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Forecasting Tool Currently Available
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GFS 00Z
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GFS 12Z
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Galvez-Davison Index and Dynamics -
GDID.CMD
The Galvez-Davison Index describes convective instability favorable for tropical
and subtropical convection. Yet, analyzing atmospheric dynamics is required
to know whether the atmosphere might be capable of utilizing this instability
to produce convection. The GDID tool plots the GDI in colors and overlays
low-level flow, low-level moisture flux convergence and divergence,
upper level flow and upper level divergence to better forecast regions
where convection and precipitation might develop.
GDID Algorithm Legend
A quick guide is on the works.
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Trade Wind Inversion Characterization -
TWIN.CMD
To understand convection types in trade wind regimes, understanding the characteristics
of the trade wind inversion and overlying airmass are crucial. TWIN diagnoses
the height of the lowest-lying stable layer with colors and its strength with
boxes. 700-500 hPa low relative humidity contours signal the potential of
dry air entrainment from the mid-troposphere into the marine layer. 700-400 hPa averaged
flow describes mid-level ridges and troughs, which generally relate to
enhanced subsidence and enhanced stability versus deep convection, respectively.
High GDI contours signal regions with the potential of deep convection.
More information in the
TWIN Algorithm Legend
. A quick guide is on the works.
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Severe Weather and Hail Environments -
GR02T.CMD
GR02T highlights regions with a general the potential for severe weather
with shades of color, and specifically detects a potential for hail
where colored boxes appear inside colored contours over a color shaded area.
Includes 925-850 hPa and 250-500 hPa winds to include impacts of low-level
and upper jets on the analysis of the severe weather and hail potential.
In addition, 500 hPa temperatures in contours show where mid-level short wave
troughs might be present, and where temperatures are sufficiently cold to
favor hail. In the Caribbean, these are often temperatures cooler than -8°C.
More information in the
GR02T Algorithm Legend
. A quick guide is on the works.
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Front and Airmass Characterization Algorithm -
FRAM.CMD
FRAM helps to identify surface fronts and airmasses of different characteristics.
It uses horizontal gradients of thickness and dewpoint in the lower troposphere,
and five variables to plot the magnitude of gradients between airmasses.
1000-925 hPa winds and 1000-925 hPa enhanced moisture flux convergence, included with boxes,
aid with the placement surface boundaries.
More information in the
FRAM Algorithm Legend
. A quick guide is on the works.
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Tropical Wave Tracking and Characterization -
TROPW.CMD
TROPW was developed to help with the tracking and characterization of tropical waves
propagating in the trades. It evaluates cyclonic curvature vorticity in the 850-600 hPa layer,
potential vorticity in the 320-325°K isentropic surfaces and 870-700 hPa flow to evaluate
features with rotation that propagate from east to west. Additionally, it includes
Galvez-Davison Index contours to highlight axes of enhanced convecive instability associated
with the waves; and 925-700 hPa enhanced moisture convergence with green boxes, which
often cluster near tropical waves and signal regions where convection might be tiggered.
More information in the
TROPW Algorithm Legend
. A quick guide is on the works.
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Caribbean + Central America
Atlantic
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Note: These algorithms are only forecast tools, not official forecasts.
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weather.gov 
