The Point Forecast Matrices (PFM) product displays various forecasted weather parameters for verification points, significant cities, and any other predefined points within a WFO’s geographic area of responsibility. Forecasts for these parameters are at 3-hour, 6-hour, and/or 12-hour intervals. The forecast is issued for five locations in central North Carolina: Piedmont Triad Airport Raleigh-Durham Airport Roanoke Rapids Rocky Mount-Wilson Fayetteville The Area Forecast Matrices (AFM) product displays various weather parameters for forecast areas specified in the valid ZFP at 3-hour, 6-hour, and/or 12-hour intervals. The PFM anf AFM products are issued at least twice at 4:00 am and 4:00 pm local time with updates when necessary. There are several forecasted parameters which appear in the PFM and AFM products. Some of these values are forecasted in 12 hour intervals while others are forecasted in 3 and 6 hour intervals. Shown below is a partial example of a PFM product, a AFM product and a description of each of its parameters.

POINT FORECAST MATRICES NATIONAL WEATHER SERVICE RALEIGH NC 415 PM EDT MON SEP 27 2004 NCZ022-281115- PIEDMONT TRIAD AIRPORT-GUILFORD NC 36.10N 79.94W 415 PM EDT MON SEP 27 2004 DATE TUE 09/28/04 WED 09/29/04 THU UTC 3HRLY 19 22 01 04 07 10 13 16 19 22 01 04 07 10 13 16 19 22 01 04 07 10 EDT 3HRLY 15 18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 03 06 MIN/MAX 66 71 60 73 54 TEMP 69 67 67 66 66 67 70 71 70 64 62 61 60 63 70 73 71 61 58 56 54 DEWPT 67 67 67 66 66 67 66 65 62 59 56 53 51 49 47 46 48 49 49 48 48 RH 93100100100100100 87 81 76 84 81 75 72 60 44 38 44 65 72 74 80 WIND DIR NE NE NE NE E E E E N NW N N N N N NE NE E E E E WIND SPD 12 12 13 13 18 17 17 19 19 13 10 10 10 9 6 6 8 10 10 9 8 WIND GUST 32 32 32 32 32 32 32 32 CLOUDS OV OV OV OV OV OV OV BK BK SC SC SC SC SC SC SC SC SC SC SC SC POP 12HR 100 100 10 10 5 QPF 12HR 1.03 1.05 0 0 0 RAIN SHWRS O O O O O O C C TSTMS C C C C C C C C DATE 09/30/04 FRI 10/01/04 SAT 10/02/04 SUN 10/03/04 MON 10/04/04 UTC 6HRLY 16 22 04 10 16 22 04 10 16 22 04 10 16 22 04 10 16 22 EDT 6HRLY 12 18 00 06 12 18 00 06 12 18 00 06 12 18 00 06 12 18 MAX/MIN 74 55 78 57 81 57 76 55 75 TEMP 70 72 59 55 73 75 62 57 76 78 62 57 72 73 60 55 71 73 DEWPT 49 51 52 53 50 54 60 57 55 56 58 54 51 50 51 52 54 56 PWIND DIR NE NE NE SE SW NW N NE E WIND CHAR LT LT LT LT GN BZ GN LT LT AVG CLOUDS SC SC SC SC SC SC SC BK BK BK BK BK SC SC SC SC SC SC POP 12HR 5 0 0 5 10 10 5 5 5 $$ AREA FORECAST MATRICES NATIONAL WEATHER SERVICE RALEIGH NC 411 PM EDT MON SEP 27 2004 NCZ021-022-038-039-281111- DAVIDSON-RANDOLPH-GUILFORD-FORSYTH- INCLUDING THE CITIES OF...LEXINGTON...ASHEBORO...GREENSBORO... HIGH POINT...WINSTON-SALEM 411 PM EDT MON SEP 27 2004 DATE TUE 09/28/04 WED 09/29/04 THU UTC 3HRLY 19 22 01 04 07 10 13 16 19 22 01 04 07 10 13 16 19 22 01 04 07 10 EDT 3HRLY 15 18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 03 06 MIN/MAX 66 72 61 73 54 TEMP 69 67 67 67 66 67 71 72 71 65 63 62 61 64 70 73 71 61 58 56 54 DEWPT 67 67 67 67 66 67 66 65 63 59 56 54 52 49 47 47 49 50 49 48 48 RH 93100100100100100 84 79 76 81 78 75 72 58 44 40 46 67 72 74 80 WIND DIR NE NE NE NE E E E NE NW NW N N N N N NE NE E E E E WIND SPD 12 12 13 13 18 17 18 19 19 13 10 10 10 9 6 6 8 10 10 9 8 WIND GUST 32 32 32 32 32 32 32 32 CLOUDS OV OV OV OV OV OV OV BK BK SC SC SC SC SC SC SC SC SC SC SC SC POP 12HR 100 100 10 10 5 QPF 12HR 0.76-1.41 0.72-1.22 0 0 0 SNOW 12HR 00-00 00-00 00-00 RAIN SHWRS O O O O O O C C TSTMS SC SC SC SC SC SC C C DATE 09/30/04 FRI 10/01/04 SAT 10/02/04 SUN 10/03/04 MON 10/04/04 UTC 6HRLY 16 22 04 10 16 22 04 10 16 22 04 10 16 22 04 10 16 22 EDT 6HRLY 12 18 00 06 12 18 00 06 12 18 00 06 12 18 00 06 12 18 MAX/MIN 74 55 78 57 81 58 77 55 75 TEMP 70 72 59 55 73 75 62 57 76 78 63 58 73 74 60 55 71 73 DEWPT 49 51 52 53 51 54 60 57 55 56 58 54 51 50 51 52 54 56 PWIND DIR NE NE NE SE SW NW N NE E WIND CHAR LT LT LT LT GN BZ GN LT LT AVG CLOUDS SC SC SC SC SC SC SC BK BK BK BK BK SC SC SC SC SC SC POP 12HR 5 0 0 5 10 10 5 5 5 $$

1. MIN/MAX: (Alternatively labeled as MAX/MIN for morning issuance)  A forecast of minimum or maximum temperatures in degrees Fahrenheit (F). The MAX temperature is valid for the period 7:00 a.m. through 7:00 p.m. local standard time, and MIN is valid for 7:00 p.m. through 8:00 a.m. local standard time (note that due to a 3-hour minimum time resolution, this element is right justified in the column beneath the approximate ending time of the MAX/MIN period). The nighttime MIN and daytime MAX may be displayed as single integer (e.g., -2, 8, 53, 102) as a range (e.g., 54 56 60) if the MAX/MIN temperatures are expected to vary across the area. In area forecasts, the middle number within the range is the representative single digit value for that area. MAX/MIN is forecast out through Day 7. 2. TEMP: TEMP is a snapshot of the expected temperature in degrees F valid at the indicated hour. The temperature is right justified in the column below the hour to which it refers. TEMP is forecast at 3-hour intervals through 60 hours, then 6-hour intervals through Day 7. 3. DEWPT: DEWPT is a snapshot of the expected dew point temperature in degrees F for the same time periods as its corresponding temperature forecast. DEWPT is located directly below the temperature line. 4. RH: The relative humidity (RH) is a snapshot of the expected RH for the same time periods as its corresponding temperature and dew point forecast. The RH row is located directly below the DEWPT row. RH is available at 3-hour increments through 60 hours. 5. WIND DIR: WIND DIR is a snapshot of the expected wind direction forecast to occur at the indicated hour, using the 8 points of a compass (i.e., N, NE, E, SE, S, SW, W, NW). If a calm wind is forecast, double zeros (00) will be listed in place of a wind direction. WIND DIR is located below the hour to which it refers. WIND DIR is available in 3-hour increments out to 60 hours. In the 6HRLY block, PWIND DIR is the predominant wind direction for the zone(s) during the 12-hour period between 6:00 a.m. and 6:00 p.m., or 6:00 p.m. and 6:00 a.m. local time. PWIND DIR is valid beyond 60 hours through Day 7. 6. WIND SPD: WIND SPD is a snapshot of the sustained wind speed in miles per hour (MPH) forecast to occur at the indicated hour. If a calm wind is forecast, double zeros (00) will be listed in place of a wind speed. WIND SPD is valid in 3-hour increments out to 60 hours. WIND CHAR codes are used beyond 60 hours through Day 7 of the forecast and denote the character of the wind for the 12-hour period between 6:00 a.m. and 6:00 p.m., or 6:00 p.m. and 6:00 a.m. WIND CHAR is comprised of range categories used in conjunction with deterministic wind speeds. Each range category is equated to a descriptive wind term, i.e., a wind character to best describe the MAXIMUM SUSTAINED wind speed during the period. Wind Character Wind Character 12-hr Maximum Sustained Wind Speed LT Light <8 mph GN Gentle 8-14 mph BZ Breezy 15-22 mph WY Windy 23-30 mph VW Very Windy 31-39 mph SD Strong/Damaging >= 40 mph 6A. WIND GUST: A wind gust row will appear in the 3HRLY block whenever forecasted wind gusts exceed the sustained wind speed (WIND SPD) by at least 10 MPH. WIND GUST is a snapshot valid on the hour indicated at the top of the corresponding column. WIND GUST is a snapshot of gusts of wind occurring at the indicated hour and is valid in 3-hour increments through 60 hours. 7. CLOUDS: The CLOUDS category provides a snapshot of sky coverage during the indicated hour. CLOUDS is divided into five category codes ranging from clear to overcast . Each code represents an equivalent percentage of sky cover in percent. CLOUDS parameter is included in 3-hour time intervals out to 60 hours. In the 6HOURLY section, AVG CLOUDS is valid for 6-hour increments beyond 60 hours through Day 7 and indicates the average amount of all clouds during the 6-hour period ending on the hour indicated at the top of the column. Sky Cover Code Sky Cover Expression Equivalent Percent Opaque Sky Cover CL Clear 0% to 6% FW Mostly Clear/Mostly Sunny 7% to 31% SC Partly Cloudy/Partly Sunny 32% to 69% BK Mostly Cloudy 70% to 94% OV Cloudy 95% to 100% 8. POP 12HR: Probability of Precipitation (POP), is defined as the likelihood, expressed as a percent, of a measurable precipitation event (1/100th of an inch) at any given point within the forecast area(s) covered by the AFM/PFM. The 12HR refers to the 12-hour valid time ending at 6:00 a.m. or 6:00 p.m. local time (0600 or 1800). The POP 12HR value is right justified in the column beneath the hour defining the ending time of the valid period. POP 12HR is forecast through Day 7. 9. QPF 12HR: This parameter, quantitative precipitation forecast (QPF) represents the total amount of liquid precipitation, in inches, expected during a 12-hour period ending at 6:00 a.m., or 6:00 p.m. local time at any point in the forecast location. The QPF is presented in locally defined ranges, (e.g., .10-.24), or single values. The QPF 12HR value is right justified in the column beneath the hour defining the ending time of the expected precipitation. QPF 12HR is forecast out to 60 hours. 10. SNOW 12HR: The expected range of total snowfall accumulation (in whole inches) forecast to occur at the specific point during a 12-hour period ending at 6:00 a.m. or 6:00 p.m. local time. SNOW 12HR will only appear during the locally defined winter period. The snow parameter contains 1 to 5 alphanumeric characters which are right justified in the column below the hour defining the ending time of the precipitation period. SNOW 12HR may appear as a one or two digit number (1, 4, 12), or as a specified range (2-4, 8-12). When no snowfall is forecast during the locally specified winter period, double zeros (00-00) will appear in the row. Snowfall that is not measurable (less than 0.1 inch of frozen precipitation) is referred to as a trace. A trace of snow is depicted by a T. SNOW 12HR is forecast out to 36 hours. 11, 12, and 13. PRECIPITATION TYPE AND CATEGORY: The PFM may list several types of precipitation. Precipitation types only appear in the PFM if they are forecast to occur during the seven day forecast. Precipitation type codes are listed in the far left column of the PFM. For each type of precipitation that is forecast, an associated POP. category is specified within the body of the product. The POP. expression for the indicated precipitation type is valid at the hour specified by the column header. Precipitation type expressions are forecast at three hour time intervals out to 60 hours, then 12-hour time intervals beyond 60 hours through Day 7. Code Qualifying Term POP (%) S Slight Chance 15% to 24% C Chance 25% to 54% L Likely 55% to 74% O Occasional/Periods of 75% to 100% D None 75% to 100% Code Areal Term Areal Coverage (%) IS Isolated 15% to 24% SC Scattered 25% to 54% NM Numerous 55% to 74% EC None (extensive coverage) 75% to 100% Code Areal Term Areal Coverage (%) PA Patchy 1% to 24% AR Areas 25% to 54% WD Widespread 55% to 74% 14. OBVIS: If an obstruction to visibility (OBVIS) is forecasted, a row labeled OBVIS will be listed underneath any forecast of precipitation. If no precipitation is forecast, then OBVIS will be listed under the row labeled AVG CLOUDS. OBVIS is forecast at 3-hour intervals through 60 hours. Code Obstruction to Visibility F Fog PF Patchy Fog F+ Dense Fog PF+ Patchy Dense Fog H Haze BS Blowing Snow H Haze BS Blowing Snow K Smoke BD Blowing Dust VA Volcanic Ash 15. WIND CHILL and HEAT INDEX: Wind Chill and Heat Index are included seasonally based upon locally defined criteria. The Wind Chill and Heat Index are forecast out to 60 hours. 16. MIN CHILL 6HR and MAX HEAT 6HR: When WIND CHILL or HEAT INDEX values appear in the PFM, a 6-hour minimum wind chill or maximum heat index may appear on the following row. These values indicate the minimum wind chill/ maximum heat index forecast to occur during the 6-hour period ending at the time indicated at the top of the column. MIN CHILL 6HR and MAX HEAT 6HR are forecast out to 60 hours.

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