZ098.
Coastal Flood Advisory from 8 AM to 4 PM EDT Thursday for
VAZ098.
Coastal Flood Advisory until 6 PM EDT Thursday for VAZ099-100.
MARINE...Small Craft Advisory until 6 PM EDT Saturday for ANZ634-650-
652-654-656-658.
Small Craft Advisory until 4 AM EDT Thursday for ANZ630-631.
Small Craft Advisory until 6 AM EDT Friday for ANZ632-633.
Small Craft Advisory until 7 AM EDT Thursday for ANZ638.
&&
$$
SYNOPSIS...ESS/SAM
NEAR TERM...ESS/SAM
SHORT TERM...ESS
LONG TERM...ALB
AVIATION...AJB
MARINE...ALB/LKB
TIDES/COASTAL FLOODING...AKQ
Area Forecast Discussion...corrected update
National Weather Service Quad Cities IA IL
912 PM CDT Wed Oct 5 2016
.UPDATE...
Issued at 859 PM CDT Wed Oct 5 2016
Have had to lower min temperatures in many locations by a few
degrees, as slower onset of clouds and very light wind allowing
temps to drop quickly into the mid to upper 50s already in river
valleys. Expect a large low temperature range with some valleys
possibly dipping down into the lower 50s in the north, while some
areas south will only drop into the mid 60s south where clouds are
quickly increasing. Most areas will likely see lows in the next few
hours before temperatures level off or possibly even climb a bit due
to increasing clouds.
As for precipitation, going forecast still appears on track with
continued increase in coverage of showers this evening with
a few more storms mixing in late evening and overnight as deeper
moisture lagging over central/southern Missouri advects into the
region. Bulk of the activity looks to occur southeast of a Dubuque
to Cedar Rapids line. As effective shear increases overnight,
expect to see some uptick in intensity of convection with the
potential for hail with a few of the stronger cells given presence
of steepening mid level lapse rates, dry air aloft and WBZ around 7-
7.5kft agl.
&&
.SYNOPSIS...
Issued at 310 PM CDT Wed Oct 5 2016
18Z surface data has a weak high over Iowa. The front ran from
western Lake Superior, through central Wisconsin, and into northwest
Missouri. Dew points were in the 60s along and ahead of the front
with 40s and 50s behind the front. Dew points in the 30s were across
the northern Plains.
&&
.SHORT TERM...(This Evening through Thursday)
ISSUED AT 310 PM CDT Wed Oct 5 2016
Quiet and warm through sunset. Nocturnal convection then slowly
develops and moves northeast into the area.
Weak high pressure will slowly move through the area late this
afternoon and evening keeping skies mainly clear. After sunset,
nocturnal convection will fire across Missouri and move northeast.
Showers will start moving into the area around mid evening and
slowly spread north toward I-80 through midnight. Thunderstorms will
also be possible with areas south of a Princeton, IL to Centerville,
IA line being the most favored.
After midnight, the areal coverage of the nocturnal convection will
slowly increase. The southeast half of the area has the best chance
of seeing rain and thunderstorms due to the better moisture feed and
forcing. Some small hail and gusty winds will be possible from the
stronger storms due to dry air aloft.
On Thursday, the models are suggesting that the rain will slowly end
across the northwest half of the area during the morning. However,
the models indicate the atmosphere will remain unstable. Thus while
the areal coverage/intensity of the rain may decrease, very light
rain or sprinkles may persist.
Convection Thursday afternoon will depend upon cloud cover,
precipitation, and temperatures across the area. The atmosphere will
remain unstable so scattered showers and possibly some thunderstorms
cannot be ruled out.
.LONG TERM...(Thursday Night through Wednesday)
ISSUED AT 310 PM CDT Wed Oct 5 2016
Thursday Night...As a sfc low tracks through central Iowa into NW
Wisconsin, south-southeast sfc winds will advect an unseasonably
warm and humid air mass, with dewpoints in the 60s, into the Upper
Mississippi River Valley. Showers and thunderstorms are likely, and
may come in the form of broken line, along and ahead of an attendant
cold front. The best chances are west of the Mississippi River.
Thunderstorm Outlook/Risks: The Storm Prediction Center has a slight
risk for severe storms along and west of a Vinton, IA to Washington,
IA to Memphis, MO line. A marginal risk extends to the east, roughly
to the Mississippi River.
Sfc-based CAPE near 1000 J/kg and high deep layer and low-level
shear (0-1 km bulk shear 30-40 kts; 0-1 km SRH potentially exceeding
250 m2/s2) raises potential for some severe, rotating storms. The
NCAR ensemble mean 2-5 km updraft helicity corroborates the
possibility for rotating cells. The primary threats from the
strongest storms are straight-line wind gusts over 50 mph and
isolated tornadoes. Isolated hail near 1" in diameter is also
possible with dry mid-level air noted on forecast soundings, but is
overall a lower threat.
Timing: Hi-Res and synoptic models are in fairly good agreement
bringing storms into the western forecast area, on the early side,
after 6-8 PM, and on the late side, after 9-10 PM. Since diurnal
timing is not optimal, thinking storms will weaken as they progress
eastward through the western half of the CWA.
Friday through Sunday...High pressure builds in behind the cold
front, ushering in drier and cooler air. Forecast highs are in the
60s, lows are in the 40s. A very nice fall weekend to say the least.
Monday through Wednesday...Becoming increasingly mild. Temps
forecast to warm into the lower to middle 70s, or 5-8 F above
average for the second week of October. Mid-level westerly winds
through the Northern Rockies progged to induce lee-side cyclogenesis
across the Northern Plains, thereby reinforcing southerly flow and
mild 850 temps above 10 C over the Midwest. Chances for rain are low
at this time. Uttech
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
ISSUED AT 647 PM CDT Wed Oct 5 2016
Challenging set of TAFs with several concerns including timing and
location of showers and storms, fog and low clouds, and low level
wind shear.
Low level wind shear...NAM appears to be an outlier depicting
substantially higher southerly winds of 40-45 kts in 1-2km ft agl
late evening into the overnight and likely attributed to
convective feedback on mass fields. Because of this I have sided
with the much weaker RAP (15-25 kts in 1-2km ft agl) and therefore
left out any mention of low level wind shear.
Precipitation...Signal present for rapid development of showers
and storms by mid evening over portions of southern Iowa and
northern Missouri, with the activity developing and or propagating
eastward into northwest Illinois overnight into Thursday morning
with a veering low level jet. Precipitation appears likely at KBRL
and KMLI and have maintained TEMPO wording after 04z through 12z.
Can`t rule out these sites being impacted by additional showers
Thursday morning with continue veering low level jet, but don`t
want to inundate the TAF with precipitation mention thus trying to
highlight most favored window. Much less confidence on
precipitation at KCID and KDBQ and for now have only mention of
VCSH later tonight into mid morning Thursday. It could be that
KCID and KDBQ stand a better chance of showers and a few storms
late morning into the afternoon per latest ESRL HRRR run, but
confidence that far out is low and therefore left out mention
although bears watching.
Fog and low clouds...anticipate low clouds and some fog developing
overnight into Thursday morning as a warm front lifts northward
into the region. Have a general MVFR flight category at all sites
for a period overnight through Thursday morning in fog and low
clouds, although the potential does exist for areas of IFR to possibly
LIFR/VLIFR conditions given magnitude of moisture advection. KCID
and KMLI may be most favored for these low conditions should they
develop, and will need to be monitored for later TAFs and amend if
needed once trends become established.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...McClure
SYNOPSIS...08
SHORT TERM...08
LONG TERM...Uttech
AVIATION...McClure
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
806 PM CDT Wed Oct 5 2016
.Update...
Issued at 759 PM CDT WED OCT 5 2016
Have shifted the area of initial convective development further north
in response to the northward shift of stronger h8 moisture
convergence. 12z/18z short range models depict the nose of the low
level jet as being further north. RAP trends support this analysis
and latest HRRR trending this way as well. And the proof in the
pudding is in the isolated convection which is popping up along a
line from STJ to CDJ to near IRK. Eventually the convection will fill
in and shift southeast overnight.
Further down the road am a little concerned on the extent of
convection during both the morning and afternoon hours. May be a
little too wet. Will see what the 00z NAM looks like before making
any significant changes.
&&
.Discussion...
Issued at 330 PM CDT WED OCT 5 2016
...Tonight...
The weak front that moved through the area this morning will begin to
lift into northern MO as a southwest-northeast oriented warm front
this evening. WAA has already increased and will be strong enough to
create some lift in conjunction with the front and increase storm
chances from east-central KS up to northeast MO and southward
starting this afternoon. The warm front will stall out along this
line and create multiple clusters of storms on the southern side in
the overnight hours. The LLJ ramps up somewhat parallel to the front
after 9 pm and will help produce convection. Instability and shear
parameters show the possibility of producing some strong to severe
weather. Damaging winds and hail are the primary threats. A decent
amount of moisture will also be present with these storms due to the
LLJ; therefore, some storms may produce locally heavy rainfall. These
showers and storms will linger into the morning hours until the LLJ
dies down.
...Tomorrow...
A few rounds of storms are possible tomorrow as the upper level
trough and surface low approach the area. Strong WAA, dew point
temperatures in the upper 60s, and CAPE values in the 2000-3000 J/kg
range will aid in the development of storms. The surface low will
move northeast from central KS into central IA. The location of the
surface low will also provide a rough location for the best chance
of severe weather tomorrow afternoon and evening. Northwest MO and
northeast KS are in an enhanced risk. As previously mentioned,
instability values will reach up to around 3000 J/kg, while 0-6 km
shear values will be between 50 and 60 kts. The primary threats being
damaging winds and hail, but we cannot rule out a few isolated
tornadoes due to helicity values up to 300 m2/s2 and 0-1 km shear
exceeding 25 kts. The area from Olathe to Kirksville is in a slight
risk with damaging winds and hail being the primary threats. Showers
and storms will hang around until Friday morning when the cold front
finally moves through the area.
...Fri-Sun...
Much calmer and cooler weather is expected for the weekend as a
surface high pressure moves in behind the cold front. Highs will
begin in the low 60s Friday and will slowly increase to the low 70s
by Sunday.
...Mon-Wed...
Temperatures will remain in the 70s for the beginning of next week
but storm chances return. An upper level trough will send a few pulses
of energy our way Monday through Wednesday, but right now chances for
widespread showers and storms appear low.
&&
.Aviation...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 647 PM CDT WED OCT 5 2016
Still expecting scattered showers and thunderstorms to form by mid
evening and affect all but northwest MO overnight. Believe MVFR fog
and ceilings will form during the pre-dawn hours over northwest into
west central and northeast MO. These should lift/mix out by mid
morning. Much debate on how much morning convection there will be.
Most models favor going with less convection and mainly impacting
west central MO and east central KS south of the KC area. Otherwise,
will have to wait until the cold front and its associated
strong/severe storms come through after 00z Friday.
In addition, expect strong and gusty southerly winds for the
afternoon hours.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
Update...MJ
Discussion...Grana
Aviation...MJ
Area Forecast Discussion
National Weather Service Grand Rapids MI
1011 PM EDT WED OCT 5 2016
LATEST UPDATE...
Update/Marine
.SYNOPSIS...
Issued at 800 PM EDT Wed Oct 5 2016
Scattered showers and thunderstorms have ended for tonight but
will be across the region Tomorrow and lingering into Friday
evening. It won`t be raining all the time, but the threat of rain
will be with us. Meanwhile temperatures will remain mild, mainly
in the 70s Thursday and Friday.
The area will dry out by late Friday night, and a dry weekend is
expected. The next chance of rain moves in Monday night and
lingering into mid week. Temperatures will cool into the 60s for
the weekend, rebounding back to around 70 into the work week.
&&
.UPDATE...
Issued at 1010 PM EDT Wed Oct 5 2016
Have issued a Dense Fog Advisory for the entire area for the rest
of the night into Thursday morning. Sfc dew pt depressions
are currently only 1-3 degrees with clear skies and light winds.
Ground is wet from earlier rain and sfc ridging is arriving - in
between the departing earlier convection and next upstream wave.
Some concern that incoming clouds from the southwest later
tonight could curb radiational cooling and alleviate dense fog
potential. If that`s the case the advisory may be able to be
cancelled early.
UPDATE Issued at 800 PM EDT Wed Oct 5 2016
Line of showers and thunderstorms is exiting to the east and we
should be dry for the rest of the night. It is possible however that
some showers will push into the western zones from the southwest
after 09-10z so will keep a late night/early morning pop along the
lakeshore. These would be the showers that are expected to develop
in the next few hours over IA and nrn MO per HRRR guidance.
Will also add fog to the fcst tonight as the broken to nearly
solid north-south band of convection brought some heavy downpours.
Moist ground from that very recent rainfall and dying winds/clr
skies should lead to quick development of ground fog this evening
that could become locally dense. May need to consider a dense fog
advisory.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 330 PM EDT Wed Oct 5 2016
Scattered showers and a few thunderstorms will cross the area
through most of the short term, starting with the front coming
through early this evening.
Deep southwest flow will continue through the short term, keeping
precipitable water values between 1.0 and 1.5 inches tonight through
Friday. Jet dynamics do not appear that great for SW MI, so the
pcpn focus will come with surface fronts.
The first front comes through this evening and slowly weakens.
Expect the pcpn to exit the eastern CWA prior to midnight. Some
gusty winds will be possible with some of the stronger storms.
After a brief lull, we should begin to see more showers and storms
head our way toward daybreak Thu. This occurs as the front
redevelops as a warm front and begins to lift back north as low
pressure moves NE across WI into Thu night. The highest risk of
rain will be north of I-96 both Thu and Thu night in this regime.
Finally the low pressure drags a cold front through the area mid day
Friday when all areas will see rain chances. We should see a mid
day high with temps falling in the afternoon. Friday night clears
with chilly lows of 45 to 50.
.LONG TERM...(Saturday through Wednesday)
Issued at 330 PM EDT Wed Oct 5 2016
Cool surface high pressure builds in for the weekend with dry
weather expected. 850mb temperatures fall to the 0C to +6C range
this weekend which will yield highs in the upper 50s to lower 60s.
Lows will be in the 40s in most areas, but we are expecting some
upper 30s across Central Lower Michigan.
A weak front tries to move in from the north early next week, but it
looks to be moisture starved. Despite the operational ECMWF and GFS
kicking out some light precipitation have a dry forecast early next
week. Temperatures will warm Mon-Wed as southwesterly flow aloft
spreads in. Readings in the upper 60s to around 70 will be above
normal, so the cool weather over the weekend will be short lived.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 800 PM EDT Wed Oct 5 2016
High aviation impacts/delays are possible early Thursday morning
due to dense fog.
Confidence is increasing that we will see LIFR/VLIFR fog
developing tonight due to the heavy rain which just occurred from
the exiting line of storms. The skies are clear behind the line of
rain and winds will be diminishing to near calm toward midnight.
That fog is expected to lift by mid morning Thursday but some MVFR
may hang around after that... possibly lifting to VFR levels in
the afternoon. Additional showers and storms are possible on
Thursday, particularly for MKG and GRR.
&&
.MARINE...
Issued at 1010 PM EDT Wed Oct 5 2016
Winds and waves are subsiding this evening, so allowed the Small
Craft Advisory to expire earlier. Areas of dense fog are possible
tonight into Thursday morning.
Hazardous seas may develop again late Thursday night, especially
north of Holland, due to strengthening southerly flow. Northwest
flow and cold advection behind the front Friday afternoon and
night may also lead to hazardous marine conditions.
&&
.HYDROLOGY...
Issued at 1137 AM EDT Wed Oct 5 2016
No river advisories are in effect and river are either stable or
steadily falling.
Not much has changed in precipitation forecasts over the last
couple of days. We are still on track to see minor rainfall
amounts near Jackson and enough rainfall from Grand Haven to Big
Rapids, northwest to Ludington, to provide the soil a pretty good
soaking. This will come in two main rounds, being late this
afternoon into tonight and again Friday afternoon. The time
between may include a scattered shower or storm with a brief bout
of locally moderate to heavy rain. Given that this will all come
over a three day period, after rivers have fallen, concerns for
flooding are low at this time.
&&
.GRR Watches/Warnings/Advisories...
MI...Dense Fog Advisory until 11 AM EDT Thursday for MIZ037>040-
043>046-050>052-056>059-064>067-071>074.
LM...None.
&&
$$
UPDATE...Meade
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...Duke
AVIATION...Meade
HYDROLOGY...JAM
MARINE...Meade
Area Forecast Discussion
National Weather Service Wilmington NC
1126 PM EDT Wed Oct 5 2016
.SYNOPSIS...
Strong high pressure will build in from the north through the mid
to late week period. The center of the high will slide well
offshore from the Northeast states by the end of the week,
allowing Hurricane Matthew to move across the Bahamas and toward
the Florida coast Thursday and near or along the Florida coast
Friday. Matthew will continue to move up the the Southeast U.S.
Coast late Friday and continuing thru the weekend. However, much
uncertainty remains during this time period. Cool high pressure
will build across the area from the west early next week in the
wake of Matthew.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
As of 1100 PM Wednesday...Winds and QPF from Friday morning thru
Sunday evening have been adjusted to account for the latest NHC
Hurricane Matthew Track. QPF guidance used in this update comes
from WPC. Remaining near term forecast remains in tact.
Previous.......................................................
As of 700 PM Wednesday...Latest satellite imagery indicates a nice
hole in the overcast across much of the ILM CWA and even includes
a portion of the MHX CWA. Have adjusted sky conditions overnight
with a more optimistic and less opaque coverage. In addition,
latest RAP and HRRR indicate pcpn chances rather dismal and have
basically taken the POPs out altogether across the ILM CWA for
tonight, bringing them back by midday Thu from east. Various model
RH Time Height displays across the region tonight thru midday Thu
indicate plenty of dry air in the mid and even upper levels. Have
also tweaked min temps a degree or 2 lower due to the less amount
and opaque clouds respectively. With a continued tightened sfc pg
and mixing from aloft to be more active without that overcast sky,
will tweak winds 1 to 3 mph higher, especially along the
immediate coast.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
As of 3 PM Wednesday...The main weather caption this period is
mounting chances for rain as Hurricane Matthew begins to ride up
along the east coast of FL. The other notable headline is a good
chance of a Hurricane Watch for NE SC into THU. Rain rates and QPF
values will remain minimal through Thursday, becoming substantial
late Thursday night onward as periods of rainfall move ashore. The
official hurricane track curls Matthew east and farther offshore of
the SC coast, but this remains susceptible to adjustment based on a
history of model inconsistencies so far. The official track implies
a 70 percent chance of at least tropical storm force winds along the
NE SC and very SE NC coast at this time by Saturday. 4-8 inch rain
amounts from late THU through SAT remains advertised for now, and 2-
4 inches farther inland of NE SC/SE NC.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 3 PM Wednesday...Uncertainty remains the key word to describe
the first and what is probably the most important portion of the
forecast period. Latest trend in the guidance has been to sharply
turn Matthew near the GA/SC border with significantly less impacts
in the local area than previously expected. However, the 12Z
ECMWF, which was the first with the sharp eastward turn idea
yesterday, has reverted back to a track up the coast albeit with a
weaker storm. The lack of consistency in the past 24 hours is
somewhat disconcerting and do not expect a lot of changes with the
next NHC advisory.
The fate of Matthew will also play a role in how next week plays
out. A track up the coast instead of kicking out to sea south of
the forecast area would linger clouds/wind/rain into Sun morning
before the storm exits and the surface/mid level ridge combo can
build in. Latest forecast maintains high pop Sat with a decreasing
trend Sat night and Sun with the remainder of the forecast dry as
west to northwest flow aloft and low level northeast flow contribute
to cool and dry conditions. Temps early next week below climo will
trend toward climo by the end of the period.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
As of 00Z...Stationary boundary stalled offshore splits the ridge
building down from New England, and a sharpening trough ahead of
Hurricane Matthew in the Bahamas. Between these two features, the
pressure gradient is pinching and NE winds have increased to around
15 kts, with gusts up to 20 kts. A nocturnal inversion will setup,
but it will take several hours for wind gusts to ease, and even
after that wind speeds will remain around 10 kts all terminals
overnight. On this NE flow, moisture will increase and MVFR stratocu
is forecast to redevelop into a cig overnight. Once this develops,
it will persist through the end of the period, and the only change
after daybreak will be an increase in wind gusts once again. A few
showers are possible, especially along the coast, Thursday aftn, but
coverage is expected to be minimal with very light intensity, so
have left out any mention attm.
EXTENDED OUTLOOK...MVFR/IFR due to low clouds/rain, along with gusty
winds, possible Friday through Sunday near the vicinity of Hurricane
Matthew. VFR Monday.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 1110 PM Wednesday...Strong SCA conditions continuing thru
this period and beyond.
The sfc pg to remain strongly tightened overnight thru Thu, a
result of the 1030 mb high centered well offshore from the NE
states but continuing to ridge back to the SW across the
Carolinas. The offshore old frontal boundary or inverted sfc trof
ie. coastal trof, will remain stationary overnight. It will begin
to make some progress westward toward the ILM Coastal waters
during Thu. Expect NE 20 to 25 KT winds overnight with some 30 KT
gusts possible, especially off Cape Fear and off Cape Romain.
Significant seas will run a solid 5 to 7 ft, except 1 to 2 ft
lower in that protected area from NE wind waves, from south of
Cape Fear to north of Murrells Inlet. A few 8 footers are possible
off Cape Fear and off Cape Romain. Dominating periods will run in
the 7 to 8 second period range, basically dealing with a pseudo
swell.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 3 PM Wednesday...Advisory conditions are certain this
period but could be superseded by a tropical storm or hurricane
watch for part of our waters into Thursday. In any case marine
conditions will become increasingly dangerous this period. By
Saturday wave guidance suggests 10-16 foot seas across the 0-20 NM
coastal waters. This could change to higher values if Matthew does
not turn east as soon as is currently forecast. Mariners are
encouraged to secure and tie down small craft at this time.
SHORT TERM /SATURDAY THROUGH MONDAY/...
As of 3 PM Wednesday...Although the magnitude of marine impacts will
depend on Matthew`s track it seems certain headlines will be in
effect Sat morning. Seas could be well into the double digit range
with winds of hurricane force if a track on the western edge of the
guidance envelope verifies. Should this happen treacherous marine
conditions would be more likely to linger through Sun and possibly
Sun night. Conditions should begin to improve at the latest on Mon
as high pressure at the surface and aloft starts building over the
region.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...Beach Hazards Statement through Thursday evening for SCZ054-
056.
NC...Beach Hazards Statement through Thursday evening for NCZ106-
108.
MARINE...Small Craft Advisory until 6 AM EDT Friday for AMZ250-252-254-
256.
&&
$$
SYNOPSIS...DCH
NEAR TERM...DCH
SHORT TERM...MJC
LONG TERM...III
AVIATION...JDW/SGL
Area Forecast Discussion
National Weather Service Wilmington OH
940 PM EDT Wed Oct 5 2016
.SYNOPSIS...
Dry weather and above normal temperatures are forecast to
continue through Friday as high pressure remains centered over New
England. Isolated showers are expected Friday night into Saturday
morning as a cold front moves east through the region.
Temperatures will cool closer to seasonal normals by the weekend.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Band of primarily mid level clouds associated with a weak trough
was located over the Whitewater and Miami Valleys at 01Z. Radar
even shows a few sprinkles or light showers falling from the mid
clouds. Band of clouds will likely hold together as it moves
across the CWA early tonight. Not sure the light precipitation
will as HRRR suggests dissipation further east at or before
midnight, but given radar trends will have to keep at least 20
pops for isolated showers for a couple more hours mainly across
west central Ohio. Any clearing later tonight may promote patchy
fog formation particularly in typical fog prone river valley
areas.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
As surface high pressure remains centered over New England, some
mid level ridging will try to assert itself a little more into the
Ohio Valley on Thursday. This will keep the weather pattern in a
status quo mode with mostly sunny skies and above normal
temperatures in the lower 80s expected again for Thursday.
For Thursday night into Friday, embedded energy moving through a
long wave trough to our west will perturb low pressure over the
Plains while a cold front begins to organize and move east. We
should squeeze out another dry day for most locations on Friday with
partly to mostly sunny skies.
For Friday night, s/wv energy will allow cold front to our west to
slowly move east through the region. Overall dynamics are weak
with instability limited as well, so have continued with a slight
chance of showers. Lows will drop into the 50s.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
The long term period will begin with a cold front moving through the
eastern parts of the FA early Saturday morning. The GFS and ECMWF
are a bit faster than the NAM, so have trended toward a faster
solution, with the front east of the area by 12z Saturday. Forcing
will be quite weak with the FROPA, but cannot rule out a few spotty
showers along and just behind the front early Saturday morning
before best forcing moves east of the area. Dry air will quickly
filter into the area, allowing for mostly sunny skies during the
late morning and afternoon hours.
As the core of cooler air settles into the region on Sunday
afternoon (850 temps ranging from 3C to 8C across the FA), expect
slightly cooler high temperatures on Sunday than on Saturday. High
temperatures will be about 5 degrees below normal on Sunday, even
with ample sunshine.
By Monday, the sfc ridge axis should move east of the FA, allowing
for temperatures to begin to moderate. Temperatures will return to
near normal on Monday, with a gradual warming trend expected to
continue through the first half of the upcoming workweek.
A weak upper-level disturbance should move east through the Great
Lakes region late Monday through Tuesday. Right now, both the GFS
and ECMWF keep best forcing and moisture west/north of the FA,
allowing for dry conditions to continue as the elongated sfc high
pressure remains stretched across the southern Ohio Valley. Have
kept the area dry through the remainder of the extended until
details become better defined on future runs.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
Band of mid level clouds is expected to move east across the
terminals during the mid to late evening. Can`t even rule out a
few sprinkles or a brief shower particularly at KDAY/KCVG/KLUK but
probability of occurrence is to low to mention in TAFs at this
time. Back edge of clouds will reach KLUK by 06Z, and clearing
skies will likely promote fog formation thereafter. Visibilities
may drop into LIFR at times. Otherwise, VFR expected at other
terminals during the TAF valid period. Expect a few cumulus with
bases of 4-5K ft for Thursday.
OUTLOOK...No significant weather is expected.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Hickman
NEAR TERM...BPP
SHORT TERM...Hickman
LONG TERM...KC
AVIATION...BPP
Area Forecast Discussion
National Weather Service Northern Indiana
736 PM EDT Wed Oct 5 2016
.SYNOPSIS...
Issued at 730 PM EDT Wed Oct 5 2016
With isolated showers ending this evening...the overnight period
will be dry with some patchy fog possible. Mild weather will
continue through Friday with low chances for rain later Friday as
well. Lows will drop near 60 tonight with highs Thursday
afternoon in the low 80s. Highs back in the 60s can be expected
this weekend with lows in the 40s.
&&
.SHORT TERM...(This Evening through Thursday)
Issued at 300 PM EDT Wed Oct 5 2016
Trailing prefrontal trough extending from sw disturbance over srn
Canada extends down across lake MI. Earlier shower activity back
through ern IL had diminished entirely as it became divorced from
better forcing aloft passing well northwest and better moisture
down near the OH river. Lastest RAP along with various 12Z highres
solutions depict minimal to no redevelopment invof of prefrontal
trough.
Focus overnight shifts well west across MO/ern IA along stalling
surface trough and see little reason not to buy into broad consensus
drier look of 12Z guidance given 1) absence of relevant focusing
mechanism 2) poor low level moisture flux underneath 3) mid level
capping inversion. Did retain slgt chance shower mention far west
late corresponding to eastward bulge of modest low level theta-e
ridging poking newd into central IL however this may very well
hold west too.
&&
.LONG TERM...(Thursday Night through Wednesday)
Issued at 300 PM EDT Wed Oct 5 2016
Large scale shift seen in gamut of model solutions overnight with
ejection/intensity of sw energy out of the Rockies on Fri with a
much weaker and faster solution aloft with lagging disturbance
lifting out of base of trough across the central plains.
Deamplifying trends with this sys and eastward weakening of sfc
frontal zone suggest little if any shower activity will persist
into the KIWX CWA on Fri and will follow previous shift trend of
limiting pops further.
Otherwise expansive ridging will return to the lakes/OH valley this
weekend into early next week. Seasonably cool temps this weekend
will give way to a moderating trend back to above normal next week
as general zonal flow develops across the Conus.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 731 PM EDT Wed Oct 5 2016
VFR conditions expected this evening. Expect some MVFR BR
restrictions late tonight with winds nearly calm and warm moist
low levels. Some gudiance suggesting dense fog forming but
majority of guidance remain in the MVFR category and will maintain
this for now. Conditions return to VFR Thursday.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...Lashley
SHORT TERM...T
LONG TERM...T
AVIATION...Lashley
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Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1047 PM CDT WED OCT 5 2016
.SHORT TERM... (Through Late Thursday Afternoon)
Issued at 332 PM CDT Wed Oct 5 2016
It is currently dry over the area with showers just south of
Reynolds county. This area could still bring isolated showers to
the far southern part of the CWA through late this afternoon. Of
more concern is that I still expect thunderstorms to redevelop this
evening across central and northeast Missouri as well as west
central Illinois this evening and overnight. Latest RAP runs
continue to show low level moisture convergence increasing over
these areas ahead of a mid level vort max currently over the central
Plains. Will continue to go with high chance and likely PoPs
tonight to account for this forcing. May still be a few strong or
possibly severe storms based of the amounts of shear and instability
available tonight.
As we go into tomorrow, the chances for showers and thunderstorms
will begin to lessen as the low level jet weakens. Will maintain a
chance for showers and thunderstorms through the day across central
and northeast Missouri and west central Illinois where will continue
to be some weak low level moisture convergence. Look like the rest
of the area will continue to be dry.
Temperatures will be relatively mild tonight and tomorrow. Stayed
close to MOS guidances which is in good agreement.
Britt
.LONG TERM... (Thursday Night through Next Wednesday)
Issued at 332 PM CDT Wed Oct 5 2016
The cold front will be moving into northwest Missouri Friday
evening. All guidance is more progressive with the front now as the
shortwave trof aloft does not amplify the longwave trof as much as
previously forecast. This faster pattern now has the front all the
way through the CWFA by 18Z Friday. Showers and thunderstorms along
the front will likely be weakening and dissipating through the
morning with diurnal minimum in heating. Some weak showers or
sprinkles will continue to be possible mainly behind the front as
low level frontogenesis increases sharply over the area. Due to the
faster movement of the front, will keep more moderate temperatures
over the area on Friday than I forecast yesterday.
High pressure will build over the region Friday night and Saturday
behind the front. This will be another true taste of Fall with
highs in the upper 60s and low 70s and lows mainly in the 40s. As
the ridge moves eastward early next week, we should get into a
return flow pattern and temperatures will get a bump back above
normal...tho right now it looks like it will only get a few degrees
above into the mid 70s. Ensemble guidance is giving us some slight
chance PoPs over central Missouri late Tuesday night and both the
GFS and ECMWF do show some weak moisture convergecne and low level
warm advection so I see no harm in leaving the slights in for now.
Other than that it should be a dry medium range with the ridge axis
still across the lower Mississippi Valley limiting moisture
return.
Carney
&&
.AVIATION... (For the 06z TAFs through 06z Thursday Night)
Issued at 1041 PM CDT Wed Oct 5 2016
Showers and storms will continue to develop late tonight across
northeast and central MO and west central IL as a south-
southwesterly low level jet intensifies over a warm front which
will lift northward through this area. These showers/storms will
impact UIN and COU. Most of this convection should dissipate by
late Thursday morning or shift north of the taf sites. Most of the
showers and storms should remain north and west of the St Louis
metro area. South-southeasterly surface winds will continue
through the period.
SPECIFICS FOR KSTL: Showers and storms will continue to develop
late tonight across northeast and central MO and west central IL
as a south-southwesterly low level jet intensifies over a warm
front which will lift northward through this area. Most of this
convection should dissipate by late Thursday morning or shift
north of this area. Most of the showers and storms should remain
north and west of the STL area. Only VFR cloudiness is expected
for STL through the forecast period. South-southeasterly surface
winds will continue through the period.
GKS
&&
.PRELIMINARY POINT TEMPS/POPS...
Saint Louis 68 86 64 71 / 10 10 20 20
Quincy 64 82 59 64 / 60 50 60 20
Columbia 64 83 58 63 / 50 40 60 30
Jefferson City 65 85 60 66 / 40 30 50 30
Salem 63 84 62 78 / 10 5 5 20
Farmington 62 84 60 74 / 10 5 5 20
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Melbourne FL
1039 PM EDT WED OCT 5 2016
.DISCUSSION...
...POWERFUL HURRICANE MATTHEW EXPECTED TO APPROACH VERY CLOSE TO THE
EAST CENTRAL FLORIDA COAST THURSDAY NIGHT AND INTO FRIDAY...
Tonight...Little change to previous forecast. Short range models
still indicate low level ENE flow backing to the NE overnight and
increasing in the h9-h8 layer to 20-30 knots late Tonight. This is
in response to tightening pressure gradient between high pressure
ridge (wedge) building down the eastern seaboard into northeast
Florida and Matthew moving into the central Bahamas. The HRRR model
shows the resulting increased moisture convergence generating a few
bands of convection over the Atlantic which move onshore and well
inland after midnight. PoPs should be likely along the coast, but
rainfall won`t be persistent (like it will be Thu afternoon into
Fri).
Previous Discussion...
Thursday...Hurricane Matthew is forecast to move northwest near the
NW Bahamas and increase the pressure gradient through the day breezy
conditions into mid day will increase into late afternoon and
evening with windy conditions developing along the coast and
possibly tropical storms winds by late afternoon/early evening along
the southern Treasure coast. Outer rain bands in the periphery of
Matthew will also increase in coverage and begin to bring more
frequent shower bands onshore through the day, with the highest
coverage of squalls expected into the Treasure coast by the
afternoon. Hurricane preparations should be rushed to completion Thu
morning before the onset of potential tropical storm winds in the
late afternoon.
Thu Night/Friday...NHC track forecast and 12z model guidance point
to a very strong hurricane moving NNW close to the east central FL
coast initially along the Treasure coast Thu night and then moving
NNW toward Brevard county into daybreak Friday. The hurricane will
then move NNW potentially near the Volusia county coast into Friday
morning and afternoon before lifting farther north Friday night.
Along the coast, devastating impacts from strong and damaging
hurricane force winds are expected. Maximum storm surge of 5-7 feet
will also produce sea water flooding in vulnerable locations. Heavy
rainfall amounts to 4-8 inches with isolated amounts to 10 inches
are forecast, which would produce fresh water flooding. A Flood
Watch has been issued for all east central Florida counties except
Lake county which is expected to see lower rainfall amounts.
There is the potential for hurricane force winds to extend into
eastern portions of the first tier of inland counties and any
deviation of the track to the west at this point could bring strong
hurricane conditions to inland locations. Hurricane Warnings are in
effect for all areas except Lake county which is in at Tropical
Storm Warning.
Previous extended...Sat-Tue...May have some lingering convergent
bands south of departing Matthew on Saturday, so left scattered PoPs
in for the daytime hours. Drier air mass pushes in by later Sat in
the wake of Matthew and high pressure building in will keep
conditions rather pleasant for Sunday into early next week. Will
keep an eye on longer ranges as 00Z GFS/ECMWF both suggesting the
remains of Matthew may drift back toward the Bahamas by middle of
next week.
&&
.AVIATION...
Scattered showers and storms will move WSW and produce brief MVFR-
IFR conditions through the night. Some MVFR stratus is possible
early Thu morning over the interior. Then increasing NE winds will
build south to north across the terminals with some gusts
approaching tropical storm force late in the afternoon mainly along
the coast from KTIX southward. Numerous squalls expected to begin
from about KMLB-KSUA in the afternoon and working northward across
the remainder of the terminals through sunset Thu.
&&
.MARINE...
No change to previous discussion.
Hurricane Warning continues for all east central Florida. Small
craft operators should have their vessels secured before the onset
of stronger winds Thursday afternoon and evening.
Tonight-Thu...Marine conditions will become hazardous for small
vessels into Thursday as winds and seas increase substantially into
Thu afternoon with seas building over 12 feet across the southern
waters.
Thu Night-Friday...The core of hurricane Matthew will bring
hurricane force winds and seas building over 30 feet offshore
across the east central Florida Atlantic waters.
Sat-Sunday...Winds and seas will slowly subside as Hurricane Matthew
moves north and northeast of the waters over the weekend.
&&
.MLB Watches/Warnings/Advisories...
FL...Hurricane Warning for Coastal Volusia County-Indian River-Inland
Volusia County-Martin-Northern Brevard County-Okeechobee-
Orange-Osceola-Seminole-Southern Brevard County-St. Lucie.
Flood Watch from Thursday morning through Friday evening for
Coastal Volusia County-Indian River-Inland Volusia County-
Martin-Northern Brevard County-Okeechobee-Orange-Osceola-
Seminole-Southern Brevard County-St. Lucie.
Tropical Storm Warning for Northern Lake County-Southern Lake
County.
AM...Hurricane Warning for Flagler Beach to Volusia-Brevard County
Line 0-20 nm-Flagler Beach to Volusia-Brevard County Line
20-60 nm-Sebastian Inlet to Jupiter Inlet 0-20 nm-Sebastian
Inlet to Jupiter Inlet 20-60 nm-Volusia-Brevard County Line
to Sebastian Inlet 0-20 nm-Volusia-Brevard County Line to
Sebastian Inlet 20-60 nm.
&&
$$
Lascody/Cristaldi/Ulrich/Combs
Area Forecast Discussion
National Weather Service Marquette MI
719 PM EDT Wed Oct 5 2016
.SHORT TERM...(This evening through Thursday)
Issued at 350 PM EDT WED OCT 5 2016
Upper level trough is over the northern plains to southern
Saskatchewan and Manitoba. Swath of showers and isolated tsra
in warm conveyor belt ahead of sfc cold front is sliding across
Upper Michigan this aftn. Dry slot and back edge of showers already
over western U.P. and should be out of eastern cwa early this
evening. Dry air evident upstream and expect skies to clear out
tonight. Lingering low-level moisture blo 1000ft may lead to patchy
fog over far east cwa after midnight. Though dry air aloft should
allow temps to fall off into the 40s over interior west tonight,
extent of dry advection should prohibit low clouds or fog. RAP
soundings for late tonight bearing this out attm. High clouds will be
on the increase late Thu morning into Thu afternoon.
Models have trended slower in bringing in next round of rain showers
and isolated thunderstorms into southern part of Upper Michigan
ahead of shortwave currently crossing northern CA and NV. Scaled
back on pops, limiting them to slight chance for scntrl and only
after 21z. Another day with above normal temps well into the 60s
if not near 70, especially with the sunshine in the morning.
.LONG TERM...(Thursday night through Wednesday)
Issued at 335 PM EDT WED OCT 5 2016
Thu night/Fri...Models in fairly good agreement on track of
shortwave and accompanying low pressure system riding ne from the
Plains into wrn Upper Mi Thu night although differ on timing. The
00Z ECMWF and 00Z GFS were a bit quicker than the 12Z NAM and the
local 12Z WRF-ARW while the 12z Canadian model was somewhere in
between. With the 12z GFS trending slower, more in line with the 12Z
Canadian, would tend to lean more toward slightly slower solution
with system. Despite the differences, models indicate a period of
vigorous dpva/deep layer q-vector convergence with pwats as high as
1.50 in over at least the central and ern cwa. This will support
high likely/categorical pops and a period of moderate to heavy rain/
perhaps a TS...especially for late Thu night into early Fri. The
guidance has come into better agreement showing more vigorous drying
/mid-level subsidence by late Fri morning west spreading east into
the afternoon in wake of the shortwave/sfc low pres lifting into
Ontario and attendant cold frontal passage. As h85 temps fall toward
-3C late in the day over the w, Fri will turn much cooler than Thu.
Fri night into Sat night...Although drying will initially persist in
the anticyclonic wnw flow in the wake of the departing low, an
approaching shortwave along with deeper moisture and h85 temps of -3
to -4c over the relatively warm waters of Lake Superior are fcst to
initiate some lake induced troughing and at least sct lake effect
showers over nw Upr MI late Fri ngt into Sat and over ne Upper Mi
Sat afternoon into Sat evening. The arrival of a shortwave
ridge/larger scale subsidence in the wake of Saturday`s shortwave
trough will bring a drying trend by late Sat night. Temps over the
interior west half could turn rather chilly on Fri ngt, but a steady
wnw flow and mixing from h925 winds 20-25 kts should limit the
diurnal temp fall a bit. Lighter winds and partial clearing with sfc
high moving overhead could lead to another chilly night on Sat
night, although the more progressive GFS indicates some waa clouds
overspreading the area late Sat ngt from west which may temper
cooling somewhat. Still wouldn`t be surprised to see some lower to
mid 30s min temps for both Fri and Sat nights over the interior west
half.
Sunday generally trending drier as models show another shortwave in
zonal flow passing well north into Canada keeping waa pcpn well
north of the area as well. Model uncertainty increases for Mon into
next Wed with differences in strength/timing of shortwaves moving
through south central Canada and also differences in timing with
cold front assoc with sfc low moving across Hudson Bay. Most of the
models with exception of 12z GFS would suggest drier conditions
persisting into Monday as higher 5h ridge heights hold over the
region. Model consensus would then indicate cold front advancing
into Upper Mi late Mon night into Tue so slight chc to low chc pops
will be probably be warranted during this time frame. In general,
since heights will be well above normal, expect above normal temps
to prevail for the first portion of the week even with the expected
passage of the cold front.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 718 PM EDT WED OCT 5 2016
MVFR conditions will continue through the end of the TAF period for
all sites.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 350 PM EDT WED OCT 5 2016
S winds 20-30 kts shift to the SW this evening into tonight,
strongest over west and north central Lk Superior. Pressure gradient
and winds will weaken for a time Thu aftn and night as a low
pressure trough develops over the Upper Lakes ahead of a low
pressure wave developing over the southern Plains. After this low
pressure wave passes late Thu night/early Fri morning, NW winds up
to 30 kts with gale force gusts to 35 kts will develop on Fri,
strongest over the e half of Lake Superior. NW winds up to 25 kts
will linger into Sat before diminishing to under 15kt late Sat into
Mon as high pres moves across.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLA
LONG TERM...Voss
AVIATION...07
MARINE...JLA
Area Forecast Discussion...UPDATED
National Weather Service Norman OK
941 PM CDT WED OCT 5 2016
.DISCUSSION...
Updated forecast will include increasing mins slightly east of
dryline and increasing pops across north-central Oklahoma. High
Rest models all continue to increase coverage of showers and
storms overnight near nose of low-level jet across Kansas and
northern Oklahoma. Post convective subsidence and continuing
convection across northern Texas may inhibit storm development
first part of the night across central and southwest Oklahoma so
pops were not significantly changed there. With deep layer shear
sufficient there could be a few severe storms overnight with large
hail the main impact.
&&
.PREV DISCUSSION... /issued 645 PM CDT WED OCT 5 2016/
AVIATION...
For 00Z TAFs, VFR conditions expected to be seen most terminals.
Isolated to scattered storms south and west of KLAW/KSPS will be
monitored for terminals impacts with amendments as needed. More
numerous showers and storms possible overnight and tomorrow with
most impacts toward and after end of forecast period as frontal
boundary approaches from Kansas.
PREV DISCUSSION... /issued 248 PM CDT WED OCT 5 2016/
DISCUSSION...
Several runs of the operational HRRR indicate a few storms may
develop by late afternoon across western north Texas and far
southern Oklahoma. This will mainly occur along and near a
dryline. Instability and shear will certainly support a few severe
storms with hail and wind.
During evening and overnight, surface winds will back and better
moisture will return to western Oklahoma. This may result in
additional showers and thunderstorms. Overnight, better chances
for showers and storms should shift into northern Oklahoma as
strong low level flow gradually decreases across southern Kansas.
A little uncertain about showers and thunderstorm chances Thursday
morning and early afternoon, but some cloud cover will linger
through the morning.
By late afternoon, a cold front will enter far northern Oklahoma as
a trough lifts from the central Rockies into the central
Plains. Better height falls will remain north of the area, but a
deep enough frontal boundary will result in scattered to numerous
showers and storms along and just behind the front. Moderate
instability ahead of the front will allow for strong to severe
storms, with strong winds and hail.
The front will clear southern Oklahoma and western north Texas by
early morning Friday. Therefore, some rain and showers may linger
near the Red River early but better chances for rain will be
across northern and central Texas.
Mainly dry conditions are expected over the weekend. A trough will
skirt northwestern Oklahoma late in the weekend/early Monday.
Some elevated showers and storms may develop as a result.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 71 87 54 67 / 30 30 80 20
Hobart OK 69 86 54 68 / 30 40 80 20
Wichita Falls TX 72 89 59 70 / 30 10 70 50
Gage OK 60 87 45 70 / 10 30 40 10
Ponca City OK 70 88 51 67 / 50 50 90 20
Durant OK 71 88 65 75 / 10 10 40 30
&&
.OUN Watches/Warnings/Advisories...
OK...None.
TX...None.
&&
$$
11/14
Area Forecast Discussion
National Weather Service Billings MT
313 AM MDT Thu Oct 6 2016
.SHORT TERM...valid for Tdy and Fri...
Slow-moving upper low now over southern Saskatchewan/Manitoba,
with cyclonic flow and below normal heights over MT. Jet is well
to our south and shortwave energy exists in CO. There are a few
showers near Livingston and McLeod, but otherwise it has been a
quiet night under partly to mostly cloudy skies. Temps have fallen
to or below freezing at some locations, but cloud cover is helping
to keep temps up. As of 3 am Billings sits at 37 degrees.
We will see gradually rising heights today as upper low to our
northeast continues to fill and drift east. The combination of
cyclonic flow aloft, reasonably steep mid level lapse rates and
boundary layer convergent flow will bring isolated-scattered
rain/snow showers again today over our mountains and foothills,
perhaps making it as far east as BIL as the HRRR suggests this
afternoon. Building surface ridge from the north will add to the
low level frontogenesis. Will keep eastern areas dry. Temps today
will be similar to yesterday with highs ranging from the mid 40s
to lower 50s. Any shower activity will decrease through the
evening as flat ridging builds from the west. The potential exists
for freezing temps again tonight, but should note that cloud cover
will likely be a factor again as there is a quick transition to
isentropic ascent ahead of next Pacific shortwave.
Surface ridge will begin its retreat on Friday as we see lee side
troffing develop. This will allow for increased SW winds and
downslope warming, of course, and temps will climb into the 50s to
near 60F. Forcing from Pacific wave will clip our north late
Friday and Friday night, and will keep slight pops to cover this.
JKL
.LONG TERM...valid for Sat...Sun...Mon...Tue...Wed...
Through the weekend things should remain quiet across southern
Montana. Flow will remain zonal, but there will be some weak
energy moving north of the area. While this should bypass most of
the the area, there could be some precipitation in the
northwestern mountains. Otherwise things should remain dry
Saturday and Sunday. Some cloud cover as the energy moves by could
limit temperatures a little.
Monday will be the next chance for some precip for much of the
area. The latest GFS has come more into alignment with a clipper
moving through Monday and Tuesday which will bring some cooler
temperatures and a quick shot at a precip. There is still some
uncertainty on how far west the cold air will make it. Along with
the cooler temperatures, north winds will favor the upslope areas
in the Beartooth and Bighorn Mountains.
After the clipper moves out Tuesday things will be dry for most of
the day Wednesday as riding starts to build into the area.
Thursday another wave of energy will try to push through the area
even with the building ridging, which will give another chance
for some rainfall. Reimer
&&
.AVIATION...
VFR conditions expected today. There could be a few showers around
the mountains along with occasional mountain obscuration. Reimer
&&
.PRELIMINARY POINT TEMP/POPS...
Tdy Fri Sat Sun Mon Tue Wed
-------------------------------------------------------
BIL 049 032/057 044/066 047/074 048/064 043/059 045/067
2/W 11/B 20/B 11/U 11/B 21/B 11/B
LVM 051 031/059 043/067 044/071 045/068 041/062 043/067
3/W 22/W 21/N 11/N 11/U 11/B 11/B
HDN 049 030/057 040/067 044/075 044/064 041/060 044/067
2/W 11/B 11/B 01/U 11/B 21/B 11/B
MLS 048 028/051 039/063 046/073 045/061 041/057 043/065
1/B 01/B 21/B 01/U 11/B 21/B 11/U
4BQ 049 029/056 039/065 044/075 046/068 042/059 044/070
1/B 10/B 11/B 01/U 11/U 11/B 11/U
BHK 046 025/049 033/060 042/071 044/061 039/054 040/064
0/B 00/B 21/B 01/U 11/U 21/B 11/U
SHR 049 026/059 038/066 043/074 044/070 042/059 042/068
2/W 21/B 10/B 01/U 11/U 11/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
AREA FORECAST DISCUSSION
National Weather Service Des Moines IA
400 AM CDT Thu Oct 6 2016
.SHORT TERM.../Today/
Issued at 358 AM CDT Thu Oct 6 2016
The biggest concern through today will obviously be thunderstorm
trends and severe potential. The current situation has the primary
short wave/PV anomaly passing through the base of the Rockies long
wave trough with models having it reach central NE by 00z. Weak but
broad vertical motion has already spread through much of the Plains
and MO Valley ahead of this feature. This lift has combined with
increasing warm/theta-e advection and 0-2km moisture convergence to
produce fairly widespread thunderstorms from OK into IL ahead of the
maturing surface front. Although the effective shear is fairly high,
the lack of instability has seemed to temper any severe potential
this far north so far.
Looking ahead confidence is high in convection but not the greatest
in the details with a range of solutions. The models are in good
agreement in the larger scale with the aforementioned broad, weak
mid level lift consolidating and strengthening later this afternoon
passing through the Siouxland area into MN by 00z with lower based
forcing through IA. Convection allowing model /CAM/ guidance
suggests linear development with embedded supercells possible in
what is forecast to be very high deep shear along the front/trough
21-00z possibly just reaching western sections of the forecast area,
which makes sense considering the degree of forcing.
The degree of recovery and how this is modulated due to the northern
extent of the surface based instability will be the question. Most
models suggest a SSW-NNE warm sector getting into IA with a triple
point near SW IA by 00z and inverted trough farther north. The
typical conceptual model would suggest the better MLCape/surface
based potential reaches about the same latitude as the triple point
with several counties north of elevated potential. Models vary in
this regard from the MO border to possibly as far north as Highway
20, but consensus would suggest farther south toward the higher SPC
Day 1 probs would be preferred, which is close where the NCAR
Ensemble depicts. All modes of severe weather, including tornadoes
will be possible wherever this favorable MLCape/Cinh can phase with
high shallow and deep shear, SRH and likely adequately low LCLs. If
one set of CAM guidance would be preferred at this point it would be
the op HRRR and ESRL HRRR which place less emphasis on convection
developing from KS into IA this morning.
.LONG TERM.../Tonight through Wednesday/
Issued at 358 AM CDT Thu Oct 6 2016
Thursday night into Friday Morning...
Forecast Confidence... Medium-High
Mesoscale/NSE described in short term portion of this AFD. Long
term will handle conclusion of event. Linear storms continue
racing eastward across CWA. Bunkers right-moving supercell suggest
storm motions in the 50 kt range and Corfidi forward-moving
supercell suggest storm motions in the 40 to 50 kt range. Looking
at the hodograph/upper air profile, this seems reasonable.
Therefore, prolonged heavy rainfall threat seems low. May be
brief heavy downpours, but once line moves through, water should
recede fairly quickly. With sunset, instability will begin to
wane...reducing what hail threat there is. Further, model
consensus, including hi-res and ensembles, showing best forcing
should begin to run east and northeast of the DMX CWA. By 06z Fri,
svr threat should be confined to the eastern portion of the DMX
CWA, and by 09z Fri, the threat looks to be east of our area.
Friday afternoon and beyond...
Forecast Confidence... Medium-High
Large-scale subsidence rapidly moves in Friday afternoon in
association with a well-forecast broad area of high pressure slated
to propagate across the heart of the country this weekend. This will
make clouds difficult to come by this weekend, let alone any rain.
850mb temps of +0C look to barely touch the IA/MN border Saturday
morning. Still have threat for patchy frost across northern Iowa
mentioned for Saturday morning.
By Sunday, the aforementioned high should be near the Ohio Valley
Region, setting up return flow to Iowa. Models trying to pick up
on an upper-level low coming onshore sometime sunday and racing
across the Rockies, impacting the Upper Midwest sometime Monday
into Tuesday. Am not completely confident in this solution yet as
upper low may not be well-captured yet by models. With broad
850-300mb anti-cyclonic flow located over the deep south during
this time period, will be difficult for Gulf moisture to be
transported into Iowa.
Westerly flow aloft highlights next week and points to rather
humdrum weather overall. Extended-range models depict a thermal
ridge builds all week over the intermountain west and eventually may
crash down over Iowa next weekend, bringing 850mb temps in excess of
+20C to Iowa. If this solution pans out, temperatures in the 80s may
be back. Record highs for that time of year are in the mid to upper
80s, so it has happened before.
&&
.AVIATION.../For the 06Z TAFS through 06Z Thursday night/
Issued at 1156 PM CDT Wed Oct 5 2016
Scattered thunderstorms are moving across southeast Iowa early in
the period and will impact the KOTM area. Some uncertainty on
stratus potential overnight starting over southern Iowa then
lifting north on Thursday ahead of a warm front. Still potential
for IFR cigs if this develops. Thunderstorm chances begin to
increase by the afternoon with the most widespread activity
developing late afternoon and into the evening.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Small
LONG TERM...Kotenberg
AVIATION...Donavon
Area Forecast Discussion
National Weather Service Hastings NE
442 AM CDT THU OCT 6 2016
.SHORT TERM...(Today and tonight)
Issued at 441 AM CDT Thu Oct 6 2016
Upper air and satellite data showing that southwesterly flow
remains in place across the region early this morning, with low
pressure spinning over south central Canada and another shortwave
disturbance pushing through the central Rockies. At the surface, a
frontal boundary is draped through the southeastern half of the
CWA, splitting up the northeasterly winds to the north and
southeasterly winds to the south. Precip-wise not a lot to talk
about currently across our area, but have had some dense fog
develop across portions of our NC KS counties. RAP has had a
pretty good handle on the evolution, suggesting it`ll be sticking
around for several more hours. Obs/calls to counties showing 1/4
visibilities around, so did issue a dense fog adv through mid
morning.
Precipitation chances will be on the increase this morning, and
continuing through the afternoon/early evening, as the above
mentioned disturbance over the Rockies continues pushing east. One
question is how much of the area will see thunderstorms, vs just
showers. Thanks to warm air/moisture advection via a strong LLJ,
there has been a gradual northward push of instability. Currently
the brunt of that remains across KS, but some models show
affecting at least a few of our east-southeast NE counties this
morning and into the afternoon. To the west, expecting any thunder
would be isolated at best. Most recent run of models aren`t in too
bad of agreement showing near/just after sunrise being when we see
more precip development in our CWA, roughly along the NE/KS state
line. Expecting to see a general east-northeastward shift to
things during the day, with some uncertainty with exactly when we
dry out. Models slowed things down just a touch, so did insert
some PoPs in for this evening.
At the surface, the boundary currently in place doesn`t look to
change much through the morning hours, but as the upper level
disturbance pushes closer, a reinforcing front will start moving
through. Because of this, confidence in temperatures is pretty low.
May end up with quite a gradient from NW to SE. Locations near ODX
may struggle to get out of the lower 50s for highs, across the far
SE (south of the front), there is a wide range in models, some
suggest mid 70s is possible, others top it out in the mid 60s.
Later this afternoon, the placement of this reinforcing cold
front will be of interest, as additional thunderstorm development
(and potential for strong/severe) is expected. Similar to the
other day, it`s be a close call our far eastern fringe, they may
be affected for a brief time, before action pushes off to the
east. Behind the front, expect increased northwest winds, gusting
near 30 MPH at times.
So then once the precipitation chances shift off to the east of
the CWA this evening, focus for tonight then turns to the
potential for frost. Expecting sky cover to diminish, esp after
midnight, and models are in good agreement showing surface high
pressure settling into the area behind the cold front. Not
expecting winds to become completely calm, but look to diminish to
around 5 mph, esp across western portions of the area. With
cooler/drier air also moving in, temps look to really drop off.
Forecast lows are in the 30s CWA- wide, and decided to issue a
Frost Adv for roughly the northwestern half of the CWA. Not out of
the question that additional counties may be added, will let day
crew get another look at model data and make that decision. At
this point went with counties that look to have the best chance
for frost.
.LONG TERM...(Friday through Wednesday)
Issued at 441 AM CDT Thu Oct 6 2016
After some potential frost, especially north, for Friday morning
as a shortwave trough axis on top of a surface high occurs, the
trough moves east and so does the surface high heading into the
weekend, with near to above normal temperatures expected into mid-
week next week as broad upper level ridging occurs. Another cold
front is introduced in conjunction with another shortwave trough
in the Tuesday night/Wednesday time frame and will potentially
give us another round of cool autumn temperatures. Trends are for
this coming in a bit faster, maybe toward Tuesday rather than
Wednesday. Expect highs to reach the 70s for a good chunk of the
forecast between Saturday and Monday, and perhaps even Tuesday,
depending on how fast the cold front arrives.
Our best shot at rain in the long term will be Sunday night as a
low- amplitude shortwave trough traverses the Central Plains and
a strong low-level jet develops ahead of this trough, with perhaps
the best low-level convergence occurring near our neck of the
woods. We will be dealing with a limited amount of moisture more
than likely, so not going crazy with precip chances at this time.
Will keep mention of thunder as the GFS indicates potential for
600+ J/kg MUCAPE, but not anything necessarily spectacular.
&&
.AVIATION...(For the 06Z KGRI/KEAR TAFS through 06Z Thursday night)
Issued at 1233 AM CDT Thu Oct 6 2016
VFR conditions are expected to stick around a bit longer, but
deteriorating conditions are expected to work their way in this
morning. At this point it looks like the main impact will be to
ceilings, and currently have MVFR conditions going. Chances for
showers increase around/after 12Z, kept as VC mention for now.
Will see how coverage evolves in the coming hours, recent hi res
models suggest better chances may mainly shift around the terminal
areas. As far as winds go, currently easterly winds are expected
to switch to the northeast, then northwest later today as a cold
front pushes through the region. Expecting gusty conditions to
develop this afternoon, with gusts near 30 MPH.
&&
.GID Watches/Warnings/Advisories...
NE...Frost Advisory from 3 AM to 9 AM CDT Friday for NEZ039-040-046-
047-060>062-072>074-082-083.
KS...Dense Fog Advisory until 10 AM CDT this morning for KSZ005>007-
017>019.
&&
$$
SHORT TERM...ADP
LONG TERM...Heinlein
AVIATION...ADP
Area Forecast Discussion
National Weather Service Grand Rapids MI
329 AM EDT THU OCT 6 2016
LATEST UPDATE...
Synopsis/Short Term/Long Term/Marine
.SYNOPSIS...
Issued at 312 AM EDT Thu Oct 6 2016
A southerly flow of mild and moist air will continue into Friday.
Well above normal temperatures are predicted. There will be some s
showers and thunderstorms around as well as the unstable airmass
persist. A cold front pushes through on Friday...with a drier and
cooler airmass moving in behind it for Saturday and Sunday.
&&
.SHORT TERM...(Today through Saturday)
Issued at 312 AM EDT Thu Oct 6 2016
Will keep the dense fog advisory going. Southern locations such as
AZO and BTL have been slow to develop thick fog. The trend in the
HRRR still has dense fog moving into the norther parts of the I94
corridor counties. Elsewhere thick fog was present.
The low level jet triggering the showers and thunderstorms
upstream is forecasted to track into northwest parts of may CWA
today. An unstable airmass will be present. As a result...will
feature the highest POPs today for Ludington to Big Rapids area.
There were some HRRR solutions that track the convection into the
GRR area around 18z. If that ends up happening...higher POPs will
be warranted further south. It still looks like a warm day...but
with convection and clouds rolling in...there is a potential for
the high temperature forecasts to be too warm.
A stronger low level jet takes aim on WI tonight. That convection
may get pushed into my CWA later at night as the cold front
advances eastward through MN and IA. Will keep POPs going to
account for this. Deep layer shear ramps up...as the instability
diminishes. I would not rule out a few strong storms still. Should
be mild night with the main axis of higher PWAT values overhead.
Some locations are likely to stay in the 60s.
Will need to monitor the forecast for Friday. Lots of deep layer
shear around...but only a narrow axis of instability moving
through with the front. It will not take too much instability to
trigger organized convection.
.LONG TERM...(Saturday night through Wednesday)
Issued at 312 AM EDT Thu Oct 6 2016
We have a mostly dry forecast through the long term. Saturday night
will be one of the coolest nights of the season...so far.
Temperatures will likely fall into the 30s across the north central
cwa and some frost is possible in low lying areas. Elsewhere...lows
in the 40s are expected. Then a gradual warming trend that will see
temps climb to the mid to upper 60s by mid week.
Not much chance for pcpn during the period. High pressure over
Ontario will feed cool dry air into the Michigan. A cold front will
approach the state mid week and we may see a shower with it...but
it`s a long way away and the stronger dynamics look to be farther
north in Canada.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 138 AM EDT Thu Oct 6 2016
Dense fog is expected overnight at most of the taf sites. We`ll
see a gradual improvement in vsbys after sunrise. Scattered
showers are also expected across southwest Lower today so we
included a vcsh comment.
&&
.MARINE...
Issued at 312 AM EDT Thu Oct 6 2016
South to southeast winds will persist today and into tonight with
values below advisory criteria. Later tonight the wind will
increase as a cold front approaches from the west. By daybreak
Friday...it appears that conditions will warrant a small craft
advisory. With the cold front pushing through on Friday and the
wind shifting to the west along with falling temperature...the
choppy conditions should persist into Friday night.
&&
.HYDROLOGY...
Issued at 1137 AM EDT Wed Oct 5 2016
No river advisories are in effect and river are either stable or
steadily falling.
Not much has changed in precipitation forecasts over the last
couple of days. We are still on track to see minor rainfall
amounts near Jackson and enough rainfall from Grand Haven to Big
Rapids, northwest to Ludington, to provide the soil a pretty good
soaking. This will come in two main rounds, being late this
afternoon into tonight and again Friday afternoon. The time
between may include a scattered shower or storm with a brief bout
of locally moderate to heavy rain. Given that this will all come
over a three day period, after rivers have fallen, concerns for
flooding are low at this time.
&&
.GRR Watches/Warnings/Advisories...
MI...Dense Fog Advisory until 11 AM EDT this morning for MIZ037>040-
043>046-050>052-056>059-064>067-071>074.
LM...None.
&&
$$
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...04
AVIATION...04
HYDROLOGY...JAM
MARINE...MJS
Area Forecast Discussion
National Weather Service Lincoln IL
327 AM CDT THU OCT 6 2016
.SHORT TERM...(Today and tonight)
ISSUED AT 326 AM CDT Thu Oct 6 2016
A wave of pre-frontal storms has overspread areas west of I-55 in a
region of warm frontogenesis. A few storms have shown weak rotation
and one report of hail has come in as well. SPC has the marginal
risk in our western counties through 12z/7am, then shifts the focus
farther west for the upcoming Day 1 outlook. Instability params show
MUCAPE values climbing to 2400 J/kg at 18z/1pm for areas N of I-72
with 30kt of Bulk Shear. So would not be surprised to see a few
strong storms during the day today as well. The HRRR and RAP models
are pointing toward continued development of waves of showers and
storms today, mainly W-NW of I-55. There should be periods of dry
conditions closer to I-55, with better chances of more frequent
showers/storms toward Galesburg. As a result, have added some
likely PoPs NW of the IL river, with chance PoPs over toward the I-
55/I-72 corridors.
Gusty south winds to 20mph will help to boost low level moisture and
temps above normal today. High temps will climb into the mid 80s S
of I-72 where more sunshine is expected, while rainy areas towards
Galesburg remain in the upper 70s. Uncomfortable dewpoints in
the mid to upper 60s are expected as well.
Tonight, the next shortwave traveling NE along the warm front will
trigger showers/storms mainly along and NW of the IL river. Have
limited chance PoPs to that area overnight, with slight chances as
far east as I-55. Generally clear conditions should prevail south of
I-72, with variable clouds N of I-72 depending on waves of precip.
Low temps will remain on the mild side, in the upper 50s to low 60s.
&&
.LONG TERM...(Friday through Wednesday)
ISSUED AT 326 AM CDT Thu Oct 6 2016
00Z forecast models take 1007 mb surface low pressure near the OK
panhandle early this morning, northeast and deepens to 1004 mb near
central Lake Superior by 12Z Fri and pull cold front southeast to
near the IL river. Low pressure continues to deepens to around 1000
mb or stronger as it approaches James Bay Canada by 00Z/Sat with
cold front sweeping southeast of the Wabash river by late Friday
afternoon. Models continue to show a narrow band of qpf with the
cold frontal passage on Friday, and continued slight chances of
showers and thunderstorms shifting from nw to se during the day
Friday. Breezy NW winds behind the cold front to usher in much
cooler air. Highs Fri contrast from mid 60s over IL river valley, to
the lower 80s southeast of I-70.
Models linger some qpf over far eastern IL on Friday evening behind
the cold front. Think Ecmwf is has qpf too far west into eastern IL
by I-57 on Friday evening. Leaned toward the further east solutions
of GFS and GEM. Clouds to decrease from nw to se during late Friday
afternoon into Friday evening. Lows Fri night range from the lower
40s nw of the IL river, to the upper 40s over southeast IL.
Sunny skies expected this weekend as large high pressure builds
eastward from the Plains into IL Sat night and the ohio river valley
on Sunday. Saturday to be the coolest day with a weak upper level
trof passing through, with highs in the mid to upper 60s. A bit
milder highs in the lower 70s Sunday as light southerly flow starts
up with high pressure slipping to the east. Seasonably cool lows Sat
night again in the mid to upper 40s.
A semi-zonal upper level flow over Midwest on Sunday to buckle
during early next work week, with upper level ridging into the mid
Atlantic states and upper level trof digging over the Plains. A
northern stream short wave passing eastward through the Great Lakes
Monday night to bring slight chances of showers to northern IL
overnight Monday night including areas from Galesburg to Lacon
north. Discounting ECMWF`s light patches of qpf Tue into Wed morning
over parts of CWA with an approaching weak upper level trof. Large
surface high pressure ridge from New England sw to Texas will cutoff
return of gulf moisture into IL, so this should tend to keep our
area drier. Pleasant highs Monday thru Thursday should be in the low
to mid 70s with lows in the low to mid 50s.
Powerful Category 3 Hurricane Matthew with sustained winds of 115
mph was located near latitude 23.7 North and longitude 76.7 West, or
100 miles SSE of Nassau in the Bahamas, drifting northwest at 10 mph
at 2 am EDT. Hurricane Matthew is forecast by the National Hurricane
Center (NHC) to move NW through the northwest Bahamas today, and
then turn NNW and track near the east coast of Florida tonight thru
Friday evening where hurricane warnings are posted. The hurricane
could strengthen back up to a category 4 with winds of 130 mph as
it approaches the Florida East coast. Stay tuned to forecasts from
the National Hurricane Center (www.nhc.noaa.gov) if you have travel
plans to the the Caribbean, Florida or southeast Atlantic coast.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1155 PM CDT Wed Oct 5 2016
Another predominantly VFR 06Z TAF period is anticipated across
the central Illinois terminals. A disturbance will track west of
the area tonight into Thursday, and will be accompanied by a showers/storms.
However, moisture is lacking and coverage is expected to be too
low to go above a VCTS mention. The more eastern terminals, KDEC &
KCMI, should remain completely dry.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Bak
Area Forecast Discussion
National Weather Service Indianapolis IN
441 AM EDT Thu Oct 6 2016
.UPDATE...
Aviation section updated
&&
.SYNOPSIS...
Issued at 250 AM EDT Thu Oct 6 2016
High pressure over the eastern US will lose its influence on our
region as broad low pressure over the west half of the country
sweeps a weak weather system into the Great Lakes today and across
the Great Lakes and Ohio Valley Friday. High pressure ridging will
follow this weekend into next week with cooler and drier weather.
Rain amounts into Friday night will average less than a quarter inch
with dry weather for much of next week.
&&
.NEAR TERM /Today/...
Issued at 250 AM EDT Thu Oct 6 2016
Issue this period is potential rain in our northwest.
Radar loops, Satellite, and higher resolution models keep current
Illinois convection out of our forecast area tracking toward NW
Indiana and Chicago. Will keep today dry unless radar trends dictate
otherwise.
Temperatures today will run similar to yesterday topping out where
current forecasts are, in the lower to middle 80s.
&&
.SHORT TERM /Tonight through Saturday Night/...
Issued at 250 AM EDT Thu Oct 6 2016
Models again appear in good enough agreement and blend works well.
Tonight...continuation of dry weather as cold front and associated
showers and storms stay well to the west. Current min temperature
forecasts upper 50s to lower 60s still appear reasonable.
Friday and Friday night...cold front with showers/storms will be
approaching but our area will stay dry into early afternoon. Like
the Wednesday system, main energy will be well north with the
surface and upper low centers. Models depict little instability so
thought of scattered light showers, and only slight chance for
thunder, at peak heating, may be best. Shower threat to move from
northwest counties early afternoon to eastern counties Friday
evening.
Limited lift and convergence looks like southern counties should
stay dry.
One more day of warm temperatures Friday with morning sun and warm
advection getting us all back close to or in the 80s one more time.
Saturday and Saturday night...high pressure will have pushed the
cold front, any clouds, and any precipitation, well east of our area
by dawn Saturday. Models all agree on a mostly clear, cool period.
Good mixing and cold advection Saturday will bring some gustiness to
the winds during the day. Current temperature forecasts in agreement
with latest guidance with only minor tweaks needed.
&&
.LONG TERM /Sunday through Wednesday/...
Issued at 217 AM EDT Thu Oct 6 2016
ECMWF keeps mainly zonal to weak SW flow in place aloft during
this period. Meanwhile in the lower levels The ECMWF suggests a
extensive High pressure system in place...stretching from New
England through the midwest to the Deep south. This will result in
dry weather through the period with temperatures at or above
seasonal normals.
Only caveat at this time is a weak short wave that the ECMWF
suggests passes through the flow on Tuesday night into Wednesday.
Low confidence in this features as well as the lack of lower level
organization and lack of moisture. Thus the dry superblend is the
preferred route for now.
&&
.AVIATION /Discussion for the 060900z ind taf update/...
VFR conditions are expected to continue this the next few hours.
Ongoing Tafs in good shape.
Ongoing warm air advection pattern will result in some AC
drifting across the TAF sites. Any TSRA development is expected to
remain well Northeast of Ind...within the better moisture and
isentropic lift as seen within the 310K Isentropic Surface. HRRR
remains to appear over done given radar trends.
Previous Discussion below
(Discussion for 060600Z TAF Issuance)...
Issued at 1145 PM EDT Wed Oct 5 2016
VFR through the period.
High pressure will remain across southern New England to
Tennessee through the period as stationary front over
northern Illinois starts to drift back to the north.
An upper disturbance will produce scattered showers and an
isolated thunderstorm over northern and central Illinois as
well as extreme northwest Indiana towards morning. Will
mention VCSH at KLAF for a few hours after sunrise. But most
of this should remain to the northwest.
For the rest of the period...expect only few-sct CU during the
day and mainly scattered mid/high clouds rest of the period.
Clouds may be broken over northwest sections.
Light southeast winds tonight will become south 7 to 10 knots
by midday Thursday and less than 5 knots Thursday night.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TUCEK
NEAR TERM...TUCEK
SHORT TERM...TUCEK
LONG TERM....PUMA
AVIATION...JH/JP
Area Forecast Discussion
National Weather Service Northern Indiana
330 AM EDT Thu Oct 6 2016
.SYNOPSIS...
Issued at 330 AM EDT Thu Oct 6 2016
Another warm day is expected today with highs near 80 degrees. Warm
and moist conditions could also support a few scattered showers and
storms across northwest Indiana and southwest Michigan today. Mainly
dry conditions are expected overnight with lows around 60 degrees. A
passing cold front will then bring another chance for scattered
showers and storms Friday afternoon and evening. Much cooler weather
expected behind this front with highs on Saturday near 60 degrees
and lows near 40. Temperatures moderate by next week though with dry
conditions persisting.
&&
.SHORT TERM...(Today)
Issued at 330 AM EDT Thu Oct 6 2016
Another morning with some fog concerns (across our north anyway)
given light winds, clear skies, and relatively high surface
dewpoints in wake of exiting pressure trough. Best chances for
widespread/dense fog across central Michigan where more widespread
rain occurred yesterday. Moisture profiles not as favorable in our
CWA and fog so far has been very limited. Therefore, not expecting
much of an impact in our area. Still expect most of the CWA to
remain dry today, save for our northwest counties. Pacific jet
streak and attendant shortwave currently rounding the base of broad
western CONUS trough. Burgeoning area of isentropic ascent ahead of
this wave still looks to remain largely upstream with upper jet axis
and associated baroclinic zone draped over the Upper Midwest. 00Z
NAM12 still suggesting convection currently over western IL on nose
of 40+ kt nocturnal LLJ will push into our CWA though, with some
support for this seen in latest WRF-ARW and NMM. RAP and HRRR are
less supportive, although last few runs have trended further E/SE
with QPF. Underlying synoptic picture is not particularly supportive
either but does show some weak 305K isentropic ascent clipping our
NW counties with warm and moist airmass (surface dewpoints
approaching mid 60s) generating 500-1000 J/kg of SBCAPE in our NW
this afternoon. Given this, along with trends in upstream radar and
hi-res CAM`s, have increased PoP`s for our northwest counties during
the late morning and afternoon. Areas generally along and east of I-
69 still expected to remain dry. Expect a fair amount of clouds
today, especially in the west, but should still reach low 80s in
most areas given thermal profiles very similar to yesterday.
&&
.LONG TERM...(Tonight through Wednesday)
Issued at 330 AM EDT Thu Oct 6 2016
Aforementioned wave will push into the Upper Midwest by late tonight
and send warm front well N/NW of our CWA. Expect generally dry
conditions overnight and into early Friday with lows around 60F.
Cold front will then swing through the area Friday afternoon and
evening. As previously mentioned, best CVA forcing/height falls pass
well north of our area and precip coverage remains in question.
Surface dewpoints will still be near 60F so there could be some
marginal instability at play but lack of deep layer forcing/moisture
will likely keep precip SCT at best. Will probably be very similar
to yesterday actually, with a broken line of convection mainly
across our northern counties. Thunder is possible but will remain
isolated and no strong or severe storms expected.
Weather conditions thereafter will be very benign and dry through
most of next week. Sprawling surface high pressure sets up in wake
of exiting trough and high-latitude zonal flow expected to develop
and persist through most of next week. A few very low chances for
rain next week as weak waves ripple through but chances too low and
exact timing too uncertain for any mention at this point. Chilly
weekend ahead with 850mb temps briefly dropping into the mid single
digits. Expect highs around 60F on Sat but should quickly warm back
to near/slightly above climo next week. Could drop to around 40F in
a few spots Sunday morning given clear skies/light winds but chance
for frost appears low at this point.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 155 AM EDT Thu Oct 6 2016
Primarily VFR conditions save for near daybreak with radiational
fog formation a concern. Greatest risk for visibility restrictions
across northeast Indiana/KFWA vicinity where expansion of early
established BR/FG patch north of airfield at present a concern.
May need to add vcsh/shra mention to later forecasts midday at
KSBN however chances appear too low for inclusion at this time and
anticipate upstream shra motion to back with time/deflect w-nw-n
of airfield.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...AGD
SHORT TERM...AGD
LONG TERM...AGD
AVIATION...Murphy
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Area Forecast Discussion
National Weather Service North Platte NE
339 AM CDT Thu Oct 6 2016
.SHORT TERM...(Today and tonight)
Issued at 311 AM CDT Thu Oct 6 2016
A fairly robust area of frontogenesis will form across the Wrn
Sandhills today. The RAP...GFS and NAM12 all show folded theta e
and deep lift in the DGZ along what is progged to be a rain snow
line. Forecast QPF in this area is 3/4 to 1 inch and this should
fall in 12 hours or less. Thus if the rain changes to snow...1
inch per hour snowfall rates would develop. The RAP shows freezing
levels falling to around 700 feet AGL across the highest
elevations of the Sandhills which are around 4000 feet. Snow
amounts in this area...Srn Garden...Swrn Cherry...Nrn Garden and
Nw Grant counties have been boosted to 4 inches which is close to
the WPC forecast of 2 to 4 inches. Forecast highs in the area are
upper 30s. A multi model super ensemble time series of 19 models
and guidance data sets shows highs below 40 in this area with 7
showing highs of 34.
The NAM12 shows 750mb computed cape of 1500 J/KG south of the rain
snow line. The RAP shows 700 J/KG. No thunder is in the forecast but
radar will be monitored for signs of deep convection.
Cold air will move tonight in the wake to todays storm. A blend of 4
guidance data sets plus bias correction puts lows be 29 across much
of western Nebraska tonight with 32 or less elsewhere. Only Boyd
county is progged to remain above freezing tonight. Frost advisories
and freeze warnings are in place for Friday morning.
.LONG TERM...(Friday through Wednesday)
Issued at 311 AM CDT Thu Oct 6 2016
Upper level ridging will build northward across the central plains
this weekend. A thermal ridge will develop beneath the upper
ridge, with mild to warm conditions expected. Highs both Saturday
and Sunday will be in the 70s. The warmest day of the period will
be Monday, when temperatures nearing 80 degrees are possible. A
cold front will sag south Tuesday into Wednesday, with a bit
cooler conditions across northern Nebraska. At this time the front
does not appear to have much push, and will maintain the 70s
across southern Nebraska.
Despite the warm temperatures, fire weather concerns will generally
remain low, as winds for the most part stay light and only moderately
low relative humidity.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1135 PM CDT Wed Oct 5 2016
VFR category conditions prevail across all of western and north
central NE at the present time with high-end VFR ceilings across
western NE based on latest satellite and sfc plot. Upstream,
similar ceilings are present. Main concerns in the aviation period
deal with the approaching system aloft with impacts to ceilings
and visibility expected late tonight-Thursday. Clouds will
continue to spread into the forecast area from the southwest.
Clouds are expected to lower in the early morning hours with sub-
VFR ceilings spreading from southwest NE to north central NE
approx 4 AM-10 AM CDT with predominantly MVFR ceilings expected.
There remains a concern that ceilings could degrade to IFR at
locations, as hinted by some guidance. We will need to monitor and
adjust if necessary at KLBF and KVTN. Visibilities will see a
reduction attributable to precipitation. Of which, most areas
will see all rain except for in portions of northwest NE. Wherein
northwest NE will see a RASN mix changing to all snow then
changing over to rain mid-late morning. Best chances for snow
will be in western Cherry, Garden, and southeast Sheridan
counties. Current thinking based on latest guidance points to
northwest NE seeing the greatest precipitation amounts with less
amounts towards central NE. Much of the forecast area will see
modest winds develop in the mid-late morning with wind gusts near
20 kts at times.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from 1 AM CDT /midnight MDT/ to 10 AM CDT /9 AM
MDT/ Friday for NEZ005-006-008>010-025>029-037-038-058-059-
069>071.
Freeze Warning from 1 AM CDT /midnight MDT/ to 10 AM CDT /9 AM
MDT/ Friday for NEZ004-022>024-035-036-056-057-094.
&&
$$
SHORT TERM...CDC
LONG TERM...Taylor
AVIATION...ET
Area Forecast Discussion
National Weather Service Marquette MI
512 AM EDT Thu Oct 6 2016
.SHORT TERM...(Today and tonight)
Issued at 511 AM EDT THU OCT 6 2016
WV imagery and RAP analysis indicated a mid/upper level low over se
Saskatchewan and a trough into the sw CONUS resulting in sw flow
through the plains to the wrn Great Lakes. A vigorous upstream
shortwave trough was moving into Colorado. At the surface, swrly
flow prevailed over Upper Michigan between a trough from cntrl
Manitoba to near James bay and a weak ridge from South Dakota into
WI. Satellite and sfc obs showed mainly clear skies over the cwa
with some shallow but dense radiation fog at IMT/MNM/ESC and patchy
high clouds over the east.
Today, After the fog s cntrl burns off this morning, expect mostly
sunny skies over the area with gradually increasing clouds this
afternoon as waa increases ahead of low pressure developing over the
plains. Temperatures will remain well above normal with highs in the
upper 60s to around 70.
Tonight, as the main upstream shortwave lifts from the cntrl plains
to near Lake Superior, strong moisture advection and 300k-310k
isentropic lift will support an expanding area of showers into the
cwa. There still are still model timing differences with the pcpn
arrival, but consensus would bring the highest pops into the cwa
btwn 06z-12z with QPF generally in the 0.25 to 0.50 inch range.
MUCAPE values to around 500 J/Kg will also bring potential for some
embedded tsra.
.LONG TERM...(Friday through Wednesday)
Issued at 452 AM EDT THU OCT 6 2016
Trof currently over roughly the w half of the CONUS will lift ne
over the next few days, leaving a lower amplitude/more zonally
oriented flow to prevail across the CONUS next week. With the
initial trof, shortwave over the southern Rockies early this morning
will lift ne, crossing the Upper Great Lakes on Fri and bringing
shra to the area tonight into Fri. With the passage of this feature,
a much cooler, more typical early Oct air mass, will move into the
Upper Lakes through Sat, generating some lake effect pcpn as temps
fall blow normal. Then, with the development of more zonally
oriented flow in addition to a pair of shortwaves moving across sw
Canada, warming will get underway again on Sun with temps back above
normal for Mon. These 2 waves will bring the next chance of pcpn in
the Mon thru early Wed time period as flow amplifies just a bit
while these waves move along the U.S./Canada border region and the
Upper Great Lakes. The slight amplification will also allow another
cooler air mass to move into the area mid week (temps back to around
normal). Over the last few days, there has been a fairly consistent
signal from the ECMWF/GFS that above normal temps will spread back
into the area late next week as broad troffing over the ne Pacific
into the western CONUS results in wsw flow developing into the Great
Lakes. Per CPC and NAEFS 8-14 day outlooks, it appears this warm
pattern will persist thru the mid month period.
Beginning Fri, shortwave lifting into the Upper Lakes will support
sfc low pres which should be located in the vcnty of the Keweenaw
Peninsula at 12z with trailing cold front into central Upper MI.
Bulk of shra/embedded thunder should be mostly n and e of the area
by 12z. There may still be a few shra/possible thunder over the e
half early until cold front exits. In addition, sct lighter shra
will lingering in the developing cyclonic upslope flow in the wake
of the low, affecting mainly western Upper MI. Bigger story will be
the winds as small, but deepening low pres passes across the area
with strong CAA in its wake. 850mb temp drop is most dramatic across
western Upper MI where 850mb temps fall upwards of 15C in 6hrs. Fast
movement of system will limit period of strongest winds, and
structure of the shortwave is not the classic look of a high wind
producer. Nonetheless, deepening sfc low and strong CAA aiding the
mixing down of 30+kt winds should yield a period of gusty winds over
30mph for much of the area. Translation of 3hr pres rises of 4-8mb
following the low should favor central Upper MI for best isallobaric
wind enhancement. In the end though, favorable west wind direction
and increasing overwater instability will lead to strongest winds
occurring on the Keweenaw. Winds will probably be right near wind
advy criteria of sustained aoa 30mph and/or gusts aoa 45mph. Solid
gales expected for most of Lake Superior. Temps over roughly the w
half will likely not get out of the 40s or will fall blo 50F during
the day. After morning temps as high as the mid 60s over the e,
temps will fall back into the 50s during the aftn.
Fri night into Sat night...combination of 850mb temps falling to -2
to -3C over the relatively warm waters of Lake Superior and an
approaching shortwave along with deeper moisture will support at
least sct lake effect -shra over nw Upper MI and the eastern fcst
area as westerly winds veer northwesterly with time. Not out of the
question that there could be a few snowflakes mixed in late Fri
night/Sat morning over the highest terrain s of the Keweenaw as wet
bulb zero heights fall blo 1500ft. Away from lake effect
shra/clouds, some frost, maybe a freeze, will be possible both
nights if there is not too much cloud cover. Better chance probably
Sat night when winds will be lighter.
Any lake effect shra will end by Sun as high pres passes. Developing
waa/isentropic ascent pattern downstream of shortwave moving across
sw Canada offers some potential of pcpn. However, with the strongest
ascent focused just n of the area later Sun into Sun night, pcpn
looks doubtful here. Lead shortwave and associated sfc low pres will
move across northern Ontario Mon with sfc cold front slowly moving
into the Upper Lakes. Meanwhile, secondary shortwave will follow a
little farther s later Tue. As forcing with this second shortwave
catches up to the slow moving sfc cold front moving across the Upper
Lakes, may see some -shra break out Tue into early Wed.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 140 AM EDT THU OCT 6 2016
MVFR conditions will continue through the end of the TAF period for
KCMX and KSAW. KIWD will drop to MVFR late in the forecast period as
rain moves in and MVFR conditions move in as well. Lower conditions
are expected at all sites after this issuance when rain and lower
vis and cigs quickly move in and develop in the rain.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 511 AM EDT THU OCT 6 2016
After a period of strong sw winds this morning ove the nw portion of
Lake Superior with 20 to 30 knot winds and a few gale gusts to 35
knots,the pressure gradient and winds will weaken for a time this
afternoon and tonight as a low pressure trough develops over the
Upper Lakes ahead of a low pressure wave developing over the cntrl
plains. After this low pressure wave passes late tonight/early Fri
morning, NW winds up to 30 kts with gale force gusts to 35 kts will
develop on Fri. NW winds up to 25 kts will linger into Sat before
diminishing to under 15kt late Sat into Mon as high pres moves
across.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Watch from Friday morning through Friday evening for LSZ243-
244-264>267.
Gale Watch from Friday morning through Friday evening for LSZ162-
241-242-263.
Gale Watch from Friday morning through Friday afternoon for
LSZ245>248.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...Rolfson
AVIATION...07
MARINE...JLB
Area Forecast Discussion
National Weather Service Spokane WA
1054 PM PDT Wed Oct 5 2016
.SYNOPSIS...
A series of upper level disturbances will prolong the cool and wet
weather through the beginning of the weekend. A drying and
slightly warmer break period will develop late this weekend
through Monday...but wet conditions are expected to return by mid
week.
&&
.DISCUSSION...
Evening update to decrease pops for the Cascades and northern
mountains. There is a wave coming into play and clouds are
increasing some but so far nothing is being identified on radar
and HRRR has trend drier over the last few runs. Did not
completely remove showers but trend pops down toward slight
chance. 295K Isentropic ascent across SE WA has been steadily
increasing with clouds starting to fill in via latest satellite.
Light showers should begin to take shape over the next few hours.
/sb
&&
.AVIATION...
06Z TAFS: Cool upper-level trough to remain over the region
through Thur delivering cool and cloudy weather conditions for
much of Ern WA and N ID. Main uncertainty attm is whether stratus
or fog develop tnt. The developing cld deck o/ SE WA is expected
to remain just south of Spokane until morning then make a run to
the north. If precip falls in these locations, I anticipate MVFR
stratus. If the showers never materialize arnd Pullman, ceilings
look to remain VFR with possible sct stratus or patchy fg. Patchy
fg more promising for the NE valleys and briefly at Felts Field
and Moses Lake. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 43 56 46 57 46 61 / 10 30 80 90 60 60
Coeur d`Alene 39 56 45 56 46 57 / 20 40 70 100 60 70
Pullman 42 57 45 57 46 66 / 20 30 40 80 70 40
Lewiston 46 63 49 64 50 72 / 30 30 30 50 40 30
Colville 38 59 43 59 43 59 / 10 30 90 100 60 60
Sandpoint 38 55 41 53 42 53 / 20 60 70 100 70 80
Kellogg 36 52 41 52 43 56 / 20 60 60 100 70 70
Moses Lake 41 65 47 68 45 69 / 10 10 80 20 40 40
Wenatchee 45 65 48 66 50 68 / 10 10 80 10 40 30
Omak 43 64 47 64 47 62 / 20 10 90 30 40 30
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
Area Forecast Discussion...Updated
National Weather Service Billings MT
851 AM MDT Thu Oct 6 2016
.UPDATE...
No updates planned this morning as the current forecast looks to
be in good shape. Upper low over southern Canada continues to
provide a cyclonic flow across the forecast area. Clouds continue
to wrap around this low which will bring a mostly cloudy day,
although some peaks of sun will be possible. The exception will be
far southeast Montana where partly to mostly sunny skies are
expected. A weak disturbance will move over portions of the
forecast area bringing a slight chance for a rain or snow shower,
mainly along and west of a Roundup-Billings-Sheridan line.
Temperatures today will remain well below normal with readings
only in the 40s. Hooley
&&
.SHORT TERM...valid for Tdy and Fri...
Slow-moving upper low now over southern Saskatchewan/Manitoba,
with cyclonic flow and below normal heights over MT. Jet is well
to our south and shortwave energy exists in CO. There are a few
showers near Livingston and McLeod, but otherwise it has been a
quiet night under partly to mostly cloudy skies. Temps have fallen
to or below freezing at some locations, but cloud cover is helping
to keep temps up. As of 3 am Billings sits at 37 degrees.
We will see gradually rising heights today as upper low to our
northeast continues to fill and drift east. The combination of
cyclonic flow aloft, reasonably steep mid level lapse rates and
boundary layer convergent flow will bring isolated-scattered
rain/snow showers again today over our mountains and foothills,
perhaps making it as far east as BIL as the HRRR suggests this
afternoon. Building surface ridge from the north will add to the
low level frontogenesis. Will keep eastern areas dry. Temps today
will be similar to yesterday with highs ranging from the mid 40s
to lower 50s. Any shower activity will decrease through the
evening as flat ridging builds from the west. The potential exists
for freezing temps again tonight, but should note that cloud cover
will likely be a factor again as there is a quick transition to
isentropic ascent ahead of next Pacific shortwave.
Surface ridge will begin its retreat on Friday as we see lee side
troffing develop. This will allow for increased SW winds and
downslope warming, of course, and temps will climb into the 50s to
near 60F. Forcing from Pacific wave will clip our north late
Friday and Friday night, and will keep slight pops to cover this.
JKL
.LONG TERM...valid for Sat...Sun...Mon...Tue...Wed...
Through the weekend things should remain quiet across southern
Montana. Flow will remain zonal, but there will be some weak
energy moving north of the area. While this should bypass most of
the the area, there could be some precipitation in the
northwestern mountains. Otherwise things should remain dry
Saturday and Sunday. Some cloud cover as the energy moves by could
limit temperatures a little.
Monday will be the next chance for some precip for much of the
area. The latest GFS has come more into alignment with a clipper
moving through Monday and Tuesday which will bring some cooler
temperatures and a quick shot at a precip. There is still some
uncertainty on how far west the cold air will make it. Along with
the cooler temperatures, north winds will favor the upslope areas
in the Beartooth and Bighorn Mountains.
After the clipper moves out Tuesday things will be dry for most of
the day Wednesday as riding starts to build into the area.
Thursday another wave of energy will try to push through the area
even with the building ridging, which will give another chance
for some rainfall. Reimer
&&
.AVIATION...
VFR conditions are expected across much of the region today. A
few showers are possible from KBIL to KSHR and west...with best
chances over mountains and nearby foothills. Localized MVFR to IFR
cigs are possible with showers...along with occasional mountain
obscuration today. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
Tdy Fri Sat Sun Mon Tue Wed
-------------------------------------------------------
BIL 049 032/057 044/066 047/074 048/064 043/059 045/067
2/W 11/B 20/B 11/U 11/B 21/B 11/B
LVM 051 031/059 043/067 044/071 045/068 041/062 043/067
3/W 22/W 21/N 11/N 11/U 11/B 11/B
HDN 049 030/057 040/067 044/075 044/064 041/060 044/067
2/W 11/B 11/B 01/U 11/B 21/B 11/B
MLS 048 028/051 039/063 046/073 045/061 041/057 043/065
1/B 01/B 21/B 01/U 11/B 21/B 11/U
4BQ 049 029/056 039/065 044/075 046/068 042/059 044/070
1/B 10/B 11/B 01/U 11/U 11/B 11/U
BHK 046 025/049 033/060 042/071 044/061 039/054 040/064
0/B 00/B 21/B 01/U 11/U 21/B 11/U
SHR 049 026/059 038/066 043/074 044/070 042/059 042/068
2/W 21/B 10/B 01/U 11/U 11/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
AREA FORECAST DISCUSSION
National Weather Service Des Moines IA
714 AM CDT Thu Oct 6 2016
.UPDATE...
Issued at 703 AM CDT Thu Oct 6 2016
There is still a north-south range in model solutions at 12z. The
06z Nam is still bullish to the north with regard to instability
while more recent RAP/HRRR runs are pointing farther south. Those
would be favored solutions at the moment with the current OK-IL
MCS likely making it difficult for too strong of return flow. Even
so the RAP/HRRR solutions show various parameters favorable for
tornadic supercells as far north as an Omaha-Ames line early this
evening.
&&
.SHORT TERM.../Today/
Issued at 358 AM CDT Thu Oct 6 2016
The biggest concern through today will obviously be thunderstorm
trends and severe potential. The current situation has the primary
short wave/PV anomaly passing through the base of the Rockies long
wave trough with models having it reach central NE by 00z. Weak but
broad vertical motion has already spread through much of the Plains
and MO Valley ahead of this feature. This lift has combined with
increasing warm/theta-e advection and 0-2km moisture convergence to
produce fairly widespread thunderstorms from OK into IL ahead of the
maturing surface front. Although the effective shear is fairly high,
the lack of instability has seemed to temper any severe potential
this far north so far.
Looking ahead confidence is high in convection but not the greatest
in the details with a range of solutions. The models are in good
agreement in the larger scale with the aforementioned broad, weak
mid level lift consolidating and strengthening later this afternoon
passing through the Siouxland area into MN by 00z with lower based
forcing through IA. Convection allowing model /CAM/ guidance
suggests linear development with embedded supercells possible in
what is forecast to be very high deep shear along the front/trough
21-00z possibly just reaching western sections of the forecast area,
which makes sense considering the degree of forcing.
The degree of recovery and how this is modulated due to the northern
extent of the surface based instability will be the question. Most
models suggest a SSW-NNE warm sector getting into IA with a triple
point near SW IA by 00z and inverted trough farther north. The
typical conceptual model would suggest the better MLCape/surface
based potential reaches about the same latitude as the triple point
with several counties north of elevated potential. Models vary in
this regard from the MO border to possibly as far north as Highway
20, but consensus would suggest farther south toward the higher SPC
Day 1 probs would be preferred, which is close where the NCAR
Ensemble depicts. All modes of severe weather, including tornadoes
will be possible wherever this favorable MLCape/Cinh can phase with
high shallow and deep shear, SRH and likely adequately low LCLs. If
one set of CAM guidance would be preferred at this point it would be
the op HRRR and ESRL HRRR which place less emphasis on convection
developing from KS into IA this morning.
.LONG TERM.../Tonight through Wednesday/
Issued at 358 AM CDT Thu Oct 6 2016
Thursday night into Friday Morning...
Forecast Confidence... Medium-High
Mesoscale/NSE described in short term portion of this AFD. Long
term will handle conclusion of event. Linear storms continue
racing eastward across CWA. Bunkers right-moving supercell suggest
storm motions in the 50 kt range and Corfidi forward-moving
supercell suggest storm motions in the 40 to 50 kt range. Looking
at the hodograph/upper air profile, this seems reasonable.
Therefore, prolonged heavy rainfall threat seems low. May be
brief heavy downpours, but once line moves through, water should
recede fairly quickly. With sunset, instability will begin to
wane...reducing what hail threat there is. Further, model
consensus, including hi-res and ensembles, showing best forcing
should begin to run east and northeast of the DMX CWA. By 06z Fri,
svr threat should be confined to the eastern portion of the DMX
CWA, and by 09z Fri, the threat looks to be east of our area.
Friday afternoon and beyond...
Forecast Confidence... Medium-High
Large-scale subsidence rapidly moves in Friday afternoon in
association with a well-forecast broad area of high pressure slated
to propagate across the heart of the country this weekend. This will
make clouds difficult to come by this weekend, let alone any rain.
850mb temps of +0C look to barely touch the IA/MN border Saturday
morning. Still have threat for patchy frost across northern Iowa
mentioned for Saturday morning.
By Sunday, the aforementioned high should be near the Ohio Valley
Region, setting up return flow to Iowa. Models trying to pick up
on an upper-level low coming onshore sometime sunday and racing
across the Rockies, impacting the Upper Midwest sometime Monday
into Tuesday. Am not completely confident in this solution yet as
upper low may not be well-captured yet by models. With broad
850-300mb anti-cyclonic flow located over the deep south during
this time period, will be difficult for Gulf moisture to be
transported into Iowa.
Westerly flow aloft highlights next week and points to rather
humdrum weather overall. Extended-range models depict a thermal
ridge builds all week over the intermountain west and eventually may
crash down over Iowa next weekend, bringing 850mb temps in excess of
+20C to Iowa. If this solution pans out, temperatures in the 80s may
be back. Record highs for that time of year are in the mid to upper
80s, so it has happened before.
&&
.AVIATION.../For the 12Z TAFS through 12Z Friday morning/
Issued at 710 AM CDT Thu Oct 6 2016
Patchy MVFR/IFR conditions are in place southeast, including near
KOTM, but they should improve to VFR by late morning. Scattered
showers in VFR conditions are anticipated through the day until
thunderstorms organized along the MO river and move eastward
through IA this evening. There is medium confidence in at least
MVFR with the passage of the storms either due to stratus or
visibilities in heavier rain. For now have noted the MVFR due to
stratus and higher confidence with nothing beyond VCTS for
convection as of yet.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...Small
SHORT TERM...Small
LONG TERM...Kotenberg
AVIATION...Small
Area Forecast Discussion
National Weather Service Hastings NE
640 AM CDT THU OCT 6 2016
.SHORT TERM...(Today and tonight)
Issued at 441 AM CDT Thu Oct 6 2016
Upper air and satellite data showing that southwesterly flow
remains in place across the region early this morning, with low
pressure spinning over south central Canada and another shortwave
disturbance pushing through the central Rockies. At the surface, a
frontal boundary is draped through the southeastern half of the
CWA, splitting up the northeasterly winds to the north and
southeasterly winds to the south. Precip-wise not a lot to talk
about currently across our area, but have had some dense fog
develop across portions of our NC KS counties. RAP has had a
pretty good handle on the evolution, suggesting it`ll be sticking
around for several more hours. Obs/calls to counties showing 1/4
visibilities around, so did issue a dense fog adv through mid
morning.
Precipitation chances will be on the increase this morning, and
continuing through the afternoon/early evening, as the above
mentioned disturbance over the Rockies continues pushing east. One
question is how much of the area will see thunderstorms, vs just
showers. Thanks to warm air/moisture advection via a strong LLJ,
there has been a gradual northward push of instability. Currently
the brunt of that remains across KS, but some models show
affecting at least a few of our east-southeast NE counties this
morning and into the afternoon. To the west, expecting any thunder
would be isolated at best. Most recent run of models aren`t in too
bad of agreement showing near/just after sunrise being when we see
more precip development in our CWA, roughly along the NE/KS state
line. Expecting to see a general east-northeastward shift to
things during the day, with some uncertainty with exactly when we
dry out. Models slowed things down just a touch, so did insert
some PoPs in for this evening.
At the surface, the boundary currently in place doesn`t look to
change much through the morning hours, but as the upper level
disturbance pushes closer, a reinforcing front will start moving
through. Because of this, confidence in temperatures is pretty low.
May end up with quite a gradient from NW to SE. Locations near ODX
may struggle to get out of the lower 50s for highs, across the far
SE (south of the front), there is a wide range in models, some
suggest mid 70s is possible, others top it out in the mid 60s.
Later this afternoon, the placement of this reinforcing cold
front will be of interest, as additional thunderstorm development
(and potential for strong/severe) is expected. Similar to the
other day, it`s be a close call our far eastern fringe, they may
be affected for a brief time, before action pushes off to the
east. Behind the front, expect increased northwest winds, gusting
near 30 MPH at times.
So then once the precipitation chances shift off to the east of
the CWA this evening, focus for tonight then turns to the
potential for frost. Expecting sky cover to diminish, esp after
midnight, and models are in good agreement showing surface high
pressure settling into the area behind the cold front. Not
expecting winds to become completely calm, but look to diminish to
around 5 mph, esp across western portions of the area. With
cooler/drier air also moving in, temps look to really drop off.
Forecast lows are in the 30s CWA- wide, and decided to issue a
Frost Adv for roughly the northwestern half of the CWA. Not out of
the question that additional counties may be added, will let day
crew get another look at model data and make that decision. At
this point went with counties that look to have the best chance
for frost.
.LONG TERM...(Friday through Wednesday)
Issued at 441 AM CDT Thu Oct 6 2016
After some potential frost, especially north, for Friday morning
as a shortwave trough axis on top of a surface high occurs, the
trough moves east and so does the surface high heading into the
weekend, with near to above normal temperatures expected into mid-
week next week as broad upper level ridging occurs. Another cold
front is introduced in conjunction with another shortwave trough
in the Tuesday night/Wednesday time frame and will potentially
give us another round of cool autumn temperatures. Trends are for
this coming in a bit faster, maybe toward Tuesday rather than
Wednesday. Expect highs to reach the 70s for a good chunk of the
forecast between Saturday and Monday, and perhaps even Tuesday,
depending on how fast the cold front arrives.
Our best shot at rain in the long term will be Sunday night as a
low- amplitude shortwave trough traverses the Central Plains and
a strong low-level jet develops ahead of this trough, with perhaps
the best low-level convergence occurring near our neck of the
woods. We will be dealing with a limited amount of moisture more
than likely, so not going crazy with precip chances at this time.
Will keep mention of thunder as the GFS indicates potential for
600+ J/kg MUCAPE, but not anything necessarily spectacular.
&&
.AVIATION...(For the 12Z KGRI/KEAR TAFS through 12Z Friday morning)
Issued at 633 AM CDT Thu Oct 6 2016
Precipitation chances will be on the increase this morning across
the area as an upper level disturbance pushes out of the Rockies.
Models continue to suggest the potential that this activity could
be scattered in nature around the terminal areas, so continued to
keep mention as VC for now. MVFR ceilings remain in the forecast
for a good chunk of the daytime hours, starting mid-morning,
though confidence in timing isn`t the highest. This disturbance
will also usher in a reinforcing frontal boundary today, resulting
in stronger northwesterly winds this afternoon. Gusts near 30 MPH
will be possible. Conditions are expected to improve this evening.
&&
.GID Watches/Warnings/Advisories...
NE...Frost Advisory from 3 AM to 9 AM CDT Friday for NEZ039-040-046-
047-060>062-072>074-082-083.
KS...Dense Fog Advisory until 10 AM CDT this morning for KSZ005>007-
017>019.
&&
$$
SHORT TERM...ADP
LONG TERM...Heinlein
AVIATION...ADP
Area Forecast Discussion
National Weather Service Grand Rapids MI
1110 AM EDT THU OCT 6 2016
LATEST UPDATE...
Update/Marine
.SYNOPSIS...
Issued at 312 AM EDT Thu Oct 6 2016
A southerly flow of mild and moist air will continue into Friday.
Well above normal temperatures are predicted. There will be some s
showers and thunderstorms around as well as the unstable airmass
persist. A cold front pushes through on Friday...with a drier and
cooler airmass moving in behind it for Saturday and Sunday.
&&
.UPDATE...
Issued at 1110 AM EDT Thu Oct 6 2016
Have allowed the dense fog advisory to expire as vsbys have come
up.
Band of showers will continue to spread into the CWA through the
day. Instability will also increase, so expecting some thunder
especially after 18z. Right entrance region of the upper jet was
over northern IL this morning, and will move over Lower MI this
afternoon and evening. 0-6km shear will be around 35 knots so a
few stronger storms will be possible. The steadiest rains should
be NW of a LWA-MOP line, but the best instability will be south of
this line, where localized heavier storms may occur.
&&
.SHORT TERM...(Today through Saturday)
Issued at 312 AM EDT Thu Oct 6 2016
Will keep the dense fog advisory going. Southern locations such as
AZO and BTL have been slow to develop thick fog. The trend in the
HRRR still has dense fog moving into the norther parts of the I94
corridor counties. Elsewhere thick fog was present.
The low level jet triggering the showers and thunderstorms
upstream is forecasted to track into northwest parts of may CWA
today. An unstable airmass will be present. As a result...will
feature the highest POPs today for Ludington to Big Rapids area.
There were some HRRR solutions that track the convection into the
GRR area around 18z. If that ends up happening...higher POPs will
be warranted further south. It still looks like a warm day...but
with convection and clouds rolling in...there is a potential for
the high temperature forecasts to be too warm.
A stronger low level jet takes aim on WI tonight. That convection
may get pushed into my CWA later at night as the cold front
advances eastward through MN and IA. Will keep POPs going to
account for this. Deep layer shear ramps up...as the instability
diminishes. I would not rule out a few strong storms still. Should
be mild night with the main axis of higher PWAT values overhead.
Some locations are likely to stay in the 60s.
Will need to monitor the forecast for Friday. Lots of deep layer
shear around...but only a narrow axis of instability moving
through with the front. It will not take too much instability to
trigger organized convection.
.LONG TERM...(Saturday night through Wednesday)
Issued at 312 AM EDT Thu Oct 6 2016
We have a mostly dry forecast through the long term. Saturday night
will be one of the coolest nights of the season...so far.
Temperatures will likely fall into the 30s across the north central
cwa and some frost is possible in low lying areas. Elsewhere...lows
in the 40s are expected. Then a gradual warming trend that will see
temps climb to the mid to upper 60s by mid week.
Not much chance for pcpn during the period. High pressure over
Ontario will feed cool dry air into the Michigan. A cold front will
approach the state mid week and we may see a shower with it...but
it`s a long way away and the stronger dynamics look to be farther
north in Canada.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 736 AM EDT Thu Oct 6 2016
Low clouds and dense fog will continue to lead to impacts for a
few hours this morning. In some cases...VLIFR will occur. By 14z
most of the fog should have given way to MVFR conditions.
By afternoon...VFR should prevail. Showers and thunderstorms will
be around into tonight as well. These could lead to localized
impacts. Fog should redevelop tonight...but not to the extent as
this morning. MVFR conditions should prevail.
&&
.MARINE...
Issued at 1110 AM EDT Thu Oct 6 2016
Will hoist a small craft advisory for areas north of South Haven
starting late tonight. South winds will increase to 20-25 knots by
then causing waves to build. These winds will shift to the west
Friday morning and northwest by Friday evening at similar speeds.
Will run the advisory through Friday night, but we may need to
extend it into Saturday too, before conditions improve.
&&
.HYDROLOGY...
Issued at 1137 AM EDT Wed Oct 5 2016
No river advisories are in effect and river are either stable or
steadily falling.
Not much has changed in precipitation forecasts over the last
couple of days. We are still on track to see minor rainfall
amounts near Jackson and enough rainfall from Grand Haven to Big
Rapids, northwest to Ludington, to provide the soil a pretty good
soaking. This will come in two main rounds, being late this
afternoon into tonight and again Friday afternoon. The time
between may include a scattered shower or storm with a brief bout
of locally moderate to heavy rain. Given that this will all come
over a three day period, after rivers have fallen, concerns for
flooding are low at this time.
&&
.GRR Watches/Warnings/Advisories...
MI...None.
LM...Small Craft Advisory from 4 AM Friday to 8 AM EDT Saturday for
LMZ845>849.
&&
$$
UPDATE...JK
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...04
AVIATION...MJS
HYDROLOGY...JAM
MARINE...JK
Area Forecast Discussion
National Weather Service Wilmington NC
1159 AM EDT Thu Oct 6 2016
.SYNOPSIS...
Dangerous category 4 hurricane Matthew will move out of the
Bahamas today and move north along the Florida coast overnight.
Matthew will continue to track along the coast to Charleston SC
by Saturday afternoon, before curling sharply offshore to the
east and southeast Saturday night and Sunday while undergoing
a weakening phase. Drier and cooler air will spread across the
Carolinas early next week while Matthew drops south into the Bahamas.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 1159 AM Thursday...A Flood Watch raised for the coast and
coastal interior for anticipated storm totals from Matthew of 7-11
inches Friday through Sunday. The other recent headline change is
hoisting of a `Tropical Storm Watch` for the 0-20 NM waters of NE
SC and SE NC.
For the near term period, nearly unyielding blanket of maritime
stratus continues to stream into NE SC and SE NC. This will
temper our maximums as has been the trend in recent days. For
the most part substantial rainfall will gear up tonight with
minimal QPF expectations today. As convergence strengthens
offshore, showers with increasing rainfall rates will move
onshore after midnight into daybreak Friday.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 300 AM Thursday...Hurricane Matthew will move out of the
Bahamas and approach the Florida east coast Friday. Confidence
becomes lower Friday night into Saturday about how far north
Matthew can make it before turning eastward. In addition to track
questions, there are questions about what Matthew`s wind field and
rainfall distribution will look like given the extreme wind shear
that should be buffeting the storm as it moves north of the
latitude of Savannah, GA. Pending any changes based on the 5 AM
NHC forecast, we are anticipating the storm to follow a clockwise-
curving path off the South Carolina coast, approaching to within
~75 miles of Cape Fear before retreating farther offshore Sunday.
Rainfall intensity should increase dramatically Friday night and
Saturday as strong onshore winds north of Matthew advect in deep
Atlantic moisture. It`s too early to post a Flash Flood Watch for
what is still a 4th and 5th period event, but the real potential for
6-12 inches of rain exists. Given the very wet September we had (12-
19 inches of rain along much of the coast) soils have little ability
to absorb runoff and and rivers are high.
Heavy rainfall may begin to taper off from west to east Saturday
night, although latest ECMWF/GFS model runs suggest rain may
continue into Sunday, especially east of I-95. Wind shear should
begin to tilt the vertical circulation of Matthew Saturday night,
with the GFS showing the 300-500 mb circulation getting pushed well
east of the weakening low-level center. Matthew is so strong that
even a weakening storm will still be capable of producing
significant wind, rain, and coastal impacts through Saturday night.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 400 AM Thursday...While the trend of uncertainty continues
with the forecast track for Hurricane Matthew for the weekend, the
concern of potential threats to the area continues. Per the latest
track from the National Hurricane Center as of 2 AM, the center of
Matthew will be roughly south-southeast of the Cape Fear region
Sunday morning, and potentially continue on a southeast track
through early next week. However, the latest ECMWF 00Z guidance
seems to be hinting at a slightly slower and northward adjustment,
while the GFS is similar, but without the slightly northward
adjustment for the weekend. With that said, expect portions of the
forecast area to still be experiencing gusty winds and precipitation
affects from Matthew on Sunday
Into next week, anticipate fairly quiet conditions to move in on
Monday as Matthew moves farther away and high pressure builds into
the area from the west. A drier and cooler airmass will bring early
fall-like temperatures to the area with high`s in the lower 70`s and
overnight lows in the mid 50`s through mid week. A slight warming
trend to climo temperatures later in the week with high`s in the
mid to upper 70`s.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
As of 12Z...Look for predominately MVFR conditions for much of the
forecast period as high pressure continues to wedge into the region
from the north. Hurricane Matthew will contribute to the pressure
gradient, with northeast winds expected to gust to around 25 kts by
late morning through the afternoon hours. The HRRR model shows
showers coming ashore at ILM this afternoon which seems fairly
plausible, given the decent moisture and low level convergence. The
main effects from the tropical system will not be felt until after
the end of the forecast period.
EXTENDED OUTLOOK...MVFR/IFR due to low clouds/rain,
along with gusty winds, possible Friday through Sunday near the
vicinity of Hurricane Matthew. VFR Monday.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 1159 AM Thursday...The large fetch of easterly winds over
the western Atlantic has maintained seas to 5-8 feet across the
coastal waters with dominant wave periods of 7-9 seconds, and this
to prevail through tonight, perhaps dropping a foot. Showers and
isolated TSTMS will impact the 0-20 NM waters as a coastal front
moves landward.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 300 AM Thursday...Hurricane Matthew and its exact track will
prove instrumental to the conditions we`ll end up experiencing
across the coastal waters. On the latest forecast track from the
National Hurricane Center, tropical storm force winds should develop
along the South Carolina coast Friday night, spreading northward to
encompass the Cape Fear waters Saturday morning. Any deviation in
speed, track, or intensity of Matthew could make huge changes in
wind/wave conditions we`ll experience. The only certainty is that
Matthew will produce adverse marine weather conditions through the
period.
LONG TERM /SUNDAY THROUGH MONDAY/...
As of 400 AM Thursday...Expect hazardous headlines across the waters
on Sunday into early Monday morning as the latest track of Hurricane
Matthew from the National Hurricane Center illustrates the system
offshore of SC around this time. Dangerous and rough water
conditions will already be in place heading into the forecast period
with seas around 10 to 15 ft Sunday morning and near 15 to 25 ft in
the outer waters. At this point, sustained east-northeast winds will
be near tropical storm force with higher gusts through Sunday night.
On Monday, northeast winds around 25 kts will continue, with seas to
near 8 to 10 ft. Will continue to note that the intensity and
strength of Hurricane Matthew remains uncertain, and will become
clearer as the storm nears the east coast in the next few days.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...Flash Flood Watch from late tonight through Sunday afternoon
for SCZ032-033-039-053>056.
Beach Hazards Statement until 8 PM EDT this evening for SCZ054-
056.
NC...Flash Flood Watch from late tonight through Sunday afternoon
for NCZ099-105>110.
Beach Hazards Statement until 8 PM EDT this evening for NCZ106-
108.
MARINE...Tropical Storm Watch for AMZ250-252-254-256.
&&
$$
SYNOPSIS...8
NEAR TERM...MJC
SHORT TERM...TRA
LONG TERM...SGL
AVIATION...DL
Area Forecast Discussion
National Weather Service Lincoln IL
943 AM CDT THU OCT 6 2016
.UPDATE...
Issued at 943 AM CDT Thu Oct 6 2016
Initial batch of heavier showers and thunderstorms has lifted
northeast into north central Illinois after producing 1.5 to 3
inches of rain around the Peoria metro into Woodford County. Radar
mosaics showing precipitation area extends southwest to the
Kansas/Oklahoma border, but lesser amounts of showers/storms
currently near the Mississippi River. Latest HRRR and RAP focus on
additional showers/storms into the afternoon mainly along and
northwest of the Illinois River, although more scattered in
nature. Have sent some updated forecasts to adjust the PoP`s
upward for mainly the morning hours in these areas. Much of
eastern Illinois south of Champaign expected to mainly stay dry.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 326 AM CDT Thu Oct 6 2016
A wave of pre-frontal storms has overspread areas west of I-55 in a
region of warm frontogenesis. A few storms have shown weak rotation
and one report of hail has come in as well. SPC has the marginal
risk in our western counties through 12z/7am, then shifts the focus
farther west for the upcoming Day 1 outlook. Instability params show
MUCAPE values climbing to 2400 J/kg at 18z/1pm for areas N of I-72
with 30kt of Bulk Shear. So would not be surprised to see a few
strong storms during the day today as well. The HRRR and RAP models
are pointing toward continued development of waves of showers and
storms today, mainly W-NW of I-55. There should be periods of dry
conditions closer to I-55, with better chances of more frequent
showers/storms toward Galesburg. As a result, have added some
likely PoPs NW of the IL river, with chance PoPs over toward the I-
55/I-72 corridors.
Gusty south winds to 20mph will help to boost low level moisture and
temps above normal today. High temps will climb into the mid 80s S
of I-72 where more sunshine is expected, while rainy areas towards
Galesburg remain in the upper 70s. Uncomfortable dewpoints in
the mid to upper 60s are expected as well.
Tonight, the next shortwave traveling NE along the warm front will
trigger showers/storms mainly along and NW of the IL river. Have
limited chance PoPs to that area overnight, with slight chances as
far east as I-55. Generally clear conditions should prevail south of
I-72, with variable clouds N of I-72 depending on waves of precip.
Low temps will remain on the mild side, in the upper 50s to low 60s.
.LONG TERM...(Friday through Wednesday)
ISSUED AT 326 AM CDT Thu Oct 6 2016
00Z forecast models take 1007 mb surface low pressure near the OK
panhandle early this morning, northeast and deepens to 1004 mb near
central Lake Superior by 12Z Fri and pull cold front southeast to
near the IL river. Low pressure continues to deepens to around 1000
mb or stronger as it approaches James Bay Canada by 00Z/Sat with
cold front sweeping southeast of the Wabash river by late Friday
afternoon. Models continue to show a narrow band of qpf with the
cold frontal passage on Friday, and continued slight chances of
showers and thunderstorms shifting from nw to se during the day
Friday. Breezy NW winds behind the cold front to usher in much
cooler air. Highs Fri contrast from mid 60s over IL river valley, to
the lower 80s southeast of I-70.
Models linger some qpf over far eastern IL on Friday evening behind
the cold front. Think Ecmwf is has qpf too far west into eastern IL
by I-57 on Friday evening. Leaned toward the further east solutions
of GFS and GEM. Clouds to decrease from nw to se during late Friday
afternoon into Friday evening. Lows Fri night range from the lower
40s nw of the IL river, to the upper 40s over southeast IL.
Sunny skies expected this weekend as large high pressure builds
eastward from the Plains into IL Sat night and the ohio river valley
on Sunday. Saturday to be the coolest day with a weak upper level
trof passing through, with highs in the mid to upper 60s. A bit
milder highs in the lower 70s Sunday as light southerly flow starts
up with high pressure slipping to the east. Seasonably cool lows Sat
night again in the mid to upper 40s.
A semi-zonal upper level flow over Midwest on Sunday to buckle
during early next work week, with upper level ridging into the mid
Atlantic states and upper level trof digging over the Plains. A
northern stream short wave passing eastward through the Great Lakes
Monday night to bring slight chances of showers to northern IL
overnight Monday night including areas from Galesburg to Lacon
north. Discounting ECMWF`s light patches of qpf Tue into Wed morning
over parts of CWA with an approaching weak upper level trof. Large
surface high pressure ridge from New England sw to Texas will cutoff
return of gulf moisture into IL, so this should tend to keep our
area drier. Pleasant highs Monday thru Thursday should be in the low
to mid 70s with lows in the low to mid 50s.
Powerful Category 3 Hurricane Matthew with sustained winds of 115
mph was located near latitude 23.7 North and longitude 76.7 West, or
100 miles SSE of Nassau in the Bahamas, drifting northwest at 10 mph
at 2 am EDT. Hurricane Matthew is forecast by the National Hurricane
Center (NHC) to move NW through the northwest Bahamas today, and
then turn NNW and track near the east coast of Florida tonight thru
Friday evening where hurricane warnings are posted. The hurricane
could strengthen back up to a category 4 with winds of 130 mph as
it approaches the Florida East coast. Stay tuned to forecasts from
the National Hurricane Center (www.nhc.noaa.gov) if you have travel
plans to the the Caribbean, Florida or southeast Atlantic coast.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 651 AM CDT Thu Oct 6 2016
An elongated area of lift south of a developing warm front will
keep chances of showers and storms across the NW half of central
Illinois this morning, and early this afternoon. PIA will see
storm chances continue through around 19z, with BMI seeing precip
end by mid morning, and SPI by 13z-14z. MVFR ceilings will mainly
affect PIA and BMI where stronger showers/storms affect this
morning. Overall, VFR conditions should prevail for the remainder
of this TAF period, as the warm front departs away to the north.
Another surge of showers and storms is forecast for late tonight
in NW Illinois, which could affect PIA late in this TAF period.
Have only included a VCSH for that time frame.
Winds today outside of thunderstorms should prevail from the south
at 10g18kt. After sunset, there are indications that sustained
winds could remain up around 10kt from the south.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
Area Forecast Discussion
National Weather Service Northern Indiana
707 AM EDT Thu Oct 6 2016
.SYNOPSIS...
Issued at 330 AM EDT Thu Oct 6 2016
Another warm day is expected today with highs near 80 degrees. Warm
and moist conditions could also support a few scattered showers and
storms across northwest Indiana and southwest Michigan today. Mainly
dry conditions are expected overnight with lows around 60 degrees. A
passing cold front will then bring another chance for scattered
showers and storms Friday afternoon and evening. Much cooler weather
expected behind this front with highs on Saturday near 60 degrees
and lows near 40. Temperatures moderate by next week though with dry
conditions persisting.
&&
.SHORT TERM...(Today)
Issued at 330 AM EDT Thu Oct 6 2016
Another morning with some fog concerns (across our north anyway)
given light winds, clear skies, and relatively high surface
dewpoints in wake of exiting pressure trough. Best chances for
widespread/dense fog across central Michigan where more widespread
rain occurred yesterday. Moisture profiles not as favorable in our
CWA and fog so far has been very limited. Therefore, not expecting
much of an impact in our area. Still expect most of the CWA to
remain dry today, save for our northwest counties. Pacific jet
streak and attendant shortwave currently rounding the base of broad
western CONUS trough. Burgeoning area of isentropic ascent ahead of
this wave still looks to remain largely upstream with upper jet axis
and associated baroclinic zone draped over the Upper Midwest. 00Z
NAM12 still suggesting convection currently over western IL on nose
of 40+ kt nocturnal LLJ will push into our CWA though, with some
support for this seen in latest WRF-ARW and NMM. RAP and HRRR are
less supportive, although last few runs have trended further E/SE
with QPF. Underlying synoptic picture is not particularly supportive
either but does show some weak 305K isentropic ascent clipping our
NW counties with warm and moist airmass (surface dewpoints
approaching mid 60s) generating 500-1000 J/kg of SBCAPE in our NW
this afternoon. Given this, along with trends in upstream radar and
hi-res CAM`s, have increased PoP`s for our northwest counties during
the late morning and afternoon. Areas generally along and east of I-
69 still expected to remain dry. Expect a fair amount of clouds
today, especially in the west, but should still reach low 80s in
most areas given thermal profiles very similar to yesterday.
&&
.LONG TERM...(Tonight through Wednesday)
Issued at 330 AM EDT Thu Oct 6 2016
Aforementioned wave will push into the Upper Midwest by late tonight
and send warm front well N/NW of our CWA. Expect generally dry
conditions overnight and into early Friday with lows around 60F.
Cold front will then swing through the area Friday afternoon and
evening. As previously mentioned, best CVA forcing/height falls pass
well north of our area and precip coverage remains in question.
Surface dewpoints will still be near 60F so there could be some
marginal instability at play but lack of deep layer forcing/moisture
will likely keep precip SCT at best. Will probably be very similar
to yesterday actually, with a broken line of convection mainly
across our northern counties. Thunder is possible but will remain
isolated and no strong or severe storms expected.
Weather conditions thereafter will be very benign and dry through
most of next week. Sprawling surface high pressure sets up in wake
of exiting trough and high-latitude zonal flow expected to develop
and persist through most of next week. A few very low chances for
rain next week as weak waves ripple through but chances too low and
exact timing too uncertain for any mention at this point. Chilly
weekend ahead with 850mb temps briefly dropping into the mid single
digits. Expect highs around 60F on Sat but should quickly warm back
to near/slightly above climo next week. Could drop to around 40F in
a few spots Sunday morning given clear skies/light winds but chance
for frost appears low at this point.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 700 AM EDT Thu Oct 6 2016
Focus on area of convection across northern IL on nose of 34-40
kt low level jet. Downstream stability and diurnal decay of jet
should allow TSRA to become increasingly sparse with time and will
hold mention to VCTS with a targeted period of predominant -SHRA
late morning into midday. Otherwise anticipate VFR conditions to
prevail. Some concern for Fri am BR formation that later forecast
iterations will assess.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...AGD
SHORT TERM...AGD
LONG TERM...AGD
AVIATION...Murphy
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Area Forecast Discussion
National Weather Service North Platte NE
1049 AM CDT Thu Oct 6 2016
.UPDATE...
Issued at 1049 AM CDT Thu Oct 6 2016
Update to the forecast to account for the recent trends. The
deformation is ongoing across the western and northwestern
Sandhills. Cooling cloud tops evident on the latest IR suggest
an expected convective element to the precipitation. Where this
is occurring, we`ve seen via NEDOR cams that the changeover to
snow has occurred and the snowfall is moderate or heavy. Ground
temperatures are in the mid to upper 50s, so the snow is
struggling to accumulate, except where rates are assumed to be on
the order of 1-2" per hour. Will cap the snow accumulations across
southern Sheridan...western Cherry...Grant and Garden counties at
2.5" with the wording that only under the intense band is where
accumulations are expected. We`ve seen rapid wet bulb cooling, so
will expand the rain snow mix wording to include much of our
northwestern zones.
The KLNX radar is down, we are using the KGLD radar to sample the
convective storms across our southwest.
UPDATE Issued at 636 AM CDT Thu Oct 6 2016
As advertised by the NAM and RAP models...thunderstorms have
formed across Swrn Neb. The models move this activity east
northeast today...generally affecting areas along and south of a
line from Ogallala to Oneill. A new forecast is out for this
feature.
&&
.SHORT TERM...(Today and tonight)
Issued at 311 AM CDT Thu Oct 6 2016
A fairly robust area of frontogenesis will form across the Wrn
Sandhills today. The RAP...GFS and NAM12 all show folded theta e
and deep lift in the DGZ along what is progged to be a rain snow
line. Forecast QPF in this area is 3/4 to 1 inch and this should
fall in 12 hours or less. Thus if the rain changes to snow...1
inch per hour snowfall rates would develop. The RAP shows freezing
levels falling to around 700 feet AGL across the highest
elevations of the Sandhills which are around 4000 feet. Snow
amounts in this area...Srn Garden...Swrn Cherry...Nrn Garden and
Nw Grant counties have been boosted to 4 inches which is close to
the WPC forecast of 2 to 4 inches. Forecast highs in the area are
upper 30s. A multi model super ensemble time series of 19 models
and guidance data sets shows highs below 40 in this area with 7
showing highs of 34.
The NAM12 shows 750mb computed cape of 1500 J/KG south of the rain
snow line. The RAP shows 700 J/KG. No thunder is in the forecast but
radar will be monitored for signs of deep convection.
Cold air will move tonight in the wake to todays storm. A blend of 4
guidance data sets plus bias correction puts lows be 29 across much
of western Nebraska tonight with 32 or less elsewhere. Only Boyd
county is progged to remain above freezing tonight. Frost advisories
and freeze warnings are in place for Friday morning.
.LONG TERM...(Friday through Wednesday)
Issued at 311 AM CDT Thu Oct 6 2016
Upper level ridging will build northward across the central plains
this weekend. A thermal ridge will develop beneath the upper
ridge, with mild to warm conditions expected. Highs both Saturday
and Sunday will be in the 70s. The warmest day of the period will
be Monday, when temperatures nearing 80 degrees are possible. A
cold front will sag south Tuesday into Wednesday, with a bit
cooler conditions across northern Nebraska. At this time the front
does not appear to have much push, and will maintain the 70s
across southern Nebraska.
Despite the warm temperatures, fire weather concerns will generally
remain low, as winds for the most part stay light and only moderately
low relative humidity.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 636 AM CDT Thu Oct 6 2016
MVFR cigs in rain and isolated thunderstorms are expected today
across much of Wrn and Ncntl Neb. IFR and local LIFR are expected
across Sheridan...Cherry...Grant and Garden counties in snow.
VFR is expected to become fairly widespread after 00z this
evening however the NAM and SREF suggest fog late tonight across
the Wrn Sandhills but this is not supported by the statistical
guidance. The forecast is VFR all areas for now.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from 1 AM CDT /midnight MDT/ to 10 AM CDT /9 AM
MDT/ Friday for NEZ005-006-008>010-025>029-037-038-058-059-
069>071.
Freeze Warning from 1 AM CDT /midnight MDT/ to 10 AM CDT /9 AM
MDT/ Friday for NEZ004-022>024-035-036-056-057-094.
&&
$$
UPDATE...Jacobs
SHORT TERM...CDC
LONG TERM...Taylor
AVIATION...CDC
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
619 AM CDT THU OCT 6 2016
.SHORT TERM...(Today and tonight)
Issued at 430 AM CDT Thu Oct 6 2016
The only thing of interest that happened locally was the watching of
a density current drop southeast on the MPX radar. This fine line on
radar was associated with a secondary cold front that worked across
the area. When it went through MSP, the temperature dropped from 56
to 52. The cold front that came through yesterday is down from KC
up to Green Bay, with satellite showing a nice baroclinic leaf
showing up over Colorado to the northwest of a developing surface
low over southeast Colorado. It is these features in Colorado that
we will become acquainted with later this afternoon and evening.
Outside of the 06.00 NAM, which was rendered unusable due to
convective feedback issues from storms it developed this morning
west of Omaha, models generally agree on the surface low following
the front off to our south. This front will come back west some as a
warm front today, with the low coming up from KC this afternoon to
around Eau Claire this evening. We did slow down the onset of precip
this afternoon and followed a blend of the ARW and ESRL-HRRR to time
precip up into the area. We like the idea of there being two areas
of higher higher QPF. One across southeast MN closer to where the
surface low will track. This will be associated with your typical
warm season type forcing...upright instability interacting with
convergence along a surface boundary. The other enhanced area of
precip will fall west of the Twin Cities and be your typical cold
season type precip. Here, it`s slantwise instability interacting
with strong frontogenesis centered around h7 that will produce a band
of enhanced precip. In both enhanced areas, amounts around 0.75" are
expected with 0.25-0.5" amounts more likely outside of these
areas.
.LONG TERM...(Friday through Wednesday)
Issued at 430 AM CDT Thu Oct 6 2016
Cool northwest flow arrives Friday behind the aforementioned
surface low and rain event. Windy conditions should develop by
Friday afternoon with cold advection and a favorable mixing
profile. Forecast soundings suggest we could see gusts between
25-30 MPH during the afternoon. A broken stratus cloud deck will
also be possible across the area both Friday and Saturday -
possibly some light showers or sprinkles on Saturday, although
most locations will remain dry. Warming begins on Sunday when the
flow backs to the south. Eventually a more robust southwest flow
sets in on Monday and temepratures will climb back up near
normal.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 618 AM CDT Thu Oct 6 2016
NAM/RAP/HRRR/GFS all have pretty similar timing on bringing rain in
this afternoon/evening. Followed the HRRR though for timing
things in which is an hour or two faster in bringing in rain than
the NAM/GFS. Surface low looks to go over/near EAU. They will be
closest to the warm sector and have the best shot at seeing TS,
hence that being the only terminal with a TS mention. Based on the
SREF, expect MVFR CIGS to develop at MSP/RWF/STC/RNH in, then
behind the rain shield, with EAU likely dropping to IFR CIGs
overnight.
KMSP...We may see a flash of lightning or two as the rain pushes
in, but at this point, chance is not high enough to warrant
mentioning in the TAF. LAMP guidance looks a bit too optimistic on
CIGS given how close the surface low will pass to MSP, so trended
CIG forecast closer to the NAM.
/OUTLOOK FOR KMSP/
Fri...VFR. Wind WNW 10G20kts.
Sat...VFR. Wind NW 5-10 kts.
Sun...VFR. Wind S 7-10 kts.
&&
.MPX Watches/Warnings/Advisories...
WI...None.
MN...None.
&&
$$
SHORT TERM...MPG
LONG TERM...CLF
AVIATION...MPG
Area Forecast Discussion
National Weather Service Marquette MI
746 AM EDT Thu Oct 6 2016
.SHORT TERM...(Today and tonight)
Issued at 511 AM EDT THU OCT 6 2016
WV imagery and RAP analysis indicated a mid/upper level low over se
Saskatchewan and a trough into the sw CONUS resulting in sw flow
through the plains to the wrn Great Lakes. A vigorous upstream
shortwave trough was moving into Colorado. At the surface, swrly
flow prevailed over Upper Michigan between a trough from cntrl
Manitoba to near James bay and a weak ridge from South Dakota into
WI. Satellite and sfc obs showed mainly clear skies over the cwa
with some shallow but dense radiation fog at IMT/MNM/ESC and patchy
high clouds over the east.
Today, After the fog s cntrl burns off this morning, expect mostly
sunny skies over the area with gradually increasing clouds this
afternoon as waa increases ahead of low pressure developing over the
plains. Temperatures will remain well above normal with highs in the
upper 60s to around 70.
Tonight, as the main upstream shortwave lifts from the cntrl plains
to near Lake Superior, strong moisture advection and 300k-310k
isentropic lift will support an expanding area of showers into the
cwa. There still are still model timing differences with the pcpn
arrival, but consensus would bring the highest pops into the cwa
btwn 06z-12z with QPF generally in the 0.25 to 0.50 inch range.
MUCAPE values to around 500 J/Kg will also bring potential for some
embedded tsra.
.LONG TERM...(Friday through Wednesday)
Issued at 452 AM EDT THU OCT 6 2016
Trof currently over roughly the w half of the CONUS will lift ne
over the next few days, leaving a lower amplitude/more zonally
oriented flow to prevail across the CONUS next week. With the
initial trof, shortwave over the southern Rockies early this morning
will lift ne, crossing the Upper Great Lakes on Fri and bringing
shra to the area tonight into Fri. With the passage of this feature,
a much cooler, more typical early Oct air mass, will move into the
Upper Lakes through Sat, generating some lake effect pcpn as temps
fall blow normal. Then, with the development of more zonally
oriented flow in addition to a pair of shortwaves moving across sw
Canada, warming will get underway again on Sun with temps back above
normal for Mon. These 2 waves will bring the next chance of pcpn in
the Mon thru early Wed time period as flow amplifies just a bit
while these waves move along the U.S./Canada border region and the
Upper Great Lakes. The slight amplification will also allow another
cooler air mass to move into the area mid week (temps back to around
normal). Over the last few days, there has been a fairly consistent
signal from the ECMWF/GFS that above normal temps will spread back
into the area late next week as broad troffing over the ne Pacific
into the western CONUS results in wsw flow developing into the Great
Lakes. Per CPC and NAEFS 8-14 day outlooks, it appears this warm
pattern will persist thru the mid month period.
Beginning Fri, shortwave lifting into the Upper Lakes will support
sfc low pres which should be located in the vcnty of the Keweenaw
Peninsula at 12z with trailing cold front into central Upper MI.
Bulk of shra/embedded thunder should be mostly n and e of the area
by 12z. There may still be a few shra/possible thunder over the e
half early until cold front exits. In addition, sct lighter shra
will lingering in the developing cyclonic upslope flow in the wake
of the low, affecting mainly western Upper MI. Bigger story will be
the winds as small, but deepening low pres passes across the area
with strong CAA in its wake. 850mb temp drop is most dramatic across
western Upper MI where 850mb temps fall upwards of 15C in 6hrs. Fast
movement of system will limit period of strongest winds, and
structure of the shortwave is not the classic look of a high wind
producer. Nonetheless, deepening sfc low and strong CAA aiding the
mixing down of 30+kt winds should yield a period of gusty winds over
30mph for much of the area. Translation of 3hr pres rises of 4-8mb
following the low should favor central Upper MI for best isallobaric
wind enhancement. In the end though, favorable west wind direction
and increasing overwater instability will lead to strongest winds
occurring on the Keweenaw. Winds will probably be right near wind
advy criteria of sustained aoa 30mph and/or gusts aoa 45mph. Solid
gales expected for most of Lake Superior. Temps over roughly the w
half will likely not get out of the 40s or will fall blo 50F during
the day. After morning temps as high as the mid 60s over the e,
temps will fall back into the 50s during the aftn.
Fri night into Sat night...combination of 850mb temps falling to -2
to -3C over the relatively warm waters of Lake Superior and an
approaching shortwave along with deeper moisture will support at
least sct lake effect -shra over nw Upper MI and the eastern fcst
area as westerly winds veer northwesterly with time. Not out of the
question that there could be a few snowflakes mixed in late Fri
night/Sat morning over the highest terrain s of the Keweenaw as wet
bulb zero heights fall blo 1500ft. Away from lake effect
shra/clouds, some frost, maybe a freeze, will be possible both
nights if there is not too much cloud cover. Better chance probably
Sat night when winds will be lighter.
Any lake effect shra will end by Sun as high pres passes. Developing
waa/isentropic ascent pattern downstream of shortwave moving across
sw Canada offers some potential of pcpn. However, with the strongest
ascent focused just n of the area later Sun into Sun night, pcpn
looks doubtful here. Lead shortwave and associated sfc low pres will
move across northern Ontario Mon with sfc cold front slowly moving
into the Upper Lakes. Meanwhile, secondary shortwave will follow a
little farther s later Tue. As forcing with this second shortwave
catches up to the slow moving sfc cold front moving across the Upper
Lakes, may see some -shra break out Tue into early Wed.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 746 AM EDT THU OCT 6 2016
VFR conditions will continue through this evening. Conditions are
expected to drop quickly to IFR/LIFR overnight as rain spreads
across Upper Michigan and southerly flow brings abundant low level
moisture across the area.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 511 AM EDT THU OCT 6 2016
After a period of strong sw winds this morning ove the nw portion of
Lake Superior with 20 to 30 knot winds and a few gale gusts to 35
knots,the pressure gradient and winds will weaken for a time this
afternoon and tonight as a low pressure trough develops over the
Upper Lakes ahead of a low pressure wave developing over the cntrl
plains. After this low pressure wave passes late tonight/early Fri
morning, NW winds up to 30 kts with gale force gusts to 35 kts will
develop on Fri. NW winds up to 25 kts will linger into Sat before
diminishing to under 15kt late Sat into Mon as high pres moves
across.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Watch from Friday morning through Friday evening for LSZ243-
244-264>267.
Gale Watch from Friday morning through Friday evening for LSZ162-
241-242-263.
Gale Watch from Friday morning through Friday afternoon for
LSZ245>248.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...Rolfson
AVIATION...JLB
MARINE...JLB
Area Forecast Discussion
National Weather Service Mount Holly NJ
945 AM EDT Thu Oct 6 2016
.SYNOPSIS...
High pressure over New England will build down into the mid-
Atlantic through Friday. A cold front will move through the area
later Saturday as Hurricane Matthew tracks near the coast of the
Southeastern states. A large area of high pressure will then build
in later in the weekend and the first half of next week, which
should keep the hurricane well to our south.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Surface high pressure was located over the Northeast and mid-
Atlantic states. Large-scale subsidence will strengthen over the
forecast area today owing to the ridge building that will occur
aloft.
Similar to yesterday, river valley fog was present this morning
with moisture trapped beneath the subsidence inversion. We issued
a SPS for locally dense fog earlier this morning in the river
valleys of northeastern PA and northwestern NJ but the fog should
steadily dissipate later this morning.
There was also some marine stratus near the coast, but compared
to yesterday, the bulk of the low clouds were located farther
inland across southeastern PA and eastern MD. Do not expect the
stratus/stratocu to be quite as extensive/persistent as it was
yesterday since onshore flow will be weaker today and the marine
layer will have more difficulty being sustained over land as a
result. The setup today will be more favorable for drier air
aloft to mix downward into the boundary layer, helping to erode
the low clouds from north to south through the first half of the
afternoon. This concept is supported by the latest HRRR, RAP and
NAM forecast soundings.
Compared to yesterday, forecast high temperatures will generally 1-
3F degrees warmer. Highs in the lower to mid 70s will be commonplace
today except cooler (mid to upper 60s) in the mountains and along
the coast.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
High pressure is forecast to continue influencing our weather for
tonight. We are expecting a mostly clear sky and a light and
variable wind. Patchy valley fog may form again in our northern
counties.
Low temperatures should be mostly in the 40s in the north and in
the lower to middle 50s elsewhere.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
High pressure over New England will remain in place as low
pressure over Ontario moves eastward, bringing a cold front with
it.
At the same time, Hurricane Matthew will be moving close to the
Florida Coast.
We should be enjoying another beautiful fall day, with dry
weather and abundant sunshine. By later Friday, clouds will
increase as the front approaches and moisture from the south
increases as well.
On Saturday, Matthew will be close to the sern CONUS coast and
the aforementioned cdfnt will be moving across our area. Rain
chances will increase during the day before decreasing in the
evening. It is psbl, that some moisture from Matthew could get
pulled into southern and eastern portions of the area but overall
impacts from the storm shud be minimal.
Matthew is still expected to take an eastward turn somewhere off
of South Carolina and whatever minimal impacts to our area should
be done with after Saturday/Saturday night except for elevated
seas.
High pressure will then build in behind the cfp and be the
dominant wx feature for the first half of next week. Expect dry
and pleasant wx. as the high moves back over New Eng. With a nely
flow establishing itself again, more cloud cover is psbl by Tue.
Temps look to be around seasonal for most of the extendd after
Fri.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
MVFR ceilings has lingered into the mid morning at ACY and
ILG...and it may even return to MIV briefly late this morning.
The stratus has already eroded farther north, including at PHL.
Expect gradual improvement to VFR across the southern terminals
midday or early afternoon.
The wind should remain light and variable at KRDG and KABE. A
light northeast to east wind is expected for KTTN, KPNE, KPHL,
KILG, KMIV and KACY for today with a light and variable wind
forecast for tonight.
OUTLOOK...
Fri...Mainly VFR. Clouds should increase later Fri, which could
result in MVFR cigs. Moderate confidence.
Sat...MVFR with lcl IFR Sat with SHRA and cfp late Sat. Any low
conditions should improve to VFR Sat night. Moderate to high
confidence. wind becoming nw after cfp
Sun...VFR. High pressure. High confidence. NW wind increase to 10
to 15 kts with gusts to 25 kts.
Mon...VFR. High confidence.
&&
.MARINE...
High pressure will continue to influence the coastal waters of
New Jersey and Delaware for today and tonight. A northeast wind
should favor the 10 to 18 knot range.
Wave heights on our ocean waters are anticipated remain around 4
to 6 feet. As a result, we will keep the Small Craft Advisory in
place.
Waves on Delaware Bay should favor the 1 to 3 foot range,
possibly reaching 4 feet near the mouth of the bay.
OUTLOOK...
Hurricane Matthew is anticipated to remain well to our south
through Monday.
Fri...While wind will remain below SCA criteria, the persistent
nely flow will keep elevated seas and we will be looking at
prolonged SCA conds. SCA will likely need to be extended further.
Sat through Mon...A cold front moves through later Sat with
Hurricane Matthew remaining well to our south. While the pressure
gradient should tighten behind the front, the positioning of the
hurricane will determine how strong the winds may get. It appears
that the wind does not reach gale force, however gusts around 30
kts are psbl on Sun and gales can not be ruled out. Wind shud
diminish Sunday night, but seas will remain elevated into Mon.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory for hazardous seas until 6 PM EDT Friday
for ANZ452>455.
Small Craft Advisory for hazardous seas until 8 PM EDT this
evening for ANZ450-451.
&&
$$
Synopsis...Nierenberg
Near Term...Klein
Short Term...Iovino
Long Term...Nierenberg
Aviation...Iovino/Klein/Nierenberg
Marine...Iovino/Nierenberg
Area Forecast Discussion...UPDATED
National Weather Service Shreveport LA
Issued by National Weather Service Jackson MS
1031 AM CDT Thu Oct 6 2016
.UPDATE...No major adjustments were made to the forecast. Hourly
temp/dewpoint/sky grids were tweaked based on current trends.
&&
.DISCUSSION...The low stratus deck which developed early this
morning has almost completely eroded over our eastern TX counties,
with just a small area hanging on along the Red River west of the
AR/TX border. Sky cover should continue to decrease through the day
as the southern end of a surface ridge axis continues to hold sway
across the ArkLaTex. A few runs of the HRRR this morning have
suggested a few showers developing near the western border of the
CWA this afternoon, but a pocket of somewhat drier air will move
westward across the area through the day, with PW progged to fall
below an inch in some areas. Thus, we will keep POPs out of the
forecast for today. /DL/
&&
.PREV DISCUSSION... /issued 449 AM CDT Thu Oct 6 2016/
The morning 11-3.9u satellite imagery this morning indicates low
stratus developing over Ecntrl TX...near and W of a TYR to LFK
line...with a sct cu field having also developed over portions of
extreme SW AR/SE OK and E TX just E of the stratus field.
However...based on the last few sfc obs...have already begun to see
slightly drier air begin to build W across Scntrl AR/NE LA along the
sfc ridge axis extending NE across the TN Valley into New England. The
stratus should not develop much farther E this morning into E TX than
where it is developing now...with the drier air associated with the
sfc/attendant H850-700 ridge continuing to mix slowly W into extreme
SW AR/E TX this afternoon. Given this...have maintained a pop-free
forecast for the region today...with max temps climbing into the lower
90s areawide...some 7-10+ degrees above normal. These temps should
remain shy of record high temp territory...although temps should cool
off a bit quicker this evening given the slightly drier air advecting
in from the E.
Still watching the broad upper trough over the Great Basin this
morning...which will advance E into the Rockies this afternoon...before
emerging out into the Cntrl Plains this evening. This trough will
reinforce a cold front SE across much of OK/NW TX tonight...with
sct/numerous convection expected to develop tonight near and behind
the front. The short term progs continue to suggest the front just NW
of the forecast area by 12Z Friday...although the frontal convection
should be in the process of weakening given the loss of frontal
forcing once sfc winds become N ahead of the front...the attendant
shortwave trough lifts NE away from the area...and the much drier air
mass that should be residing in place. However...it/s possible that
the organized convection that develops tonight may produce a mesoscale
bndry which accelerates just out ahead of the front late...which may
result in isolated elevated convection affecting the far Wrn sections
of E TX/SE OK/adjacent SW AR. Have maintained slight chance pops for
McCurtain/Red River Counties late...but extended slight chance pops
farther S for areas mainly W of a TYR to OSA to DEQ line.
However...given the potentially elevated nature of this decaying
convection...QPF amounts will remain very light.
Despite the elevated cloud cover spilling E ahead of the
front/associated shortwave...could still see some compressional
heating occur Friday afternoon ahead of the shallow front...as it
slows its SEward progress in response to the higher terrain of the
Ouachitas of SE OK/Wrn AR. It still appears that a widespread swath of
lower 90s will again be reached Friday afternoon over portions of
Lower E TX into much of N LA...still just shy of record high temp
territory. Should finally see the cooler and drier air slowly settling
S into the region Friday evening/night...returning temps back to near
normal but also ushering in much drier air in its wake. Could see an
enhanced fire danger develop Saturday afternoon over SE OK/SW AR and
possibly portions of extreme NE TX as min RH/s fall to near/below
30%...and NNE post-frontal gradient winds of 10-15kts continue in wake
of the fropa across the already dry areas that haven/t see much
appreciable rain in the last month plus. However...the fire danger
should ease slightly by Sunday as the post-frontal winds weaken as sfc
ridging builds Swd into the region from the OH Valley.
Both the GFS/ECMWF continue to suggest that abnormally high 588-591
dam ridging at H500 /for this time of year/ developing over much of
TX Saturday morning...before expanding E across our region Saturday
afternoon through Sunday. This increased subsidence should result in a
gradual compressional warming of our air mass...with max temps
returning back above normal by early next week even as the ridge
shifts farther E along the Gulf Coast. Both progs also suggest a
subtle shortwave also translating E across the Srn Plains/Lower MS
Valley late Monday into Tuesday...but perhaps only some cirrus is
expected given the the lack of any low/mid level return flow. Sfc
ridging will also remain in place over the region through much of next
week...maintaining the very warm afternoons but cool nights through
the period. Unfortunately...no rain is in sight through the extended
and even into the start of the third week of October...which will only
result in an expansion of drought conditions across the region.
Prelims to follow below...
15
&&
.AVIATION... 12Z TAF Discussion.
Areas of dense fog have begun developing in lgt winds and clear
skies, across southern portions of the area, including both KLFK
and KMLU where vsbys recently fell to 1/4 sm. Low mvfr to ocnl ifr
stratus also movg nwd across ne TX, affecting KTYR and likely KGGG
as well. Isold cumulus clouds this aftn with SKC possible further
east over KMLU and KELD. Some patchy fog possible again late
tonight, although stronger ridging may keep low stratus away from
ne TX. Mostly se wind 5 to 10 kts expected this aftn./VII/.
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 92 64 92 63 / 0 0 10 10
MLU 92 62 92 61 / 0 0 0 0
DEQ 90 62 84 56 / 10 10 20 10
TXK 90 64 88 58 / 0 10 10 10
ELD 90 59 89 58 / 0 0 0 10
TYR 91 67 88 62 / 10 10 20 10
GGG 91 64 90 62 / 10 0 10 10
LFK 91 66 92 64 / 10 0 0 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
JAN/SHV
Area Forecast Discussion
National Weather Service Lincoln IL
253 PM CDT THU OCT 6 2016
.SHORT TERM...(This evening through Friday)
ISSUED AT 245 PM CDT Thu Oct 6 2016
Precipitation shield tracking northeast out of Missouri has been
shrinking over the last couple hours, with associated showers mainly
west of the Illinois River. However, an area of convection has
recently started to fire along the I-55 corridor. Main feature will
be later in the night though, as the cold front works its way
eastward. Latest HRRR shows main area of showers and thunderstorms
from southwest Wisconsin into southwest Missouri at midnight, but on
a weakening trend, and other high-resolution models show a similar
trend as the precipitation pushes into central Illinois. Have
largely limited the overnight PoP`s to areas along and west of the
Illinois River, and east of there to the Indiana border and north of
I-70 Friday morning into early afternoon.
The front itself should be near the Indiana border by midday,
resulting in a large temperature gradient across the forecast area.
Highs in the 70s still expected from about I-57 eastward with a few
80 degree readings near the Wabash Valley, while low-mid 60s prevail
from I-55 west.
&&
.LONG TERM...(Friday night through Thursday)
ISSUED AT 245 PM CDT Thu Oct 6 2016
500 mb trof axis forecast to shift to our east Friday night taking
any lingering threat for showers to our east early in the evening.
The upper flow will then transition more to a zonal flow into a good
portion of next week bringing mainly dry conditions with temperatures
slightly above normal for the second week of October. It appears the
coolest temperatures this period will be on Saturday when early morning
lows drop into the low and mid 40s with afternoon highs mainly in the
upper 60s. After that, we look for temperatures to rise back into the 70s
starting on Sunday and the continuing into the new work week.
As we head into the second half of the week, medium range models suggest
a trof will shift east into the Midwest bringing a front across the region.
However, moisture appears to be rather limited ahead of this feature, as a
result, will only be carrying low chance POPs for isolated showers ahead
of the trof Wednesday night.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1222 PM CDT Thu Oct 6 2016
Earlier patches of IFR ceilings near KPIA have been lifting
recently as the initial rain areas move northeast and dissipate. A
larger area of showers continues southwest along the Illinois
River into Missouri and is moving northeast, but is dissipating
with time. Have limited afternoon thunder mention to KPIA/KSPI for
a few hours from about 20-23Z. Additional storms are possible as a
cold front moves in from the west late in the night, but currently
thinking that the storm potential will be waning as the front
approaches, and will leave out any VCTS mention at this time.
However, the front will be bringing a period of MVFR ceilings with
it for about 2-3 hours Friday morning. Have held off mention at
KCMI on this for now since conditions may be improving by the time
the front gets that far east, but have mentioned at other TAF
sites.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Geelhart
LONG TERM...Smith
AVIATION...Geelhart
AREA FORECAST DISCUSSION
National Weather Service Northern Indiana
222 PM EDT Thu Oct 6 2016
.SYNOPSIS...
Issued at 223 PM EDT Thu Oct 6 2016
Dry conditions are expected overnight with lows around 60.
A passing cold front will then bring another chance for scattered
showers and isolated thunderstorms Friday afternoon and evening.
Much cooler weather is expected behind this front with highs on
Saturday near 60 degrees and lows near 40. Temperatures moderate
by next week though with dry conditions persisting.
&&
.SHORT TERM...(This Evening through Friday)
Issued at 223 PM EDT Thu Oct 6 2016
Composite outflow from decaying convective complex that shifted
out of ne IL this morning firing isolated storms from here ne.
Better near term focus immediately upstream over ern IL within
area of enhanced sfc convergence and increasing cape. Prior hrrr
solutions along with 12Z SPC NNM initiate storms in this area this
aftn which then tracks ne into srn MI. Prior update followed this
idea and held.
Otherwise dry tonight into Fri am as dynamical focus shifts west
along approaching cold frontal boundary extending southward of
disturbance lifting up across the wrn lakes. Essentially slowed w-e
progression of pops Fri versus previous fcst. Best implied low
chance timed with peak diurnal destablization Fri aftn cntrl/ern IN
zones.
&&
.LONG TERM...(Friday Night through Thursday)
Issued at 223 PM EDT Thu Oct 6 2016
Brief but modest post frontal cold advection wraps in Sat
followed by rapid moderation thereafter as high zonal flow
develops across the Conus. Mos guidance temps have oscillated
somewhat last several cycles with latest blends looking a bit
underdone dys 5-7.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 137 PM EDT Thu Oct 6 2016
Low confidence in TAF`s at KSBN with moderate to high in VFR
conditions persisting at KFWA. Morning shower/isol storm activity
has moved NE of KSBN with additional showers west of the site,
where they are expected to remain. Area of focus will be from
east-central IL back into Missouri where hi res models suggest
additional development is possible. With lack of strong signals,
will stick close to previous forecast and amend if convection does
develop. Any activity should generally remain west of KFWA but
will need to at least monitor remnant outflow boundary into Noble
county that was sparking isolated showers/storms. Believe this
will remain NW of the site and not pose an issue at this time.
Fog potential does exist tonight but again confidence low in
impacts on TAF sites so will defer for now.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...T/AGD
SHORT TERM...T
LONG TERM...T
AVIATION...Fisher
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Area Forecast Discussion
National Weather Service Omaha/Valley NE
259 PM CDT THU OCT 6 2016
.SHORT TERM...(tonight through Sunday)
Issued at 242 PM CDT Thu Oct 6 2016
As expected, a warm front has lifted northward from KS today, now
located across southeast NE through central IA. Conditions have
become very unstable along/south of the boundary with CAPE values
ranging from 500-1500 J/kg and effective shear 50-60 knots.
Additional breaks in the overcast should help destabilize the
atmosphere along and south of the boundary, thus a tornado watch
was just issued that goes through 02z. Latest HRRR model runs
suggest that as the upper impulse moves in from the high plains,
storms will begin to intensify and move in from the west by 4-5
pm then quickly race eastward through the early evening. A couple
of thoughts here, we will be able to cancel counties out of the
tornado watch from west to east much sooner than 02z. Also, the
better tornado threat appears to be along the frontal boundary, in
southeast NE and southwest IA. Areas up to I80, on the northwest
side of the front, including the LNK and OMA metro areas may still
see storms with large hail potential, but the tornado threat
appears a little lower there.
After the rain and severe weather moves out this evening, we
should see clearing skies, and colder air moving in from the west.
Indeed, western NE is seeing snow, and while we won`t see that
here, we will see the cooler temperatures. Lows tonight dip into
the lower to mid 30s for portions of eastern NE. Thus a frost
advisory was issued for several counties. Would not be surprised
to see a few favored locations hit 32 for an hour or two, but not
widespread enough to issue a freeze warning.
After a cool day Friday with highs in the lower 60s, we should
see temps rebound into the lower 70s for Saturday and Sunday with
dry weather expected as zonal flow develops across the Plains.
.LONG TERM...(Sunday night through Thursday)
Issued at 242 PM CDT Thu Oct 6 2016
Another weak wave moves onto the Plains late Sunday night into
Monday which brings another chance of storms. Dry Tuesday with
zonal flow. Another weak wave and associated cool front moves in
on Tuesday night into Wednesday. GFS is a little further south,
but the new 12Z EC is a little further north. Have precip chances
Wednesday along the KS/NE border, but may have to shift those
northward if models continue to trend further north.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1228 PM CDT Thu Oct 6 2016
Initial round of convection ahead of the warm front should
continue to lift northeast through 19Z or so with additional
storms developing between 20 and 21Z as cold front moves into
the area. KOMA and KLNK most likely to experience a period of
storms during this time. IFR cigs and vsbys also expected with
the storm activity through at least 00z with local LIFR cigs
possible 00Z to 06Z. VFR conditions then develop across the area
after 06Z.
&&
.OAX Watches/Warnings/Advisories...
NE...Frost Advisory from 3 AM to 9 AM CDT Friday for NEZ011-012-
015>018-030>033-042-043-050-065-078.
IA...None.
&&
$$
SHORT TERM...DeWald
LONG TERM...DeWald
AVIATION...Fobert
Area Forecast Discussion
National Weather Service Norman OK
248 PM CDT THU OCT 6 2016
.DISCUSSION...
A few storms have formed this afternoon near the Kansas and Oklahoma
border along and north of an outflow boundary. Farther west, a
few weak radar returns in western Oklahoma are associated
with increasing cloud cover & along an 9-85h moisture gradient.
Several HRRR runs develop storms across southwest/west central
Oklahoma this afternoon with increasing coverage as storms move
eastward through the early evening. Additional storms are expected
to form along a cold front in northwest/north central Oklahoma by
early evening.
35-40 kts of deep layer shear and moderate to high instability should
result in several severe storms, with the best chance during the
late afternoon and early evening. The best tornado
potential appears to be across far north central Oklahoma/southern
Kansas along and near a retreating outflow boundary (back winds &
lower LCL).
Storms will continue to form along a cold front during the evening
and overnight with a risk of hail and damaging winds. Showers
and storms may linger for several hours behind the surface front
as elevated instability will be around 500 J/KG.
Showers and storms will clear southern Oklahoma and north Texas by
mid to late Friday morning.
Showers and thunderstorm chances will increase Sunday into Monday
as a trough lifts across the central Plains.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 50 65 45 73 / 80 0 0 0
Hobart OK 51 65 44 72 / 70 10 0 0
Wichita Falls TX 55 67 48 75 / 90 30 0 0
Gage OK 44 66 40 75 / 10 0 0 0
Ponca City OK 48 66 40 74 / 80 0 0 0
Durant OK 60 70 53 79 / 90 30 0 0
&&
.OUN Watches/Warnings/Advisories...
OK...Flood Watch until midnight CDT tonight for OKZ007-008-012-013-
020.
TX...None.
&&
$$
Area Forecast Discussion
National Weather Service Seattle WA
345 PM PDT Thu Oct 6 2016
.SYNOPSIS...A low pressure center will move eastward across
southern Vancouver Island early Friday morning. Widespread rain
and windy conditions will precede the low over western Washington
tonight. After a brief break later Friday, another wet system
will settle over the area this weekend. Drier weather will prevail
for a short time around Monday night and Tuesday, followed by a
stormy pattern returning around next Wednesday.
&&
.SHORT TERM...Watching with interest the developing eastward-
moving surface low center near 48N 131W. A warm front extends
southeast from the low center, accompanied by widespread rain and
increasing south-southeast pressure gradients. Widespread rain
has already spread onto the coast and will easily reach the
interior over the next 1-3 hours. Rainfall will be intense at
times, with 0.2" to 0.4" per hours for the coast and parts of the
interior lowlands. Over the southeast Olympic Mountains, the 21z
HRRR shows a one-hour rainfall peaking near 0.6" around 05z.
Thankfully, this is a progressive weather system, so duration for
such rainfall intensities will only last for a couple of hours.
Appears the Skokomish River will survive without going over the
revised flood stage of 17.0 feet.
In the North Cascades, snow levels near 6000 feet will translate
to moderate to heavy snow above 6000 feet (see Special Weather
Statement). Expecting 6 to 12 inches tonight over the high country
from the Glacier Peak area on north. This will not affect any of
the paved highways over the passes, but folks should be prepared
for snow tonight in the high country, for example along the
Pacific Crest Trail near Harts Pass.
The low center will peak in strength in a few hours at 992-996 mb
soon after passing 130W, then start filling as it moves east
across southern Vancouver Island. Through late tonight, south-
southeast pressure gradients will pick up markedly as the low
center approaches southern Vancouver Island. Bellingham-Port
Hardy gradient should peak near +7 mb tonight, a good reflection
of the "southeast sucker" wind pattern over the North Interior.
The Portland-Bellingham gradient should peak near +8 mb late
tonight. Statistical guidance is indicating peak sustained speeds
of 25-30 knots tonight at both Hoquiam and Whidbey Island.
Meanwhile, 925 mb winds of 40-50 knots tonight favor peak gusts of
45-50 mph at the aforementioned windy spots. These speeds
ordinarily fit into the category for a Wind Advisory, but impacts
from the first advisory-level event of the season have often
fallen in line with what we expect from a warning-level event,
especially in the extent of tree damage. For this reason, have
issued a High Wind Warning for the Coast and North Interior for
tonight, not so much for the speeds but rather for the heightened
threat to life and property.
The low will quickly move into south-central B.C. and weaken
further on Friday morning. Warm advection will cut off, causing
rain to taper off. For the lowlands, Friday may be more dry than
wet.
An upper disturbance will quickly arrive early Saturday in strong
westerly flow aloft. Rain will precede this disturbance and spread
across western Washington starting late Friday evening. A slow-
moving front oriented from west-east will be draped across the
area in its wake. This will act as a focus for the continuation of
rain on Saturday afternoon and evening, eventually focusing more
over the northern half of the forecast area on Saturday night.
Models agree in bringing a narrow east-west axis of heavy
rainfall amounts over northwest Washington. The official QPF
forecast calls for over one inch of rain at Bellingham on Saturday
night. This east-west boundary will continue over northwest
Washington all the way through Sunday. In contrast, southwest
Washington should be warmer and drier, with the Seattle metro area
being in the transition between cooler wetter weather to our north
and the warmer drier weather to the south.Haner
.LONG TERM...The east-west boundary over northwest Washington will
finally budge southward on Sunday night and Monday while weakening
along the way. The front should have dissipated and dried out by
Monday night.
Tuesday should start off rain-free with breaks in the clouds in
response to an upper ridge axis passing across the Pacific
Northwest. Once the upper ridge moves east later Tuesday, it will
open the door to a negatively tilted shortwave trough spreading
rain back into western Washington around Tuesday night. By
Wednesday and Thursday, a consolidated upper jet should gather
steam across the Pacific and take aim at the Northwest. The days
6-7 forecast appears stormy and wet at this point. Will need to
watch the second half of next week for rain and wind impacts.
Haner
&&
.AVIATION...Rain will increase tonight as the next Pacific storm
system moves in. The flow aloft is westerly. The air mass is moist
and stable. It will be windy on the coast and north interior with
gusts to 40 kt. Rain will continue through Friday morning with
MVFR cigs likely. Strong onshore flow will develop behind this
system late Friday morning with showers mainly affecting the
Cascades. 33
KSEA...Rain developing this evening with cigs lowering to MVFR
range. South winds increasing overnight with gusts to 25 kt. 33
&&
.MARINE...Southerly flow will increase tonight and continue
through Friday morning as a Pacific storm system approaches WA
then moves inland. This system will bring a 995-1000 mb low into
central Vancouver Island late tonight. Models show a tight S/SE
pressure gradient across Western WA with gale force winds possible
over all waters. Strong onshore flow will continue on Friday as
this system moves east over southern B.C. A warm front will lift
north through Western Washington on Saturday then stall over the
WA/B.C. border on Sunday...then weaken further on Monday as it
shifts back south. The next front will arrive Tuesday night. 33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...High Wind Warning from 8 PM this evening to 9 AM PDT Friday for
Admiralty Inlet Area-San Juan County-Western Skagit County-
Western Whatcom County.
High Wind Warning from 8 PM this evening to 6 AM PDT Friday for
Central Coast-North Coast.
PZ...Small Craft Advisory for rough bar from 5 AM to 5 PM PDT Friday
for Grays Harbor Bar.
Gale Warning until 7 AM PDT Friday for Coastal Waters From Cape
Flattery To James Island 10 To 60 Nm-Coastal Waters From
Cape Flattery To James Island Out 10 Nm-Coastal Waters From
James Island To Point Grenville 10 To 60 Nm-Coastal Waters
From James Island To Point Grenville Out 10 Nm-Coastal
Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-
Coastal Waters From Point Grenville To Cape Shoalwater Out
10 Nm-West Entrance U.S. Waters Strait Of Juan De Fuca.
Gale Warning until 2 PM PDT Friday for Central U.S. Waters
Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of
Juan De Fuca.
Gale Warning until 9 AM PDT Friday for Northern Inland Waters
Including The San Juan Islands.
Gale Warning until 11 AM PDT Friday for Admiralty Inlet-Puget
Sound and Hood Canal.
&&
$$
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