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An increasing number of National Weather Service offices are now providing detailed digital forecast data known as the Revised Digital Forecast or RDF. The RDF displays various forecasts averaged across a geographic zone group in 3-hour and 12-hour intervals. The 3-hourly and 12 hourly forecasts are up to 60 hours in the future, while the extended portion of the RDF provides 7-day, 12-hourly forecasts.
ARZ035-036-048-049-MSZ001-007-008-TNZ088-150939-
CRITTENDEN-CROSS-DE SOTO-LEE-SHELBY-ST. FRANCIS-TATE-TUNICA-
239 PM CDT SUN JUL 14 2002
MON 07/15/02 TUE 07/16/02
CDT 15 18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 03 06
POP 12HR 30 30 20 20 10
QPF 12HR .01-.09 .10-.24 0 .10-.24 0
MN/MX 74 89 74 91 75
TEMP 84 81 77 74 77 80 86 89 86 81 77 74 78 82 87 90
DEWPT 70 69 69 69 69 69 69 69 69 69 69 69 71 71 71 70
RH 63 67 76 84 76 69 57 52 57 67 76 84 79 69 59 52
WIND DIR N NE -- N NE E S S S S S SW SW SW SW SW
WIND SPD 2 2 0 2 2 2 5 5 2 5 2 2 2 5 10 10 10 10 5 5
CLOUDS B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1
TSTMS SC SC SC SC SC SC S S IS IS
HEAT INDEX 88 84 82 90 93 90 84 86 92 95
WED 07/17/02 THU 07/18/02 FRI 07/19/02 SAT 07/20/02
CDT 09 15 21 03 09 15 21 03 09 15 21 03 09 15 21 03 09 15
POP 12HR 30 30 40 40 10 10 10 10 0
MN/MX 94 75 95 76 95 75 96 76 96
CLOUDS B1 B1 B1 B1 B1 B1 B1 B1 B1
TSTMS C C C C
FORECAST PARAMETERS EXPLAINED:
POP 12HR - This parameter is forecast for all 7 days. The probability of precipitation is for the 12 hour period ending at 6 a.m. or 6 p.m. local time. This percentage probability is listed toward the ending time of each period out to 60 hours, then in the middle of each 12-hour time period for days 3 through 7.
QPF 12HR - This parameter is forecast out to 60 hours in the RDF. A quantitative precipitation forecast, QPF 12HR lists the average precipitation expected across the zone group if precipitation falls. QPF 12HR is forecast in 12 hour periods ending at 6 a.m. or 6 p.m. local time. QPF 12HR is located toward the ending time of each 12 hour period and amounts are given in a range.
SNOW 12HR - The expected range of snowfall accumulations (in inches) during a 12-hour period ending at 6 a.m. or 6 p.m. local time.
MN/MX - A forecast of maximum or minimum temperature during the daytime or nighttime hours.
TEMP - The temperature in 3-hour intervals.
DEWPT - The dew point temperature in 3-hour intervals.
RH - The relative humidity in 3- hour intervals.
WIND DIR - The expected wind direction during a 3-hour time period. The wind direction uses the 8 points of a compass.
WIND SPD - The expected average wind speed in miles per hour, during each 3-hour time period.
CLOUDS - The expected cloud cover during each 3-hour time period. Contractions mean the following:
CL-clear; SC-Mostly Clear; B1 - Partly Cloudy; B2 - Mostly Cloudy; OV- Cloudy
Precipitation - The RDF may list several types of precipitation. The precipitation types are only shown in the RDF if they are forecast to occur at any point in the 7-day forecast. The types of precipitation are: RAIN - Rain; RAIN SHWRS - Rain Showers; TSTMS - Thunderstorms; DRIZZLE - Drizzle; SNOW - Snow; SNOW SHWRS - Snow Showers; FLURRIES - Flurries; SLEET - Sleet; FRZNG RAIN - Freezing Rain; FRZNG DRZL - Freezing Drizzle. The probability contractions and their meanings are as follows: S - Slight Chance (< 20%); IS - Isolated (< 20%); C - Chance (30%-50%); SC - Scattered (30%-50%); L - Likely (60%-70%); NM - Numerous (60%-70%); O - Occasional (80%-100%); D - Definite (80%-100%); WP - Widespread (80%-100%)
OBVIS - An obstruction to visibility. Obstructions to visibility are forecast in 3-hour intervals.
WIND CHILL and HEAT INDEX - When the wind chill is forecast to be 30 degrees or lower with 5 mph or greater wind speed a row titled WIND CHILL will be listed under any forecast precipitation types. When the temperature is forecast to be 80 degree or higher a row titled HEAT INDEX will be listed under any forecast precipitation types.
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