[Tropical] Tropical Weather Discussion

Sat Jun 6 12:04:10 CDT 2020

AXNT20 KNHC 061703
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1003 AM PDT Sat Jun 6 2020

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1200 UTC surface analysis and satellite imagery through
1220 UTC.

...SPECIAL FEATURES...

The center of Tropical Storm Cristobal is near 23.9N 90.2W at
06/1200 UTC. Cristobal is morning N, or 360 degrees, at 12 knots.
Cristobal is about 365 nm south of the mouth of the Mississippi
River. The estimated minimum central pressure is 992 mb. The
maximum sustained winds are 45 knots with gusts to 55 knots. A
broad band of strong thunderstorms is located within 360 nm E of
the center, as well as extending N to S along 87W from the
north central Gulf to the Yucatan Channel. Across all of the NE
Gulf and north central Gulf to the E of 88W, scattered moderate
to isolated strong convection exists. Scattered moderate
convection is also ongoing across the NE Gulf and FL peninsula.

Cristobal should continue moving northward at a similar pace as
it remains between a western Atlantic ridge and western Gulf
trough. This will bring Cristobal over the central Gulf today and
approach the northern Gulf coast Sunday while slowly
strengthening. Once Cristobal moves inland late Sunday, weakening
will begin.

Damaging and deadly flooding has already been occurring over
parts of Mexico and Central America in association with
Cristobal. The storm is likely to produce additional rainfall
amounts of 1 to 3 inches in Quintana Roo and Yucatan, causing
storm totals to approach 25 inches. It is possible that this
rainfall may cause widespread life-threatening flash floods and
mudslides. Please read bulletins and forecasts that are issued by
your local or national meteorological service, for more details.

Rainfall amounts of 4 to 8 inches, with isolated amounts of up to
12 inches, are forecast across portions of the eastern and
central Gulf Coast and Lower Mississippi Valley through early
next week. Flash flooding as well as flooding on streams and
rivers may result.

Please, read the latest HIGH SEAS FORECAST issued by the National
Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml,
and the latest Cristobal NHC Forecast/Advisory and Public
Advisory at www.hurricanes.gov, for more details.

...EXCESSIVE RAINFALL IN CENTRAL AMERICA AND MEXICO...

A Central American Gyre remains in southern Mexico and northern
Central America. The broad cyclonic circulation around the gyre
is characterized by a northward displacement of the monsoon
trough in Central America, and associated deep convective
precipitation usually is found to the south of the trough.

Expect additional heavy rainfall in parts of southeastern Mexico
and northern Central America through tonight. The heaviest
additional rainfall is expected in the southeastern Mexican
provinces of Chiapas, Yucatan, and Quintana Roo, and in parts of
Guatemala and Belize. It is possible that the rainfall may cause
widespread life-threatening flash floods and mudslides. Please
read bulletins and forecasts that are issued by your local or
national meteorological service, for more details.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 36W from 16N southward,
moving west 15 knots. Scattered moderate convection exists on
either side of the tropical wave to about 180 nm.

An Atlantic Ocean tropical wave is along 53W, from 18N southward,
moving west 15 knots. Scattered moderate convection exists about
200 nm in the vicinity of this wave.

A Caribbean Sea tropical wave is along 65W, from 17N southward,
moving west 10 to 15 knots. No significant deep convection is
apparent with this tropical wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of Sierra
Leone near 08N13W to 05N40W. The ITCZ continues from 05N40W to
00N49W. Numerous moderate to scattered strong convection is from
02N to 08N between 12W and 26W. Scattered showers exists
elsewhere along the ITCZ from 01N to 05N between 40W and 50W.

GULF OF MEXICO...

Please read the SPECIAL FEATURES section, for details about
Tropical Storm Cristobal.

Tropical Storm Cristobal will move north through the central Gulf
through late Sunday, then move ashore in Louisiana. Thereafter,
it will weaken and move away from the area. Once Cristobal moves
inland, wind and seas will gradually subside. Moderate to fresh
southerly flow will be present across most of the north-central
Gulf waters through late Tue.

CARIBBEAN SEA...

Please read the SPECIAL FEATURES section, for details about the
heavy rainfall event that is occurring in Central America.

The tail end of Tropical Storm Cristobal extends into the
Yucatan Channel in the NW Caribbean Sea. Scattered moderate to
strong convection extends from 18N86W to 23N85W.

A part of the monsoon trough extends from northern Colombia near
09N75W, into the SW Caribbean Sea, across Nicaragua from SE to
NW. Scattered moderate convection exists within 100 nm of the
Panama and Nicaragua coast.

Elsewhere in the Caribbean, high pressure is keeping mainly dry
conditions in place, with some scattered tradewind showers mainly
w of 70W.

The Central American Gyre will persist over northern Central
America and southern Mexico for several days, producing
widespread showers and thunderstorms in far NW Caribbean through
Sunday. Strong to near gale force SE to S winds and seas of 10
to 15 ft in the NW Caribbean will gradually diminish into
tonight. Fresh to strong winds will prevail over the south-
central Caribbean through tonight. Otherwise, a pair of tropical
waves will cross mainly the southern Caribbean through early next
week, bringing a few additional showers and thunderstorms.

ATLANTIC OCEAN...

Upper level cyclonic wind flow covers the eastern Atlantic Ocean
from 20N northward from 30W eastward. A surface trough extends
from 29N53W to 23N57W. Scattered showers are observed in the
vicinity of the trough. A second trough is also noted to the west
near 29N63W to 24N66W with scattered showers extending about 100
nm on either side of the trough.

Abundant tropical moisture spreading NE from the NW Caribbean
and Tropical Storm Cristobal will continue to support scattered
showers and thunderstorms near Florida and to the north of the
Bahamas through the weekend. Early next week, a weak cold front
will approach the northern waters before stalling and dissipating
by the middle of the week. Otherwise, high pressure will support
fresh trade winds, highest to the north of Hispaniola this
weekend.

$$
MMT
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