axnt20 knhc 210547
Tropical weather discussion
NWS National Hurricane Center Miami FL
205 am EDT Tue may 21 2013
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
Based on 0000 UTC surface analysis and satellite imagery through
tropical wave extends from 7n36w to eq38w moving W at 10-15 kt.
Wave coincides with a weak moisture maximum on the total
precipitable water imagery with curvature evident on the 700 mb
streamlines and satellite derived winds. Wave also disrupts the
Tropical wave extends from 14n63w to inland over South America
to near 6n65w moving W at 5-10 kt. Wave coincides with a
moisture maximum on the total precipitable water imagery that is
beginning to shift northward over the E Caribbean with a weak
curvature on the 700 mb streamlines. Scattered showers/isolated
thunderstorms dot the W tropical Atlc/E Caribbean S of 18n
the monsoon trough extends across Africa into the E tropical
Atlc near 12n16w continuing along 4n23w to 4n27w where the ITCZ
begins and continues along 5n31w to 4n35w then resumes W of the
tropical wave near 1n39w then S of the Equator near 40w to
inland over South America near 2s45w. Clusters of scattered
showers and isolated thunderstorms are within 150 nm along the
coast of W Africa S of 11n E of the prime Meridian. Clusters of
isolated moderate convection are from 2n-6n between 12w-20w...
from 3n-7n between 25w-38w...and from 2n to the Equator between
Gulf of Mexico...
a shortwave upper trough extends from se Georgia to over the
Florida Peninsula to near Miami. Scattered showers and embedded
thunderstorms over the Florida Peninsula have dissipated over
all but se Florida. A broad upper ridge extends along the E
coast of Mexico and Texas covering the remainder of the Gulf. A
surface ridge extends from the W Atlc across central Florida to
over the E Gulf with southerly return flow covering the
remainder of the Gulf. Water vapor imagery indicates strong
subsidence and dry stable air aloft dominating the Gulf
tonight...thus clear skies for all but the far W Gulf where low
level clouds are within 90/120 nm along the coast of Texas and
Mexico N of 21n. Model guidance continues to show high moisture
and precipitation potential over the far E Gulf and over the
Florida Peninsula through early Wed before the upper trough is
expected to move E of Florida. A cold front may drop into the NE
Gulf Fri slowly sinking S through Sat.
an upper ridge extends along the N coast of South America giving
the Caribbean S of 16n SW flow aloft. The area N of 16n is under
near zonal westerly flow aloft. The upper flow is drawing
tropical moisture aloft over the S Caribbean and is generating
scattered showers/thunderstorms S of 12n between 67w-84w.
Afternoon thunderstorms continue over portions of Cuba and
within 75 nm along the S coast between Guantanamo and the Gulf
of Ana Maria. Isolated showers are from 16n-19n between 75w-81w.
The E Caribbean is covered in the tropical wave section above.
Surface ridge over the W Atlc will maintain moderate to fresh
trade winds over the region with stronger winds at times off the
coast of Colombia and in the Gulf of Honduras through mid week.
currently afternoon showers and thunderstorms have dissipated
with some isolated showers within 30 nm along the se coast of
the Dominican Republic between the Mona Passage and La Romana.
Model guidance indicates a similar pattern will persist tomorrow
with the most likely precipitation to be during the afternoon
and early evening hours across the island when peak daytime
heating and instability occur. Any areas that receive measurable
amounts of rainfall will likely be prone to localized flooding.
Moisture from a tropical wave may increase activity over the
island Tue into Wed.
a shortwave upper trough over the Florida Peninsula is amplifying
an upper ridge over the far W Atlc that extends from the Bahama
Islands near 24n75w to beyond 32n78w and is enhancing the
scattered showers/thunderstorms from 24n-32n between 79w-81w
including se Florida. A surface ridge extends from a 1026 mb
high near 33n62w across central Florida into the Gulf of Mexico.
A broad upper trough covers the remainder of the W Atlc into the
central Atlc supporting a cold front that enters the region near
32n48w along 28n55w to 27n60w. Scattered showers are within 45
nm of the front E of 54w. A weak surface trough is to the se
extending from 29n48w through an equally weak 1019 mb surface
low near 27n48w to 24n46w. This feature is not producing any
significant weather. A broad surface ridge covers the E Atlc
anchored by a 1036 mb high N of the Azores. A cold front may
move into the NW portion Fri slowly moving E across the waters N
of 27n through Sat.
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