Friday, September 22, 2017

Jose Weakens And Becomes Extratropical While Meandering South Of Cape Cod

Area Forecast Discussion
National Weather Service Caribou ME
427 PM EDT Fri Sep 22 2017

Tropical Storm Jose will remain southeast of Cape
Cod and will slowly weaken through this weekend while High
pressure both at the surface and upper atmosphere builds across
the region from the west.


Strong high pressure will persist to the southwest of New
England and continue to build tonight into Saturday. Expect
clouds from Jose to persist along coastal areas until late this
evening but skies over the remainder of the forecast area are
expected to remain mostly clear. Temperatures are expected to be
much warmer Saturday as high pressure to the southwest continues
to build.


Models showed good run to run continuity from prev model runs
thru Sun erly aftn, but aftwrds, very poor continuity from
late Sun aftn into erly next week. Chgs include an earlier back
door cold front from late Sun aftn across the N to Sun eve
Downeast. Also, models indicate enough hi llvl dwpts upwards to
mid to upper 60s for possible isold to sct tstms Sun aftn and
erly eve across Nrn and Ern ptns of the Rgn as the front crosses
thru, so we added this to the fcst. Not enough confidence to
mention any enhanced wording due to relatively stable mid lvl
lapse rates and dry antecedent ground moisture that could result
in more mixing of slightly drier air from alf on Sun, lowering
aftn dwpts and the potential of cnvctn this
fcst for isold-sct tstms Sun aftn is a middle ground apch for

After mild ovrngt lows Sat ngt and erly morn patchy fog Sun morn
due to increasingly humid air, hi temps will apch or exceed
record hi temps at some lctns (see climate section of disc) as
fcst max aftn 925mb temps reach the the lower to mid 20s C.
With llvl cool advcn with NE to E winds Sun ngt, we removed the
mention of patchy fog late Sun ngt.

Mon will be ptly to msly sunny, but at this point, not as warm
as Sun, although still sig abv normal for this tm of season.
Temps will climb more quickly toward hi temps Mon aftn as the
front returns back toward Wrn ptns of the FA as a warm front
late in the day and Mon eve.


Longer range models are now indicating Tue to be dry and much
warmer than thought to be ystdy attm. For now, given the run to
run uncertainty of the models, we did raise hi temps
considerably for Tue, but not as much as what current dtmnstc
12z models like the ECMWF and GFS are implying. We will adjust
hi temps Tue upwards in later updates based on a stable model

Otherwise, both the dtmnstc 12z GFS and ECMWF are also faster
by 6 to 9 hrs with the next major cold frontal system and
associated upper trof for later Wed into Thu morn than shown for
ystdy attm. We did raise hi temps a few deg F for Wed aftn ahead
of the leading edge of shwrs. Speaking of shwrs, there was
enough fcst SBCAPEs to mention aftn/eve tstms across the N hlf
of the FA. Shwrs will cont late Wed ngt into Thu morn before
ending Thu aftn well behind the cold front, with Nrn ptns of
the FA potentially receiving about a half inch downwards to a
quarter inch or less Downeast. Temps will be definitely
returning to more normal values Thu ngt and Fri under mdtly
strong llvl cool advcn with SC cld cvr persisting longest across
the N.


NEAR TERM: VFR Next 24 hours.

SHORT TO LONG TERM: Mainly VFR all TAF sites with IFR vsbys and
clgs possible with fog late Tue ngt msly ovr Downeast sites and
MVFR clgs and vsbys at any TAF site with any tstm or heavier
shwrs later Wed aftn.


Have used the NAM to initialize the wind grids, however there
is still a strong inversion resulting from the relatively cold
sea surface temperature. Therefore have reduced the wind speeds
from the NAM by 20 percent to adjust for high bias. For Waves:
Currently long period swell from Jose (6-7 feet/11 seconds) is
still entering the Gulf of Maine and is still the primary wave
system. This wave system will continue to subside tonight into
Saturday. Expect the wave spectrum to become more bi-modal later
tonight as long period swell from Jose subsides and the
northeasterly wind wave system persists and may become the
primary wave group late tonight. Will use the Nearshore Wave
Prediction System (NWPS) to initialize the wave grids but will
lower model wave heights by 1 foot to adjust for high bias
resulting from cold sea surface temperature. Will extend the SCA
until 0600Z.

SHORT TO LONG TERM TERM: Initially no hdlns will be needed Sat
ngt thru Sun ngt, but long pd swell wv hts will increase back
into the SCA range possibly as erly as Mon and cont thru mid
week as Maria moves Nwrd into the open Atlc to E of Cape
Hatteras. Beach hi surf and rip current potential will likely
become high again by Tue aftn or so. Kept close to WW3 wv
guidance for fcst wv hts with wv pds fcst again in the 12 to 16
sec range.


Currently long period swell from Jose which is running at 11
seconds/6-7 feet continues to enter the Gulf of Maine. Waves are
expected to to slowly subside Tonight and Saturday.
Gerling/Hanson plots from NWPS Model indicate that the long
period wave group will fall below 5 feet/10 seconds late
tonight, so will extend the high surf advisory until 0600Z

Concern is that long period waves high impact in the surf zone,
and can run up much higher on the shore than shorter period
waves resulting in the danger of spectators being washed into
the ocean. Dangerous Rip Currents are also expected.

Some minor beach erosion is possible however Runup, splashover,
flooding due to storm surge are not expected.


Record high temps are possible at Bangor and Houlton Saturday
afternoon and at multiple locations Sunday afternoon. Current
records for these dates are:

Saturday September 23rd

Bangor........80 deg set in 1989
Houlton.......84 deg set in 1965

Sunday September 24th

Caribou.......80 deg set in 1958
Bangor........88 deg set in 1930
Houlton.......81 deg set in 1958
Millinocket...86 deg set in 1920


ME...High Surf Advisory until 2 AM EDT Saturday for MEZ029-030.
MARINE...Small Craft Advisory until 2 AM EDT Saturday for ANZ050>052.



Near Term...Mignone
Short Term...VJN
Long Term...VJN
Tides/Coastal Flooding...TM

WTNT42 KNHC 222034

Post-Tropical Cyclone Jose Discussion Number  70
NWS National Hurricane Center Miami FL       AL122017
500 PM AST Fri Sep 22 2017

After 70 advisories, enough is enough.  The tropical-storm-force
winds from Jose have finally subsided and moved out of the
southern New England.  Thus, the wind hazard to land has decreased,
and this will be the last advisory on Jose since it is already
post-tropical. A slow decay over cold water is forecast while the
low drifts southeastward to southward.  The cyclone should
degenerate into a trough within 3 days as forecast by the global

The swell and rip current threat will remain across large portions
of the U.S. east coast for quite some time, due to the wave field
from both Jose and Maria.


INIT  22/2100Z 39.3N  69.1W   40 KT  45 MPH...POST-TROPICAL
 12H  23/0600Z 39.1N  69.1W   35 KT  40 MPH...POST-TROPICAL
 24H  23/1800Z 38.7N  68.7W   30 KT  35 MPH...POST-TROP/REMNT LOW
 36H  24/0600Z 38.4N  67.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  24/1800Z 38.2N  68.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  25/1800Z...DISSIPATED

Forecaster Blake