Issued at 500 PM AST Sun Sep 29 2019

000
WTNT43 KNHC 292045
TCDAT3

Hurricane Lorenzo Discussion Number 30
NWS National Hurricane Center Miami FL

AL132019
500 PM AST Sun Sep 29 2019

The cloud pattern has continued to degrade throughout the day with
cold cloud tops filling in the eye, with a gradual erosion of the
convection over the southwest quadrant. A recent AMSR2 pass confirms
that the eyewall is indeed open on the western side, and suggests
there may be another eyewall replacement cycle occurring. The NOAA
Hurricane Hunters are currently performing multiple experimental
flights inside and around Lorenzo, and are providing NHC with
valuable data. The wind data from the SFMR are indicating that the
hurricane-force winds extend outward farther than previously
thought, about 60-70 n mi from the center in all quadrants. The
aircraft also reported an adjusted minimum central pressure of 948
mb, a peak flight level wind of 99 kt, and an image capture from an
on-board radar that confirmed the break in the eyewall. The
available objective and subjective intensity estimates range from
102 kt to 114 kt. Based on a compromise of these data, the initial
intensity has been set at 100 kt, but this may be a little generous
given much lower dropsonde wind speeds measured by the aircraft.

Lorenzo continues north-northeastward at 9 kt through a weakness in
the subtropical ridge. A mid-latitude trough will approach Lorenzo
from the west in a couple of days. Increasing southwesterly flow
ahead of the trough will force the hurricane to turn northeastward
and accelerate beginning on Monday. The forecast track confidence
remains very high through 48 hours, and the new forecast is
essentially an update of the previous one. By 72 hours, the guidance
continues to diverge significantly, likely due to how they are
handling the interaction between Lorenzo and a larger extratropical
cyclone to its north late in the forecast period. The ECMWF/UKMET do
not have Lorenzo being absorbed into the larger low. Instead, they
track Lorenzo to the east-northeast toward Europe ahead of the
associated upper trough. The rest of the guidance has Lorenzo
absorbed into the low several hundred miles west of the British
Isles. The forecast track confidence remains low beyond 72 hours,
and was nudged just a little to the left from the previous advisory.

The aircraft near-surface dropsonde data suggests that Lorenzo is
moving over cooler waters of 24-25 degrees C, a few degrees cooler
than model guidance indicates, due to the upwelling of the waters
with lower oceanic heat content. The environmental conditions
for the next 48 hours are characterized by moderate southwesterly
shear, decent moisture, and strong upper-level divergence. Due to
the presence of the shear and cooler waters, gradual weakening is
anticipated for the next couple of days. By 72 hours, much stronger
shear and the interaction with the approaching mid-latitude trough
should cause the cyclone to weaken at a faster rate and begin to
transition to an extratropical cyclone. By 96 hours or so,
extratropical transition is expected to be complete. The official
intensity forecast was adjusted lower than the previous one
through 48 hours, and then is similar thereafter. This solution is
near the various multimodel consensus aids.

Key Messages:

1. Lorenzo is a large and powerful hurricane, and its hurricane-
and tropical-storm-force wind fields are expected to expand further
during the next several days. Regardless of Lorenzo's exact track
near the Azores, strong winds are becoming increasingly likely on
those islands Tuesday night and Wednesday, and residents there
should monitor the progress of the hurricane. Watches could be
issued for those islands later today or tonight.

2. Large swells generated by Lorenzo will continue to spread across
much of the north Atlantic basin during the next few days. These
swells will produce life-threatening surf and rip currents.

FORECAST POSITIONS AND MAX WINDS

INIT 29/2100Z 26.9N 44.2W 100 KT 115 MPH
12H 30/0600Z 28.2N 43.6W

90 KT 105 MPH
24H 30/1800Z 30.1N 42.6W

85 KT 100 MPH
36H 01/0600Z 32.4N 40.6W

85 KT 100 MPH
48H 01/1800Z 35.6N 37.0W

80 KT 90 MPH
72H 02/1800Z 44.6N 26.3W

70 KT 80 MPH
96H 03/1800Z 52.2N 17.2W

55 KT 65 MPH...POST-TROP/EXTRATROP
120H 04/1800Z 55.0N 15.9W

45 KT 50 MPH...POST-TROP/EXTRATROP

$$
Forecaster Latto

Issued at 2100 UTC SUN SEP 29 2019

000
WTNT23 KNHC 292043
TCMAT3

HURRICANE LORENZO FORECAST/ADVISORY NUMBER 30
NWS NATIONAL HURRICANE CENTER MIAMI FL

AL132019
2100 UTC SUN SEP 29 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

INTERESTS IN THE AZORES SHOULD MONITOR THE PROGRESS OF LORENZO.
WATCHES COULD BE ISSUED FOR THOSE ISLANDS LATER TODAY OR TONIGHT.

HURRICANE CENTER LOCATED NEAR 26.9N 44.2W AT 29/2100Z
POSITION ACCURATE WITHIN 15 NM

PRESENT MOVEMENT TOWARD THE NORTH-NORTHEAST OR 15 DEGREES AT

9 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 948 MB
EYE DIAMETER 20 NM
MAX SUSTAINED WINDS 100 KT WITH GUSTS TO 120 KT.
64 KT....... 70NE 60SE 60SW 70NW.
50 KT....... 90NE 90SE 100SW 100NW.
34 KT.......210NE 220SE 140SW 180NW.
12 FT SEAS..390NE 330SE 420SW 420NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 26.9N 44.2W AT 29/2100Z
AT 29/1800Z CENTER WAS LOCATED NEAR 26.4N 44.4W

FORECAST VALID 30/0600Z 28.2N 43.6W
MAX WIND 90 KT...GUSTS 110 KT.
64 KT... 70NE 60SE 60SW 70NW.
50 KT... 90NE 90SE 100SW 100NW.
34 KT...210NE 220SE 140SW 180NW.

FORECAST VALID 30/1800Z 30.1N 42.6W
MAX WIND 85 KT...GUSTS 105 KT.
64 KT... 70NE 70SE 60SW 70NW.
50 KT...110NE 110SE 110SW 110NW.
34 KT...220NE 200SE 160SW 180NW.

FORECAST VALID 01/0600Z 32.4N 40.6W
MAX WIND 85 KT...GUSTS 105 KT.
64 KT... 70NE 70SE 60SW 70NW.
50 KT...120NE 120SE 110SW 110NW.
34 KT...240NE 240SE 180SW 180NW.

FORECAST VALID 01/1800Z 35.6N 37.0W
MAX WIND 80 KT...GUSTS 100 KT.
64 KT... 80NE 80SE 60SW 70NW.
50 KT...140NE 140SE 110SW 110NW.
34 KT...260NE 280SE 200SW 200NW.

FORECAST VALID 02/1800Z 44.6N 26.3W
MAX WIND 70 KT...GUSTS 85 KT.
50 KT...160NE 160SE 110SW 110NW.
34 KT...330NE 330SE 240SW 240NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY

OUTLOOK VALID 03/1800Z 52.2N 17.2W...POST-TROP/EXTRATROP
MAX WIND 55 KT...GUSTS 65 KT.

OUTLOOK VALID 04/1800Z 55.0N 15.9W...POST-TROP/EXTRATROP
MAX WIND 45 KT...GUSTS 55 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 26.9N 44.2W

NEXT ADVISORY AT 30/0300Z

$$
FORECASTER LATTO

Issued at 1100 AM AST Sun Sep 29 2019

000
WTNT33 KNHC 291455
TCPAT3

BULLETIN
Hurricane Lorenzo Advisory Number 29
NWS National Hurricane Center Miami FL

AL132019
1100 AM AST Sun Sep 29 2019

...INTERESTS IN THE AZORES SHOULD MONITOR THE PROGRESS OF LORENZO...
...WATCHES COULD BE ISSUED FOR THOSE ISLANDS LATER TODAY OR
TONIGHT...

SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...25.9N 44.4W
ABOUT 1315 MI...2115 KM SW OF THE AZORES
MAXIMUM SUSTAINED WINDS...145 MPH...230 KM/H
PRESENT MOVEMENT...NNE OR 15 DEGREES AT 10 MPH...17 KM/H
MINIMUM CENTRAL PRESSURE...938 MB...27.70 INCHES

WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.

Interests in the Azores should monitor the progress of Lorenzo.
Watches could be issued for those islands later today or tonight.

DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the center of Hurricane Lorenzo was
located near latitude 25.9 North, longitude 44.4 West. Lorenzo is
moving toward the north-northeast near 10 mph (17 km/h) and this
motion is expected to continue through tonight. A turn to the
northeast along with an increase in forward speed should occur on
Monday and continue through Wednesday.

Maximum sustained winds are near 145 mph (230 km/h) with higher
gusts. Lorenzo is a category 4 hurricane on the Saffir-Simpson
Hurricane Wind Scale. Steady weakening is expected over the next
few days, but Lorenzo is still expected to be a potent hurricane in
a couple of days.

Lorenzo is a large hurricane, with hurricane-force winds extending
outward up to 80 miles (130 km) from the center and
tropical-storm-force winds extending outward up to 275 miles (445
km).

The estimated minimum central pressure is 938 mb (27.70 inches).

HAZARDS AFFECTING LAND
----------------------
RAINFALL: Lorenzo is expected to produce total rain accumulations
of 3 to 6 inches over much of the western Azores and 1 to 2 inches
over the central Azores Tuesday and Wednesday. This rainfall could
cause life-threatening flash flooding in the western Azores.

SURF: Swells generated by Lorenzo are spreading across much of the
North Atlantic basin. These swells are likely to cause
life-threatening surf and rip current conditions. Please consult
products from your local weather office.

NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.

$$
Forecaster Latto

5-Day Uncertainty Track last updated Sun, 29 Sep 2019 08:34:49 GMT



Wind Speed Probabilities last updated Sun, 29 Sep 2019 08:34:49 GMT