NBM v4.1 Weather Elements by Category

These are the weather elements available in NBM v4.1, the regions they are available, and their definitions. Weather elements new to NBM v4.1 are marked with an * . Regions available are marked by x in a the region column. The regions are: CONUS (CO), Alaska (AK), Puerto Rico (PR), Hawaii (HI), Guam (GU) and Oceanic (OC). The elements are separated into six tables, each with a category of data: surface, aviation (includes 10m winds), fire weather, winter weather, marine, and upper air.

You can use the Page Contents menu to skip to a given category, and click on the up-arrow next to a category label to return to the top of this page.

NBM V4.1 SURFACE WEATHER ELEMENTS

Available surface weather elements and regions available (x in column) for: CONUS (CO), Alaska (AK), Puerto Rico (PR), Hawaii (HI), Guam (GU) and Oceanic (OC)
Surface Weather Elements	CO	AK	PR	HI	GU	OC	Definition
TEMPERATURE
MaxT	x	x	x	x			12z to 06z except in Guam 18z to 12z; dynamically weighted mean
MinT	x	x	x	x			00z to 18z except in Guam 06z to 00z; dynamically weighted mean
MaxT SD	x	x	x	x			12z to 06z except in Guam 18z to 12z; SD from a subset of about 25 inputs
MinT SD	x	x	x	x			00z to 18z except in Guam 06z to 00z; SD from a subset of about 25 inputs
PMaxT	x	x					12z to 06z except in Guam 18z to 12z; percentiles from 1-99 with up to 171 members
PMinT	x	x					00z to 18z except in Guam 06z to 00z; percentiles from 1-99 with up to 171 members
PMaxT Mean	x	x					12z to 06z except in Guam 18z to 12z; true mean from up to 171 members
PMinT Mean	x	x					00z to 18z except in Guam 06z to 00z; true mean from up to 171 members
PMaxT SD	x	x					12z to 06z except in Guam 18z to 12z; SD from up to 171 members
PMinT SD	x	x					00z to 18z except in Guam06z to 00z; SD from up to 171 members
Temp	x	x	x	x	x	x	Top of hour value; hourly through 36 hours, then 3 hourly to 192 hours, then 6 hourly to 264.
Temp SD	x	x	x	x	x		SD from subset of about 25 inputs
AppT	x	x	x	x			Derived parameter from Temp, Td, and wind speed
WBGT *	x		x	x	x		Measure of heat stress using NBM Temp, Td, Sky, Wspd, and MSLP
PRECIPITATION
QPF01	x	x	x	x	x		Hourly rainfall or melted liquid equivalent to 264 hours
QPF06	x	x	x	x	x		Expert weighted mean
PQPF06	x	x	x	x		x	Derived from Quantile Mapping and Dressing; percentiles from 1-99 with up to 171 members
PQPF12	x	x	x	x		x	Derived from Quantile Mapping and Dressing; percentiles from 1-99 with up to 171 members
PQPF24	x	x	x	x		x	Derived from Quantile Mapping and Dressing; percentiles from 1-99 with up to 171 members
PQPF48 *	x	x	x	x		x	Derived from Quantile Mapping and Dressing; percentiles from 1-99 with up to 171 members
PQPF72 *	x	x	x	x		x	Derived from Quantile Mapping and Dressing; percentiles from 1-99 with up to 171 members
PQPF06 Mean	x	x	x	x		x	Mean value from up to 171 members
PQPF12 Mean	x	x	x	x		x	Mean value from up to 171 members
PQPF24 Mean	x	x	x	x		x	Mean value from up to 171 members
PQPF48 Mean *	x	x	x	x		x	Mean value from up to 171 members
PQPF72 Mean *	x	x	x	x		x	Mean value from up to 171 members
PoP01	x	x	x	x	x		Expert weighted mean to 36 hours
PoP06	x	x	x	x	x		Expert weighted mean
PoP12	x	x	x	x	x		Expert weighted mean through 36 hours
QMD PoP06	x	x	x	x		x	Output from Quantile Mapping and Dressing without expert weights in short term
QMD PoP12	x	x	x	x		x	Output from Quantile Mapping and Dressing without expert weights in short term
QMD PoP24 *	x	x	x	x		x	Output from Quantile Mapping and Dressing without expert weights in short term
Wx	x	x					Predominant Weather derived field
Duration	x	x	x	x			Number of hours within a 12 hour period that at least 0.01" of QPF is forecast
PROBABILITIES OF SPECIFIC AMOUNTS
ProbMaxT (<0F, >100F, etc)	x	x					Threshold probabilities from 171 member ensemble valid 12z to 06z
ProbMinT	x	x					Threshold probabilities from 171 member ensemble valid 00z to 18z
ProbQPF06 *	x	x	x	x		x	Threshold probabilities from 171 member ensemble
ProbQPF12 *	x	x	x	x		x	Threshold probabilities from 171 member ensemble
ProbQPF24	x	x	x	x		x	Threshold probabilities from 171 member ensemble
ProbQPF48 *	x	x	x	x		x	Threshold probabilities from 171 member ensemble
ProbQPF72 *	x	x	x	x		x	Threshold probabilities from 171 member ensemble
HUMIDITY
Td	x	x	x	x	x		Top of hour value; hourly through 36 hours, then 3 hourly to 192 hours, then 6 hourly to 264.
Td SD	x	x	x	x	x		SD from subset of about 25 inputs
RH	x	x	x	x	x		Derived from Temp and Td
MaxRH	x	x	x	x			Derived from highest hourly/3 hourly/6 hourly value
MinRH	x	x	x	x			Derived from lowest hourly/3 hourly/6 hourly value
PRESSURE
PMSLP						x	10th, 25th, 50th, 75th, and 90th percentiles
PMSLP Spread						x	Standard Deviation from ~100 member multi-model ensemble

NBM V4.1 AVIATION WEATHER ELEMENTS

Available aviation weather elements and regions available (x in column) for: CONUS (CO), Alaska (AK), Puerto Rico (PR), Hawaii (HI), Guam (GU) and Oceanic (OC)
Aviation Weather Elements	CO	AK	PR	HI	GU	OC	Definition
WIND
10-m Speed	x	x	x	x	x	x	Top of hour sustained value; hourly through 36 hours, then 3 hourly to 192 hours, then 6 hourly to 264.
P10m-Speed						x	Top of hour sustained value 10th, 25th, 50th, 75th, and 90th percentiles; 3 hourly temporal resolution
30-m Speed	x	x	x	x	x	x	Top of hour sustained value; hourly through 36 hours, then 3 hourly to 192 hours, then 6 hourly to 264.
80-m Speed	x	x	x	x	x	x	Top of hour sustained value; hourly through 36 hours, then 3 hourly to 192 hours, then 6 hourly to 264.
10-m Gust	x	x	x	x	x	x	Top of the hour gust value; hourly through 36 hours, then 3 hourly to 192 hours, then 6 hourly to 264.
10-m Direction	x	x	x	x	x	x	Top of the hour value
10-m Speed SD	x	x	x	x	x		Standard Deviation of ~100 member multi-model ensemble
10-m Gust SD	x	x	x	x	x		Standard Deviation of ~100 member multi-model ensemble
30-m Directon						x	Top of the hour value
80-m Direction						x	Top of the hour value
PMaxSpeed24 *	x						Maximum wind speed in 24-hour period percentiles from 1-99; Derived from ~200 model members
PMaxGust24 *	x						Maximum wind gust speed in 24-hour period percentiles from 1-99; Derived from ~200 model members
PMaxSpeed24 Mean *	x						Mean of PMaxSpeed24
PMaxGust24 Mean *	x						Mean of PMaxGust24
PMaxSpeed24 SD *	x						Standard deviation of PMaxSpeed24
PMaxGust24 SD *	x						Standard deviation of PMaxGust24
LLWS Height	x	x	x	x			Intended to provide Low Level Wind Shear guidance (up to 2,000 feet AGL) for WFO TAFs
LLWS Speed	x	x	x	x			Intended to provide Low Level Wind Shear guidance (up to 2,000 feet AGL) for WFO TAFs
LLWS Direction	x	x	x	x			Intended to provide Low Level Wind Shear guidance (up to 2,000 feet AGL) for WFO TAFs
Low-Level Turbulence	x	x	x	x			Low level and mountain wave induced turbulence guidance
Ellrod Index	x	x	x	x			High level turbulence guidance for roughly the 300-200 mb layer
CLOUDS AND OBSTRUCTIONS
Cover	x	x	x	x	x		Mean Sky Cover 0-100%
Cover SD	x	x	x	x	x		SD from subset of about 25 inputs
Cig	x	x	x	x	x		Ceiling from GLMP through 36 hours, then blend of NAM MOS and GFS MOS 39-78 hours
Vis	x	x	x	x	x	x	Visibility from GLMP through 36 hours, then blend of NAM MOS and GFS MOS 39-78 hours
Base Height	x	x	x	x	x		Lowest cloud base regardless of ceiling height (could be FEW or SCT layer)
AWC Primary *	x						height of cloud base, top, and coverage of digital aviation service's primary cloud layer
AWC Secondary *	x						height of cloud base, top, and coverage of digital aviation service's secondary cloud layer
AWC Teritary *	x						height of cloud base, top, and coverage of digital aviation service's tertiary cloud layer
AWC High Level *	x						height of cloud base, top, and coverage of AWC's cirrus cloud layer
PROBABILITIES OF SPECIFIC AMOUNTS
ProbCig	x						Threshold Probability of VLIFR (0 or 100), LIFR (200-400), IFR (500-900), and MVFR (1,000-3,000) ceilings
ProbVis	x						Threshold Probability of VLIFR (0), LIFR (1/4-3/4), IFR (1-3), and MVFR (3-5) visibilities
ProbCWASP	x						Probability of 50-64 (Marginal), 65-69 (Slight), 70-74 (Enhanced), 75-84 (Moderate), or 85-100 (High) Values of Craven Wiedenefeld Aggregate Severe Parameter: designed to detect environments favorable for significant hail and significant tornadoes
ProbMaxSpeed24 Thresholds *	x						Probability of maximum wind speed exceeding threshold in 24-hour period
ProbMaxGust24 Thresholds *	x						Probability of maximum wind gust speed exceeding threshold in 24-hour period
CONVECTION
18 dbZ Echo Tops	x	x	x	x	x		Top of the hour height above mean sea level of highest light precipitation echoes (hourly 1-36 hours)
PoT01	x	x	x	x		x	1 hour expert weighted probability of thunder through 36 hours
PoT03	x	x	x	x		x	3 hour expert weighted probability of thunder through 192 hours
PoT06	x	x	x	x		x	6 hour expert weighted probability of thunder through 192 hours
PoT12	x	x	x	x		x	12 hour expert weighted probability of thunder through 192 hours
Max Reflectivity	x	x	x	x	x		Maximum reflectivity in the column over the past hour in dBZ (hourly 1-36 hours)
T-storm Coverage *	x	x	x	x		x	A product closely follows AWC’s three defined probabilistic categories of thunderstorm coverage: Isolated (10-20%), Scattered (30-50%), and Numerous (60-100%)
VIL	x	x	x	x	x		Top of the hour vertically integrated liquid (hourly 1-36 hours)
SBCAPE	x	x	x	x	x		Expert weighted mean surface based convectively available potential energy
SBCAPE SD	x	x	x	x	x		SD from subset of about 25 inputs
CWASP	x						Expert weighted mean of Craven Wiedenfeld Aggregate Severe Parameter (75% of EF2+ tornadoes have CWASP of 65+)
Percentile CWASP	x						5th, 10th, 25th, 50th, 75th, 90th, and 95th percentile of CWASP using roughly 25 inputs
SPC ProbSevere 4 hour *	x						SPC-POST calibrated HREF 4hr probability of severe hazards (wind/hail/tornado)
SPC ProbSevere 24 hour *	x						SPC-POST calibrated HREF 24hr probability of severe hazards (wind/hail/tornado)

NBM V4.1 FIRE WEATHER ELEMENTS

Available fire weather elements and regions available (x in column) for: CONUS (CO), Alaska (AK), Puerto Rico (PR), Hawaii (HI), Guam (GU) and Oceanic (OC)
Fire Weather Elements	CO	AK	PR	HI	GU	Definition
POTENTIAL
Haines Index	x	x	x	x		Calculation of six hour maximum value of Haines Index based on NBM unified terrain elevation (Low Haines up to 999 feet MSL, Mid Haines 1,000-2,999 MSL, and High Haines 3,000+ MSL)
Fosberg Index	x	x	x	x		6 hour maximum Fosberg Fire Weather Index using 2-m temperature, 10-m wind speeds, and 2-m dew point/relative humidity
Mixing Height	x	x	x	x		Combination of PBL height and modified Stull Method using 0.5K warm bubble (height above ground level)
Solar Radiation	x	x	x	x		Incoming solar radiation
Prob DryThunder *	x					The joint probability in the SREF of one or more CG flashes within 20 km over the previous 3-h period in an environment favorable for dry thunderstorms [as defined by P(precip) <0.10" x P(2-m RH) <30% x P(PW) <1"]
MaxRH					x	Maximum Relative Humidity from 0000 to 1800 UTC
MinRH					x	Minimum Relative Humidity from 1200 to 0600 UTC
WIND
Transport WindSpd	x	x	x	x		Mean wind speed in the layer defined by mixing height
Transport WindDir	x	x	x	x		Mean wind direction in the layer defined by mixing height
Ventilation Rate	x	x	x	x		The product of the mixing height and the transport wind speed

NBM V4.1 WINTER WEATHER ELEMENTS

Available winter weather elements and regions available (x in column) for: CONUS (CO), Alaska (AK), Puerto Rico (PR), Hawaii (HI), Guam (GU) and Oceanic (OC)
Winter Weather Elements	CO	AK	PR	HI	OC	Definition
EXPECTED AMOUNT
SnowAmt01	x	x				1 hour snow accumulation through 36 hours
SnowAmt06	x	x				6 hour snow accumulation through 264 hours
SnowAmt24 *	x	x				24 hour snow accumulation through 264 hours
SnowAmt48 *	x	x				48 hour snow accumulation through 264 hours
SnowAmt72 *	x	x				72 hour snow accumulation through 264 hours
IceAccum01	x	x				1 hour flat ice accumulation using FRAM technique through 36 hours
IceAccum06	x	x				6 hour flat ice accumulation using FRAM technique through 264 hours
IceAccum24 *	x	x				24 hour flat ice accumulation using FRAM technique through 264 hours
IceAccum48 *	x	x				48 hour flat ice accumulation using FRAM technique through 264 hours
IceAccum72 *	x	x				72 hour flat ice accumulation using FRAM technique through 264 hours
ACCUMULATION PRECENTILES (INCHES)
SnowP01 *	x	x				1 hour snow accumulation percentiles
SnowP06 *	x	x				6 hour snow accumulation percentiles
SnowP24	x	x				24 hour snow accumulation percentiles
SnowP48	x	x				48 hour snow accumulation percentiles
SnowP72	x	x				72 hour snow accumulation percentiles
IceP06 *	x	x				6 hour flat ice accumulation (FRAM) percentiles
IceP24	x	x				24 hour flat ice accumulation (FRAM) percentiles
IceP48	x	x				48 hour flat ice accumulation (FRAM) percentiles
IceP72	x	x				72 hour flat ice accumulation (FRAM) percentiles
PROBABILITIES OF SPECIFIC AMOUNTS (>1", >12" etc)
ProbSnow01 *	x	x				1 hour threshold probability of exceedance for snow accumulation
ProbSnow06 *	x	x				6 hour threshold probability of exceedance for snow accumulation
ProbSnow24	x	x				24 hour threshold probability of exceedance for snow accumulation
ProbSnow48	x	x				48 hour threshold probability of exceedance for snow accumulation
ProbSnow72	x	x				72 hour threshold probability of exceedance for snow accumulation
ProbIce06 *	x	x				6 hour threshold probability of exceedance for flat ice accumulation (FRAM)
ProbIce24	x	x				24 hour threshold probability of exceedance for flat ice accumulation (FRAM)
ProbIce48	x	x				48 hour threshold probability of exceedance for flat ice accumulation (FRAM)
ProbIce72	x	x				72 hour threshold probability of exceedance for flat ice accumulation (FRAM)
Snow or Sleet > 0.25" Liquid Equiv	x					24 hour probability of liquid equivalent of melted snow and sleet exceeding 0.25"
PRECIPIATION TYPE (PTYPE)
PType	x	x				Probability of Snow, Rain, Sleet, or Freezing rain (instantaneous top of hour)
Frzg Spray	x	x			x	Categorical freezing spray potential
Snow Ratio	x	x				Snow to Liquid Ratio (using combination of Cobb, Roebber, MaxTaloft, and thickness)
Snow Level	x	x	x	x		Elevation where the wet bulb temperature reaches 0.5 degrees C
PSnow Ratio *	x	x				Snow to Liquid Ratio there is a given percent chance of being at or below (ex: p75 = 75% chance the SLR is the given number or less)
PSnow Level *	x	x	x			Snow level elevation there is a given percent chance of being at or below (ex: p75 = 75% chance the Snow level is the given elevation or less)

NBM V4.1 MARINE WEATHER ELEMENTS

Available marine weather elements and regions available (x in column) for: CONUS (CO), Alaska (AK), Puerto Rico (PR), Hawaii (HI), Guam (GU) and Oceanic (OC)
Marine Weather Elements	CO	AK	PR	HI	GU	OC	Definition
WATER
WaveHgt	x	x	x	x	x	x	MAE weighted mean of significant wave height
WaveHgtSD	x	x	x	x	x	x	SD calculated from roughly 10 inputs
PWaveHgt *	x	x	x	x	x	x	10/50/90 percentile of significant wave height
SST	x	x				x	Mean top of the hour sea surface temperature
Frzg Spray	x	x				x	Categorical freezing spray potential
Ice Coverage *		x					Expert-weighted precent sea ice coverage inside gridbox
Ice Thickness *		x					Expert-weighted mean sea ice thickness
WIND
Tropical Speed *	x	x	x	x	x	x	Expert-weighted tropical cyclone wind speed forecast placed over NBM wind speed background
Tropical Direction *	x	x	x	x	x	x	Expert-weighted tropical cyclone wind direction forecast placed over NBM wind speed background

NBM V4.1 UPPER AIR WEATHER ELEMENTS

Available upper air weather elements and millibar atmosphere levels available
Upper Air (Global)	250mb	500mb	700mb	850mb	925mb	Definition
Temperature	x	x	x	x	x	00Z & 12Z forecasts. 6-hourly through 384. Expert-weighted, bias corected forecasts for 100 members.
Pressure height	x	x	x	x	x	00Z & 12Z forecasts. 6-hourly through 384. Expert-weighted, bias corected forecasts for 100 members.
RH	x	x	x	x	x	00Z & 12Z forecasts. 6-hourly through 384. Expert-weighted, bias corected forecasts for 100 members.
Wind Speed	x	x	x	x	x	00Z & 12Z forecasts. 6-hourly through 384. Expert-weighted, bias corected forecasts for 100 members.
Wind Directon	x	x	x	x	x	00Z & 12Z forecasts. 6-hourly through 384. Expert-weighted, bias corected forecasts for 100 members.
Height Standard Deviation		x	x			Standard deviations at 500mb and 700mb heights. 00Z & 12Z forecasts. 6-hourly through 384

NBM v4.1 Weather Elements - MDL